JP2756296B2 - Camera and lens unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a camera system such as a video camera.

(Background Art) Conventionally, interchangeable lenses have been widely implemented in camera systems. In recent years, there has been a strong demand for an interchangeable lens video camera system in a camera system including a video camera, an electronic camera, and the like. In parallel with this, an automatic focus adjustment device (AF) and an automatic exposure device (A
E), power zoom mechanism, etc. (ZOOM), automation and multi-functionalization. Therefore, based on the control information supplied from the camera side, the lens,
A plurality of driving means such as a motor for driving a driven portion such as an aperture are provided.

By the way, since such a driven part and a driving part are connected by power transmission means by a normal gear, there is a backlash. During the backlash period, the driven parts are not driven even though the drive system is driven by the control information.

To explain the AF operation as an example, the lens does not move during the backlash period even though a lens movement command is issued from the camera side. A state occurs in which the focus signal does not change. This state is similar to the operation at the time of reaching the focal point in the hill-climbing control in which a component corresponding to the degree of focus in the video signal is extracted and the lens is moved so that the component is maximized. There is a danger that the AF circuit will mistakenly detect this as the focal point and stop the lens. The backlash creates a so-called dead zone when the driving direction is reversed,
There is a disadvantage that the lens stops every time the driving direction of the lens is changed.

In order to solve such a problem, the applicant of the present application disclosed a previously filed Japanese Patent Application No. 63-216929, which outputs a busy signal to the camera body during the crush removal period on the lens side, and outputs the busy signal to the camera side. In the period during which the busy signal is output,
There is proposed a lens in which calculation of control information or transmission of control information to the lens side is temporarily stopped or suspended, thereby preventing malfunction during a backlash removal period.

(Problems to be Solved by the Invention) However, in the above-mentioned Japanese Patent Application No. 63-216929, it has been found through further research and development that further improvements can be made.

That is, according to the above device, the camera body stops or suspends transmission to the lens until the busy signal from the lens disappears, so other units such as automatic iris adjustment and zooming corresponding to changes in the video signal other than AF are also included. A system problem arises, such as temporary stoppage of operation or suspension of transmission of control information.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above problems, and is characterized by a lens unit that is detachable from a camera body. A driving unit for driving a driving unit in the lens unit based on a control signal from the camera body, a detecting unit for detecting a driving state of the driving unit and outputting detection information, and the driving unit for the control signal The lens unit includes an identification signal generating means for detecting a drive delay of the camera and generating a predetermined identification signal, and a communication means for transmitting the detection information and the identification signal to the camera body.

Another feature of the present invention is that a driving unit in the lens unit, a driving unit for driving the driving unit, a control unit for generating a control signal for driving the driving unit, and a driving unit for driving the driving unit Detecting means for detecting a state; identifying means for identifying occurrence of a delay in the driving state of the driving means with respect to the control signal based on detection information output from the detecting means; and occurrence of the delay by the identifying means. Is detected, a camera is provided with an identification signal generating means for generating a predetermined identification signal indicating the occurrence of the delay, and a communication means for transmitting the detection information and the identification signal to the control means. .

(Operation) By this, it is possible to detect a response delay between each driven unit in the lens unit and the driving means, and to detect the response of each driven unit without affecting other driving systems. It is possible to prevent a malfunction of the control system due to a difference between the control information and the actual operation.

(Embodiment) One embodiment of a camera and a lens unit according to the present invention will be described below in detail with reference to the drawings.

The overall schematic circuit configuration of the embodiment will be described with reference to FIG. The camera body is on the right side and the lens is on the left side with respect to the one-dot chain line in the center of the drawing. The light of the subject 1 is imaged by the optical system 2 on the image sensor 3 such as a CCD. The output is converted into a television signal by the camera signal processing circuit 4 and output. On the other hand, the television signal is a well-known AW
It is used for various automatic adjustment mechanisms such as a B (auto white balance) circuit 5, an AF circuit 6, and an AE circuit 7 (automatic exposure control). A control circuit 5 as a control signal source of the automatic adjustment mechanism;
Control signals are output from 6 and 7. The control signal of the AWB circuit 5 for adjusting the color balance of the camera signal processing is input to the processing circuit 4, and the remaining control signals are transmitted to the camera man
Is input to The control signal generated by the zoom switch 8 for setting the focal length of the optical system 2 is also transmitted to the camera microcomputer 9.
Is input to The data communication path 13 is connected to the lens microcomputer 14, and all communication data is once received by the lens microcomputer 14. Various control signals input to the camera microcomputer 9
C1, C2, and C3 are processed according to a program stored in a ROM in the camera microcomputer 9, and information related to the lens is supplied to the lens microcomputer 14 via the data communication path 13. Reference numeral 28 denotes a zoom motor, which is a drive source for controlling the movement of a lens related to the zoom operation in the optical system 2 in the optical axis direction. The zoom motor 28 is driven by the lens microcomputer 14 receiving the operation signal (C3) of the zoom switch 8 via the camera microcomputer 9 and activating the driver 25. Reference numeral 29 denotes an AE motor, which is a drive source for controlling opening and closing of the aperture in the optical system 2. This motor
In the drive of 29, the camera microcomputer 9 receives the control signal (C2) of the AE circuit 7, performs an operation for obtaining an appropriate aperture value, issues a drive command to the lens microcomputer 14, and based on the command, the lens microcomputer 14 is performed by activating the driver 26. Reference numeral 30 denotes an AF motor, which is a drive source for controlling movement of a lens related to focusing in the optical system 2 in the optical axis direction. To drive the AF motor 30, the camera microcomputer 9 receives the control signal (C1) of the AF circuit 6, performs an operation for obtaining the focusing direction and the amount of defocus, and issues a drive command to the lens microcomputer 14. This is performed by the lens microcomputer 14 operating the driver 27 based on the command. Reference numeral 31 denotes a zoom encoder which detects the movement of the lens related to the zoom action by using a code plate or a pulse plate, and detects the detected information by the lens microcomputer 14.
To supply. An aperture encoder 32 detects the movement of the aperture moving member and supplies the detection information to the lens microcomputer 14. 33 is an encoder for AF,
The movement of the lens related to focusing is detected by pulse reading using a pulse plate linked to a not-shown distance ring or the like of the lens, and the detected information is supplied to the lens microcomputer 14. Note that the encoder 33 is configured to be able to determine the movement of the lens related to focusing in both directions, that is, the movement to the closest side and the movement to the infinity side. Of course, the signal supplied from the encoder 33 to the lens microcomputer 14 also includes information on the lens movement direction related to the focusing.

The control of the motors 28, 29, 30 by the lens microcomputer 14 controls the rotation direction, drive / stop, speed, and the like. Data transmission from the lens microcomputer 14 to the camera microcomputer 9 is output as time-division serial data.

Next, FIG. 2 shows the camera microcomputer 9 and the lens microcomputer 14.
4 shows communication data between the server and the server. The control information CTL transmitted from the camera microcomputer to the lens microcomputer includes AF, AE, Z
The OOM circuit has a structure in which control instructions are stored serially in order for each unit to form one packet. This is synchronized with a vertical synchronizing signal (V cycle) of a television signal on the camera side, and the lens microcomputer 14 is controlled. Send to.

On the other hand, the data communication circuit 13 is constituted by a bidirectional bus, and the lens microcomputer 14 receives the control signal from the camera microcomputer 9 and, at the same time, receives the AF, AE, and ZOOM encoders 33, 32,
Detection information indicating the state of the optical system detected by
The detection information LTC which is sequentially stored according to each data area of the CTL and is made into one packet is returned to the camera microcomputer 9. CTL
The lens microcomputer 14 receives the control information CTL from the camera microcomputer, detects the result of controlling the optical system based on the control information CTL, and returns the result to the camera microcomputer 9 based on the control information CTL. Therefore, the detection information is returned in the next V period, for example. In the figure, the packets corresponding to each other are indicated by arrows.

As described above, the lens microcomputer 14 is switched to the camera microcomputer 9
, Encoder information etc. (LTC) for each unit is transmitted.

On the other hand, the data structure in each of the CTL and LTC packets is as shown in FIG. 2 (b), and a header of a predetermined data pattern indicating the start of the packet is formed at the head of the CTL. AF control information (speed information, etc.), AE control information, and zoom control information are arranged serially, and LTC takes the same data format,
The head is followed by the focusing lens position detection information, the aperture value detection information, and the zoom, that is, the focal length information. Particularly, in the LTC, a bit indicating the drive delay of the driven system is provided in the encoder information of each unit (hereinafter, referred to as a busy signal). This busy signal is a flag bit that is set to 1 when a drive error due to backlash or the like occurs between the driven system and each drive system when driving each driven system according to a command in the control information transmitted from the camera microcomputer. Yes, LTC
At the same time, it is returned to the lens microcomputer.

Next, the operation of the lens microcomputer 14 according to the point of the embodiment will be described based on the flowchart of FIG.

This control flow is started when the motor 28, 29 or 30 on the lens side is driven to change the state of the optical system in accordance with the command of the control information CTL transmitted from the camera microcomputer 9.

When the flow starts, the control information CTL transmitted from the camera myco 9 on the camera body side is received, and the contents of the command are decoded (step 1). Lens side motor 28,
Regarding any of the motors 29 and 30, the flow is separated (Step 2) depending on whether the immediately preceding movement direction is forward rotation (+ end point) or reverse rotation (−end point). Proceed to 6. These steps are
Since a backlash always exists between the drive gear and the driven gear of the motor output transmission system, the drive gear is output at the time when the command for controlling the rotation of the lens-side motor 28, 29 or 30 is issued from the camera microcomputer 9 this time. This is because it is necessary to determine in which direction the gear is engaged with the driven gear.

That is, when viewed in FIG. 4, the subsequent flow is different depending on whether it is the state of FIG. 4 (a) or the state of FIG. 4 (b).

FIGS. 4 (a) and 4 (b) show the state of the backlash d in the drive system for driving the lens in the different rotation directions between the drive unit side gear 100 and the driven unit side gear 101, respectively. It is shown.

In the lens microcomputer 14, flags “REVERSE” indicating these driving directions are provided. 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 flag of “REVERSE” is “0”. 1 "stands.

Then, when the "REVERSE" flag is "0" in step 3, the finger of the camera microcomputer 9 switches to the opposite direction this time (the current motor driving direction and the current command are reversed). If this is the case, the process proceeds to step 4, and if not, the process proceeds to step 5 if the current motor drive direction and the present command are the same forward direction.

When the process proceeds to step 4, the flag of "REVERSE" is set to "1" and the process proceeds to step 9.

If the process has proceeded to step 5, the process proceeds to END of step 12 while the flag of "REVERSE" remains "0", and the flow ends.

If the direction is reversed in step 2 and the process proceeds to step 6, if the “REVERSE” flag is “1”,
When the command from the camera microcomputer 9 is in the reverse direction, which is the same direction as the previous command, the process proceeds to step 7, and instead, the current command is the forward direction with respect to the reverse direction, which is the current motor driving direction. If so, go to step 8.

If the process has proceeded to step 7, the process proceeds to step 13 END while keeping the "REVERSE" flag at "1".

If the process proceeds to step 8, the flag of "REVERSE" is set to "0" and the process proceeds to step 9.

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

In step 10, a busy signal is transmitted to the camera microcomputer 9, and in step 11, when the timer time of the timer means has reached the set value, the process proceeds to step 12 as END, and when the timer set time has not yet been reached, Return to step 10 to continue outputting the busy signal.

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

Next, the operation of the camera microcomputer will be described with reference to the flowchart of FIG.

This control flow starts when the detection information LTC corresponding to the 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, the AF signal representing the focus state in the AF circuit in the camera body is sampled while referring to the detection information in the AF drive system, and in step 23 the value is compared with the current value. When there is a change in the focus state, regardless of the state of the busy signal, step 25
Then, the control information to be transmitted to the lens side is updated.
If there is no change in the AF signal in step 23, it is determined whether the focus busy signal of the LTC sent this time is 0 or 1 (step 24). If it is 0, it is not the backlash OFF period. To update the control information transmitted to the lens side. If the busy signal flag is set in step 24, the process skips step 25, ends the AF control, and shifts to AE control in step 26 and subsequent steps. That is, in this case, the control information and the command transmitted to the lens side do not change from the previous time, and even if there is a backlash or the like and the lens is not driven according to the command, the AF circuit malfunctions as described above and the out-of-focus position is obtained. Inconveniences such as stoppage can be eliminated, and stable and high-precision control can be performed. It should be noted that even if the busy signal is output in AF control, each drive unit can be controlled independently without affecting the vertical automatic exposure system and zoom control system. It is.

Another point is that if there is a change in the AF information regardless of the presence or absence of the busy signal, the data is updated and control is continued. In other words, if the backlash is small and can be removed immediately, or if a further change occurs in the AF signal, the next control can be performed without waiting for the busy signal period, so that the responsiveness is improved. That is.

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

In the AE control, in step 26, the AE on the camera body side is referred to while referring to the detection information in the AE drive system.
The AE signal representing the focus state in the circuit is sampled, and in step 27 the value is compared with the current value. If there is a change in the exposure state, the process proceeds to step 29 regardless of the state of the busy signal, and the control information to be transmitted to the lens is updated. If there is no change in the AE signal in step 27, the LTC AEbusy signal sent this time is set to 0.
It is determined whether or not it is 1 (step 28). If it is 0, it is not the backlash period, so the process proceeds to step 29 to update the control information to be transmitted to the lens side. If the busy signal flag is set in step 28, the process skips step 29, terminates AE control, and shifts to zoom lens control in step 30 and subsequent steps.

In the zoom lens control, in step 30, the zoom switch 8 is operated to perform zooming, and in step 31, the zoom bus in the control information LTC transmitted this time is transmitted.
It is determined whether the y signal is 0 or 1, and if it is 0, it is not the backlash period, so the process proceeds to step 32 to update the control information to be transmitted to the lens side. If the busy signal flag is set in step 31, skip step 32 and
After ending the zoom control, the process proceeds to step 33, and the control information obtained by performing processing such as updating or holding the previous value in each unit such as the above-mentioned automatic focus adjustment, automatic exposure control, zooming, etc. is described in FIG. To send to the lens side.

In the above-described embodiment, the operation of the flowchart of FIG. 3 is effective not only for merely instructing the camera microcomputer 9 of the time related to the backlash absorption, but also for quickly stopping the moving motor, for example. In the case of the reverse rotation, the busy time can also be transmitted for each unit as the time lag in the command from the camera microcomputer 9 when the rotation is stopped. By using the focus busy signal, the AE or zoom is not held as a drive command. Since the drive command can be held only for the AF motor, system problems can be eliminated.

According to the above-described example, the case where the malfunction of the camera-side control circuit during the period of removing the backlash is prevented has been described.However, the difference between the control information supplied from the camera side to the lens side and the actual operation of the control target is , And not only by the backlash, but also by the motor control method.

For example, a motor for automatic focus control needs to greatly change the lens drive speed according to the distance to the focal point, the depth of field, and the like. Can not get. Therefore, when performing this type of control, duty control (PWM control) of the motor is performed.
Thus, a sufficient drive torque can be obtained even at the time of low-speed drive.However, in the duty control, the motor drive period is controlled by changing the width of the drive pulse, that is, the ON period. Period exists. During this period, the lens does not move in spite of the fact that the drive command is issued according to the control information from the camera side, which causes the automatic focus control device to malfunction similarly to the above-mentioned backlash. .

FIG. 6 shows a control algorithm in the case where the busy signal is output while the motor drive pulse duty is OFF in the lens microcomputer 14, and the control information is received from the camera and the lens is controlled. When the operation on the side is started, the lens control command is decoded from the received information in step 41, and the process proceeds to step 42 in which the motor is driven by a drive pulse having a duty corresponding to the command speed. Then, in step 43, it is determined whether the drive pulse is in the ON period or the OFF period. If it is on, go to step 44 and bu
After the sy signal flag is set to 0, the process proceeds to steps 46 and 47, and information about the detection of the lens state including the busy signal is returned to the camera. If the duty is OFF in step 43, the flow advances to step 45 to set the busy signal flag to 1, and then the flow advances to step 44 to return the information on the detected state of the lens to the camera.

Hereinafter, the control on the camera side is as described above, and the description is omitted.

(Effect of the Invention) According to the present invention, a time lag state such as absorption of backlash generated by the rotation direction of the motor can be transmitted to the camera body side as a specific signal for each driven unit and each drive unit. It is possible to independently take measures to prevent malfunctions, such as stopping the computation or transmission of control information for each unit, without stopping other units at the same time or hindering operation, and eliminating system problems. This is extremely effective in a camera system with interchangeable lenses.

[Brief description of the drawings]

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 a camera and a lens, and FIG. 3 is control of a main part in a lens microcomputer. FIG. 4 is a flowchart for explaining the operation of the lens drive system and the backlash, FIG. 5 is a flowchart for explaining the control operation of the main part in the camera microcomputer, and FIG. 6 is a control operation of the lens microcomputer. 9 is a flowchart illustrating another embodiment.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-64512 (JP, A) JP-A-60-52812 (JP, A) JP-A-62-198809 (JP, A) (58) Investigation Field (Int.Cl. ⁶ , DB name) G02B 7/00

Claims (2)

(57) [Claims] 1. A lens unit detachable from a camera main body, comprising: a driving unit for driving a driving unit in the lens unit based on a control signal from the camera main body; and a driving state of the driving unit. Detecting means for detecting and outputting detection information; identification signal generating means for detecting a delay of driving of the driving means with respect to the control signal to generate a predetermined identification signal; A lens unit comprising: communication means for transmitting data to a camera body. A driving unit in the lens unit; a driving unit for driving the driving unit; a control unit for generating a control signal for driving the driving unit; and a detecting unit for detecting a driving state of the driving unit. Means, identification means for identifying the occurrence of a delay in the drive state of the drive means with respect to the control signal based on the detection information output from the detection means, and when the occurrence of the delay is detected by the identification means A camera which comprises: identification signal generating means for generating a predetermined identification signal indicating occurrence of the delay; and communication means for transmitting the detection information and the identification signal to the control means.