JPH06175014A - Camera provided with autofocusing mechanism - Google Patents

Abstract

PURPOSE:To realize accurate range-finding at an optional range-finding position even in a camera capable of changing a focal distance. CONSTITUTION:This camera is provided with an autofocusing mechanism where range-finding is performed by an infrared light projecting part 4a and an infrared light receiving part 4b, and a variable apex angle prism 5 arranged on the front side of the projecting part 4a, the irradiating direction of infrared light is corrected in right-and-left and up-and-down directions by rotating a plate constituting the prism 5 in two directions by driving means 6a and 6b, so that range-finding is performed at an optional position in a range shown on the screen of a finder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having an automatic focusing mechanism adopting an infrared light irradiation system.

[0002]

2. Description of the Related Art Conventionally, an automatic focusing device mounted on a compact camera irradiates an object with infrared light from an infrared light projecting section and reflects the infrared light reflected by the object on the camera body. An active method that detects the incident angle of the infrared light received by the infrared light receiving part provided at another position and measures the distance from the camera to the subject by the triangulation method from that angle Some have been adopted.

A position sensitive device (PSD) is provided in the infrared light receiving portion of such an automatic focusing device as a light receiving element for detecting the condensing position of the incident infrared light corresponding to the incident angle of the infrared light. The distance from the camera to the subject is obtained from the light receiving position of the light receiving element and the distance (base line length) between the infrared light projecting unit and the infrared light receiving unit.

In such a distance measuring method, the range of infrared light irradiation is predetermined, and it is necessary to position the subject within the range of infrared light irradiation. A conventional camera has a light projecting unit that projects three or five infrared rays, and projects three or five predetermined irradiation positions in the left-right direction, respectively, and obtains a subject distance obtained as a result. Focusing drive is performed according to the closest data. Infrared light is separately applied to these three or five positions.

Conventionally, when the infrared light is separately emitted in different directions as described above, when the finder is horizontally oriented and the camera is held, it is scattered in the horizontal direction (long side of the finder). However, the range was previously determined and could not be arbitrarily selected.

Therefore, the camera is held vertically, that is,
If you try to shoot with the camera held vertically in the viewfinder, infrared light will be emitted only in the vertical range of the central part, and the effect of emitting infrared light in multiple directions will be halved. was there. In order to solve such a problem, if the light emitting unit and the light receiving unit are arranged in both the vertical and horizontal directions, the distance measuring device becomes large, and it is practically difficult to mount it on the camera. .

Further, depending on the composition, it is sometimes desired to focus on a position outside the original irradiation range, such as the right corner or the left corner. In such a case, once the irradiation position is made to coincide with the position to be focused to bring the subject into the focused state, the focused state is locked, and the desired composition is restored again for shooting, so the shooting operation is slow. There is a drawback that

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera having an automatic focusing mechanism capable of arbitrarily selecting the irradiation direction of infrared light from the infrared light projecting section.

[0009]

The above object is achieved by the present invention described below.

(1) An infrared light projecting unit for irradiating infrared light toward a subject, and an infrared light receiving unit for receiving infrared light emitted from the infrared light projecting unit and reflected by the subject Installed on the optical path of the infrared light projecting section, and a distance measuring means having a section, an automatic focusing mechanism for driving a lens so as to obtain a focused state based on the distance measuring information obtained by the distance measuring means. An optically transparent and easily deformable substance is interposed between at least a pair of plates facing each other, and at least one projecting variable apex angle prism capable of changing the angle formed by the plates; And a drive means for changing the angle of the plate with respect to the reference plane of the variable vertical angle prism, and the projection direction is arbitrarily adjusted by changing the angle of the plate with respect to the reference plane. A camera with a focus mechanism.

(2) The camera having the automatic focusing mechanism according to (1), wherein the angles of at least one pair of plates constituting the variable projection vertical prism for light projection with respect to the reference plane are changed in different directions.

(3) A plurality of variable apex angle prisms for projecting light are arranged on the optical path, and the angles between at least a pair of plates of the variable apex angle prism and the reference surface are different in each of the pair of variable apex angle prisms. A camera having the autofocus mechanism according to (1) above, which is changed to.

(4) Further, an optically transparent and easily deformable substance is provided between at least a pair of opposing plates provided on the optical path of the infrared light receiving section, and an angle formed by the two plates is formed. Has at least one variable light receiving variable vertical angle prism, and a drive means for changing the angle of the light receiving variable vertical angle prism with respect to the reference plane of the plate, and the angle of the plate with respect to the reference plane is red. The condensing position in the external light receiving section is adjusted so as to be located on a straight line connecting the infrared light receiving section and the infrared light projecting section.
A camera having the autofocus mechanism according to any one of (3).

(5) The angle of the plate with respect to the reference plane is
The automatic focusing mechanism according to (4) is characterized in that the focus position of the infrared light reflected by the subject at the same distance at the infrared light receiving section is adjusted to be constant. camera.

(6) The automatic focusing mechanism according to (4) or (5), wherein the angles of at least one pair of plates constituting the light-receiving variable vertical angle prism with respect to the reference plane are changed in different directions. camera.

(7) A plurality of variable apex angle prisms for receiving light are arranged on the optical path, and the angle between the plate of at least a pair of variable apex angle prisms and the reference plane is set to a different direction for each of the pair of variable apex angle prisms. A camera having the autofocus mechanism according to (4) or (5), which is changed.

(8) The directions in which the angle formed by the plate with respect to the reference plane is changed are two directions orthogonal to each other in a projection view on a plane perpendicular to the optical axis of the infrared light immediately after being irradiated from the light projecting section. A camera having the autofocus mechanism according to any one of (1) to (7) above.

(9) Further, it has a focal length varying mechanism and a focal length detecting means for detecting the focal length, and the focal length detecting means is arranged so that the relative position of the infrared light irradiation portion with respect to the angle of view becomes constant. A camera having the automatic focusing mechanism according to any one of (1) to (8), wherein the apex angle of the variable apex prism for projecting light is adjusted based on the focal length information obtained by the above.

(10) The automatic focusing according to any one of (4) to (9) above, wherein the variable vertical angle prism for projecting light and the variable vertical angle prism for receiving light are constituted by a common variable vertical angle prism. A camera with a mechanism.

[0020]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram of a photographing control system in a compact camera according to a preferred embodiment of the present invention. The shooting control system shown in FIG.
0, the photometry unit 11, the photometry release switch 12, the zooming operation switch 13, the distance measurement unit 14, the drive circuit 15 for driving the zoom mechanism, the changeover switch 16 for switching the distribution direction of the infrared light to be emitted, and optionally in the viewfinder. It has a distance measuring position selection switch 17 for selecting the infrared light irradiation position in.

The control circuit 10 controls the focusing operation,
Performs exposure calculation, shutter drive control, sequence control, display device control, flash circuit control, wind motor drive control, self-timer control, etc.
For example, it is composed of a microcomputer. Photometer 11
Measures the brightness of the subject and inputs the value to the control circuit 10. The photometric release switch 12 is a two-step switch. When the switch portion constituting the photometric release switch 12 is pushed in to turn on the first stage, the photometric portion 11 is turned on. When the second stage is turned on, the shutter is driven. The zooming operation switch 13 has two switches, a tele direction operation switch and a wide direction operation switch. By operating these two switches, the variable focal length mechanism is driven in the tele direction or the wide direction. The distance measuring unit 14 measures the distance from the camera to the subject and outputs the distance measurement information to the control circuit 1.
Enter 0.

Next, the focal length changing mechanism will be described. The drive circuit 15 operates by operating the zooming operation switch 13 to drive the zooming motor 21.
A small gear 22 is connected to the drive shaft of the zooming motor 21, and the small gear 22 is rotated by driving the zooming motor 21. The zoom lens 3 includes a lens barrel 30.
And a cam ring 31 mounted on the lens barrel 30, and a gear 32 that meshes with the small gear 22 is formed on the peripheral surface of the rear end of the cam ring 31. A cord portion 33 is provided on the outer peripheral surface of the cam ring 31. A conductive plate 331 forming a terminal is attached to the code portion 33. By the conductive plate 331, four conductive terminals are arranged in a predetermined pattern in the axial direction to form a zoom code.

The four brushes of the zoom code reading section 23 fixed to the camera body side come into contact with the zoom code of the code section 33. The rotational position of the cam ring 31 divided into 1/16 in the circumferential direction is detected by the ON / OFF pattern between the brushes when the four brushes come into contact with the zoom code, and the zoom drive corresponding to this position is detected. The subsequent focal length is specified. The code section 33 and the zoom code reading section 23 constitute a focal length detecting means. On the outer peripheral surface of the cam ring 31, a cam groove 34 is formed obliquely with respect to the circumferential direction.
The cam ring 3 is inserted into the cam ring 3 by a protrusion (not shown).
By rotating 1 the variator lens group can be moved in the axial direction.

Next, a distance measuring mechanism as a distance measuring means for measuring the distance to the object will be described. The distance measuring mechanism inputs the measured distance measuring data to the distance measuring unit 14. As shown in FIG. 1, this distance measuring mechanism includes an infrared light projecting section 4a.
, Infrared light receiving section 4b, and variable apex angle prism 5 for projecting light.
, Driving means 6a, 6b for driving the variable projection vertical angle prism 5, light receiving variable vertical angle prism 8, and driving means 60a, 60 for driving the light receiving variable vertical angle prism 8.
b. The infrared light projecting unit 4a includes a light source 41a that emits infrared light and a light projecting lens 42a that is arranged on the irradiation side of the light source 41a, and the infrared light receiving unit 4b.
Is a light receiving element (position sensitive device (PSD)) 41b for detecting the light receiving position of incident infrared light.
And a light receiving lens 42b on the light incident side of the light receiving element 41b.

The infrared light emitted from the light source 41a is emitted to the subject through the light projecting lens 42a, and the infrared light reflected by the subject is received through the light receiving lens 42b.
It is focused on 1b. The light receiving element 41b is configured by arranging photoelectric conversion elements on a straight line connecting the infrared light receiving section 4b and the infrared light projecting section 4a, and infrared rays reflected on the photoelectric conversion element are arranged. The light is focused. Then, the light receiving element 41
In b, the position where the incident infrared light strikes is specified by specifying the collected photoelectric conversion element. This position,
Distance information from the camera to the subject is obtained from the distance (baseline length) between the infrared light projector 4a and the infrared light receiver 4b. Based on this distance, the focusing drive motor is driven to drive the lens to obtain the focused state.

Here, in the optical path of the infrared light projecting section 4a,
A variable projection vertical apex prism 5 as shown in FIG. 2 and FIG. 3 is provided, and the same light reception as the variable projection apex prism 5 for light projection is provided in the optical path of the infrared light receiving section 4b. A variable apex angle prism 8 is provided. The variable apex angle prism 5 for projecting light and the variable apex angle prism for receiving light 8 each have an optically transparent and easily deformable substance interposed between a pair of opposed plates, and a plate on the subject side by a driving means. Is configured to rotate in the left-right direction and the plate on the light source side in the vertical direction. Hereinafter, the configuration of the illustrated variable apex angle prism 5 for light projection will be representatively described.

The projecting variable vertical angle prism 5 has a pair of flat plates 51 and 52 facing each other. Both flat plates 51 and 5
Examples of the shape of 2 include a circle, an ellipse, and a rectangle. The outer peripheral portions of the flat plates 51 and 52 are liquid-tightly connected to each other by a flexible bellows-shaped connecting member 54 over the entire circumference. Ring-shaped fixing members 511 and 521 each having a groove shape whose cross section is open inwardly are fitted onto the peripheral edges of the flat plates 51 and 52 so as to sandwich the end of the connecting member 54, and the flat plates 51 and 52. The connection member 54 is liquid-tightly joined. Then, in the space surrounded by both the flat plates 51, 52 and the connecting member 54, an optically transparent liquid 53
Is filled. The constituent materials of the flat plates 51 and 52 and the connection member 54, the type of the liquid 53, and the like will be described in detail later.

A rotary shaft 55 is provided at the peripheral end of the flat plate 52 on the irradiation direction side of the flat plates 51 and 52 so as to project in the diametrical direction of the flat plate 52 and in the vertical direction of the camera.
A rotary shaft 58 is provided at the peripheral end portion of the flat plate 51 on the light source 41a side so as to project in the diametrical direction and in the left-right direction of the camera. That is, the rotating shaft 55 and the rotating shaft 58 are orthogonal to each other in the projection view in the optical axis direction of incidence from the light source 41a to the variable apex prism 5 for projecting light. The flat plates 52 and 51 swing about the rotary shafts 55 and 58, and an angle is formed between the flat plates 51 and 52. further,
An arm 56 is provided on the flat plate 52. An extension of the axis of the arm 56 is orthogonal to the axis of the rotary shaft 55 at the center of the flat plate 52. At the tip of the arm 56, there is provided a connecting portion 57 connected to the driving means 6a described later. A slit hole 571 is formed in the connecting portion 57 in the axial direction of the arm 56.

On the other hand, the flat plate 51 has an arm similar to the flat plate 52 and a connecting portion provided at the tip of the arm (not shown). The driving means 6b having the same structure as the driving means 6a is connected to this connecting portion. Since the driving means 6b has the same structure as the driving means 6a, the driving means 6a will be representatively described below. The driving means 6 connected to the connecting portion 57 includes a pinion 61 and a return member 62.
And the return member 62 includes the pinion 61
A rack 63 that meshes with is formed. The pinion 61 is connected to a drive shaft of a motor (not shown) and rotationally driven, and the drive of the motor is controlled by the distance measuring unit 14.

The returning member 62 is arranged parallel to the optical axis of the optical system constituted by the infrared light projecting section 4a and the projecting variable apex angle prism 5, and with respect to the optical axis. Move back in the parallel direction. The returning movement of the returning member 62 is performed by the pinion 6
This is done by turning 1. At the end of the return member 62,
The pin 64 is erected. The pin 64 is inserted into the slit hole 571 of the connecting portion 57, and the return movement of the return member 62 causes the arm 56 to swing integrally with the flat plate 52.

On the other hand, a plurality of slits 65 formed at right angles to the backward moving direction are arranged in the backward moving member 62 at equal intervals in the backward moving direction. An encoder 66 is arranged so as to face the position where the slit 65 is formed. The encoder 66 has a light emitting unit and a light receiving unit, and the light from the light emitting unit is received by the light receiving unit via the slit 65. The output of the light receiving section is sent to the control circuit 10. When the return member 62 moves, the plurality of slits 65 pass between the light receiving section and the light emitting section, so that the light receiving section receives it. The light is momentarily blocked and the output from the light receiving unit changes. The control circuit 10 counts the number of times of this change and detects the movement amount of the returning member 62.

Similarly to the driving means 6a described above, the amount of movement of the returning member in the driving means 6b is also detected. In this way, the flat plate 52 and the flat plate 51 are rotated about the rotating shafts 55 and 58 whose directions are different by 90 degrees by the two driving means 6a and 6b, and the variable apex angle for projection is changed by the change of their relative positions. The apex angle of the prism 5 is configured. In Figure 2,
A cross-sectional view of the variable projection vertical prism 5 for projecting is shown in plan view so that the state where the flat plate 52 is inclined can be seen from the state where the flat plate 51 and the flat plate 52 are positioned in parallel. 2 and 3, the X axis indicates the left-right direction of the camera body, the Y axis indicates the front-rear direction, and the Z axis indicates the up-down direction.

Here, the flat plates 51 and 52 are parallel to each other,
A plane parallel to the flat plates 51 and 52 in a state where the incident light from the light source 41a is perpendicularly incident on the flat plates 51 and 52 is used as a reference plane. The flat plates 52 and 51 are rotating shafts 55,
When rotated around 58, the reference plane and the flat plates 52, 5
Rotation angles α and β are formed between the two. The rotation angle α is shown in Fig. 2.
It is formed in the XY plane inside, and the rotation angle β is formed in the YZ plane in FIG. The rotation angles α and β can be known by the amount of movement of the return member of the driving means 6a and 6b.

As described above, the prism action is generated by the apex angle of the variable apex prism 5 for projecting light. Due to the rotation of the flat plate 52, the optical path on the front side (subject side) bends in the left-right direction at the deflection angle θ ₁ as shown in FIG. 2, and the rotation of the flat plate 51 as shown in FIG. Bends up and down at a deflection angle θ ₂ . When distributing the emitted infrared light in the left-right direction (long side of the finder), only the flat plate 52 is rotated to adjust the rotation angle α, and when distributing in the vertical direction (short side of the finder), only the flat plate 51 is rotated. Then, the rotation angle β is adjusted.

As described above, the variable vertical angle prism 5 for projecting light is used.
The deflection angles θ ₁ and θ ₂ when the optical path is divided by the distance measurement are performed such that infrared light always strikes the distance measurement position display section 71 in the viewfinder as shown in FIG. It can be determined based on the focal length of time.

For example, in the camera of this embodiment, distance measurement is performed by irradiating infrared light as follows. Front and left and right from the front direction (finder long side direction)
Infrared light is distributed to a total of three directions, which are two directions equally distributed to each other, and distance measurement is performed for each direction. Front and up and down from the front (viewfinder short side direction)
Infrared light is distributed to a total of three directions, which are two directions equally distributed to each other, and distance measurement is performed for each direction. Designate any position in the viewfinder and irradiate that position with infrared light for distance measurement.

The above can be selected by the change-over switch 16. For example, when the camera is held vertically (in the vertical direction of the long side of the finder) and the image is taken, the changeover switch 16 is used to switch the distribution direction of infrared light from the above. Such switching may be configured such that the tilt sensor detects the attitude of the camera, not the changeover switch 16, and the attitude is automatically changed depending on the attitude of the camera.

Further, in the case of, as shown in FIG. 5, the distance measuring position display section 7 is further provided in the finder.
1 are arranged vertically and horizontally, and the plurality of distance measurement position display portions 71 are arranged.
From among these, the position for distance measurement is selected by the distance measurement position selection switch 17 and only that position is measured. Alternatively, it is also possible to perform distance measurement on all the distance measurement position display units 71.

In this embodiment, the infrared light is distributed to a total of 3 directions, that is, the front and two directions equally distributed to the left and right from the front direction, and the distance measurement is performed for each direction. Here, an example of the relationship between the focal length and the deflection angle θ ₁ and the rotation angle α is shown in Table 1 when the refractive index n of the variable projection vertical angle prism 5 is 1.6, and the focal length and the deflection angle are shown in Table 1. Table 2 shows an example of the relationship between θ ₂ and rotation angle β (flat plates 51, 52, liquid 53).
Calculated with the refractive index of n = 1.6).

[0040]

[Table 1]

[0041]

[Table 2]

4 and 5 show the distance measuring position display section 71 displayed on the finder 7. In the case of the camera of the present invention, the distance measuring position is changed as the focal length is changed. The deflection angle θ of the infrared light is adjusted so that the display unit 71 is irradiated with the infrared light. That is, even if the focal length is changed by driving the zoom, the distance measuring position display unit 71 and the position 72 where the infrared light is actually irradiated always match. Therefore, as shown in FIGS. 4 and 5, it is possible to accurately display the irradiation position of the infrared light, and it is easy to determine the composition in consideration of the irradiation position of the infrared light in the viewfinder. it can.

When the projection direction from the infrared light projecting section 4a is distributed as described above, an error occurs in the condensing position in the infrared light receiving section 4b. The error in the length direction of the base line is
It can be corrected by performing a correction calculation within. To correct the error that occurs in the vertical direction, use the PSD in the vertical direction.
Or a wide PSD may be arranged in the vertical direction so that the photoelectric conversion element is always located at the condensing position.

On the other hand, the flat plates 51 and 52 in the above construction are optically transparent, and the constituent materials thereof are, for example, borosilicate glass (BK series), crown glass (SK series) or SF series. , BaSF system, LaSF
And various optical glasses such as LaK series and glass (white plate) having the same function as these.

As the constituent material of the connecting member 54,
For example, natural rubber, isoprene rubber, butadiene rubber,
Diene rubbers such as styrene-butadiene rubber, nitrile rubber and chloroprene rubber, olefin rubbers such as ethylene-propylene rubber and butyl rubber, ether rubbers, polysulfide rubbers and urethane rubbers, fluoro rubbers, silicone rubbers, etc. Elastic materials such as rubber materials, various thermoplastic elastomers such as urethane-based, ester-based, amide-based, olefin-based, styrene-based, vinyl chloride-based, fluorine-based, ionomer-based, isoprene-based, or mixtures thereof (alloy) Can be used.

Examples of the liquid 53 include water, alcohol, ethylene glycol, propylene glycol,
Glycerin, carbon tetrachloride, chloroform, halogenated alkyls such as ethylene bromide, organic acids such as formic acid and acetic acid, esters such as methyl acetate and ethyl acetate, ethers, ketones, low molecular weight polyethers, low molecular weight polyesters, aromatics Examples thereof include organic liquids such as group compounds, liquid paraffin, viscous liquids such as silicone oil and polyvinyl alcohol, mixed liquids of two or more thereof, or solutions in which solids are dissolved in these liquids.

The flat plates 51, 52 and the connecting member 54
In selecting the constituent material of (3), it is necessary to use a material that is inert (for example, does not dissolve or deteriorate) with respect to the liquid 53 used. Hereinafter, a case will be described in which a variable apex angle prism having the same optical property such as a refractive index is used for the optical path of the infrared light projecting section 4a and the optical path of the infrared light receiving section 4b. The configuration of the variable light receiving vertical apex prism 8 is the same as the configuration of the variable light emitting variable apex angle prism 5 described above, and driving means 60a, 60b for driving the light receiving variable vertical angle prism 8
The configuration of is also the same as the configuration of the driving means 6a and 6b described above.

The pair of flat plates forming the variable light receiving vertical apex prism 8 is controlled by the distance measuring unit 14 like the pair of flat plates 51 and 52 forming the light projecting variable vertical angle prism 5. , Are driven so as to rotate in the same direction as the flat plates 51, 52 of the light projecting variable apex angle prism 5 and to rotate at the same angle. For this reason,
When the distance from the camera to the subject is the same, even if the irradiation direction of the infrared light from the infrared light projecting unit 4a is changed by the projecting variable apex angle prism 5, the light receiving variable The apex angle prism 8 can change the optical path to the light receiving element 41b to make the position of the infrared light focused on the light receiving element 41b constant.

Therefore, it is not necessary to correct the error of the focusing position by changing the irradiation direction of infrared light, and the control circuit can be simplified. Further, since the light receiving element 41b can be made small, the mounting space in the camera can be reduced, and the camera can be made compact. The control operation of the photographing control system in the above configuration will be described based on FIGS. 6, 7 and 8. When the photometric switch is turned on (step 101), reading of the focal length of the taking lens is started, and the read value is input to the control circuit 10 (step 102).

It is determined whether or not the distance measuring position is selected by the distance measuring position selection switch 17 (step 1).
03). If the selection has not been made, the position of the changeover switch 16 is detected, and the beam distribution direction is selected to be the long side direction or the short side direction of the finder (step 104). When the tilt sensor is used instead of the changeover switch, the beam distribution direction is determined based on the posture of the camera detected by the tilt sensor.
When the beam distribution direction is the long side direction (horizontal direction) of the finder, the operation is as follows.

The memory (counter) n for counting the number of measurements is cleared (step 105). In the control circuit 10, a deflection angle θ ₁ for irradiating infrared light selected from the data table from the read focal length.
And the rotation angle α of the flat plate of the variable apex angle prism 5 for projecting to set the deflection angle to θ _1, and further, the rotation angle of the flat plate of the variable vertical angle prism for light reception 8 is set to the variable apex for projection. The same angle as the rotation angle of the flat plate of the prism 5 is determined. Then, the respective driving amounts of the driving means 6a and the driving means 60a necessary for obtaining the rotation angle are converted into the number of pulses from the encoder, and these values are outputted to the distance measuring section 14 (step 106).

Driving means 6a for projecting the variable apex angle prism 5
Is driven to count the number of pulses from the encoder and stop when the count reaches the input number of pulses (step 107). Next, the driving means 60a of the variable light receiving vertical apex prism 8 is driven to count the pulses from the encoder and stop when the count reaches the input number of pulses (step 10).
8). By this operation, the optical path is divided into the left and right directions, and the reflected light that enters the infrared light receiving section 4b is corrected for the error in the left and right focusing position. Drive means 6a,
By driving 60a, the distance is measured at the position where the optical path is swung (step 109). Here, since one distance measurement has been completed, 1 is added to the memory n (step 110).

The distance s measured as L _n is stored (step 111). It is determined whether the value of the memory n is 3 (step 112). That is, it is determined whether or not distance measurement has been performed three times. If the memory n is not 3, the process returns to step 107 and the deflection angle θ ₁
Variable apex angle prism 5 for projecting light so that the optical path moves
Is driven (step 107), and the flat plate of the variable light receiving vertical apex prism 8 is rotationally driven so as to form a rotation angle α which is the same as that of the variable light emitting vertical apex prism 5 (step 1).
08), and steps 109 to 112 are executed again.

When the memory n becomes 3 (when the distance measurement is completed in the front direction and the total deflection angle θ ₁ from the front direction to the total of 3 directions), the distance measured in each direction is compared. The focus drive is performed on the shortest one of these distances (that is, the closest subject). That is, the sizes of L ₁ and L ₂ are compared (step 113). When L ₁ is small, L ₁ and L ₃ are further compared (step 11).
4). When L ₁ is small, the distance L between the camera and subject
Then, L ₁ is input (step 115).

When L ₃ is small, L ₃ is input as the distance L between the camera and the subject (step 118). As a result of step 113, when L ₂ is small, L ₂ and L
The sizes of ₃ are compared (step 116). When L ₂ is small, L ₂ is input as the distance L between the camera and the subject (step 117). When L ₃ is small, the distance L between the camera and the subject, and inputs the L ₃ (step 118). With such an operation, the shortest measurement value is adopted as the distance L to the subject.

After photometry (step 119), it is judged whether the release switch is on or off (step 120). When the release switch is turned on, the focus lens is driven so as to match the distance L to the subject. (Step 121)
An in-focus state is obtained, a release operation is performed, and shooting is performed (step 122). At this time, the postures of the flat plates of the light projecting variable vertical angle prism 5 and the light receiving variable vertical angle prism 8 are reset, and the angles of the respective flat plates with respect to the reference plane are returned to zero.

On the other hand, when it is determined in step 104 that infrared light is to be distributed vertically, the following operation is performed. Memory (counter) n that counts the number of measurements
Is cleared (step 123). Control circuit 10
In the above, the deflection angle θ ₂ for irradiating infrared light selected from the data table based on the read focal length, and the rotation of the flat plate of the variable vertical angle prism 5 for projecting to set the deflection angle θ ₂ The angle β is determined, and further, the rotation angle of the flat plate of the variable light receiving vertical apex prism 8 is determined to be the same as the rotation angle of the flat plate of the variable light emitting vertical apex prism 5. Then, the driving means 6b and the driving means 60b necessary for obtaining the rotation angle are provided.
The respective drive amounts of are converted into the number of pulses from the encoder, and these values are output to the distance measuring unit 14 (step 1
24).

Driving means 6b for the variable apex angle prism 5 for projecting light
Is driven to count the number of pulses from the encoder and stop when the count reaches the number of input pulses (step 125). Next, the driving means 60b of the light-receiving variable apex angle prism 8 is driven to count the pulses from the encoder and stop when the counted number reaches the input pulse number (step 12).
6). By this operation, the optical path is divided into the left and right directions, and the error of the vertical focusing position of the reflected light entering the infrared light receiving section 4b is corrected.

By driving the driving means 6b and 60b, the distance is measured at the position where the optical path is swung (step 127). Here, since one distance measurement has been completed, 1 is added to the memory n (step 128). The distance s measured as L _n is stored (step 129). The value of memory n is 3
Is determined (step 130).
That is, it is determined whether or not distance measurement has been performed three times.

If the memory n is not 3, the process returns to step 125, and the variable projection vertical prism 5 is driven so that the optical path moves by the deflection angle θ ₂ (step 12).
5), the flat plate of the variable light receiving vertical apex prism 8 is rotationally driven so as to form the same rotation angle as the variable light emitting vertical apex prism 5 (step 126), and step 127.
~ 130 again. When the memory n becomes 3 (when the distance measurement is completed in the front direction and the total deflection angle θ ₂ from the front direction in three directions), the distance measured in each direction is compared (from step 113 onward). .

In addition to the above embodiment, first, the variable vertical angle prism 5 for projecting light is driven in the left-right direction and the up-down direction,
Later, the light receiving variable apex angle prism 8 may be configured to be driven in the left-right direction and the up-down direction. Alternatively, the up-down drive may be performed first and then the left-right drive may be performed. Further, the light projecting variable apex angle prism 5 and the light receiving variable apex angle prism 8 may be simultaneously driven. With the above configuration, even if the focal length is arbitrarily changed, the deflection angle θ of the infrared light is automatically changed accordingly,
In the viewfinder, the irradiation position 72 (focusing position) of infrared light is always located at the same position.

Therefore, it is possible to determine the composition without paying attention to the focusing position in the finder, depending on the difference between tele and wide. On the other hand, when the distance measurement position is selected in step 103, the beam angle in the horizontal direction and the beam angle in the vertical direction are calculated (step 131, step 132), and the steps 107, 10 are performed.
Similar to 8, 125, 126, each variable apex angle prism 5,
The flat plate of No. 8 is driven to a desired posture (step 133-
136). By this operation, the irradiation position of the infrared light coincides with the distance measuring position 72 selected in the finder 7.
Distance measurement is performed in this state (step 137), and step 1
The operations after 13 are performed.

In the above embodiment, the variable vertical angle prism 5 for projecting light and the variable vertical angle prism 8 for receiving light are variable vertical angle prisms having the same optical property. As the variable vertical angle prism 5 for light and the variable vertical angle prism 8 for light reception, variable vertical angle prisms having different optical properties may be used. In such a case, in the flat plate of the variable light receiving vertical apex prism 8, the deflection angle θ of the irradiation light in the light projecting variable vertical angle prism 5 and the deflection angle of the incident light in the light receiving variable vertical angle prism 8 are the same. The rotation angle is adjusted so that the angle is the same, that is, the condensing position on the light receiving element 41b of the infrared light reflected by the subject at the same distance from the camera is constant.

That is, the infrared light incident on the light receiving element 41b due to the vertical deflection of the light receiving variable apex prism 8 is incident on the straight line connecting the infrared light projecting section 4a and the infrared light receiving section 4b. The optical path is modified to collect light. The lateral deflection of the variable-angle prism 8 for light reception corrects the optical path so as to correct the error in the linear direction on the light receiving element 41b.
9 and 10 show another embodiment of the infrared light projecting section 4a. The illustrated example shows a structure in which the light projecting variable apex angle prisms 5a and 5b are arranged on the optical path of the infrared light projecting section 4a.

The variable apex prism 5a for projecting light is arranged on the object side. Flat plates 51a, 52a, connecting member 54
The structure composed of a and the liquid 53a is similar to that of the projecting variable vertical angle prism 5 described above, but only the flat plate 52a on the subject side rotates. The same applies to the variable projection vertical prism 5b. On the flat plate 52a of the variable angle prism 5a for projection on the subject side,
Rotating shaft 55 protruding in the vertical direction (Z-axis direction) from the peripheral portion
a is provided, and the flat plate 5 is centered around the rotary shaft 55a.
2a rotates, and as shown in FIG. 9, the irradiated infrared light beam is distributed in the left-right direction by the flat plate 52a.

On the other hand, on the flat plate 52b on the object side of the variable apex angle prism 5b for projecting light on the side of the light source 41a, there is provided a rotary shaft 55b protruding in the left-right direction (X-axis direction) from the peripheral portion,
The flat plate 52b rotates about the rotary shaft 55b,
As shown in FIG. 10, the emitted infrared light beam is vertically distributed by the flat plate 52b. The variable projection vertical prisms 5a and 5b are driven by driving means 6a and 6b, respectively. The configurations of these driving means 6a and 6b are the same as the configurations of the above-described embodiment, and therefore will be omitted. The above configuration can also be used for the light-receiving variable apex angle prism 8.

FIG. 11 is a sectional view showing another embodiment of the present invention. The configuration of the camera shown in the figure is the same as that of the embodiment shown in FIG. 1 except the distance measuring means, and the distance measuring means is the same as that shown in FIG.
In this embodiment, the variable apex angle prism 5 for projecting light and the variable apex angle prism 8 for receiving light are configured by a common variable apex angle prism 9. In this embodiment, since the variable apex angle prism 9 and the driving means 90a and 90b for driving the variable apex prism 9 need to be provided one by one, the structure of the drive mechanism and the like can be simplified and downsized, and the variable apex can be changed. The drive control of the angular prism 9 also becomes easy.

The control operation of the photographing control system having the above configuration will be described with reference to FIGS. 12, 13 and 14. When the photometric switch is turned on (step 101),
Reading of the focal length of the taking lens is started, and the read value is input to the control circuit 10 (step 102). It is determined whether or not the distance measuring position has been selected by the distance measuring position selection switch 17 (step 103). If the selection has not been made, the position of the changeover switch 16 is detected, and the beam distribution direction is selected to be the long side direction or the short side direction of the finder (step 1).
04). When the tilt sensor is used instead of the changeover switch, the beam distribution direction is determined based on the posture of the camera detected by the tilt sensor. When the beam distribution direction is the long side direction (horizontal direction) of the finder, the operation is as follows.

The memory (counter) n for counting the number of measurements is cleared (step 105). In the control circuit 10, a deflection angle θ ₁ for irradiating infrared light selected from the data table from the read focal length.
And a variable apex angle prism 9 for setting the deflection angle to θ _1.
Determines the rotation angle of the flat plate. Then, the drive amount of the drive means 90a required to obtain the rotation angle is converted into the number of pulses from the encoder, and these values are output to the distance measuring unit 14 (step 106).

The driving means 90a of the variable apex angle prism 9 is driven to count the pulses from the encoder and stop when the counted number reaches each input pulse number (step 107). By this operation, the optical path is divided into the left and right directions, and the reflected light that enters the infrared light receiving section 4b is corrected for the error in the left and right focusing position.

By driving the driving means 90a, the distance is measured at the position where the optical path is swung (step 109). here,
Since one distance measurement has been completed, 1 is added to the memory n (step 110). The distance s measured as L _n is stored (step 111). It is determined whether the value of the memory n is 3 (step 112). That is,
Determine if the distance measurement was performed 3 times. Memory n is 3
If not, the process returns to step 107 and the variable apex angle prism 9 is moved so that the optical path moves by the deflection angle θ _1.
Is driven (step 107), and steps 109 to 11
Execute 1 again.

When the memory n becomes 3 (when the distance measurement is completed in the front and the total of three deflection angles θ ₁ from the front to the right), the distances measured in the respective directions are compared. The focus drive is performed on the shortest one of these distances (that is, the closest subject). That is, the sizes of L ₁ and L ₂ are compared (step 113). When L ₁ is small, L ₁ and L ₃ are further compared (step 11).
4). When L ₁ is small, the distance L between the camera and subject
Then, L ₁ is input (step 115).

If L ₃ is small, L ₃ is input as the distance L between the camera and the subject (step 118). As a result of step 113, when L ₂ is small, L ₂ and L
The sizes of ₃ are compared (step 116). When L ₂ is small, L ₂ is input as the distance L between the camera and the subject (step 117).

When L ₃ is small, L ₃ is input as the distance L between the camera and the subject (step 118). With such an operation, the shortest measurement value is adopted as the distance L to the subject. Next, perform photometry (Step 11
After 9), it is judged whether the release switch is on or off (step 120), and when it is turned on, the focus lens is driven so as to match the distance L to the subject (step 121). Then, the release operation is performed and the photographing is performed (step 122). At this time, the flat plate posture of the variable apex angle prism 9 is reset, and the angle of each flat plate with respect to the reference plane is returned to zero.

On the other hand, when it is determined in step 104 that the infrared light is to be distributed vertically, the following operation is performed. Memory (counter) n that counts the number of measurements
Is cleared (step 123). Control circuit 10
From In, the focal length read, be selected from the data table and the deflection angle theta ₂ which irradiates infrared light, the rotational angle β of the flat plate of the variable apex angle prism 9 to the deflection angle and theta ₂ decide. Then, the drive amount of the drive means 90b required to obtain the rotation angle is converted into the number of pulses from the encoder, and these values are output to the distance measuring unit 14 (step 124).

While driving the driving means 90b of the variable apex angle prism 9 to count the pulses from the encoder,
When the count number reaches the input pulse number, the operation is stopped (step 125). By this operation, the optical path is divided into the left and right directions, and the error of the vertical focusing position of the reflected light entering the infrared light receiving section 4b is corrected. The distance is measured at the position where the optical path is swung by the driving of the driving means 90b (step 127).

Since the distance measurement has been completed once, 1 is added to the memory n (step 128). The distance s measured as L _n is stored (step 129). It is determined whether the value of the memory n is 3 (step 130). That is, it is determined whether or not distance measurement has been performed three times. If the memory n is not 3, the process returns to step 125, and the variable apex angle prism 9 is driven so that the optical path moves by the deflection angle θ ₂ (step 125),
The steps 127 to 130 are executed again.

When the memory n becomes 3 (when the distance measurement is completed in the front direction and the total deflection angle θ ₂ from the front direction in three directions), the distances measured in the respective directions are compared (step 113 and later). On the other hand, step 103
When the distance measurement position is selected, the horizontal beam angle and the vertical beam angle are respectively calculated (step 131, step 132), and the step 10 is performed.
Similar to steps 7 and 125, the flat plate of the variable apex angle prism 9 is driven to a desired posture (steps 133 and 135). By this operation, the irradiation position of the infrared light coincides with the distance measuring position 72 selected in the finder 7. In this state, distance measurement is performed (step 137), and the operations after step 113 are performed. In addition to the above-described embodiment, the variable apex angle prism 9 may be driven in the vertical driving direction first and then in the horizontal driving direction.

With the above-mentioned structure, even if the focal length is arbitrarily changed, the deflection angle θ of the infrared light is automatically changed accordingly. Therefore, in the viewfinder,
An effect similar to that of the first embodiment is exhibited, in which the infrared light irradiation position 72 (focusing position) is always located at the same position.

In the embodiment described above, the relationship between the irradiation direction of infrared light and the apex angle of the variable apex angle prism on which the reflected infrared light is incident is, for example, the incident side variable apex angle prisms 8 and 9. When the total refractive index n is 1.6 and the angle formed by the optical path of the infrared light radiated to the front and the optical path of the infrared light radiated in the left and right directions is ± 5.0 degrees, respectively, the rotation angle α Is 8.3
It is regarded as a degree.

The camera of the present invention may not have the focal length changing mechanism. Although the camera of the present invention has been described above with reference to some illustrated configuration examples, the present invention is not limited to these. For example, the opposing plates of the variable apex angle prism 5 are not limited to the flat plates described above, and may have a function of a curved plate or a lens.

In the light projecting variable vertical angle prism 5, the optically transparent and easily deformable substance interposed between the opposing plates is not limited to the liquid 53, but is, for example, silicone rubber. It may be a solid such as a transparent elastic body. In the illustrated configuration example, both the flat plates 51 and 52 are deviated when adjusting the apex angle of the variable apex prism 5 for projecting light, but only one of the flat plates is deviated in two orthogonal directions. It can also be configured to be ranked.

Further, in the illustrated configuration example, the infrared light projecting section 4
The variable projection vertical angle prism 5 is installed in the forefront (subject side) in a, but the positional relationship is not limited to this. For example, the variable projection vertical angle prism 5 is
It may be installed between the light source 41a and the projection lens 42a. The variable apex angle prism 8 for light reception and the variable apex angle prism 9 may be made of the above-mentioned various constituent materials similarly to the variable apex angle prism 5 for light projection.

[0084]

As described above, in the camera of the present invention, multipoint distance measurement can be performed at the same distance measuring position regardless of the vertical and horizontal photographing postures, and even if the photographing posture of the camera is changed, the distance measuring position can be changed. You can shoot without worrying about it.

Further, since the distance measuring position can be arbitrarily determined, there is an advantage that it is possible to focus on an arbitrary position, and the restriction of the focusing position when determining the composition in the viewfinder is eliminated. The operability is improved.
Further, by using the variable apex angle prism, it is possible to perform multi-point distance measurement using the infrared light projector and the infrared light receiver of the one-point distance measuring camera. If the variable apex angle prism unit is unitized, versatility increases.

Further, by disposing the variable apex angle prism at the light receiving position, the light receiving position of the infrared light receiving unit can be changed according to the change of the irradiation direction of the infrared light when performing multi-point distance measurement at an arbitrary position. No correction is needed. Furthermore, since the light receiving element can be made small, the size of the camera can be reduced by reducing the mounting space.

When used in a camera having a variable focal length mechanism, for example, regardless of the difference between tele and wide,
The relative position of the infrared light irradiation part with respect to the angle of view can be made constant, and there is a restriction that the composition in the viewfinder must be determined in consideration of the fluctuation of the infrared light irradiation part due to the change of tele and wide. Less and improved operability. As a result, inconveniences such as occurrence of out-of-focus due to the shift of the position of the focus point and missing of a photo opportunity are reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a photographing control system in a compact camera according to a preferred embodiment of the present invention.

FIG. 2 is a plan sectional view showing a structure of a distance measuring unit.

FIG. 3 is a side sectional view showing a structure of distance measuring means.

FIG. 4 is a plan view of the finder showing a relationship between a display unit displayed on the finder screen and an actual irradiation range of infrared light.

FIG. 5 is a plan view of the finder showing the relationship between the display unit displayed on the finder screen and the actual irradiation range of infrared light.

FIG. 6 is a flowchart showing an operation sequence of control means.

FIG. 7 is a flowchart showing an operation sequence of control means.

FIG. 8 is a flowchart showing an operation sequence of control means.

FIG. 9 is a plan sectional view showing the structure of a distance measuring mechanism when two variable apex angle prisms are arranged in series.

FIG. 10 is a side sectional view showing a structure of a distance measuring mechanism when two variable apex angle prisms are arranged in series.

FIG. 11 is a schematic diagram showing another configuration example of the distance measuring means in the present invention.

FIG. 12 is a flowchart showing an operation sequence of the control means in the case of another distance measuring means.

FIG. 13 is a flowchart showing an operation sequence of the control means in the case of another distance measuring means.

FIG. 14 is a flowchart showing an operation sequence of control means in the case of another distance measuring means.

[Explanation of symbols]

 10 Control Circuit 11 Metering Section 12 Metering Release Switch 13 Zooming Operation Switch 14 Distance Measuring Section 15 Drive Circuit 16 Changeover Switch 17 Distance Measuring Position Selection Switch 21 Zooming Motor 22 Small Gear 23 Zoom Code Reading Section 3 Zoom Lens 30 Lens Tube 31 Cam Ring 32 gear 33 code part 331 conductive plate 34 cam groove 4a infrared light emitting part 4b infrared light receiving part 41a light source 42a light emitting lens 41b light receiving element 42b light receiving lens 5 light emitting variable apex prism 5a, 5b for light emitting Variable apex angle prism 51, 51a, 51b Flat plate 52, 52a, 52b Flat plate 53, 53a, 53b Liquid 54, 54a, 54b Connection member 55, 55a, 55b Rotation shaft 56 Arm 57 Connection part 571 Slit hole 58 Rotation shaft 6a, b , 60a, b, 90a, b Drive means 6 Pinion 62 backward member 63 rack 64 pin 65 slit 66 encoder 7 variable angle prism 9 variable angle prism for receiving the finder screen 71 display 72 actual infrared light irradiation portion 8 101-137 Step

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 13/36

Claims (10)

[Claims] 1. An infrared light projector that irradiates an object with infrared light, and an infrared light receiver that receives infrared light emitted from the infrared light projector and reflected by the object. A distance measuring unit having :, an automatic focusing mechanism that drives a lens to obtain a focused state based on the distance measuring information obtained by the distance measuring unit, and is installed on the optical path of the infrared light projecting unit. An optically transparent and easily deformable substance is interposed between at least a pair of plates facing each other, and at least one variable apex angle prism for projecting light capable of changing an angle formed by the two plates; A driving means for changing the angle of the variable apex angle prism with respect to the reference plane of the plate, wherein the projection direction is arbitrarily adjusted by changing the angle of the plate with respect to the reference plane. A camera with a mechanism. 2. A camera having an automatic focusing mechanism according to claim 1, wherein the angles of at least one pair of plates constituting the light projecting variable vertical angle prism with respect to the reference plane are respectively changed in different directions. 3. A plurality of variable vertical angle prisms for projecting light are arranged on an optical path, and an angle between at least a pair of plates of the variable vertical angle prism and a reference surface is set to a different direction for each of the pair of variable vertical angle prisms. A camera having the autofocus mechanism according to claim 1, which is changed. 4. An optically transparent and easily deformable substance is interposed between at least a pair of opposing plates provided on the optical path of the infrared light receiving section, and the angle formed by the two plates is At least one variable light receiving vertical apex prism that can be changed, and drive means that changes the angle of the light receiving variable vertical apex prism with respect to the reference plane of the plate, wherein the angle of the plate with respect to the reference plane is The light-condensing position of the light-receiving unit is adjusted so as to be located on a straight line connecting the infrared-light receiving unit and the infrared-light projecting unit. Camera with automatic focus mechanism. 5. The angle of the plate with respect to the reference plane is adjusted so that the focus position of the infrared light reflected by the subject at the same distance at the infrared light receiving section becomes constant. A camera having an autofocus mechanism according to claim 4. 6. A camera having an automatic focusing mechanism according to claim 4, wherein the angles of at least one pair of plates constituting the light-receiving variable apex angle prism with respect to the reference plane are respectively changed in different directions. 7. A plurality of light receiving variable apex angle prisms are arranged on an optical path, and an angle between at least a pair of plates of the variable apex angle prism and a reference surface is changed in a different direction for each of the pair of variable apex angle prisms. A camera having the automatic focusing mechanism according to claim 4 or 5. 8. The direction in which the angle formed by the plate with respect to the reference plane is changed is two directions orthogonal to each other in a projection view on a plane perpendicular to the optical axis of infrared light immediately after being irradiated from the light projecting unit. A camera having the automatic focusing mechanism according to claim 1. 9. A focal length varying mechanism and a focal length detecting means for detecting the focal length are provided, and the focal length detecting means is provided so that the relative position of the infrared light irradiation portion with respect to the angle of view becomes constant. The apex angle of the variable apex prism for projecting light is adjusted based on the obtained focal length information.
A camera having the autofocus mechanism according to any one of 8 to 8. 10. A camera having an automatic focusing mechanism according to claim 4, wherein the variable vertical angle prism for projecting light and the variable vertical angle prism for receiving light are constituted by a common variable vertical angle prism. .