JPH06186467A - Optical instrument - Google Patents

Abstract

PURPOSE:To provide an interchangeable lens which can be used by the same operation as a conventional front focusing system though it is provided with an inner focusing system optical system. CONSTITUTION:A distance display to an object is provided on the outer circumference 12b of a manual focus ring 12 and an encoder for detecting an absolute position is provided on the ring 12. Besides, a dedicated motor 31 driving the ring 12 is provided. By such constitution, the ring 12 is rotated by the motor 31 at an automatic focusing time and an object distance at the automatic focusing time can be recognized by a user by the object distance display on the ring 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device such as an interchangeable lens for a camera, and more particularly to an optical device having a power focus type lens driving device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 8 and 9, a manual focus of an inner focus lens is provided with an uneven groove 101a which is integrally formed with a ring 101 which goes around the circumference of a lens barrel.
And two sets of photo interrupters 102 for pulse counting the groove 101a, the infinity side during manual focusing,
Direction detection on the near side and how many pulses are driven C (not shown)
It was configured to send to the PU to drive the focusing lens.

[0003]

However, in the above-mentioned conventional example, there is a drawback that it is an action only for focusing and there is no indication of the distance to the subject, and it is unnatural for a person who can use the front lens focus. It was difficult to use.

Therefore, it is an object of the present invention to provide an inner focus type interchangeable lens which can be used in the same operation as a front lens focus type interchangeable lens.

[0005]

In the optical device according to the present invention, the distance to the subject is displayed on the outer circumference of the focusing ring,
An absolute position encoder corresponding to the display is provided, and
By equipping a dedicated motor that drives this ring, the focusing ring rotates even during autofocus, and the distance to the subject can be displayed. In addition, in order to swivel the focusing ring to a precise position quickly, the initial position is stopped at an intermediate position between infinity and the closest point when the power is turned on. It is possible to move to an accurate position quickly by stopping it in the immediate middle.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 to 3, 1 is a front lens and 2 is a front lens.
Is a zoom lens, 3 is an afocal lens, 4 is a focusing RR lens, 5 is a lens body barrel, 6 is a relay holder, 7 is a guide bar for moving the RR lens 4 to the optical axis, and 8 is a rotation stop guide. A bar, 9 holds the RR lens 4, a moving ring that moves in the optical axis direction by the guide bar 7, a rack that moves the RR moving ring 9 to the optical axis, a feed screw 11 that is connected to the rack 10, and a 12 Ring for manual focus, 1
3 is a cover, 14 is a manual zoom ring, 15 is a front frame, 1
6 is a brush for encoder, 17 is a substrate for variable resistance, 1
8 is a plate for holding the substrate 17, 19 is a diaphragm motor, 2
0 is a pulse motor for driving the RR lens, 21 is a drive circuit, 22 is a contact for power supply or communication, 23 is a mount for interchangeable lens, 24 is a ball for moving the moving ring of the variable power lens 2 in the optical axis direction. A leaf spring for one-sided pressing, 25 a feed screw, 26 a DC motor for power zoom, 27 a gear connecting the manual zoom ring 14 and the feed screw 25, 2
Reference numeral 8 is a linear encoder that indicates the position of the variable power lens 2 in the optical axis direction, and 29 is a gear that rotates the manual focusing ring 12. Reference numeral 30 is a slip spring, and the gear 29 idles during manual focusing. Reference numeral 31 is a DC motor that drives the manual focus ring 12.

In the above structure, the object distance display is printed at the position 12b on the outer circumference of the manual focusing ring 12, and the index is printed on the cover 13. Further, a brush 16 forming an encoder 17a (described later) is fixed to the ring 12. 4 and 5 show the ring 12
The object distance display and the output voltage of the encoder are shown. The horizontal axis shows the object distance and the vertical axis shows the voltage. As shown in FIG. 5, the brush 16 rotates integrally with the manual focusing ring 12 at 120 ° from ∞ (infinity) to 0.1 m. At that time, a constant current is constantly applied to the variable resistance encoder 17a (which is composed of the brush 16 and the variable resistance substrate 17) to increase the generated voltage on the infinity side as shown in FIG. , Is set to be low on the closest end side (0.1 m) so that the subject distance corresponding to the turning position of the manual focusing ring can be known.

FIG. 6 is a schematic diagram showing the configuration of an electrical control system when an interchangeable lens constructed by applying the present invention is attached to the camera body of an interchangeable lens video camera.

In the figure, 12 is the above-mentioned manual focus ring, 14 is the above-mentioned manual zoom ring, and 17a is an encoder for generating an output in accordance with the rotation of the ring 12, the above-mentioned brush 16 and the above-mentioned variable lens. Resistor board 1
7 is a variable resistance encoder, 28 is the aforementioned encoder that generates an output according to the rotation of the manual zoom ring 14, 19 is a diaphragm motor that drives an unillustrated diaphragm, and 20 is the aforementioned RR lens drive. Pulse motor, 21 is a microcomputer (that is, lens CPU) mounted on the interchangeable lens, 31 is a DC motor that rotationally drives the manual focus ring 12, 22 is a lens CPU and a camera CPU 34 in the camera body electrically. Connected contacts, 23 is a mount provided in the interchangeable lens, 35 is an auto focus (AF) device provided in the camera body, 36 is an AF (auto focus) switch provided in the camera body, 37 is the camera body The provided zoom switch, 38 is operated when resetting the compensator lens Compensator reset switch, the eye box encoder for detecting the opening of the aperture 39, 32 to 35 is a drive circuit (driver) of any motor.

FIG. 7 shows a camera CPU in the configuration of FIG.
34 shows control operations performed by the lens 34 and the lens CPU 21.

The operation of the above-mentioned camera will be described below with reference to FIGS. 7 and 6.

Step 1: It is detected whether or not the AF switch 36 is ON, and if the AF switch 36 is ON, the process proceeds to step 2, and if the switch 36 is OFF, the process proceeds to step 9.

Step 2: Manual focus ring 12
The (F ring) is driven to an intermediate position between ∞ (infinity position) and N (closest end).

Step 3: Reset the position of the RR lens 4, and proceed to step 4.

Step 4: Drive the RR lens 4, and proceed to step 5.

Step 5: It is judged whether or not the object is in focus. If the object is in focus, the procedure proceeds to step 6, and if the object is not in focus, the procedure returns to step 4.

Step 6: Manual zoom ring 14 (Z
The output of the encoder 28 interlocked with the ring is detected to determine whether the position of the zoom lens 2 is on the wide side or not. If it is on the wide side, the process returns to step 2, and if it is not the wide side, the process proceeds to step 7.

Step 7: The position of the RR lens 4 is detected, and the distance is determined according to the position of the RR lens 4. Go to step 8.

Step 8: Manual focus ring 12
Drive (F ring) to display the distance. Go to step 9.

Step 9: It is checked whether the focus is manual focus. If the focus is manual focus, the process proceeds to step 10. If the focus is not manual focus, the process returns to step 1.

Step 10: Manual focus ring 12
Rotate (F ring) by hand. Go to step 11.

Step 11: The position detection values of the F ring and the Z ring are fetched into the lens CPU 21. Step 12
What.

Step 12: Reset the RR lens position. Go to step 13.

Step 13: The RR lens 4 is driven according to the instruction of the CPU.

Step 14: When focus is achieved, the procedure returns to step 1.

The above operation is summarized as follows.

When the AF switch is turned on, the manual focus ring 12 is automatically moved to an intermediate position between infinity and the closest end to stand by.

Next, the RR lens is driven to reset and focus. In addition, because the distance display is inaccurate on the wide angle side due to the position of the zoom ring 14, the zoom ring 14 is moved to an intermediate position. Otherwise, the CPU calculates the distance from the zoom position and the position of the RR lens, and the motor 12 manually drives the manual focusing ring 12 (F ring). Further, when the AF switch is OFF (during manual focusing), the rotation amount of the manual focus ring 12 is detected by the encoder 17a and the encoder 17 is detected.
The output of a is taken into the CPU, the position of the RR lens is calculated according to the zoom position, and the RR lens is driven and focused only by the pulse calculated by the pulse motor 20.

[0029]

As described above, according to the present invention,
Display the distance to the subject on the manual focus ring,
An encoder corresponding to the distance is provided, and at the same time, it can be driven by a dedicated motor, so that it is possible to display the subject distance as well as the front focus even with the inner focus lens, and there is an interchangeable lens effect with good operability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an interchangeable lens embodying the present invention.

FIG. 2 is a horizontal sectional view of the interchangeable lens shown in FIG.

FIG. 3 is a cross-sectional view of the interchangeable lens.

FIG. 4 is a diagram showing a relationship between an output voltage of a focus ring encoder provided in the interchangeable lens and a subject distance on the focus ring.

FIG. 5 is a plan view of the encoder.

FIG. 6 is a schematic diagram showing an electrical configuration of a camera equipped with the interchangeable lens of the present invention.

7 is a flowchart of control operation performed in the electrical configuration of FIG.

FIG. 8 is a schematic diagram of a conventional focus ring and encoder.

FIG. 9 is a schematic view of a conventional focus ring and encoder.

[Explanation of symbols]

1 ... Front lens 2 ... Zoom lens 3 ... Afocal lens 4 ... Focusing RR
Lens 5 ... Lens body lens barrel 6 ... Relay holder 7 ... Guide bar 8 ... Non-rotating guide bar 9 ... Moving ring 10 ... Tech 11 ... Feed screw 12 ... Manual focus ring 17a ... Focus ring encoder 16 ... Focus ring encoder Brush 13 ... Cover 14 ... Manual zoom ring 17 ... Variable resistance board 15 ... Front frame 19 ... Aperture motor 20 ... RR lens drive pulse motor 22 ... Contact point 23 ... Mount 26 ... Power zoom DC motor 24 ... Leaf spring 31 ... Motor for driving manual focus ring 25 ... Feed screw 28 ... Encoder 29 ... Gear wheel 30 ... Slip spring 34 ... Camera CPU 35 ... AF device 36 ... AF switch 37 ... Zoom switch 38 ... Competition reset switch

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 13/36

Claims (1)

[Claims] 1. An inner focus type optical system and an optical system for electrically instructing the position of a focusing lens in the optical system or rotating the focusing lens in the optical system by hand by rotating the optical system by hand. In an optical device equipped with a focus ring for driving and an autofocus function, a distance display to a subject or an observation target is provided on the outer peripheral surface of the focus ring, and an output corresponding to the distance display is provided. An encoder for detecting an absolute position that occurs is provided in association with the focus ring, drives the focus ring at the time of autofocusing, and supplies power O to the optical device.
An optical device having a dedicated motor for positioning the focus ring at a position corresponding to an intermediate position between infinity and the closest end at N.