JPS6328415Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an in-viewfinder display device that displays the focus adjustment state of an automatic focusing camera in the viewfinder.

FIG. 1 is a partially cutaway view of a viewfinder cover to show the configuration of a viewfinder system of a camera having an automatic focus adjustment device.

The light from the direction of the subject that enters the scanning mirror 2 and the fixed mirror 3 passes through the reflecting prism 4,
input to the autofocus module 1. When the photographic lens is moved forward or backward, the lens position transmission cam moves forward or backward, the connecting lever 15 rotates around the shaft 15a, the mirror lever 14 follows, and the scanning mirror 2 is rotated. This rotation performs optical distance scanning from close range to infinity or vice versa, and a correlation signal indicating the degree of coincidence between the scanned image and the fixed image is formed, and a signal indicating the focal position based on the correlation signal is sent from the autofocus module 1. Output. In such a camera,
It is advantageous if the adjustment state of the objective lens can be displayed in the viewfinder.

However, the current general trend is to make cameras more compact, and when using a rangefinder like the one shown in FIG. 1, it is not easy to display the information in the viewfinder.

It is also important to achieve miniaturization, but it becomes a problem if the display in the viewfinder visual field obstructs the visual field.

Therefore, in the present invention, the frame display is used both to display the distance measurement target range and to display the focus adjustment state.

Since it is extremely important to determine which part of the subject to focus on, the distance measurement range of an automatic focus detection device is narrower than the angle of view of the camera's objective lens.

Therefore, it is necessary to inform the user about which part of the subject the automatic distance measurement is to be performed and the focus adjustment to be performed. The present invention attempts to solve the problems of displaying the distance measurement target range and displaying the focus adjustment state at the same time.

SUMMARY OF THE INVENTION An object of the present invention is to provide an in-finder display device that can display the distance adjustment state and automatic distance measurement range in the same area in the finder.

In order to achieve the above object, the in-viewer display device according to the present invention displays the focus adjustment state within the viewfinder. 1 shows a prism block having a half mirror inserted in a viewfinder, and a corresponding area within the viewfinder field of view of the distance measurement target range of the focus detection device, in a camera having a focus detection device that generates a focus signal by comparing A frame disposed on the illumination light incident side of the prism block, an illumination light source that illuminates the frame, and a focus adjustment device that is started in synchronization with the start of a device that moves the objective lens forward and backward using the output of the focus detection device. A display circuit that inverts and turns off the light source when it detects that the focus adjustment has been completed, and a display circuit that displays the distance measurement target range within the viewfinder field of view during focus adjustment to indicate that the focus adjustment state is in progress, and that the focus adjustment is completed. The distance measurement target range display is sometimes changed to indicate completion of focus adjustment.

The present invention will be explained in more detail below with reference to the drawings and the like.

In the apparatus according to the present invention, light is introduced from below the prism block 6 shown in FIG. 1 to indicate the image of a frame indicating the range to be measured and the state of focus adjustment.

The structure of this portion will be described in detail with reference to Figures 2 and 3. In each figure, 7 is a viewfinder lens, and 5 is an eyepiece lens. A prism block 6 is inserted between the viewfinder lens and the eyepiece lens, and a semi-transparent mirror portion 6a is provided in the prism block 6. As shown in Figures 2A and 3, the prism block 6
Below this, a lens 8, a frame 9, a colored filter or diffuser 10, and a light source 11 are arranged.

The lens 8 is a convex lens for creating an image of the transparent portion of the frame 9 illuminated by the light source 11 at a distance of clear vision.

The frame 9 has a rectangular transparent portion as shown in FIG. When the light source is turned on, the portion 13 shown in black in FIG. 2B becomes bright. The portion indicated by 13 surrounds the portion where a scanned image is formed by optical distance scanning.

Next, the light source 1 described above with reference to FIGS. 4 and 5
The lighting control circuit No. 1 will be explained. FIG. 4 is a block diagram showing the configuration of the lighting control and lens drive motor control circuit. This circuit operates the distance measurement display circuit 30 when the circuit power is turned on, and generates a stop signal from the focus detection module 1 shown in FIG. 1 (signal from block 21 in FIG. 4) to activate the distance measurement display circuit. 30 is deactivated and the light source 11 shown in FIGS. 2A and 3 is turned off.
This circuit has flip-flops 26, 27, and 28, and the output logic of these flip-flops determines whether the lens drive motor 29 should be rotated forward or reverse, and whether the distance measurement display circuit 30 should be driven or stopped.

The initial condition determining circuit 25 is a circuit for determining the initial state of each of the flip-flops 26, 27, and 28 when the power is turned on.

Switch 22 is a switch that generates a signal indicating that the objective lens has been brought to a close position, and switch 23 is a switch that generates a signal that indicates that the objective lens has been brought to an infinite position. The stop signal is input to flip-flop 28 via inhibit gate 24. Figure 5 is a circuit diagram that further embodies the above configuration, and the main parts are shown in the fourth diagram.
The same numbers are assigned to correspond to those in the figure. The operation of this circuit consists of a first step in which the power switch SWA is turned on and the lens is moved toward infinity, a second step in which the lens is moved from the infinity position to the close-up direction, and a second step in which the lens is moved from the infinity position to the focal point. The explanation can be divided into a third step in which the object is moved and a fourth step at which the third step is completed.

(First step) When the power switch SWA is turned on, the first step starts.

The moment the switch SWA is turned on, the terminal voltage of the capacitor _C1 of the initial condition determining circuit 25 becomes L level, so each flip-flop 26, 27, 28
The initial conditions for are determined. The upper output terminals of each flip-flop are all at H level. As a result, the transistor Tr1 is turned off, the transistor Tr2 is turned on, the relay Ry2 is activated, and a current is supplied to the motor M to drive the objective lens in the infinite direction.

At this time, since the lower output of the flip-flop 28 is at the L level, the base potential of the transistor Tr3 of the distance measurement display circuit 30 is at the H level, and the lamp 11 is lit.

(Second Step) When the motor M brings the objective lens to the infinite position in the first step and turns on the switch 22, the second step is started.

When the switch 22 is closed, the flip-flop 26
is reversed. The base potential of transistor Tr1 becomes L level and turns on, activating relay Ry1,
The rotation of the motor M is reversed to drive the objective lens from infinity to close range. At this time, the flip-flop 28 still maintains its original state, and the lamp 11 is lit.

(Third step) When the objective lens is brought to a close position in the second step, the switch 23 is closed, the flip-flop 27 is inverted, Tr1 is turned off, and Tr2 is turned off.
is turned on, relay Ry2 is activated, and the objective lens moves in the infinity direction. In this case as well, the lamp 11 is lit.

(Fourth step) When the focus position signal position detected in one complete scan cycle in the second step is applied as an input to the inhibit gate 24 in the third step, the flip-flop 28 is inverted and each relay is
Ry1 and Ry2 become inactive, and lamp 1
1 is turned off. In other words, the objective lens is brought to the in-focus position and stopped, and the lamp 11 is turned off, so that the frame within the viewfinder's field of view becomes dark, allowing the user to confirm that focus adjustment has been completed. .

The inhibit gate 24 is configured to generate a stop pulse only in the third step and invert the flip-flop 24 depending on the state of each flip-flop or switch.

As is clear from the above description, the device according to the present invention can display information in relation to the range to be measured within the viewfinder field of view. If more lamps are used, it is possible to display information corresponding to each step. Also switch
It is also possible to have the lamp light up as long as SWA is on, and display only that the focus is being adjusted.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of the viewfinder optical system of a camera using the device according to the present invention, FIG. This figure is an enlarged perspective view of the prism block shown in FIG. 2A. Figure 4 is a block diagram of the motor control circuit, Figure 5
The figure is a circuit diagram showing the motor control circuit in more detail. 1... Autofocus module, 2... Scanning mirror, 3... Fixed mirror, 4... Reflection prism, 5
...Eyepiece, 6...Prism block, 7...
...Finder lens, 8...Insert lens, 9...
Frame, 10...Colored filter, 11...Light bulb, 12...Finder visual field, 13...Display frame,
14...Mirror lever, 15...Connection lever, 1
6...Lens position transmission cam, 21...Stop signal circuit, 22...Infinity switch, 23...Proximity switch, 24...Prohibition gate, 25...Initial condition circuit, 26, 27, 28...Flip-flop,
29...Motor, 30...Display circuit.

Claims (1)

[Scope of utility model registration request] In a camera having a focus detection device that generates a focus signal by photoelectrically comparing a scanned image obtained by optically distance scanning a part of the object direction with a fixed image,
a prism block having a half mirror inserted into the viewfinder; a frame disposed on the illumination light incident side of the prism block to indicate a corresponding area within the viewfinder field of view of the distance measurement target range of the focus detection device; An illumination light source that illuminates the frame, and a display that is activated in synchronization with the start of a device that moves the objective lens forward or backward based on the output of the focus detection device, and that is reversed to turn off the light source when it is detected that focus adjustment has been completed. The circuit is configured to display the distance measurement target range within the viewfinder field of view during focus adjustment to indicate that the focus adjustment state is in progress, and to change the distance measurement target range display when the focus adjustment is completed to indicate completion of the focus adjustment. 1. A viewfinder display device configured to display a focus adjustment state in a viewfinder.