JPS58194006A - Photographic lens barrel capable of interlocking with focus detector - Google Patents

Abstract

PURPOSE:To make focusing operation heavy almost in an in-focus state and to perform the focusing operation accurately and speedily, by placing a load on a focusing lens in moving in an optical axis direction by a load generating means which operates in response to a detection signal for showing a nearly in-focus position. CONSTITUTION:Object light from a submirror 12 is made incident to two sensor arrays 16a and 16b at positions equivalent to a photoreceptor 22 through a beam splitter 14 and a signal corresponding to the contrast is inputted to a focusing detecting circuit 24. A camera side C transmits a focusing signal J and a direction signal K to a lens side L through C1 and C2. The lens side L incorporates a focus ring which engages with the holding frame 82 for the focusing lens 80 threadably on helicoil basis and is not shown in a figure. Electromagnets Mg1 and Mg2 are powered on under the control based upon the focusing signal J and direction indicating signals K1 and K2 passed through a timer 70 to attract levers 84 and 86 against springs 88 and 90, inhibiting the lens holding frame 82 and a fixed cylinder from moving relatively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photographic lens barrel that can be linked with a focus detection device. The focusing lens in the lens barrel is moved in the optical axis direction by manual operation, and a focus detection device indicates the in-focus position of the focusing lens or a position within the allowable depth of focus for the aperture diameter of the aperture in the lens barrel. The focus detecting device N that generates a signal indicating the focusing lens or a signal for moving the focusing lens in the focusing direction is disclosed in, for example, Japanese Patent Application Laid-open No. 55-117131 and Japanese Patent Application No. 5FI-205787, Meisho 1, etc. Proposed.

These focus detection devices r, J: As shown in FIG. 1, a plurality of sensors a, b, for example, are arranged at an imaging point and a close position slightly apart from the imaging point.2. The difference in brightness is detected by the two one-hinner.

As a result, it is possible to generate a signal 9 indicating the in-focus position of the focusing lens and a movement signal (direction indication signal>ff) indicating the direction in which the focusing lens is to be moved.

Figure 1 shows contrast signals from two sensors, with the horizontal axis representing the amount of lens extension and 1. It is expressed as A
The range indicated by 9 indicates that the focusing lens is at the in-focus position, and the range indicated by 9 Bl/B indicates that the focusing lens is at the front focus or rear focus position and the focus detection device determines the amount of defocus. This indicates the range in which direction can be indicated, in which the direction of movement of the focusing lens can be determined.

C2 and C1 indicate the range where the contrast difference is small at the position where the subject is significantly unraveled.

l:d In a focus detection device that performs contrast detection like the one above, when the focusing lens is in the range A, the goldfish signal (J) is output from the focus detection device t,, B
, -B, a direction indicating signal 1 (, ·K) is output to drive the focusing lens.

In this contrast detection type focus detection device, a motor for driving the focusing lens is built into the shooting lens barrel.
7 Not only does it use a dedicated lens that performs focusing operations in response to a signal from the camera side, but it also moves the focusing lens by manual operation. A cylinder can also be used.

When using the interchangeable lens exclusively for manual operation with the above-mentioned contrast detection type focus detection device (rifi, f) camera, the direction indications shown in the viewfinder as 1..2.3 in Figure 1 are provided. Shigumata C3I focusing table O
Check and perform all manual operations. In this case, the focus heating position may be overshot 1. If the subject is dark in the row, it takes time to calculate the distance, and the 17 focusing lenses move back and forth between the focus points by manual operation. The present invention relates to a device that solves all of these problems, and when a direction indicating signal is output from the focus detection device, this signal pC, r: Put a load on the holding frame of the focusing lens, making manual operation difficult and making it move slightly, and move the useless lens to the in-focus point or within the in-focus range 1: Operate accurately and quickly (9) In order to solve the above problems, the present invention is intended to solve the above problem. To provide a lens barrel that can adopt a configuration that does not lose the appearance dimension of a cylindrical cross section.

Embodiments of the present invention will be described below with reference to FIG. 2. FIG. After this occurs, a load (pressure action) is applied to the holding frame.

The part C shown in the figure and surrounded by the two-dot chain line, the camera mirror,
12 is a nap mirror that is attached to the back of the mirror 10 and guides the transparent iM 9, Beano, and splitter 14; and the sensors I, 6a, and +6bK. 111, focusing glass, 20-digit pentaprism, 22, two sensors placed at positions equivalent to and close to the position of the frame 22, +, +--, and I-rays 16a and 1.
An electrical signal corresponding to the contrast of 6b is output 1. It is input to the focus detection circuit 24.

FIG. 3 shows a circuit for generating all contrast signals from the image sensor 16a or 16b.
No. 7131. In the figure, 16a (16b) is C
It is a self-scanning image sensor such as CD, B B ]-), and the charges generated in each light receiving element 16a-1 to 16a-b are accumulated for a predetermined time and then transferred.
All gates 26 are transferred to corresponding bits of analog sheet register 28 simultaneously. Next, the clock pulse of the clock pulse generator 30 transfers the I word in the target register to the right side. 32 and 34 are registers added to the number of light-receiving elements. 7 and 36 are differential absolute value circuits that calculate all the absolute values of the difference between the outputs of two adjacent elements. 38 is an integrator that calculates the sum of the absolute values. It is a vessel.

40i, a focus signal J, a sample hold N path for holding integral values for calculating all direction signals; 42, a transfer gate drive circuit; 44, a reset pulse generation circuit for the integration circuit 38; 46, sample and hold timing This is a circuit that generates all pulses. With the above configuration, a contrast signal is generated.

Figure 4 Q; 1. The above-mentioned contrast (change sound of the difference signal of M No. The range of A, x-'r>t, and the range of X>6 is the range of B1·B in FIG.

FIG. 5 shows an example of a circuit that generates a 9-coin signal J and a direction signal K, and the two line sensors 16a and 16b are the contrast signal generating circuits 50A and 50B shown in FIG. 3, respectively.
The differential absolute value circuit 52 extracts 1x-yl. 54°56.58 are respectively lx−ε+
, ly-ε1°11X-Yl-CI is necessary in a differential absolute value circuit that calculates all. 60, 62.64 are A, N I) gates, and 6fi&:tNOT circuits. Now 1lx-yl
-C1ku'0 and lx-εl<o, ly-εl<o
A focusing signal J is generated in the case of . This is Figure 1.

This corresponds to the range A in FIG. Also, 1x-yl-ε>g
, and lx-gl>・0.

A direction signal is generated, which corresponds to B in Figs. 1 and 4.
This corresponds to the range B2.

Returning to FIG. 2, 70 is a timer circuit, and 72 is a display circuit that displays the lens movement direction and focus state in all viewfinders. C7/C2 - Signal transmission terminal for transmitting the above-mentioned signals from the camera side C to the lens side. For focusing inside the lens side/Z80. 3 for manual operation with the holding frame 82 of the focusing lens 80
t, a focus ring (not shown) for controlling the movement of the focusing lens 80, the holding frame and a mount that holds the focus ring and attaches the interchangeable lens L to the camera C;

My + and M are the focus signal J output from the distance measuring circuit 24 and sent to the lens side via the timer circuit 70, and the direction indication signal, and the first and second energization controlled by -K. It is an electromagnet.

84-s 6 r, r 21 above! The claw part 84 at one end of the lever 84 is a lever that is attracted and operated by the second electromagnet M y 1"My t and is pulled counterclockwise and clockwise by each spring 88 and 90, respectively.
a is configured to lock with a locking tooth 82a provided on the outer periphery of the lens holding frame 82, and one end 86a of the lever 86 is configured to lock with the outer periphery of the lens holding frame 82 [7. Generates a frictional force that prevents relative movement with the fixed cylinder.

Figure 6 shows ×top electromagnet M9. This is an example of a drive circuit of
Terminals 64' 6r:r are connected to the output terminals of the A and N Dl circuits 4 in FIG. 92ul) flip-flop, 94 is A N D
rm path + timer circuit such as 9617t one/yotsuto multivibrator, Myl is the above-mentioned focusing lens 80
1, which is a stop electromagnet, the output of the AND) circuit becomes "1" by the first focusing signal J after defocusing by the circuit shown in FIG. , 1rL magnet is energized 1° When the subject is dark, the S/N of the signal of the line seven law is completely reduced.
It becomes necessary to increase the accumulation time of the line sensor shown in the figure. Generally, for subject conditions of EV5, approximately 250
It requires an accumulation time of about 1 TISec. father,
The calculation time is constant regardless of the brightness of the subject and is 50m5.
It is about eC.

The longest interval C where the focus signal appears ↓ approx. 300m5ec
reach a certain degree.

The operation of the embodiment shown in FIG. 2 will be explained. When moving the focusing lens by manual operation 1. .

When the lens is in the area 01.C in FIG.
・The four springs 88 ・1)()(-) are tensioned on the 86 and cannot be loaded against the movement of the focusing lens holding frame 82.

Single figure B by fully moving the lens, ・13. When it comes to the Jj direction indication range, the distance measuring circuit sends a lens direction indication signal,
2 occurs on my father's side. This direction signal 1 (, (Kt)
The electromagnet Mv2 is energized and the lever 86 is attracted.
Because of this IId+ action, one end 86aI of the lever 86 acts to apply a load to the movement of the lens holding frame 82, so the operator recognizes that it is close to the focusing device by the direction indication signal in the indexer. 7. Due to the load on the lever 86, the slight movement of the lens holding frame V1 becomes i'J function, and the lens can be set to the in-focus A1 device without going over the entire in-focus point.

When the lens comes to the in-focus point, instead of the j-direction instruction signal from the range finder circuit, ! <When the signal J is output t, the energization of My 2 is released and the lever 84 locks the movement of the lens holding frame 82 against manual operation by energizing ft, , M, .

FIG. 7 in FIG. 7'5 shows the second embodiment of the present invention 7F:
1-, This actual MtI example is characterized in that a pressure element assembly is used as a means for completely preventing movement of the MiJ compound focusing lens holding frame. Although it is possible to obtain a large load with the load generating means using the electromagnet in the first embodiment, the electromagnet must be assembled into the lens barrel in an appropriate manner and the shape of the lens barrel must be changed.

It is also conceivable that unforeseen problems may occur if the master changes the specifications of the mold needles, etc. The second embodiment is a conventional and well-known method that generates a load on a lens holding frame that moves by manual operation when a direction signal is issued without requiring a significant change in the structure of the lens bell face. It is a lens barrel into which means can be inserted.

In the figure, +00 is a fixed barrel of the lens barrel, and 102 is a lens 1 holding frame that holds the focusing lens 104 and is helicoidally coupled to the fixed barrel 100.

The lens holding frame 102 is moved in the optical axis direction by operating a manual operation member (not shown).

]06A-10fiB and 106C are shown in Figure 8":
It is a plate-shaped piezoelectric element having a piezoelectric effect made of material such as barium titanate, which is placed between the fixed tube 100 and the lens holding frame 020, and is fixed at one end with a screw 108.
Attach all the friction members 110 with a rubber material No. 4 with a large friction coefficient to the other end r [17] on the free end. , 112&, J: An electrical signal terminal holding part provided in the fixed tube 100, and the terminal 11
2a and 112bffi are held and the fifth
-K to the direction signal shown in the figure.

The electric signal bow is configured to be able to transmit. 114 is piezoelectric element 1
This is a tactile terminal that was installed in 06, and a part of it is exposed on the first part of the lens barrel, and it is placed in a position where it can be touched when the photographer holds the lens barrel toward the subject. .

FIG. 9 shows an entire bimorph type piezoelectric element made by pasting together two piezoelectric element plates 120A and 120B.

The piezoelectric element plates 120A and 120B are elements whose polarization directions are the same, and by applying a voltage as shown in Figure 1, 12
0A shrinks in the longitudinal direction, 12013 extends in the longitudinal direction,
The overall bending curvature is reduced.

! The displacement δ of the piezoelectric element cannot be given by −vr to δ−. Here, k is a constant and is approximately 2.5 x 10'rare/
'V.

V6 is the applied voltage, l is the effective length, and t is the thickness. .

Now, if V=4V, Il=50mra, and t=0.5-, δ will be about 0.1wa+. In order to increase the amount of displacement, it is necessary to make the effective length large, and the configuration shown in FIG. 8 is effective.

FIG. 10 shows a linear approximation of the relationship between the displacement force P generated by the bimorph and the load F that moves the distance ring by providing unevenness on the contact surface between the mast member 203 and the distance ring 204. ing.

For simplicity, the figure ignores the blinding coefficient between the tether member and the distance ring. Also, 7. Only the force that the mounting member receives is shown. From the figure, it becomes F-, , 7□, and now θ=1
If it is 0°, F=5.7P.

Load can be increased. In reality, since there is a trench, the load will be slightly larger, and if the trench coefficient is set to 03, then F
= about 6P.

Next, the operation of this embodiment will be described.

The lens barrel shown in FIGS. 7 and 8 is connected to a camera having a focus detection circuit shown in FIGS. 3 and 5.

The two electric signal output terminals are connected to a direction indicating signal for lens movement, and to all signal terminals 112a and 112b. When the focusing lens was moved manually by 1.■ until it reached the direction indicating range B, straddle B, shown in Figure 1, my father heard the direction indicating signal shown in Figure 5. Full output, each pressure element plate 10
A predetermined voltage is applied to 6A, 106B, and 106C,
Each piezoelectric element plate expands and contracts in the longitudinal direction, and the lens holding frame 102
vr, a pushing force of 1 to 0 is applied by the friction member 110. This generates a resistance force against the movement of the focusing lens holding frame 102 in the optical axis direction -\, and a large force is generated by the operating force of the lens holding frame 102. The lens holding frame 102 can be moved a small distance by fine movement operation, and the focus detection signal J is generated without the in-focus point going too far.a) The lens holding frame can be stopped at the 7th position.

As described above, in the present invention, when the position of the focusing lens is close to the in-focus point, a signal is output from the focus detection circuit to instruct the lens in all directions of movement. Focus detection solves the problem of the lens moving back and forth in front of and behind the in-focus point by applying a load, making the lens movement heavier and allowing for slow movement.Focus detection enables quick focusing. You can get the system. Furthermore, although the embodiments of the present invention have been described in terms of an interchangeable lens mirror, it is of course applicable to a photographic lens that is integrated with a camera.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing contrast signals from two sensors, with the vertical axis representing the contrast signal and the horizontal axis representing the amount of defocus. FIG. 2 is a diagram showing a camera-side block equipped with a load generating means, a lens barrel for shifting the load, and a focus detection device according to the first embodiment of the present invention. Figure 3 is a circuit diagram for obtaining a contrast signal using an analog shift register. FIG. 4 is a diagram showing changes in the difference signal of contrast No. 46 between the two sensors. FIG. 5 is a circuit diagram for detecting K2 and goldfish signal J in the lens movement direction instruction signal. FIG. 6 is an operating circuit diagram of the itt magnet M. Figures 7 to 10 show a second embodiment of the present invention. Figure 7 is a sectional view of the main part of the lens barrel. FIG. 8 is a sectional view of the main part of the lens barrel in the direction perpendicular to the optical axis. FIG. 9 is an explanatory diagram of a bimorph piezoelectric element used in this example. FIG. 1O is an explanatory diagram of generating a load by a piezoelectric element. 80... Focusing lens 82-102... Lens (
M holding frame My1/My2... Electromagnet 84/86...
Locking levers 106A-106B/106C...Piezoelectric element Applicant: Canon Co., Ltd. Agent: Gi Marushima;? i 3

Claims (1)

[Claims] (1) The position of the focusing lens is near the in-focus position I
In a photographing lens barrel that is connected to a focus detection device that outputs a detection signal for detecting the presence of NK, the photographing lens barrel is provided with a load generating means that is activated by a detection signal indicating a position in the vicinity of the focus, and the square load generating means operates to detect the A photographing lens barrel linked with a focus detection device, which is characterized by providing a focusing lens with a load of movement in the optical axis direction.・2) Is the load generating means located near the focus? Claim (1) is characterized in that it is comprised of an electromagnetic means that is actuated by a detection signal shown, and a member that applies a frictional force to a holding frame that holds the entire focusing lens by the electromagnetic means. (3) The load generating means is a piezoelectric vibrator. Claim (1) is characterized in that a movement preventing force is applied to the holding frame holding the focusing lens in response to a detection signal indicating the movement of the focusing lens in the direction of the optical axis. Photographic lens barrel that works with the focus detection device.