JP2768469B2 - Focus adjustment device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a focus adjustment device that can selectively generate a signal for focus adjustment for a plurality of targets.

[Prior art] Conventionally, a camera equipped with an automatic focus detection device (AF device) is provided with a distance measurement mark near the center of a shooting screen. Many. However, sometimes the subject is located outside the center of the screen, and in this case, the operation of the AF device results in so-called out-of-focus shooting, making it difficult to use.

Therefore, there is a camera equipped with a focus lock device in consideration of focusing on a position other than the center of the screen. However, this camera has a drawback that after locking the focus, a photo opportunity is missed in order to perform a layout.

Furthermore, some cameras automatically measure the distance of a plurality of subjects, select the closest subject distance information from the plurality of subject distance information, and focus on the subject, but the subject to be focused is not necessarily at the closest distance. In some cases, it was not always easy to use.

[Problems to be Solved by the Invention] On the other hand, Japanese Patent Application Laid-Open No. 58-158 discloses an apparatus in which a target for performing focus adjustment can be arbitrarily selected from a plurality of targets so that a desired target can be adjusted. No. 9013.

However, the proposed method has a problem that in order to actually start an operation for focus adjustment with respect to a selected target, another operation for the operation is required, and the operation becomes very complicated. was there.

The present invention has been made in view of the above circumstances, and provides a focus adjustment device capable of selectively forming a signal for focus adjustment for a plurality of targets. It is an object of the present invention to provide a focus adjusting device capable of forming a signal for focus adjustment quickly and efficiently.

Means for Solving the Problems In order to achieve the above object, the present invention provides a focus adjustment device for selectively forming a signal for focus adjustment for a plurality of targets. Target selection means for arbitrarily selecting a target to form a signal of, and automatically activated in response to a selection operation of the target selection means, for focusing on the target selected by the target selection means. And a signal forming means for forming the above signal.

Embodiment 1 An example of a focus detection optical system having a plurality of focus detection (target) regions according to the present invention will be described with reference to FIG.

In FIG. 4, _Lo is a projection lens, and _La and _Lb are areas on the pupil plane of the projection lens _Lo through which the focus detection light flux passes. Reference numeral 21 denotes a focus detection area mask disposed immediately after the planned focal plane. Openings 21a, 21b, and 21c formed in the focus detection area mask 21 define three focus detection areas 11, 12, and 13 on the projection screen. (See Fig. 5).

Openings 21a, 21b and 2 on the focus detection area mask 21
Immediately after 1c, condenser lenses 22a, 22b and 22c are arranged, respectively. These condensers 22a, 22b and 22c
Is one which forms an aperture mask 23a~23f in the exit pupil of the projection lens L _o. That is, the aperture masks 23a and 23b
Is a condenser lens 22a, and respectively focused on the regions L _a and L _b in the exit pupil of the projection lens L _o, aperture mask 23c and 23d
It is by the condenser lens 22b, respectively imaged region L _a and L _b in the exit pupil of the taking lens L _o. Also, the aperture mask 23
e and 23f are projected lens L _o by the condenser lens 22c.
Respectively imaged region L _a and L _b in the exit pupil. in this way,
Diaphragm mask 23a~23f is taking lens L _o focus detection light beam region L _a at the exit plane of, but to determine the L _b.

Immediately after the aperture masks 23a to 23f, the imaging lenses 24a to 24f
Are arranged respectively. These imaging lenses 24a-24f
Is for secondary imaging the image formed on the line sensor 26 in the vicinity of the focal plane F of the photographic lens L _o. The cylindrical lens 25 disposed immediately after the imaging lenses 24a to 24f has a refracting power only in a direction orthogonal to the direction in which the aperture masks 23a to 23f are arranged, and reduces an image in that direction on the run sensor 26 to form an image. Image. This cylindrical lens 25
Since the vertical direction of the line sensor 26 is shorter than the horizontal direction (the direction in which the aperture masks 23a to 23f are arranged), the focus detection area is enlarged in the vertical direction by reducing the vertical image from the horizontal direction. But not required. 26a-26c
An image sensor composed of a one-dimensional sensor such as a CCD.The sensor 26a is formed at a position for receiving an image formed by the imaging lenses 24a and 24b, and the sensor 26b is formed by the imaging lenses 24c and 24d. At a position for receiving an image, the sensor 26c is disposed at a position for receiving an image formed by the imaging lenses 24e and 24f, respectively. Therefore, the sensors 26a, 26b, and 26c are provided in three different areas (focus detection areas 11, 12, and 13) on the photographing screen.
, The distance can be measured separately.

FIG. 5 is a view showing an example of the display in the viewfinder. In FIG. 5, reference numeral 10 denotes the entire field-of-view image, and small areas 11, 12, and 13 indicated by dotted lines (or solid lines) indicate distance measurement areas. I have. In this embodiment, three ranging areas are shown, but the invention is not particularly limited to this.
The above-mentioned area display is constituted by a display element such as a guest-host liquid crystal, for example, and is colored by energizing the display element of the distance measurement area selected by the distance measurement switching operation described later, and is selected in the finder. The distance area can be checked. FIG. 5 shows a state in which the distance measurement area 11 indicated by a solid line is selected (colored).

FIG. 2 is a perspective view showing the external appearance of the camera according to the present embodiment. The AF-M switch lever 4 has a manual focus ring used for focus operation during manual focus,
Reference numeral 5 denotes a known release switch composed of a two-stage switch that performs photometry and distance measurement in the first stroke and releases the light in the second stroke.

FIG. 3 is a diagram for explaining details of the AF-M switching mechanism of the present embodiment. 3 is an AF-M switching lever shown in FIG. 2, and 4 is a manual focus ring similarly shown in FIG. Reference numeral 6 denotes a motor for driving the focus lens 8 in response to a control signal from a control circuit (not shown) of the camera body during AF, and a transmission gear 31 and 33 rotatably fixed to the gear train 7 and then to the AF-M switching lever. The driving force of the motor 6 is transmitted to the gear portion 81 of the focus lens 8 via the.

The AF-M switching lever 3 has an arm 3a integrally extended therefrom, and the tip thereof faces the inner peripheral surface of the manual focus ring 4 in the state of AF shown in FIG. And a pair of distance measurement area switching switches 34 and 35 are provided on both sides in the circumferential direction. On the inner periphery of the manual focus ring 4, the distance measurement area switching A projection 42 is provided for operating the switch 34, 35 by engaging the same. The switches 34 and 35 and the protrusion 42 of this example are
In a state illustrated in FIG., The first state of the switch 34, 35 Izu insertion also is turned off, the projections 42 of the manual focus ring 42 is rotated in the D ₁ direction in FIG engaged with the switch 34, which a second state when the is turned on, and the protruding portion 42 by the manual focus ring 42 is rotated in the D ₂ direction in FIG engaged with the switch 35 in the opposite, third state when turning on this In this way, a total of three states can be selected, whereby any one of the small areas 11, 12, and 13 indicating the distance measuring area shown in FIG. 5 can be selectively colored.

Further, in the configuration of the present example, the gear train 7 for AF driving and the transmission gear 31 are disengaged by moving the AF-M switching lever 3 in the direction D3 in FIG. ₃ , and the manual focus operation can be performed. As described above, the switches 34 and 35 are provided at the tip of the arm 3a integrally extended from the AF-M switching lever 3 as described above.
So that the outside also facing relationship with the switches 34, 35 and the manual focus ring 4 by the movement of the D ₃ direction of Fig of M switching lever 3.

Therefore, even if the manual focus ring 4 is rotated, the switches 34 and 35 are not turned on and off.
Further, by this switching, the transmission gear 32 rotatably fixed to the AF-M switching lever 3 is engaged with the gear portion 41 of the manual focus ring 4, and thus the transmission gears 32 and 33 are rotated by the rotation of the manual focus ring. , The focus lens 8 can be driven.

FIG. 1 is a circuit block diagram for explaining the relationship between the operation of selecting and switching the distance measurement area in the present embodiment and the operation of focus adjustment operatively associated therewith. In this figure, 101 is a CCD (corresponding to reference numeral 26 in FIG. 4) which is a distance measuring element, 106 is a CCD drive circuit for driving and controlling this CCD, and 102 is a distance measuring area changeover switch 107 (FIG. 3). Sign 3 of
4, 35) corresponding to the distance measurement area (for example,
A selection circuit for selecting a signal of the CCD 101 corresponding to reference numeral 11) in the drawing, a known arithmetic circuit 103 for calculating a signal from the selected CCD and calculating a movement amount of the lens, and a motor 105 (Corresponding to reference numeral 6 in FIG. 3) a motor drive circuit for driving the motor;
Display element 109 corresponding to the ranging area selected by 07
(Corresponding to reference numerals 11, 12, and 13 in FIG. 5). Reference numeral 110 denotes a motor control circuit, which controls the motor drive / stop rotation amount by a lens movement amount signal output based on the distance measurement information calculated by the arithmetic circuit 103 in accordance with the signal from the distance measurement area changeover switch 107. Control.

In this block circuit of the present example, a signal from the distance measurement area changeover switch 107 is input to the motor control circuit 110, and when the distance measurement position is selectively switched by this, a predetermined The focus adjustment operation based on the distance measurement information is performed immediately. That is, in a normal camera, the focus adjustment operation is started by pressing the release switch up to the first stroke, and the distance measurement operation is completed when the photographing lens reaches the focus position.

For this reason, when switching the ranging area, the release switch is newly turned off after switching the ranging area,
It is necessary to depress the release switch to the first stroke again, and the operation is very complicated.

The present invention effectively switches the distance measurement area without any extra operation.

That is, the first method is to start a new focus adjustment operation based on the switching information from the distance measurement area switch while keeping the release switch pressed down to the first stroke. The second method is as follows. Regardless of the release switch, a new focus adjustment operation is started based on the switching information from the distance measurement area switch,
If the focus adjustment operation is completed when the photographing lens reaches the in-focus position, multipoint ranging can be performed effectively.

For example, assume that the case where the ranging area 12 at the center of the finder in FIG. 5 is selected is assumed to be a standard state, and the case where the switch 34 or 35 in FIG. 3 is turned on (selection of the ranging area 11 or 13). At the time of switching, focus adjustment of a pre-selected distance measurement area is performed by pressing a normal release button. When the distance measurement area is switched, a signal based on whether the distance measurement area changeover switch 34 or 35 is turned on or off is input to the motor control circuit 110, and a focus adjustment operation based on predetermined distance measurement information is started. .

Usually, the ranging area is often used in the standard state at the center. Therefore, the standard state may be initially set only when the mode is switched from the manual focus mode to the automatic focus mode.

Next, the operation of the above-described embodiment will be described. First, power is supplied to each circuit by turning on a power supply (not shown). Look through the viewfinder to determine the composition for shooting. At this time, for example, it is assumed that the manual focus ring 4 is in the state shown in FIG. 3 and the distance measurement area is displayed at 12, and the focus is adjusted by pressing the release switch to the first stroke, but the focus is on the background, and It is assumed that the intended main subject is large blur and the composition is not well understood. Therefore, in this case, by turning the manual focus ring 4 counterclockwise, the distance measurement area changeover switch 34 is turned on.
Turn on. As a result, the display selection control circuit 108 turns off the display of the distance measurement area 12 and displays the distance measurement area 11.
At the same time, the selection circuit 102 selects a CCD corresponding to the distance measurement area 11 according to the ON signal of the distance measurement area changeover switch 34, and the arithmetic circuit 103 calculates the CCD.
To output a signal of a predetermined lens movement amount. Further, a signal from the distance measurement area changeover switch 107 is also input to the motor control circuit 110, whereby the motor control circuit 110 outputs a lens movement amount and a drive start signal to the motor drive circuit to drive the motor. The driving force of this motor is transmitted to the focus lens 8 via the gear train 7 transmission gears 31 and 33 as described above. This allows the finder to see an image that is in focus on the main subject, so that the composition can be determined instantaneously.

When manual focusing is desired, the gear train 7 and the transmission gear 31 are disengaged as described above by switching the AF-M switching lever 3 to the M side, and the AF-M
The distance measurement area changeover switches 34 and 35 of the M changeover lever 3 are deviated from the position corresponding to the protrusion 42 of the manual focus ring 4. When the manual focus ring 4 and the transmission gear 32 are engaged with each other and the manual focus ring is rotated, the focus lens 8 can be driven via the transmission gears 32 and 33 without a load caused by motor yucking.

Second Embodiment In the device shown in the first embodiment, three specific points can be measured. However, considering the case where distance measurement can be performed at more positions, there is no problem if you can directly select the position you want to measure (it is almost impossible to select directly while looking through the viewfinder from the actual operation), For example, it is common to select in order as shown by reference numerals in FIG. 6, which simplifies the configuration of the apparatus. However, for example, when it is desired to focus on the distance measurement position, if the same as in the first embodiment, if the distance measurement position is first, the manual focus ring is rotated to focus on the distance measurement position. Similarly, by rotating the manual focus ring, the focus is sequentially adjusted to, and the operation becomes very complicated. Therefore, if a predetermined delay circuit (timer, etc.) 111 is provided in a signal system for linking the signal indicating that the ranging position has been switched and the operation of detecting the focus, for example, as shown in FIG. With this delay circuit, it is possible to determine whether switching is being performed or whether the distance measurement position has been set. This can eliminate the complexity of switching the distance measurement position.

According to the present embodiment, the complexity of the ranging position switching operation can be eliminated by providing the delay means between the ranging position switching signal and the start of the new focus adjustment. If the display in the viewfinder is delayed by the delay means, the timing of the display in the viewfinder when the ranging position is switched is shifted, which complicates the operation. Therefore, as described above, the ranging position switching signal and the start of the focus adjustment are used. It is preferable that the display in the viewfinder be switched immediately by switching the distance measurement position by providing a delay means between the two.

Third Embodiment The effect of eliminating the complexity of the ranging position switching operation by providing the delay means between the ranging position switching signal and the start of focus detection shown in the second embodiment can be obtained by other configurations. it can. That is, a new focus adjustment is performed by the ranging position switching signal, but when the ranging position switching signal comes subsequently, the focus adjustment and lens driving during operation are immediately interrupted, and a priority circuit for prioritizing the ranging position switching signal is provided. If it is provided, a similar effect can be obtained. Further, the use of this priority circuit is advantageous in that it can cope with a case where the photographer is hesitant to switch the distance measurement, and can eliminate the delay caused by the delay means. In the circuit shown in FIG. 1, when a switching signal of the distance measurement area changeover switch 107 is input to the motor control circuit 110, the motor control circuit 110 having a built-in priority circuit (not shown) determines the last drive amount. The operation is stopped, and the lens is driven again by the lens movement amount signal of the arithmetic circuit 103 for this time.

(Correspondence between Invention and Embodiment) In the above embodiment, the distance measurement area changeover switch 107
Are the selection circuit 102 and the arithmetic circuit 103 as target selection means of the present invention.
Are the signal forming means of the present invention, the motor driving circuit 104, the motor 105, and the motor control circuit 110 are the lens driving means of the present invention, the delay circuit 111 is the time measuring means of the present invention, the display selection control circuit 118, the display element 109. Correspond to the display means of the present invention.

[Effects of the Invention] As described above, in a focus adjustment device capable of selectively forming a signal for focus adjustment with respect to a plurality of targets, a new focus adjustment is automatically performed by selecting the target. By forming a signal and further disclosing a lens drive based on the signal, the conventional complexity of having to perform both the operation of selecting the target and the operation of starting the focus adjustment operation can be eliminated and used. There is an effect that an operation for focus adjustment can be promptly performed with good operability on a target intended by the user.

Further, by providing a time measuring means for delay between the selection of the target and the start of the new lens driving, it is possible to eliminate an effect that unnecessary driving of the lens is started during the target selection. can get. Further, in this case, by displaying the target selection position in the viewfinder without using a time measuring means for delay, there is an effect that a deviation between the timing of the target selection operation and the timing of the target selection confirmation can be eliminated.

Further, by making the target selection prior to signal formation for focus adjustment or lens drive for focus adjustment, the composition can be determined quickly if used for a camera, for example.
Effects such as not missing a photo opportunity can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit according to a first embodiment of the present invention for explaining a link between a distance measurement position switching operation and a focus adjustment operation, FIG. 2 is an external perspective view of a camera, and FIG. FIG. 4 is a view showing an example of a focus detection optical system, FIG. 5 is a view for explaining a state of display in a finder according to the first embodiment, and FIG. 6 is an embodiment. FIG. 7 is a diagram for explaining the state of display in the finder of FIG. 2, and FIG. 7 is a block diagram showing a circuit of Embodiment 2 having a delay circuit. DESCRIPTION OF SYMBOLS 1 ... Camera main body 2, ... Shooting lens 3 ... AF-M switch lever 4 ... Manual focus ring 5 ... Release switch, 6 ... Motor 7 ... Gear train 8 ... Focus lens, 10 ... Field of view Entire image 11, 12, 13… Small area 21… Focus detection area mask 21 a-21 c… Focus detection area 22 a-22 c… Condenser lens 23 a-23 f… Aperture mask 24 a-24 f… Imaging lens 26… ... Line sensors 26a-26c ... Image sensors 31,32,32 ... Transmission gears 34,35 ... Switches, 41 ... Gear parts 42 ... Protrusion parts, 81 ... Gear parts

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Juichi Tsunekawa 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Inside the Tamagawa Office of Canon Inc. (56) References JP-A-58-9913 1-133113 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02B 7/11

Claims (7)

(57) [Claims] A focus adjustment device capable of selectively forming a signal for focus adjustment with respect to a plurality of targets, wherein a target for arbitrarily selecting a target for forming a signal for focus adjustment is provided. Selecting means, and signal forming means which automatically starts in response to a selecting operation of the target selecting means and forms a signal for focus adjustment with respect to the target selected by the target selecting means. Focus adjustment device. 2. The apparatus according to claim 1, further comprising a lens driving unit that automatically starts in response to a selection operation of said target selection unit and drives a lens according to a signal from said signal forming unit. Focus adjustment device. 3. The focus adjusting device according to claim 2, wherein said lens driving means has time measuring means for starting operation after a lapse of a delay time from a selection operation of said target selecting means. 4. The lens driving device according to claim 1, wherein the second selecting operation of the target selecting device is performed before the delay time elapses after the first selecting operation of the target device. 4. The focus adjusting apparatus according to claim 3, wherein the lens driving is not performed in accordance with a signal from the signal forming unit with respect to the target selected in step (a). 5. The focus adjusting device according to claim 3, further comprising display means for displaying a state of the selection of the target selecting means before the elapse of the delay time after the selection operation of the target selecting means. 6. The lens driving means stops the lens driving operation when the target selecting means is selected during the lens driving operation, and stops the lens driving operation with respect to the target selected by the target selecting means. 4. The lens drive according to claim 2, wherein the lens is driven in accordance with a signal from the signal forming means.
The focus adjusting device according to 4 or 5. 7. When the target selecting means is selected during the signal forming operation for focus adjustment, the signal forming means stops the signal forming operation, and the signal forming means is selected by the target selecting means. The focus adjustment apparatus according to claim 1, wherein a signal for focus adjustment is formed with respect to the target.