JPH02210313A - Lens unit for camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to camera systems such as video cameras and the like.

(Background Art) Conventionally, interchangeable lenses have been widely used in camera systems. In recent years, there has been a strong demand for interchangeable lens video camera systems in camera systems including video cameras, electronic cameras, etc., and in parallel, automatic focus adjustment devices (AF) and automatic exposure devices (AE
), power zoom mechanism, etc. (ZOOM), automation and multi-functionality. Therefore, a plurality of driving means such as motors are provided within the lens unit to drive driven parts such as the lens and the diaphragm based on control information supplied from the camera side.

By the way, since such a driven part and a driving part are usually connected by a power transmission means using gears, backlash exists. During this backlash period, even though the drive system is being driven by the control information, the driven portion is not being driven.

Now, to explain the AF operation as an example, even though there is a command to move the lens from the camera side.

Since the lens does not move during the backlash period, in the AF circuit on the camera side, a state occurs in which the focus signal does not change even if the lens is moved.

This state is similar to the operation when the in-focus point is reached in mountain-climbing control, in which a component corresponding to the degree of focus is extracted from the video signal and the lens is moved so that the component is maximized, and the camera side There is a risk that the AF circuit will mistakenly detect this as the in-focus point and stop the lens. Backlash causes a so-called dead zone when the driving direction is reversed, resulting in the inconvenience that the lens stops every time the driving direction of the lens is changed.

In order to solve these problems, the present applicant proposed a system in which a busy signal is transferred to the camera body during the backlash removal period on the lens side in accordance with the previously filed Japanese Patent Application No. 63-216929.
A lens that outputs a signal and suspends or suspends the calculation of control information or the transmission of control information to the lens side during the period when the busy signal is output on the camera side, thereby preventing malfunctions during the backlash removal period. is proposed.

(Problems to be Solved by the Invention) However, in the above-mentioned Japanese Patent Application No. 63-216929, subsequent research revealed that further improvements were possible.
We learned this through development.

In other words, according to the above device, the camera body stops or suspends transmission to the lens until there is no busy signal from the lens, so other functions other than AF, such as automatic aperture adjustment and zooming in response to changes in the video signal, are performed. System problems may occur, such as units temporarily not working or transmission of control information being suspended.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and is characterized by a lens unit that is detachable from the camera body. a plurality of drive means for driving a plurality of driven parts in the lens unit based on a signal from the camera body side; a detection means for detecting the state of each of the driven parts and outputting detection information; means for detecting a drive delay between each of the driven parts and the drive means and generating a predetermined control signal for a period capable of absorbing the drive delay; The lens unit of the camera includes communication means for time-divisionally supplying the lens to the camera body.

(Function) As a result, it is possible to detect a delay in response between each driven unit in the lens unit and the drive means, and control information can be sent to each driven unit without affecting other drive systems. It is possible to prevent malfunctions of the control system due to deviations between the actual operation and the actual operation.

(Example) Hereinafter, an example of the lens unit according to the present invention will be described in detail with reference to each figure.

The overall schematic circuit configuration of the embodiment will be explained using FIG. The camera body is on the right side, and the lens is on the left side of the dotted line in the center of the drawing.

Light from a subject 1 is transmitted through an optical system 2 to an image sensor 3 such as a CCD.
rise to the top. The output is converted into a television signal by the camera signal processing circuit 4 and output. On the other hand, the television signal has the well-known AWB (automatic white balance)
Circuit 5. It is used in various automatic adjustment mechanisms such as the AF circuit 6 and the AE circuit 7 (automatic exposure control). Each control signal is output from a control circuit 5.6.7 as a control signal source for the automatic adjustment mechanism. AW to adjust color balance of camera signal processing
The control and open signals of the B circuit 5 are input to the processing circuit 4, and the remaining control signals are input to the cameraman controller 9.

Furthermore, a control signal generated by the zoom switch 8 for setting the focal length of the optical system 2 is also input to the camera microcomputer 9. The data communication path 13 is connected to the lens microcomputer 14, and all communication data is received by the lens microcomputer 14. Various control signals C1 input to the camera microcomputer 9
, C2, and C3 are processed according to a program stored in the ROM in the camera microcomputer 9, and information related to the lens side is sent to the lens microcomputer 1 via a data communication path 13.
4. Reference numeral 28 denotes a zoom motor, which is a drive source for controlling the movement of lenses related to the zoom action in the optical system 2 in the optical axis direction. This zoom motor 2
8, the lens microcomputer 14 receives the operation signal (C3) of the zoom switch 8 via the camera microcomputer 9, and the driver 2
It is driven by operating 5. , 29 is an AE motor, which is a drive source for controlling opening and closing of the aperture in the optical system 2. To drive this motor 29, the camera microcomputer 9 receives the control signal (C2) from the AE circuit 7, performs calculations to find an appropriate aperture value, issues a drive command to the lens microcomputer 14, and based on this command, the motor 29 is driven. This is done by the lens microcontroller 4 operating the driver 26. 30 is an AF motor, which is a drive source for controlling the movement of lenses related to focusing in the optical system 2 in the optical axis direction. The AF motor 30 is driven by the AF circuit 6.
The camera microcomputer 9 receives the control signal (C1), performs calculations to determine the focusing direction and defocus amount, issues a drive command to the lens microcomputer 14, and based on this command, the lens microcomputer 14 drives the driver. This is done by activating 27. Reference numeral 31 denotes a zoom encoder, which detects the movement of the lens related to zooming using a code plate or a pulse plate, and supplies the detected information to the lens microcomputer 14. A diaphragm encoder 32 detects the movement of the diaphragm moving member and supplies the detected information to the lens microcomputer 14. 33 is an encoder for AF, which detects the movement of the lens related to focusing by reading pulses using a pulse plate linked to a distance ring (not shown) of the lens, and supplies the detected information to the lens microcomputer 14. . Note that the encoder 33 is configured to be able to determine whether the lens is moving in both directions related to focusing, that is, movement toward the closest side and movement toward the infinity side. Of course, the signal supplied from the encoder 33 to the lens microcomputer 14 also includes information regarding the moving direction of the lens related to the above-mentioned focusing.

In addition, each motor 28, 29, 3 by the lens microcomputer 14
Control 0 controls the rotation direction, drive/stop, speed, etc. Data transmission from the lens microcomputer 14 to the camera microcomputer 9 is output as time-division serial data.

Next, Figure 2 shows the camera microcomputer 9 and the lens microcomputer 14.
Indicates communication data between. The control information CTL sent from the camera microcomputer to the lens microcomputer is the AF
, AE, and 200M circuits, the control commands are serially stored in order to form l packets, and this is synchronized with the vertical synchronization signal (V period) of the television signal on the camera side. It is transmitted to the lens microcomputer 14.

On the other hand, the data communication path 13 is composed of a bidirectional bus, and the lens microcomputer 14 receives control signals from the camera microcomputer 9, and at the same time receives optical signals detected by the AF, AE, and ZOOM encoders 33, 32, and 31. Pressure detection information LTC, which is detection information representing the state of the system, is sequentially stored in accordance with each data area of CTL and returned to the camera microcomputer 9 as one packet. The CTL and LTC packet transmission cycles are performed almost simultaneously in V cycles, but the lens microcomputer 1
4 receives control information CTL from the camera microcomputer, detects the result of controlling the optical system based on this, and sends it back to the camera microcomputer 9, so the detected information is sent back, for example, in the next V period.

In the figure, mutually corresponding packets are indicated by arrows.

In this way, from the lens microcomputer 14 to the camera microcomputer 9
Encoder information (LTC) for each unit is transmitted to.

On the other hand, the data structure in each CTL and LTC packet is
As shown in Figure (b), a header with a predetermined data pattern indicating that it is the start of a packet is formed at the beginning of the CTL, followed by AF control information (speed information, etc.), AE control information, etc. The zoom control information is arranged serially, and the LTC has a similar data format, with a header at the beginning, followed by focusing lens position detection information, aperture value detection information, and zoom, that is, focal length information, arranged serially. The configuration is as follows. In particular, in LTC, a bit is provided in the encoder information of each unit to indicate the drive delay of the driven system (hereinafter referred to as bu).
This busy signal (referred to as the Sy signal) is generated when driving errors due to backlash etc. occur between the drive unit and the drive unit when each driven system is driven according to commands in the control information sent from the camera microcomputer. This is a flag bit that is set to 1 when this happens, and is sent back to the lens microcomputer along with the LTC.

Next, the operation of the lens microcomputer 14 related to the main points of the preferred embodiment will be explained based on the flowchart of FIG.

In this control flow, the lens-side motor 28.2 is controlled by the control information CTL transmitted from the camera microcomputer 9.
It is started when driving 9 or 30 to change the state of the optical system.

When the flow starts, the control information CTL transmitted from the camera microcomputer 9 on the camera body side is received, and the command content is decoded (step 1).The lens side motor 2
8.For either 29 or 30 motors,
The direction of movement immediately before that is forward rotation (+ end point), reverse direction (one end point)
Depending on the situation, the flow will separate (step 2); if the rotation is forward, proceed to step 3; if the rotation is reverse, proceed to step 6. These steps are necessary because backlash always exists between the drive gear and driven gear of the motor's output transmission system.

Lens side motor 28.2 from this camera microcomputer 9
This is because it is necessary to determine in which direction the driving gear and the driven gear were meshing at the time when the command related to the rotational control of 9 or 30 was issued.

In other words, if you look at Figure 4, is it the state shown in Figure 4(a)?
This is because the subsequent flow differs depending on whether the state shown in FIG. 4(b) is reached.

FIGS. 4(a) and 4(b) show states of backlash d in different rotational directions between the drive unit side gear 100 and the driven unit side gear 101 in the drive system that drives the lens, respectively. This shows that.

A flag rREVERSEJ indicating these driving directions is provided in the lens microcomputer 14. In the state immediately before the current CTL command, if the driving direction of the lens side motor 28, 29 or 30 is forward rotation, the rREVERSEJ flag will be set to "0", and if it is in the reverse direction, the flag will be set to "l". Are standing.

Then, in step 3, when the flag "rREVERSE" is "0", the finger of the camera microcomputer 9 switches to the opposite direction this time (the motor drive direction up until now and the command just received are reversed). If so, proceed to step 4, and if not (if the previous motor drive direction and the current command are in the same normal rotation direction), proceed to step 5.

If the process proceeds to step 4, the flag ``rREVERSE'' is set to ``l'' and the process proceeds to step 9.

If the process proceeds to step 5, the process proceeds to step 12, END, with the flag ``rREVERSE'' kept at ``0'', and the flow ends.

If the direction is reversed in step 2 and you proceed to step 6, if the rREVER3EJ flag is "1", the command from the camera microcomputer 9 is in the same direction as the previous command. The process advances to step 7, and if the current command is for the forward rotation direction as opposed to the previous motor drive direction, which is the reverse direction, the process proceeds to step 8.

If the process proceeds to step 7, the process proceeds to step 13, END, with the flag ``rREVERSE'' remaining at 1''.

If the process proceeds to step 8, the flag "rREVERSE" is set to "O" and the process proceeds to step 9.

In step 9, when driving the lens side motor 28, 29 or 30 in a direction opposite to the previous direction, a timer means configured in the lens microcomputer 14 and set to a timer time slightly longer than the time lag caused by backlash is activated. Let it start.

In step 10, a busy signal is sent to the camera microcomputer 9, and in step 11, when the timer time of the timer means reaches the set value, the process proceeds to step 12 and the EN signal is sent.
D, and if the timer setting time has not yet been reached, the process returns to step 10 to continue outputting the busy signal.

After performing the above operations, this flow ends in step 12.

Next, the operation of the camera microcomputer will be explained based on the flowchart shown in FIG.

This control flow starts when detection information LTC corresponding to lens information is received from the lens microcomputer 14.

In step 21, each lens encoder information is received from the lens microcomputer 14 on the lens side, and this information is decoded.

In step 22, an AF flaw signal representing the focus state in the AF circuit on the camera body side is sampled while referring to the pressure detection information in the AF drive system.
3 compares that value with the current value. If there is a change in the focus state, the process proceeds to step 25 and the control information transmitted to the lens side is updated, regardless of the state of the busy signal. If there is no change in the AF scratch signal in step 23, the focus bu of the LTC sent this time
Step 24) Determine whether the sy signal is O or 1. If it is 0, it is not the backlash OFF period, so step 2
Proceed to step 5 to update the control information sent to the lens side. If the busy signal flag is set in step 24, step 25 is skipped, the AF control is ended, and the process proceeds to step 26 and subsequent AE sub-controls. In other words, in this case, the control information and commands sent to the lens side are unchanged from the previous time, and even if there is backlash or the like and the lens is not driven according to the command, the AF circuit may malfunction and become out of focus as described above. It is possible to eliminate the inconvenience of stopping at a certain position, and to perform stable and highly accurate control. What should be noted here is that the bus
Even if the y signal is output, it does not affect the other automatic exposure systems and zoom control systems (this is because each drive unit can be controlled independently).

Another point is that regardless of the presence or absence of the busy signal,
If there is a change in the F information, the data is updated and control continues. In other words, if the backlash is small (and can be removed immediately, or if the AF scratch signal changes further), it is possible to move on to the next control without waiting for the busy signal period, improving responsiveness. It is to be done.

The control flow from step 26 to step 29 shows the control operation of the automatic exposure control device (AE).

In the AE control, in step 26, an AE multiplied signal representing the focus state in the AE circuit on the camera body side is sampled while referring to the detection information in the AE drive system, and in step 27, this value is compared with the current value. If there is a change in the exposure state, the process advances to step 29 and the control information transmitted to the lens side is updated, regardless of the state of the busy signal. A in step 27
If there is no E times signal change, the L sent this time
Step 28) Determine whether the TC's AEbusy signal is O or L. If it is O, it is not a backlash period, so
Proceeding to step 29, the control information transmitted to the lens side is updated. If the busy signal flag is set in step 28, step 29 is skipped, the AE sub-control is ended, and the process moves to zoom lens control from step 30 onwards.

In zoom lens control, in step 30, the zoom switch 8 is operated to perform zooming, and in step 31, it is determined whether the zoom busy signal in the control information LTC sent this time is O or 1, and if it is 0, the back Since it is not the rush period, the process advances to step 32 to update the control information transmitted to the lens side. If the busy signal flag is set in step 31, step 32 is skipped, zoom control is ended, and step 33
Then, the control information, which has undergone processing such as updating or holding the previous value in the automatic focus adjustment, automatic exposure control, and zoom equal volume unit described above, is transmitted to the lens side at the timing explained in FIG. 2.

In the above-mentioned embodiment, what is effective in the operation of the flowchart in FIG. When reversing, the time required for stopping is also a time lag in commands from the camera microcomputer 9, and a busy signal can be sent to each unit, and by using the focus busy signal, drive commands for AE and zoom can be held. Since the drive command for only the AF motor can be held without any system problems, system problems can be eliminated.

According to the above example, we explained the case of preventing malfunction of the camera-side control circuit during the period of removing backlash, but there may be a discrepancy between the control information supplied from the camera side to the lens side and the actual operation of the controlled object. This is not caused only by backlash, but may also be caused by the motor control method.

For example, the motor for automatic focus control needs to adjust the lens drive speed depending on the distance to the in-focus point, depth of field, etc., but if the motor is controlled by voltage, the voltage will drop at low speeds, so It is not possible to obtain the driving torque. Therefore, when performing this type of control, duty control (PWM control) of the motor is performed.

However, in duty control, the motor drive period is controlled by changing the width of the drive pulse, that is, the ON period, so the motor OFF period during driving is exist.

During this period, despite a drive command being issued by control information from the camera side, the lens does not move contrary to this command, which causes the automatic focus control device to malfunction, similar to the above-mentioned backlash.

FIG. 6 shows a control algorithm when the lens microcomputer 14 outputs a busy signal while the duty of the motor drive pulse is OFF. When the side operation is started, a lens control command is decoded from the received information in step 41, and the process proceeds to step 42, where the motor is driven with a duty drive pulse corresponding to the command speed. Subsequently, in step 43, it is determined whether the drive pulse is in an ON period or an OFF period. If it is on, the process proceeds to step 44, where the busy signal flag is set to O, and then the process proceeds to steps 46 and 47, where information on detecting the state of the lens including the busy signal is sent back to the camera side. If the duty is in the OFF period in step 43, the process proceeds to step 45, where the busy signal flag is set to 1, and then the process proceeds to step 44, where information on the detected lens state is returned to the camera side.

From now on, the control on the camera side is as described above.
Explanation will be omitted.

(Effects of the Invention) The present invention is capable of transmitting time lag conditions such as absorption of backlash caused by the rotational direction of the motor to the camera body as a specific signal for each driven part and drive unit. Measures to prevent malfunctions, such as stopping the calculation or transmission of control information, can be taken independently for each unit, without simultaneously stopping other units or interfering with their operations (and preventing system problems). It is extremely effective in camera systems with interchangeable lenses.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram of a camera system showing an embodiment of the present invention, Fig. 2 is a diagram for explaining communication timing and data structure between the camera and lens, and Fig. 3 is control of main parts in the lens microcomputer. Flowchart showing the operation. Figure 4 is a diagram to explain backlash in the lens drive system. Figure 5 is a flowchart to explain the control operation of the main parts in the camera microcomputer. Figure 6 is the control operation of the lens microcomputer. FIG. 2 is a flowchart showing another embodiment of FIG. IQ□ iot: 11 Uni J- to the camera microcontroller

Claims (1)

[Claims] A lens unit that can be attached to and detached from the camera body,
a plurality of driving means for driving a plurality of driven parts in the lens unit based on a signal from the camera body side; a detection means for detecting a state of each of the driven parts and outputting detection information; , means for detecting a drive delay between each of the driven parts and the respective driving means and generating a predetermined control signal for a period capable of absorbing the drive delay, and each of the detected information and each of the control signals. and communication means for time-divisionally supplying the camera with the camera body.