JPS60256112A - Automatic focusing device of camera - Google Patents

Abstract

PURPOSE:To attain off-axis focusing and also bring plural subjects into focus by putting the target subject at the shortest distance in focus during normal photography, and calculating the depth of focus according to the purpose and setting the optimum distance of a photographic lens. CONSTITUTION:Line sensors RL and RR start scanning synchronously with each other with a power switch ON. At the same time, the photographic lens 11 is extended and stops at the shortest distance. When a normal photograph is taken, a spot light projection tube 1 is rotated and an infrared-ray RED2 emits pulse light to make a scan once. At this time, the distance of each subject is calculated by using reflected light from the surface of the subject and the result is stored in a memory 14 successively. Then, the shortest distance is found and the lens 11 is set to the shortest distance. When subjects are shot by a movie camera, the projection tube 1 is scanned continuously and the best distance for bringing the subjects into focus is calculated on the basis of respective subject distances, stop information, and the focus length of the lens 11, thereby performing focusing operation intermittently and continuously.

Description

Detailed Description of the Invention "Industrial Application Field 1 The present invention generally relates to cameras such as still cameras, movie cameras, and television cameras, and to automatic focusing devices for use with cameras such as still cameras, movie cameras, and television cameras. The present invention relates to an automatic focusing device that irradiates a beam of light toward the subject, detects reflected light from the subject using a light receiving element, measures the distance to the subject using trigonometry, and focuses on the subject.

``Prior art'' Conventionally, a light beam has been irradiated toward a subject, or light from the subject has been received by a light-receiving element without irradiation and photoelectric conversion has been performed to measure distance using a triangulation method. Various automatic focusing devices are known, such as those that perform focusing by detecting blur using a solid-state image pickup plate. In these cases, in both still cameras, mobile cameras, and television cameras, the focus center is generally located at the center of the viewfinder field frame, that is, approximately on the optical axis of the camera's photographing lens. Galley] (focusing indicator) is provided.

1-Problems solved and auspicious by the invention-1 In conventional automatic focusing devices such as still cameras, Moo-Vis cameras, and TV cameras, as mentioned above, targets (markers) are used to indicate the range-finding area, that is, the focusing area. was provided in the center of the viewfinder field frame, and its distance measurement optical axis was approximately on the optical axis of the photographing lens, so when measuring (focusing) a subject off the optical axis, it is difficult to use, for example, a still camera. In this case, it is necessary to measure the distance to the subject on the optical axis, memorize it by operating the first stage of the release button, etc., and then change the direction of the camera away from the optical axis.
With movie cameras, it is difficult to focus on the center of the viewfinder, and it is impossible to focus on the sides of the viewfinder frame.

In other words, in order to focus on a subject with a still camera, it is necessary to use a focus target, and when focusing on a subject that is off the optical axis, it is necessary to use photographic techniques unique to autofocus cameras such as a double-lens camera. On the other hand, with movie cameras and the like, it is impossible to focus on areas other than the central target.Furthermore, with the automatic focusing devices of these conventional cameras, it is impossible to avoid focusing on multiple subjects with different subject distances.

``Object of the present invention'' The present invention has been made in view of the points stated in ``-''. 17, the focus target object can be focused no matter where in the viewfinder field of view the target object, which is generally the closest among the object plane containing multiple objects, is located at any position in the viewfinder. It eliminates the photographic techniques unique to autofocus cameras as mentioned above, making them easier to use, and also makes it possible to focus on objects other than the focus target, which was previously possible with movie cameras. It is possible to focus on multiple subjects depending on the situation. In order to solve this problem, two sets of position detection light receiving devices consisting of a light receiving lens and a light receiving element capable of detecting the left and right deviation (displacement) of the light receiving point were installed.
The respective optical axes are arranged in a line with a predetermined interval between them, and an irradiation means is provided near the position detection light receiving device to scan and irradiate the subject side with spot light such as infrared light. C
) is received and detected at the same timing by the reflected light of During normal shooting, the subject at the closest distance [ ] is generally selected and focused.17 Depending on the purpose, the aperture information based on the brightness of the subject surface and the focal length of the photographing lens are determined. Calculate the depth of focus from the distance of multiple subjects 11' [7], set the distance Pil of the photographic lens based on the distance signal [7] This makes it possible to perform focusing.

[Embodiment 1] Hereinafter, one embodiment of the present invention will be explained based on the attached drawings.

Figure 1 is an overall configuration diagram of the self-U + focusing device for unfired IJ'l, and Figure 2 shows an arbitrary subject, a pair of light receiving lenses and light receiving elements in Figure 1, and a warped/sparked light.

FIG. 3 is a plan view showing the distance relationship between light receiving points.

In the figure, (1,,) and (■, 1lIyl on the top of the camera to receive the reflected light beam from the sword 1-J'ge body or C9.
A pair of light receiving lenses' (
, 11. The optical axes of each are arranged at a predetermined interval of 1 momme.
A predetermined distance (focal length of the light-receiving lens) is set at a line processor, which is an optical element. Near the two sets of left and right position detection light receiving devices consisting of a light receiving lens and a light receiving element f- (in the middle in the figure), an infrared light emitting diode (IRED), which is a light emitting element, is installed to scan the subject side with pulsed light. A spot light projecting tube i11 having a projecting lens 13) on the same axis is mounted on a shaft (1a) and is driven by a pulse motor (PM+) K to rotate from side to side. The above line processor (P+j.

(Rn) consists of a large number of high-density photoreceptors so that the amount of left and right deviation on the light-receiving surface of the light-receiving point (pulse spot) (Pb) and (PR) due to the reflected pulsed light flux from the subject can be detected. Each line processor (P+, ), (RR) is a microcomputer (5
), the line sender driver (61 scans the light receiving part of the line sensor (P+, ), (R1 ()) and focuses the light on the light receiving surface. A pulse signal is generated from each photoreceptor. Figure 5 shows the relationship when the pulse light flux is focused on the left and right line sensors (P+, ) and (RR) and generates a pulse signal. The line sensor (P+j, (R
Pulse honor (Pe) is applied to each photoreceptor that makes up R).
I:), (PI!+t) is also −, ″(
Figure (b) is a diagram showing the state when light is focused, Figure (b) is an illuminance distribution diagram on the photoreceptor surface, and Figure (c) is a diagram showing the state of the output voltage due to photoelectric conversion on each photoreceptor surface 1-5. The output voltage of line sensor (P+,), (Rn) is 1 amplifier (7
1,) , (7n) increases the width by 1[J]
In addition, the analog quantities of the output voltages are digitized by converters (8t') and (8at), respectively, and input to the microcomputer 15) at intervals of pulses (P+, ), (Pn) in the same time period.・Software I (program) is installed in the microcomputer (51) to calculate the distance between objects covered by the object.(I) in Fig. 1.

song, (110 is the direction in the 1h direction of the camera, y of the distance
4 represents multiple independent objects. In the figure, when spot light projector (1) is projected and scanned left and right, the reflection from famous object (1), (rl), fllD is reflected by q-t * , sequentially line senna (P+,) to the east
, The light receiving point (pulse spot) of (Rh) is 4J8!1il in the same time zone according to the scanning of the light emitted to 1-.
This shows the state of J. That is, in this way, the distances calculated from the intervals between the pulse spots in the same time period are sequentially stored in the distance information memo 141, and
The required distance Nt is calculated by interacting with a microcosciputer (51) and inputting aperture information 115 depending on the application. In this example, a line sensor consisting of a large number of high-density photoreceptors was used to detect the deviation of the reflected light flux, but any suitable sensor (e.g. Of course, it is also possible to use a method that replaces displacement with resistance change.

In this case, a circuit capable of outputting the pulse position in the form of a voltage is connected, and the output thereof is input to the A/7J inverters (St, ) and (Rn).

(2) On the other hand, the pulse motor (PMl) connected to rotate the spont light projection tube (1) described in -F in the left and right direction is connected to the If continuous scanning is not possible, a microcoscipi- tor (
6), the pulse signal for the required motor rotation is P
M I dry, < +91 human power 3 IIzeImiI)') +2) it
, In order to generate the nollus light, the necessary light emitting pulse pulse (1-1 or 11<1) is input from the microphone IJ:J nobyota (5) to the driver (10) and becomes the Wth signal, which is output from the infrared light emitting diode ( 2) Enter "," which is configured in 71.

In addition, a pulse motor (PL1.,) connected to the drive system of the photographic lens (11) drives the photographic lens (111) to the alignment position 1r1.
PM l, which is the drive circuit of - [PMl with reverse signal
, l'Leiper (12) is manually operated to generate a multiphase U+ signal, and the pulse smoke (PMI,) is configured to rotate. However, as a preparatory step for shooting, at the start of shooting, for example, by pressing the release button, etc.
When a source (not shown) enters, the photographing lens 111) which is in the state of focusing stop is extended to an arbitrary position, and the closest distance switch 03) for detecting the initial position of the lens is extended to the maximum distance.
software (program) is installed in the microcomputer tel so that it can detect and send a signal to the microcomputer (5) to move the photographing lens to the starting position, the closest distance position, and then move it to the focusing position. ing.

That is, the misfire 11j device emits and scans a spot light beam such as infrared light from a spot light projection tube (1), and sends the reflected light beam from the object to a pair of left and right light receiving lenses (r-1) and (L2).
through the respective line sensor (P+,).

(R+t) receives light from 1~, calculates the subject distance from the received light signals of (P+,'), (Pat) on the line sensor at the same time, and records the distance information memo IJ.
The shortest distance is selected from the distance information memo IJ-+141 according to the purpose from multiple subject distances qt, and the distance information memory (1 aperture information 115) is stored sequentially in the distance information memory (
14) and the microphone Ul': J computer (5) exchange multiple subject distances to calculate the optimal shooting distance, and move the shooting lens + 11) to the required predetermined distance from the closest distance to a predetermined position. It is configured to cause the user to move wJ.

Next, let us explain the distance measurement principle in the present invention. As shown in Figure 2, the distance between an arbitrary object +2+ and a pair of light-receiving lenses O-+), (1,,2) is I) The reflection point of the spot light beam on the target object tZj is (e), and the intersection of the optical axis of the light receiving lens (r-1) and (t, 2) with the reflected light beam is l.

If you cross r, lr 7 〒LPR,'-otelr (No 11 e P
L PR pulse spot (Pl,), (1',,
) is defined as B', and from Equation 11 (2), D = B, -
B (31 In equation (3), B , f rJi constant value, ',
I) is a function of B'.

That is, the object distance is determined by measuring B'. now,
In Figure 2, the left end of the line sensor (R1,) is the reference 0, and the right end is xl, 1.The line sensor (RR)
Considering that the left end is located at X2 + the right end is at x3, the imaged pulse spots (PI, ) and (P + ζ) are jla and b L respectively, B' = (ba - a) ・
(4) So B' is 5. Elaharu.

Therefore, B' is calculated from the spot positions a and b on the line sensors (P+,) and (RR), and the subject distance I) is calculated using equation (3). In this case, “Linessen”)
(P+, ) and (Rn) are placed at a distance of You can think of it as an arrangement of photoreceptors. In other words, the photoreceptor forming the pixel in the left line sensor (P+,') is O
, I, 2, -kl, and the photoreceptors are similarly distributed to high-density 1 (with addresses m, m+I, +1-1, n) in the right line sensor (Rn). The photoreceptors of the virtual pixels between them are arranged at high density, and the photoreceptors of the virtual pixels are arranged in consecutive addresses (,(,), thereby making it possible to imagine that the photoreceptors are 1- (P+,').

(PR) position a, blc and address No. 411 are input into the Ninonobuku tel.
, (P/1+) has a width of 1'l, but the pulse width is (1'l,).

The output voltage of (P R) is small in Figure 5 1-→
Detect the pulse oscillation [IJ change u) at the focal point as shown in FIG.
, (1'++) are used as representatives to calculate the distance B'.

Figure 3 shows how to reduce the moving state of the reflected light at the same timing at arbitrary reflection points e+, ez, ('ai) on the subject side when continuously measuring the distance of the subject, which is a continuous surface. In the example, it is assumed that 181!) "A plurality of objects with 11 degrees to (-1 single German q object'θ
g1 is actually covered body side 611 general (but,
Jl, can be taken as an independent target 't, J 4 ζ
- It can be considered that the dimensions are included in I). Also,
Line sensors (P+,
The scanning of the light projected onto the object by I''i is performed at a slower speed than the scanning of the light receiving section, but both pulse spots (PI, ), (
Strictly speaking, the continuous distance measurement of the object surface by PR) is high-density sampling distance measurement.

Next, the operation of the apparatus of the present invention will be explained.

FIG. 6 is a flowchart of operation w1 when unexploded gun 1 is used for normal photography with a still camera.

First, when taking a picture, turn on the power switch (V in the illustration) by pressing the release button, etc., and the line sensor (P+,
), (R+ζ) is the line sensor driver +61 by the control signal from the microcomputer (5).
Synchronous scanning is started via the camera, and at the same time the photographing lens (1
1) is extended and the lens initial position detection closest distance switch (13) is activated to stop F at the closest distance position. The 1-light projector tube (1) is connected to the microphone [control (
5) Kashi)'s (Ii bow (I'M.

The driver (9) connects the driver (9) to the pulse driver (
PFII+) times! lv+ cell=mera h, same 1
- < IREI) I RE I) +21 or infrared pulsed light is emitted through the l' driver t1+11 to 1
Scanning is performed P+ times. , in this case, as in theory 11 above, there is a
The pulses of the same time period are sequentially detected by the reflected light from the body surface (1'+, ), (1'n) or the intermediate value of Furukawa Rikichu II, and the interval between them [Lean Ik[
J combination, -ta (5 (incorporated?l! again)) 71・(zologram) gives the name target'ge body distance 'j'J1tl i!
/"l (The results are stored sequentially in the distance information recorder IJ 1141. Then, the same microphone U combination, -ta (5)
The shortest χg distance is determined from the lf distance, and this shortest distance (
: Converted to the amount of movement of the I shooting "L/lens 11)", and the "r" is the number (+1 signal) and the lens movement pulse.
PM is input to the driver 1121i, and the pulse motor (1'M, . . .) is moved to IJl (IIIl+l), and the photographing lens (11) is brought into focus with respect to the imaging plane tS+ to focus on the subject at the shortest distance position. After focusing, take the photographic lens (11)
The camera stops at that position, remains in that stopped state even after the release button is released and the power is turned off due to the completion of photographing, etc., and the above operation is repeated when the power switch is turned on by pressing the release button next time.

FIG. 7 is a flowchart of the operation of field A when the present invention is used in a movie camera.

First, when the power switch (not shown) is turned on by pressing the release button, etc., the 1irJ period scanning of the line sensors (R, , ) and (RR) starts, and after the release button is restored, the shooting that was in the stopped state at the wax position is started. The lens is extended and stopped at the closest distance position, as in the case of the above-mentioned still camera. At this time, the lens movement counter using the register of the microcomputer (5) is reset and its contents M are cleared to O. Next, spot light projector (
1) starts continuous reciprocating scanning operation 794 times by reciprocating rotation of the pulse motor (1'M+) in response to a signal from the microcomputer (5). At this time, the reflected light from the subject surface including multiple independent subjects sequentially produces the same time zone's balsossubo y ) (h,'), (Pi)
The force is detected and the distance between them is more microconopi.

- Each object distance is calculated by software (program) K incorporated in the computer (5), and the results are sequentially stored in the distance information memo IJ 1141. Next, the shortest distance is determined from the plurality of subject distances using software installed in the microcomputer (5), and this shortest distance is converted into the amount of movement dK of the photographic lens (11), and d and the contents of the movement amount counter ~1 If d'>M (initial content M =
O1 (subsequently fluctuated) retraction The photographing lens (11) is retracted by the left signal (positive signal) and the lens is shifted! 1llJ H product counter is counter h7-tuff lens movement amount d
When the photographing lens 111) is retracted until -M and becomes focused, the photographing lens 111) stops, and if d<M instead of d. 11i1J R: d = MK, and when the lens is in focus, the photographing lens (11) stops, and the camera moves continuously by movie operations such as panning. When a new pulse (P+, ), (Pa+) is detected, the photographing lens (11) moves to the alignment position and stops, and focuses intermittently and continuously, and when the release button is released and the power is turned off. The photographing lens 111) stops at that position. That is, by continuous scanning, it is possible to follow the subject moving at the shortest distance, sequentially determine the photographing lens distance, and perform focusing operations intermittently and continuously. Note that the focusing during the intermittent focusing depends on the depth of focus of the photographing lens.

Figure 8 shows misfire+! 1 is a flowchart of the operation in the case of so-called pan-focus photography in which a still camera is used to focus on a plurality of subjects.

First, the power switch (not shown) must be turned off by pressing the release button, etc.
) is turned on, the line sensor (R1,), (RR) is activated as in normal shooting situations.
After the release button is restored, the photographic lens, which had been stopped at an arbitrary position, is extended and stopped at the closest distance position. Next, Subono (・Light projector f + l starts the cycle 1σ1 in the same way as above, and [I REL) +2
1 emits infrared pulsed light 1. One scanning is performed. At this time, the reflected light from the subject surface including multiple independent subjects sequentially captures pulses in the same time period.
(r”, ) and (Pa) are detected, and from these intervals, the software (program) built into the microcomputer (5) calculates each object distance, and the results are sequentially recorded in the distance information memo (January 14). Next, the software similarly calculates these multiple subject distances, information based on the brightness of the body surface (for example, the aperture value of a 70g shutter, etc.), and the focal length of the photographic lens. The optimum distance for focusing on multiple subjects is calculated based on the depth of focus, and this shooting distance is used to shift the photographic lens C11).
Convert to j total, and calculate the shift f! The JJM photographing lens (11) retracts and focuses on a plurality of subjects. The operation at the next focusing start t when the power switch is turned on at the next release after focusing is the same as described above. Although this embodiment has been described with respect to the panties 3-cass π in a still camera, it is also possible to apply this principle to a movie camera and the like to perform continuous focusing operations with continuous focus.

It goes without saying that the focusing procedure in the above flowchart is performed within a short period of time after the power switch is turned ON at the time of release, and the photographing lens is moved to focus by -117.

Effect of 1 shot 111-] From the above explanation, it is clear that 1-1 + j According to the unfired IJI, the effect of conventional still cameras and movie cameras is 1-1+j. The target foot (index) to indicate the focus area, which was essential in the IIJ focusing device, has been removed from the viewfinder field frame, and anyone can easily focus by placing a target within the viewfinder field frame. The lx
(This is to provide a device that can easily create automatic focusing power. In other words, when focusing on a target off the optical axis with a conventional automatic focusing still camera, the distance of the target is determined by Autofocus cameras used to require photography techniques such as memorizing the IP address and then changing the direction of the camera off the optical axis. It is now possible to focus off the optical axis, which was previously impossible, and 3\
In addition, depending on the application, it is possible to focus on multiple subjects f)
simplification of operations (it is easier for people to

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. 11 automatic” (point neck 1.
Figure 2 shows the body and the body and Figure 1 7) Light-receiving lens. Figure 3 is a diagram of the distance relationship between the light receiving element and the reflected light due to the weight of the reflected light. Figure 3 is a diagram of the state of reflected light when continuously measuring a subject on a continuous surface. Figure 4 is a diagram of the state of reflected light when a pair of line sensors is used. Arrangement diagram of the photoreceptor and the virtual photoreceptor. Figure 5 is a relationship diagram when the curless light flux is focused on the line sensor and generates a pulse signal. Figure (A) is a diagram of the convergence state of the pulsed light flux. , Figure (B) is an illuminance distribution diagram, Figure H is t
Figure 6 is a flowchart of the operation when the unexploded W1 is used for normal photography with a still camera.
FIG. 7 is a 70-chart of the operation when the unexploded IJI is used in a movie camera, and FIG. 8 is a flowchart of the operation when the present invention is used in a still camera. (L+), (L2')・Light receiving lens, (P+,)
, (RR') = = line sensor, (1) spot light projector, (2) infrared light emitting light 1° (eye<I
T1), t:<1 light emitting lens, (5) Microphone, (61-・Line sensor trial/
(81,) (8n A/D converter, P
MI) rus-(-ri, +91- PM Tori° Rhino(
, Io+ ■R[) ): Rai/gu, 111) Photographing lens, PMl, ノ(/less motor, +121 PMI,
Dry/(,114) Distance information memory, B Optical axis interval of light receiving lens, B' Pulse interval, (P+, ), (Pll) ・
・／'Av Subbot, D Distance between any subject and the light receiving lens, f ・Light receiving lens and light beam! Distance between nori. For patent) Sadato Sekiko Minami Camera Co., Ltd. + ILF Institute] 1 or 2 people

Claims (1)

[Scope of Claims] 1. A pair of light-receiving lenses whose optical axes are arranged at a predetermined interval, and left and right shift claws on the light-receiving surface of the light-receiving point of the reflected light, which are arranged at the light-converging position of each light-receiving lens. a light-receiving element configured to detect the light-receiving element; a light-emitting means disposed near the light-receiving lens to emit a spot light beam and to scan forward in the left and right directions of both optical axes; A signal converting means for converting the light reception signal of the light receiving element into a countable one, a means for controlling the scanning of the light emitting means, a means for controlling the movement of the photographing lens to the in-focus position, and a distance of the subject from the microcomputer. A distance information/mori that stores information, and at least a limb game that calculates distances to multiple objects from each shift signal received and detected in the same time period due to reflected light from an object surface that includes multiple objects. Equipped with a micro-combination system incorporating means for detecting body distance 4 and selecting a required distance from a plurality of subject distances, a micro-combination lens incorporating one stage of distance l1ll# selection 1 is installed, and is sequentially irradiated. The distance of multiple limbs and bodies is determined by the reflection from the subject using light signals of the same time period, the m3 distance is determined, and the shadow lens is moved to that distance to focus on the desired subject. I'! in a camera characterized by the following. ν) Focusing device. 2 The distance calculation means V1, the two threads t+q”
Based on the predetermined interval between the two optical axes described in (g), the distance between each light receiving point is calculated using j.1. - The first claim is characterized in that the distance from the target object is converted.
The force described in Section 4/Unima 4 and the self-focusing device. 3-11 Distance selection of the photographing lens R step tt, calculation of the distance of the irradiation means in the above section σ)
An automatic focusing device for a camera according to claim 1 or 2, characterized in that the closest distance is selected from the object distance by 1°. 4. The distance selection means of the photographic lens comprises: A patent characterized in that the shortest distance is selected in bulk from a plurality of object distances calculated by continuous repeated scanning of the irradiation means, and the lens distance is sequentially determined by following the moving object of the shortest distance. An automatic focusing device in a camera according to claim 1 or 2. 5. The distance selection means for the photographing lens is configured to select the aperture information ♂ based on the brightness of the object surface, the focal length of the photographing lens, and the −F object surface. 3. An automatic focusing device for a camera according to claim 1 or 2, wherein an optimum photographing distance based on a depth of focus is calculated from a plurality of subject distances.