JPH0216343Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a focus adjustment device, and particularly to a focus adjustment device that can adjust the focus of a photographic lens of a camera or the like in an automatic focus adjustment mode and a manual focus adjustment mode. Conventionally, this type of focus adjustment device used automatic focus adjustment mode to adjust the focus, but when it became difficult to do so, it was possible to switch to manual focus adjustment mode and adjust the focus in that mode. be. An example of such a device is the one described in Japanese Patent Laid-Open No. 54-97017. In this device, the focus of the photographic lens is first adjusted in automatic focus adjustment mode, and when manual focus adjustment becomes necessary, the user operates a switch to turn off the automatic focus adjustment circuit. Next, another switch is operated to operate the photographing lens drive motor to perform manual focus adjustment. Here, manual focus adjustment means that the focus is adjusted at the photographer's will by cutting off the relationship between the output of the focus detection means and the photographic lens driving motor. However, when the above-mentioned device is applied to a type of focusing device in which the photographing lens follows the movement of the subject in real time, automatic mode and manual mode are often used alternately in a series of shootings. It becomes necessary to operate a changeover switch each time to switch between automatic mode and manual mode. This makes the operation complicated and becomes a major obstacle in operation. In order to eliminate such obstacles, the present invention aims to make it possible to use automatic mode and manual mode properly without performing a switching operation. Therefore, in the device of the present invention, even when the focus is adjusted in automatic mode, the lens drive means is prevented from responding to the output of the focus detection means in response to an external operation, and a manual lens drive signal is generated to manually adjust the focus. Allows focus adjustment in mode. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 generally shows an embodiment of the invention.
A pair of re-imaging lenses 2 and 3 are arranged symmetrically with respect to the optical axis of the photographing lens 1. A portion of the light flux that has passed through the photographic lens 1 is guided via re-imaging lenses 2 and 3 onto the light receiving surfaces of a pair of photoelectric conversion elements 4 and 5, respectively. As the pair of photoelectric conversion elements 4 and 5, a photoelectric conversion element array that acts as a photoelectric converter for image position detection can be used. The processing circuit 6 inputs the output signals of the elements 4 and 5 from terminals a and b, respectively, and compares both outputs to determine the front pin,
Shooting lens 1 in either rear focus or in-focus state
The focus detection output is sent to terminals d and e.
Output to. The re-imaging lenses 2 and 3, the photoelectric conversion elements 4 and 5, and the processing circuit 6 constitute the focus detection means of the present invention. The limit signal output device 7 is connected to the photographic lens 1
When the photographic lens 1 reaches a close-up position or a position where it is focused on an infinite distance, a signal is sent to the processing circuit 6 via the terminal c. The processing circuit 6 inputs this signal and performs processing to drive the photographing lens 1 in a desired direction. The manual mode interrupt logic 8 and the external operation switches S∞ and S _N constitute the manual lens drive signal generating means of the present invention. The switch S∞ generates a signal to move the photographing lens 1 in a direction to focus on infinity in response to an external operation. Switch S _N responds to external operations.
A signal is generated to move the photographing lens 1 in a direction to focus on a close position. Switch S _N and S∞ are both
When it is OFF, the manual mode interrupt logic 8 does not act on the focus detection signal from the processing circuit 6, and the signal is directly transmitted to the motor drive circuit 11, and the motor drive circuit 11 constituting the lens drive means The motor 12 is operated to move the lens 1 to the in-focus position via the gear train 13.
This time is the automatic focus adjustment mode. Next, when the switch S _N is turned on and the switch S∞ is turned off, the manual mode interrupt logic 8 cuts off the output of the processing circuit 16, transmits the signal generated by the switch S _N to the circuit 11, and sends the signal to the photographing lens. 1 in the direction to focus on the closest position. On the other hand, Switch S∞
When the switch _S∞ is turned on and the switch S Move in the direction of focus. Finally, switch S _N , S∞
When both are turned ON, the manual logic interrupt circuit 8 sends the lens drive stop signal to the motor drive circuit 11.
is applied to stop the photographing lens 1. Note that a single seesaw switch can be used instead of the two independent switches S _N and S∞, but in this case, it is not possible to turn on the switches S _N and S∞ at the same time, so it is not possible to use the manual switch as it is. In this mode, the movement of the photographing lens 1 cannot be stopped by the motor drive circuit 11. The above is the manual focus adjustment mode. These operations can be summarized as shown in Table 1 below.

[Table] Next, a specific example of the circuit of this embodiment will be described. FIG. 2 shows a specific example of the processing circuit 6. As shown in FIG. Outputs from photoelectric elements 4 and 5 are input to input terminals a and b, respectively. Those values are transmitted to a comparator 101 via a differential amplifier 100,
102 and compared with threshold voltages Vr ⁺ and Wr ^- . On the other hand, the comparator 111,
The voltage is input to gate 112, compared with threshold voltage Vr ⁺ , and its output is input to gate 113. and,
Since the outputs of the comparators 101 and 102 and the gate 113 described above are input to the gate 114,
The gate 114 is L when focusing and H otherwise.
Output. Therefore, gates 115, 116
When the output of gate 114 is L, both output L regardless of the output of flip-flop 110, and when the output of gate 114 is H, the output of flip-flop 110 is output as is. Also, the outputs of the comparators 101 and 102 are the gate 10
8,109 is also input, and the flip-flop 11
0 as a signal instructing the rotation direction of the motor 12. Further, according to the position of the photographic lens 1, the input terminal c is applied with either Vc.c at the close limit position, ground at the infinite limit position, or open at other positions by the limit signal output device 7. and gate 1
03 and 104 receive the Q and output of the flip-flop 110 and the output of a transistor group that varies depending on the c input, and invert the output of the flip-flop 110. Now, when terminal c is open, conductive wires 105 and 10 are connected to gates 103 and 104.
Vcc is input through 6, but it is not connected to terminal c.
When Vcc is applied, gate 104 connects conductor 106
Since the ground is input through the gate 109, only when the output of the flip-flop 110 is L, that is, only when the motor 12 is driving the photographing lens 1 from infinity to close range, the output of the gate 104 is input to the flip-flop 110 through the gate 109. inverts the output of Note that even if the terminal c is applied to Vcc, the flip-flop 110 will not be reversed if the rotation direction of the motor 12 is reversed. Similarly, when ground is applied to terminal c, gate 1
Since the ground is input to 03 through the conductor 105, the output of the gate 103 inverts the output of the flip-flop 110 only when the motor 12 is driving the photographing lens 1 from close range to infinity. Thus, AND gate 115,1
The outputs of flip-flops 110 and 114 are input to 16, and the outputs are transmitted to terminals d and e. In the out-of-focus state, the terminals d and e output different signals, either H or L, depending on the direction in which the photographing lens 1 is driven. In the focused state, both terminals d and e become L. FIG. 3 shows a specific circuit example of the motor drive circuit 11 in FIG. 1, and the input/output terminals f,
g, h, and i are the same as in FIG. In the figure,
When both terminals f and g are L, transistor 1
20 and 122 are turned off and the transistor 121
and 123 are turned ON, terminals b and i are short-circuited, and the motor 9 connected between them is stopped.
When terminal f outputs H and terminal g outputs L, transistors 121 and 122 are on, transistors 120 and 123 are off, and current flows from terminal i to terminal h via motor 12, and the motor Reference numeral 12 rotates the photographing lens 1 so as to move it in a direction to focus on a nearby object. When the terminal f is L and the terminal g outputs H, the opposite is true. FIG. 4 shows a specific circuit example of the manual mode interrupt logic 8 shown in FIG. This circuit consists of power supply Vcc, external operation switch S _N , S∞, switch
ANP gates 130, 131 and inverters 132, 13 constitute means for cutting off the output of the focus detection means when either S _N or S∞ is operated.
3. OR gate 134, 135, switch S _N , S
It consists of a NAND gate 136 and AND gates 137 and 138, which constitute means for generating an output that stops driving the photographing lens when ∞ is operated. Next, the operation will be explained. First, the automatic focus adjustment mode will be explained. Now, when both switches S _N and S∞ are OFF,
Since Vcc is applied to both input terminals on one side of AND gates 130 and 131, AND
Gates 130 and 131 output signals equivalent to the input signals from terminals d and e, respectively. Further, since Vcc is also input to inverters 132 and 133, their outputs both become L. Therefore, the OR gate 134 which receives the output of the AND gate 130 and the output of the inverter 133 outputs a signal equivalent to the signal from the terminal d, and the OR gate 135 receives the output of the AND gate 131 and the inverter 1.
The NAND gate 136 outputs H as the logical sum of the inverters 132 and 133, and outputs a signal equivalent to the signal at the terminal e. The H output from this NAND gate 136 is
AND gates 137 and 138 are input to each, so AND gates 137 and 138 are
The outputs of OR gates 134 and 135, that is, the signals at terminals d and e, are output as they are to terminals f and g.
Thus, when the operating switches S _N and S∞ are both OFF, the manual mode interrupt logic 8 outputs signals equivalent to the signals at the input terminals d and e to the output terminals f and g. In this case, the photographing lens 1 is driven by the motor drive circuit 11 in automatic focus adjustment mode. Next, the manual focus adjustment mode will be explained. First, turn on the switch S _N , and turn the switch S∞
When turned off, AND gate 130 outputs a signal equivalent to terminal d, inverter 132 outputs L, AND gate 131 outputs L, inverter 133 outputs H, and OR gate 134 outputs L.
outputs H, OR gate 135 outputs L,
AAND gate 136 outputs H, AND gate 137 outputs H, and AND gate 138 outputs L. Therefore, in this case, the output terminal f outputs H and the output terminal g outputs L regardless of the signals at input terminals d and e. This output is transmitted to the lens drive circuit 11, and the photographing lens 1 is driven so as to focus on a close position. Conversely, turn on the operation switch S∞ and turn off S _N.
Similarly, the output terminal f outputs L and the output terminal g outputs H, regardless of the signals at input terminals d and e. Therefore, this signal is transmitted to the lens drive circuit 11.
, and the photographing lens 1 is driven in manual mode so as to focus at infinity. Finally, both operation switches S _N and S∞ are turned on.
In the case of a structure that allows both to be turned ON, output terminals f and g both output L regardless of the signals at input terminals d and e. Therefore, this output is transmitted to the lens drive circuit 11, and the photographing lens 1 is stopped. Taking advantage of this, turn on both switches after focusing on a specific subject in automatic focus adjustment mode.
Then, the lens is fixed in that position from now on, so a so-called focus lock becomes possible. Next, FIG. 5 shows another embodiment of the manual mode interrupt logic 8 shown in FIG. 1, and the feature of this circuit is that it does not use any active elements. In the figure, input/output terminals d, e, f, g and operation switches S' _N and S'∞ are the same as in FIG. 1. First, the automatic focus adjustment mode will be explained. Now, if we turn off both the operation switches S′ _N and S′∞,
A conductive member 148 fixed to the operation switch S′∞,
149 makes electrical contacts 140 and 145 and electrical contacts 141 and 144 equipotential, respectively, and operates the operation switch.
Conductive members 158 and 159 fixed to _S
4 to have the same potential, the signals at the input terminals d and e are transmitted as they are to the motor drive circuit 11 shown in the third diagram via the output terminals f and g, respectively. Therefore, in this case, the photographing lens 1 of FIG. 1 is controlled in automatic focus adjustment mode according to the output of the processing circuit 6. Next, the manual focus adjustment mode will be explained. The following describes the case where the operation switch S∞ is turned off and the operation switch S _N is turned on, as shown in FIG. In this case, input terminals d, e
Regardless of the signal, the output terminal f has an electrical contact 152, a conductive member 159, and an electrical contact 157.
Vcc is applied to the output terminal g, and ground is applied to the output terminal g via the electrical contact 156, the conductive member 158, and the electrical contact 153. Therefore, the photographing lens 1 in FIG. It is driven in the direction to focus on the subject at the position. Conversely, turn on the operation switch S∞ and turn the switch
When S _N is turned OFF, the ground is connected to the output terminal f.
Since Vcc is applied to g, the photographing lens 1 of FIG. 1 is driven in a direction so as to focus on an object at an infinite distance. In addition, if the structure is such that both operation switches S _N and S Therefore, the photographing lens 1 stops at that position. In addition, although the operation switches S _N and S∞ are shown as rotary switches in the figure, this is used to explain the principle, and in reality, as shown in FIG. 7 below, It would be more convenient to use an automatic return type push button switch or seesaw switch. In this embodiment, by creating the logic without using active elements, it is possible to expect a significant cost reduction. When all circuits are integrated into a lens barrel or an equivalent focusing lens drive adapter,
It has many advantages, such as not only preventing the circuit to be built from becoming too large, but also eliminating the need for an IC power supply or booster circuit in some cases. FIG. 6 shows yet another embodiment of manual mode interrupt logic 8. In this embodiment, a lens drive limiting means, that is, a resistor R 1 , detects that the photographic lens ₁ has reached an infinity or close focusing position and generates a signal to stop the driving of the photographic lens 1 at that time. ~R ₄ , comparator 160,1
61, inverter 162, 163, OR gate 1
64, 165, and an AND gate 166. The other configurations are similar to the circuit shown in FIG. Next, the operation will be explained. Now, when the photographing lens 1 in FIG. 1 reaches the nearest limit or a position corresponding thereto, the potential of the input terminal c becomes H. Therefore, resistance
If the resistance values of R ₁ to _{R 4} are set as R ₁ > R ₂ > R ₃ > R ₄ , comparators 160 and 161
Both outputs become L. Further, when the photographing lens 1 reaches the infinite limit or a position corresponding thereto, the potential of the input terminal c becomes L, and the outputs of the comparators 160 and 161 both become H. When the photographing lens 1 is located between the infinite limit and the close limit, that is, when the input terminal c is open, the output of the comparator 160 is H,
The output of comparator 161 becomes L. The OR gate 164 outputs L only when the photographing lens 1 is in the close range limit, the comparators 160 and 161 output L, and the operation switch S _N is ON and outputs L, and at other times. is H.
In the OR gate 165, when the photographing lens 1 is at the infinite limit, the comparators 160 and 161 output H, and both outputs are negated by the inverters 162 and 163, and both become L, and the operating switch S
It outputs L only when ∞ is ON and outputs L, and at other times it outputs H. Therefore, AND gate 1 with OR gates 164 and 165 as inputs
66 is when the shooting lens 1 is at the infinite limit and the switch S∞ is ON, or when the shooting lens 1
is at the close limit and the switch S _N is ON, outputs L, which is the AND gate 167,1
68 and output terminals f and g are both set to L,
Stop the motor drive. In addition, in other cases, the AND gate 166 outputs H, so
AND gates 167 and 168 are AND gate 166
The embodiment of FIG. 4 becomes an equivalent logic system, regardless of the input from. As described above, in this embodiment, when the photographing lens 1 reaches a close position or a position where it focuses at infinity, the driving of the lens 1 is forcibly stopped. Moreover, it has the advantage that this can be achieved without providing a special clutch mechanism. Figure 7 shows the operation switch S∞ of the device of the present invention.
FIG. 3 is an external view of an example in which an _SN is incorporated into a lens drive adapter. The entire device shown includes an adapter body 169, a member 170 for attaching the adapter 169 to a lens barrel, camera body, or other fixing member, and a lens barrel 1.
71 and a camera 172. Operation switch S _N ,
S∞ is the operating switch S _N and S∞ shown in Fig. 1, Fig. 4, Fig. 5, and Fig. 6, respectively, and is normally pushed upward by a spring member not shown. The structure is such that they both remain in the OFF state, are turned on by manually pushing down, and return to the OFF state when released. Figure 8 shows the operating switches S _N and S of the device of the present invention.
FIG. 2 is an external view of an embodiment in which ∞ is incorporated into a camera. In the figure, a camera 173 includes operation switches S _N and S∞. Figure 9 shows the operation switch S∞ of the device of the present invention.
FIG. 3 is an external view of an embodiment in which the _SN is assembled into a lens barrel. In the figure, a lens barrel 175 is attached to a camera body 174, and switches S _N and S∞ are built into the lens barrel 175. In this embodiment, the camera body itself, or if the exchangeable viewfinder is removably attached to the camera body, the camera body and the exchangeable viewfinder are both referred to as a camera. Figure 10 shows an example of display of shooting information in the viewfinder. When the control system is under the control of auto mode, there are two types of display: a compatible state, a state deviated from that state to one side, and a state deviated from that state to the other, such as the output of a light meter. It functions as a display that shows the state of deviation. In the figure, a display element 176 indicating the closest direction and a display element 180 indicating the infinite direction are located on both sides, and the display element 177 lights up when the front focus is on, and the display element 179 lights up when the rear focus is on. The display element 178 lights up in the focused state. Then, when the control system is under the control of the manual mode, when the operation switch S∞ shown in FIG. 1 is turned ON, the display element 177 lights up, and when the operation switch S _N is turned ON, the display element 1
79 lights up, and each becomes a display for displaying the moving direction of the photographing lens 1. In addition, the operation switch
If the structure is such that S _N and S∞ can be turned on at the same time, the display element 17 can be turned on at the same time.
7 and 179 light up at the same time. Note that the display elements 176 to 180 shown in this figure are display elements that respond to electrical signals, such as LEDs, liquid crystals, and electrochromic elements. The present invention has been described above with reference to embodiments.
However, it is clear that various obvious changes can be made without departing from the scope of the present invention as described in the claims of the utility model registration of this application. For example, in this embodiment, an example was shown in which the device of the present invention is incorporated into a lens drive adapter, a camera, or a lens barrel, but the same function can also be obtained by incorporating it into a unit that can be attached to and detached from a camera. Needless to say. Also, in this embodiment, Vcc and ground were used for the signals generated by the switches S _N and S∞, but
Other signals may be used as long as both signals can be distinguished from each other. Regarding the distance measurement method, although the TTL method was used in this embodiment, the present invention can also be implemented in a focus adjustment device using other distance measurement methods such as an external light method or an active method. . As described above, according to the present invention, it is possible to switch between the manual focus adjustment mode and the automatic focus adjustment mode without operating a dedicated switch, making it easy to operate and adjusting the shooting lens according to the movement of the subject. This has the effect of making it possible to adapt to focus adjustment that follows in real time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an overall example of an embodiment of the present invention, FIG. 2 is a diagram showing a specific circuit example of a processing circuit, and FIG. 3 is a diagram showing a specific circuit example of a motor drive circuit. FIG. 4 is a diagram showing a first specific circuit example of manual mode interrupt logic,
Figure 5 shows the second manual mode interrupt logic.
FIG. 6 is a diagram showing a third specific circuit example of the manual mode interrupt logic, and FIG. 7 is a diagram showing a third specific circuit example of the manual mode interrupt logic. FIG. 8 is a diagram illustrating an example in which the device of the present invention is incorporated into a camera body, and FIG. 9 is a diagram illustrating an example in which the device of the present invention is incorporated in a lens barrel. FIG. 10 is a diagram illustrating the display in the finder. Explanation of symbols of main parts, 2 to 6... Focus detection means, 11 to 13... Lens driving means, S∞, S _N
...External operation means, 132, 133, 136,
Vcc...means for generating a manual lens drive signal, 130, 131...switching means, 132, Vcc
...First signal generating means, 133, Vcc...Second signal generating means, S∞...First switch, S _N ...
Second switch, 136... Means for generating an output to stop, S∞, S _N ... First and second operating members,
R ₁ to R ₄ , 16 to 166...lens drive limiting means,
140, 141, 148, 149, 144, 14
5...first switching member, 150, 151, 15
2,153,154,155,156,157...
...Second switching member, Vcc...First signal generating element, Vcc...Second signal generating element.

Claims (1)

[Scope of Claim for Utility Model Registration] Focus detection means for generating a focus detection signal for moving the photographic lens to a focal position where the photographic subject image is focused in accordance with the focusing state of the photographic subject image by the photographic lens; , an external operating means; and while the external operating means is being operated;
means for generating a manual lens drive signal for bringing the photographic lens to a desired position; and photographic lens drive means for electrically moving the photographic lens in response to either the focus detection signal or the manual lens drive signal. , an automatic focus adjustment mode in which the focus detection signal is transmitted to the photographic lens drive means to drive the photographic lens in accordance with the focus detection signal; and an automatic focus adjustment mode in which the manual lens drive signal is transmitted to the photographic lens drive means to drive the photographic lens in accordance with the focus detection signal. a manual focus adjustment mode in which the photographic lens is driven in accordance with the manual lens drive signal; A focus adjustment device characterized in that the automatic focus adjustment mode is switched to the manual focus adjustment mode by blocking transmission of the detection signal and transmitting the manual lens drive signal instead.