JPS6246183Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display for an autofocus camera.

Conventionally, as a display device for an autofocus camera, one is known that displays a focus by lighting a lamp or LED when the camera is in focus. On the other hand, automatic focus cameras usually focus on the subject captured in the distance measurement field of view, and the distance measurement field of view is usually set at the center of the screen, so the camera only focuses when the subject is in the center of the screen. A match is made. Therefore, if you want to take a picture with the subject on the side of the screen, first focus on the subject at the center of the screen, use the focus lock operation to lock the lens in that position, and then move the subject to the side of the screen. It is necessary to compose the image and take the picture.

When trying to take a picture by composing the subject focused using this method on the side of the screen,
The distance measurement field of view is in a state where it is measuring a different object than the above-mentioned subject, so the display device makes a display for focusing on the object in that state, which is troublesome for the photographer and also causes trouble. The display is wasteful and results in unnecessary power consumption.

The present invention has been developed in view of the above-mentioned matters, and is an attempt to solve the above-mentioned problems by disabling the focus indicator in conjunction with the focus lock operation.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a detailed circuit diagram as an embodiment of the present invention, in which 1 is a known focus state detection device, for example, two rows of light receiving lines before and after a position conjugate to the focal plane of a single-lens reflex camera. The output is focused by arranging the element rows, calculating the difference in output between adjacent pixels in each light-receiving element row, calculating the total sum, and subtracting the sum of the differences in the output of each light-receiving element row. When the value at or near the focal plane is zero, when the focal point is in front of the focal plane (hereinafter referred to as front focus), there is a positive voltage proportional to the focal plane; conversely, when the focal point is behind the focal plane (hereinafter referred to as front focus), Similarly, the rear pin (referred to as the rear pin) outputs a negative voltage proportional to the differential focus. There are two comparators 9 and 10 which receive the output of the focus state detection device 1 as inputs, a driving amplifier 13 for driving the lens, and a driving inverting amplifier 14. 6, 7, and 8 are resistors connected in series, one end of which is connected to the power supply voltage +V _DD , and the other end connected to the power supply voltage -V _DD . The middle of the resistor 7 is grounded, one end has a +V (positive) voltage and is connected to the non-inverting input side of the comparator 9, and the other end has a -V (negative) voltage and serves as the inverting input of the comparator 10. connected to the side. The output of comparator 9 is used as an input to INHIBIT gate 17 and AND gate 11, and also as an input to INHIBIT gate 18.
are also applied to the inverting input side of each. The output of comparator 10 is input to INHIBIT gate 17 and AND gate 11, and its output is input to INHIBIT gate 19.
is applied to the inverting input side of The output of the comparator 9 is inverted from the "high" level to the "low" level when the output of the focus state detection device 1 detects the state of the front focus and reaches a voltage of +V or more. The output of the comparator 10 is inverted from a "high" level to a "low" level when the output of the focus state detection device 1 detects the state of the rear focus and reaches a voltage of -V or less. Therefore, both comparators 9 and 10 output "high" level signals when the voltage is in focus between +V and -V. Reference numeral 2 is a switch for autofocus locking, and reference numeral 3 is a pull-up resistor.When the lock is not engaged, the pull-up resistor causes the focus to go to a "high" level, and when it is locked, it becomes a "low" level. This signal is input to an inverter 4, the output of which is applied as an input to a NOR gate 12, INHIBIT gates 18 and 19, and its output is applied to the inverting input side of an INHIBIT gate 17, respectively. The output of the NOR gate 12 is given as a power source for the driving amplifier 13 and the driving inverting amplifier 14. The output of the INHIBIT gate 18 is connected via a front pin display element 20 to a current limiting resistor 23 which is connected to a power supply.
The output side of the INHIBIT gate 17 is connected to a resistor 23 via a focus display element 22. INHIBIT
The output side of the gate 19 is connected to a resistor 23 via a rear pin display element 21. 5 is inverter 4
This line is for supplying the output of 15 and 1.
6 is an output terminal of each of the driving amplifier 13 and the driving inverting amplifier 14. A lens drive mechanism (not shown) is connected between these terminals 15 and 16.

Next, the operation of the circuit having such a configuration will be explained. Switch 2 for auto focus lock when non-auto focus lock
Since the line 5 is open, the pull-up resistor 3 and the inverter 4 cause the line 5 to be at a "low" level. The output of AND gate 11 is “low” except when in focus.
The output of the NOR gate 12 becomes a "high" level together with the "low" level of the line 5, and the drive amplifier 13 and the drive inverting amplifier 14 for driving the lens drive mechanism and adjusting the focus. Allow output, for example, in the case of the front pin, 1
Since positive signals are input to both amplifiers 3 and 14, a "high" level is output to terminal 15 and a "low" level is output to terminal 16 to drive the lens drive mechanism and move the lens in the focusing direction. Automatically adjust. When the output of the focus state detection device 1 falls within the focus tolerance range between +V and -V, both the outputs of the comparators 9 and 10 become "high" level, and the AND gate 1
The output of 1 also becomes "high" level, and the output of NOR gate 12 becomes "low" level, so 13,
Since the power supplies of both amplifiers No. 14 are at a "low" level, the output of both amplifiers is inhibited to stop unnecessary adjustment operations within the depth, thereby reducing power consumption. At the same time, along with the "low" level of line 5,
The output of the INHIBIT gate 17 is set to a "low" level and the focus display element 22 is turned on through the resistor 23 to indicate the completion of the adjustment. During the above automatic focusing, line 5 is at “low” level, so
The INHIBIT gates 18 and 19 are closed, their outputs are at a "high" level, and the front pin display element 20 and rear pin display element 21 do not light up, so that no direction is displayed. Next, when automatic focus locking is performed, by closing switch 2 for automatic focus locking, the output of the inverter 4 becomes a "low" level despite the pull-up resistor 3, so that the output of the inverter 4 becomes a "high" level. That is, line 5 becomes a "high" level. As a result, the output of the NOR gate 12 becomes a "low" level, inhibiting the outputs of both amplifiers 13 and 14, and stopping the automatic focus drive of the lens drive mechanism. At the same time, a "high" level is input to the inverting input side of the INHIBIT gate 17 through line 5, so its output becomes a "high" level.
Since the INHIBIT gate 17 is closed, even if the camera is in focus, the focus display is erased and the locked state is displayed. Since the detection device 1 outputs a voltage higher than +V, the output of the comparator 9 becomes "low" level, and the output of the comparator 10 becomes "low" level.
The output becomes “high” level. INHIBIT gate 19 assumes that the output of comparator 10 is at “high” level.
INHIBIT gate 19 when input to the inverted input side of
The output becomes "high" level, and the rear pin display element 21 does not light up. Conversely, when the output "low" level of the comparator 9 is input as a "low" level to the inverting input side of the INHIBIT gate 18, the output of the NAND gate becomes "low" level, the front pin display element 20 lights up, and the front pin is turned on. Display something. When it is the rear pin, the rear pin display element 21 lights up to indicate that it is the rear pin, in the opposite manner to the above operation. Another example is to turn off the power to the autofocus system by operating a switch (not shown) or the like when using an autofocus lens, and therefore there is no possibility of reconfirming the defocus display when the autofocus is locked. , 23 can be connected to the autofocus switch 2 instead of _VDD , so that no display is performed at all when the lens is locked. It is also easy to switch between the embodiments described above and the above.

As described above, in the present invention, since in-focus display is prohibited by performing a focus lock operation, problems such as power consumption due to wasteful display can be solved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the automatic focus display circuit of the present invention. 1...Focal state detection device, 2...Switch for automatic focus lock, 3...Pull-up resistor, 9,1
0... Comparator, 13... Drive amplifier, 14...
Drive inverting amplifier, 17, 18, 19...
INHIBIT gate, 20...Front pin display element, 2
1... Rear focus display element, 22... Focus display element.

Claims (1)

[Claims for Utility Model Registration] A focus detection circuit that detects the displacement state of a photographic lens with respect to the focus position and outputs a signal representing the focus state, and a lens that moves the lens to the focus position based on the signal from the detection circuit. In a display circuit for an autofocus camera, the display circuit includes a drive circuit and a display unit that displays an in-focus state when an in-focus state is achieved according to a signal from the focus detection circuit, wherein the photographing lens is locked by an auto-focus lock operation. An automatic focus lock switch which is a switch for maintaining the state at the time of operation and which manually shifts from a first state to a second state when the automatic focus lock is operated; a lens drive inhibiting means for inhibiting lens drive based on a signal from the focus detection circuit of the lens drive circuit and inactivating the lens drive circuit by transitioning the switch from the first state to the second state; 1. A display circuit for an autofocus camera, comprising display control means for setting the display means in an inactive state upon transition to .