JP2839245B2 - Power Focus Device for Interchangeable Lens Camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a power focusing device for an interchangeable lens type camera, and more particularly, to a motor for auto focusing in a single-lens reflex camera or the like having a lens exchangeable and auto focusing function. The present invention relates to a power focus device using the method. [Prior art] In an interchangeable lens camera such as a single-lens reflex camera having an autofocus (hereinafter, referred to as AF) function, an AF motor is skillfully used for manual focusing, and a switch is used. A so-called power focus in which the lens is driven by an on / off operation can be performed. And about this power focus means,
The present applicant has previously provided the same in Japanese Patent Application Laid-Open No. 59-64816. In this technical means, a power focusing function is mounted on a lens barrel in which an AF motor is built in the lens barrel. [Problems to be Solved by the Invention] The above-described conventional power focus (hereinafter, referred to as PF) means simply uses an AF motor. However, the rotation speed of the motor was constant and the lens was driven. Therefore,
In the case of a long focal length, there is a disadvantage that it takes time to drive the lens, and no contrivance regarding this has been taken. SUMMARY OF THE INVENTION An object of the present invention is to provide a power focusing device that moves a taking lens at an optimum driving speed according to a focal length, a focal position, and the like in order to eliminate such a conventional disadvantage. [Means and Actions for Solving the Problems] The power focus device of the interchangeable lens camera according to the present invention is provided in the interchangeable lens, and information on the lens drive speed during power focus corresponding to the focal length or the shooting distance. , A reading unit for reading information on the lens driving speed at the time of the power focus from the storage unit, a power focus operation unit for instructing the power focus, and a power focus operation by the power focus operation unit. The rotation speed of the motor for changing the driving speed of the taking lens corresponding to the focal length or the taking distance based on the information on the lens driving speed at the time of the power focus read from the storage means provided in the interchangeable lens. And control means for changing Further, the information is a coefficient corresponding to a focal length, and the reading means reads the coefficient according to the focal length information of the photographing lens. Further, the information is a coefficient corresponding to a photographing distance of the photographing lens, and the reading means reads the coefficient according to photographing distance information of the photographing lens. Further, the information is information for setting a duty ratio of a drive pulse current supplied to the motor. [Embodiment] An embodiment in which the present invention is applied to an interchangeable lens camera having an AF function will be described below. FIG. 1 is an overall block diagram mainly showing power supply of a camera system to which the present invention is applied. Power battery
The voltage V _CC of 11 is boosted by the DC / DC converter 13 when the power switch 12 is closed, and the voltage between the lines l ₀ and l ₁ is made constant at the voltage V _DD . Line l _0, l main CPU14 between _1, bipolar II circuit 15, bipolar I circuit 16, the strobe control circuit 1
7, the lens data circuit 18 and the data back circuit 19 are connected, and the power supply control of the bipolar II circuit 15 is controlled by the main CP.
Power supply control of the bipolar I circuit 16 to the data back circuit 19 is performed by a power control signal from the bipolar II circuit 15. AF consisting of focus sensor 20, A / D converter 21, and AF CPU 22
The block is connected via the power control transistor 23
l _0, which is connected between l _1, on of the transistor 23 the power supply control for the AF block by the signal from the AF power control circuit of the main CPU 14, is performed by the off control. The AF CPU 22 is a circuit for performing an algorithm operation for AF, and displays in-focus and out-of-focus.
The AF display circuit 24 is connected. The main CPU 14 is wound up,
A circuit for controlling the sequence of the entire camera, such as a rewinding and exposure sequence, is connected to a display circuit 25 for performing a display other than the in-focus display. Bipolar II circuit
Reference numeral 15 denotes a circuit including various drivers necessary for a camera sequence, such as a motor control for winding and rewinding, lens driving and shutter control, and the like.
Etc. are connected. The bipolar I circuit 16 is a circuit mainly responsible for photometry, and has a photometric element 28.
The flash control circuit 17 controls the light emission of a built-in or external flash 29. The lens data circuit 18 is a circuit configured with a ROM provided in the interchangeable lens for each interchangeable lens and storing unique lens data necessary for AF, photometry, and other camera control, which is different for each lens. . Among the lens data stored in the lens data circuit 18, data necessary for AF include:
The information includes a lens magnification coefficient (zoom coefficient), a macro identification signal, absolute distance coefficients a and b, a power focus duty coefficient, an AF accuracy threshold ETh, a lens moving direction, an open F value, and the like. The bipolar II circuit 15 monitors the state of the power supply voltage V _DD , and sends a system reset signal to the main CPU 14 when the power supply voltage falls below a specified voltage, and
The circuit 15 to the power supply of the data back circuit 19, and the AF including the focus sensor 20, the A / D converter 21 and the AF CPU 22
The power supply of the block is cut off. Main CPU1
Power supply to 4 is performed even at a specified voltage or less. FIG. 2 is a system diagram showing transmission and reception of signals centering on the AF block. The AF CPU 22 and the main CPU 14 exchange data via a serial communication line, and the communication direction is controlled by a serial control line.
The contents of this communication include unique lens data in the lens data circuit 18 and absolute distance information. Further, the information of the camera mode (AF single mode / AF sequence mode / PF mode / other modes) is decoded from the main CPU 14 to the AF CPU 22 through the mode line. Furthermore, AFEN from the main CPU 14 to the AF CPU 22
The A (AF enable) signal controls the start and stop of each mode of AF and PF.
The EOFAF (end of AF) signal from 2 to the main CPU 14 is AF,
This signal is issued at the end of the operation in the PF mode and permits the shift to the exposure sequence. Further, the bipolar II circuit 15 decodes the signal of the AF motor control line from the AF CPU 22 and drives the AF motor drive circuit 26. When the AF motor (lens drive motor) 31 rotates by the output of the AF motor drive circuit 26, the slits 32 provided at equal intervals in the rotating member of the lens barrel rotate, and the light emitting unit 33a sandwiches the passage of the slit 32. The photointerrupter 33 in which the light-receiving unit 33b and the light-receiving unit 33b are arranged to count the slit 32. That is, the slit 32 and the photo interrupter 33 constitute an address generating section 34, and the address signal (count signal of the slit 32) generated from the address generating section 34 is shaped into a waveform and taken into the AF CPU 22. The sub lamp (hereinafter abbreviated as S lamp) signal sent from the AF CPU 22 to the bipolar II circuit 15 is an AF auxiliary light circuit.
The S lamp 27a is turned on when the subject is low light (low brightness) and low contrast. The AF display circuit 24 connected to the AF CPU 22 has an in-focus OK display LED (light emitting diode) 24a that lights up when focusing and an in-focus inability LED 24b that lights up when focusing is impossible. A clock oscillator 35 and a reset capacitor 36 are connected to the AF CPU 22. The AF CPU 22 and the A / D converter 21 exchange data via a bus line, and the transmission direction is controlled by a bus line control signal. And AF CP
A sensor switching signal and a system clock signal are sent from the U22 to the A / D converter 21. And A / D
For example, the converter 21 sends a CCD drive clock signal and a CCD control signal to a focus sensor 20 composed of a CCD, reads a CCD output from the focus sensor 20, converts the read analog output of the CCD output into a digital signal, and performs AF conversion. Send to CPU22. The AF block is, as shown in FIG.
By turning on the AF power control circuit, the transistor 23 is turned on to supply the power supply voltage V _DD , whereby the execution of the power-on reset routine shown in FIG. 3 is started. When this power-on reset routine starts,
First, the drive circuit of the AF block is initialized in the <I / O Initialize> subroutine. Specifically, the AF display circuit 24, the AF motor drive circuit 26, the AF auxiliary light circuit 27, etc. are turned off, and the serial communication line with the main CPU 14 is initialized. Next, in the <mode read> subroutine,
After reading out the mode line signal (mode signal) from the CPU 14 and determining which lens drive mode to execute, a certain period of time is passed in the <timer> routine, and the mode is read again through the <mode read> routine. The switching point is read. Then, the process returns to the first <mode read> until the mode switching is completed. The reason why the <mode read> subroutine is passed twice with the <timer> interposed is to prevent erroneous reading at the time of mode switching. When the mode switching is securely performed and the mode before and after the switching becomes the same, the mode after the switching is read and the process proceeds to the subroutine of each mode. That is, the lens driving modes include <lens reset>, <PF
(Power Focus)>, <AFSIN (AF Single)>,
There are modes of <AFSEQ (AF sequence)>. When one of these modes is selected, the subroutine of the selected mode is executed, and then the routine returns to the above (I / O initialization) routine. Reset>, <PF
When none of the modes>, <AFSIN>, and <AFSEQ> is selected, and when the <other> mode is selected, this is regarded as mere noise, and a certain time elapses in the <timer> routine. Then, the process returns to <I / O Initialize>. Here, in the operation of the <lens reset> mode, the lens is forcibly moved to the position at infinity (∞), whereby the relative distance signal, that is, the distance measurement output signal output from the focus sensor 20 is output. This is an initialization operation for converting the number of pulses from the position at infinity (∞) to an absolute distance signal, ie, an operation for clearing the absolute distance counter. If <lens reset> is selected,
After clearing the absolute distance counter, for example, after 5 ms, the process returns to the I / O initialization operation. In the <PF> mode, the distance ring of the lens is driven not by the manual operation but by the lens driving motor 31, and the focusing operation of the lens is performed by using the manual focusing or the focus aid. More specifically,
It described later PFUP (up) for operating switch SW _1, PFDN (down) for operating switch SW ₂ on, feeding of the lens by off, so that the renormalization is performed. Also, <
The operation in the mode AFSIN> is a one-shot AF operation in which focus is locked after an AF operation is performed on a subject. Further, the <AFSEQ> mode is continuous AF. In this mode, the AF operation is continuously performed as long as the first step of the release button is continuously operated. Meanwhile, as the operation switch for each mode of the lens driving, as shown in Table 1 below, four operation switches SW ₁ to SW ₄ is used. The first and second operation switches SW ₁ and SW ₂ shown in Table 1 are AF
Mode and PF mode are commonly used.
When the operation switch SW ₃ is off, the AF mode is set.
F mode is selected. In the AF mode, when both the first and second operation switches SW ₁ and SW ₂ are off, the lens reset mode is set. When both are on, the AF sequence mode is set, the first operation switch SW ₁ is off, and the second operation switch SW AFSIN mode is set when ₂ is on. When the first and second operation switches SW ₁ and SW ₂ are both off or both on in the PF mode, the operation is in the stop mode. When the first operation switch SW ₁ is on, the motor is used to move the distance ring to a short distance. PFUP mode to rotate the lens to the side and extend the lens.
The PFDN (down) mode convolving the lens by rotating the distance ring far side when the operation switch SW ₂ is ON. The fourth operating switch SW ₄ in the on-the stop mode of either mode and PF modes of AF mode, but no change be in any off, when on in PF mode HI (High speed) mode, the lens drive motor 31 rotates at high speed to perform coarse movement of the distance ring. When the lens ring is off, the mode becomes LO (low speed) mode, and the motor 31 (see FIG. 2) rotates at low speed to perform fine movement of the distance ring. Is performed. Next, in the flow shown in FIG. 3, when the mode <PF> is selected, the routine <PF> shown in FIG. 4 is called. In this <PF> routine, first, the AFENA signal is determined, and if the signal is not active, the routine returns. If the signal is active, that is, if the first stage of the release button is on, By setting the EOFAF signal, the operation of the second stage of the release button can be accepted. That is, it is possible to shift to the exposure sequence at any time during the PF. Thereafter, <lens read> is called, and lens data such as a power focus duty coefficient (hereinafter, referred to as a PFDUTY coefficient) in the lens data circuit 18 is read out, and then the state change flag is cleared. There are two types of PFDUTY coefficients for HISPEED (for high-speed rotation) and LOSPEED (for low-speed rotation).
This parameter determines ON / OFF DUTY at the time. This coefficient is saved in SPREGHI / SPREGLO, respectively. The status change flag is set when the speed changes
There is a DIFSP (speed change) flag and a DIFMOD (mode change) flag set when the mode changes. after this,
<Mode lead> is called, where the instruction of the lens rotation direction and the lens driving speed is read, and UP (up) and DN (down) of the lens rotation direction are set or cleared, and SP (speed). The flag is set or cleared. That is, the ON of Table 1 Operation relates to a lens driving mode switch SW ₁ to SW ₄ shown in, it is turned off is read. This <PF>
In the mode, the operation switch SW ₃ is on, and the PFU
Lens rotating direction when the P manipulation switch SW ₁ turned on (feeding lens) UP becomes direction, the lens direction of rotation while turning on the PFDN manipulation switch SW ₂ is (retracting lens) DN becomes direction. Then, the determination of the SP flag is performed, the SP flag is to be set when turning on the operation switch SW _4. When the SP flag is set, SPREGHI is read, and the value
Determine ON / OFF DUTY for high-speed driving. In this case, the on / off duty ratio of the pulse current for driving the lens drive motor 31 (see FIG. 2) is set high, and the lens is extended or moved in at high speed. When the operation switch SW ₄ is off, the SP flag is cleared.In this case, read SPREGLO and
Determine ON / OFF DUTY for low-speed driving. Therefore, the duty ratio of the motor drive pulse current is set low, and the movement of the lens is performed at a low speed. Thereafter, the <PDRV> subroutine is called. In this <PDRV>, on / off of the motor 31 is controlled based on the set duty ratio, and lens driving for one pulse is performed. Next, after it is determined whether the lens has stopped at infinity (∞) or the closest limit position, if the lens has stopped at the limit position, the motor is braked for about 100 ms. And call <SDISCNT> to set the absolute distance counter. Then, in this state, check if there is no change in the mode signal. <Mode change>
Weight while going around the loop. This <mode
In Change>, the status change (mode change) of the PFUP operation switch SW ₁ and the PFDN operation switch SW _{2 and} the state change (speed change) of the speed operation switch SW ₄ are checked. If the speed changes, the DIFMOD flag is set.
The flag is set. If the DIFMOD flag has been set, this is determined and the process returns to step S1. On the other hand, in the case of a normal power focus operation in which the lens does not reach the limit position, the above-described motor is turned on / off in the routine of <SPCTL> so that the lens driving speed becomes the predetermined coarse movement and fine movement speed. Fine adjustment of the duty ratio. That is, speed adjustment by turning on and off the lens drive motor is performed by <PDRV> and <SPCTL>. Thereafter, the AFENA signal is checked, and when the AFENA signal is active, that is, the first release button is pressed.
When the operation of the second row is on, call <Mode Change>, and at this time, the speed is changed and
If the DIFSP flag is set, the operation returns as it is. If the speed does not change, and if the DIFMOD flag is set and the mode changes, <brake> is called to stop the motor, and the <SDISCNT> Set the absolute distance counter and return to. If there is no speed change or mode change, return to <PDRV>, and as long as the operation of the first stage of the release button is kept on, <PDRV> and <SPCTL>
The PF operation according to> is continued. When the first stage of the release button is turned off, the AFENA
The signal becomes inactive, that is, the end of the PF operation is instructed from the main CPU 14, <brake> is called to stop the motor, and the absolute distance counter is set in <SDISCNT>. Then, from the set contents of the absolute distance counter, that is, the number of moving addresses from the infinity (∞) position and the absolute distance coefficients a and b in the lens data circuit 18, a calculation is performed by <CALDIS> to obtain the absolute value. The distance is calculated, and the calculated absolute distance information is sent to the main CPU. After this <CALDIS> return, power on
Return to the initial state of reset. Next, the actual PFDUTY coefficient will be described. In the case of interchangeable lenses with a built-in ROM, generally, as a method of determining the address, there is no encoder. With a single focus lens with a focal length encoder. With a zoom lens distance encoder. Can be If there is no restriction on space, if the above + is merged, it will have more information. Then, the method of determining the PFDUTY coefficient suitable for each lens can be devised so that the degree of blur on the focus glass changes at a constant speed by adopting a configuration having the above-described ROM address input format. Specifically, f
In the case of = 35 to 70 mm, the duty factor may be set so that the speed on the 70 mm side is about four times faster than that on the 35 mm side. When the above type is used, for example, when the lens is used for a full-range macro lens or the like, as the shooting magnification increases, when the amount of extension increases rapidly, the speed corresponding to this increases.
If the duty factor is set in the UP direction, quick focusing becomes possible. FIG. 5 shows a signal flow of the read PFDUTY coefficient. That is, when the interchangeable lens is mounted on the camera body, the lens is connected to the main CPU 14 in the camera body, for example, by four electric contacts J _{1 to} J ₄ provided on the connector J.
Thus, data can be transmitted / received through the power supply voltage supply line, the clock signal supply line, the data transfer line, and the enable signal line, which are connected by the above. The interchangeable lens attached to the camera body has a lens RO that digitally stores information about the lens required for exposure.
An M300, a distance encoder 320, and a focal length encoder 310 in the case of a variable focal length lens are incorporated therein. The lens ROM 300 stores information such as the PFDUTY coefficient, the lens open FNo., The minimum FNo., And the open metering error. A focal length encoder 310 whose output information changes by the zoom ring is connected. That is, the distance output information and the focal length output information are:
The conductive contacts provided on the distance ring and the zoom ring on the lens barrel slide on the code plate provided on the peripheral surface of the mirror copper, and information corresponding to the position of the contact is output. It has become. FIG. 6 shows the relationship between the encoder and the ROM in more detail for the case of a variable focus lens, and includes a distance ring and a zoom ring (not shown) provided rotatably on the lens barrel. , the conductive pattern P ₀ to P ₃ and P ₁₀ to P ₁₃ to the conductive contact pieces 41, 42 in sliding contact respectively on the code substrate provided on barrel circumference is attached. The conductive pattern P ₀ to P ₃ is the distance to the subject, for example 0.5~∞
The distance information [m] corresponding to the sliding position of the conductive contact pieces 41 outputs, conductive pattern P ₁₀ to P ₁₃ is the focal length, for example 35 to 70
The distance information of [mm] is output according to the sliding contact position of the conductive contact piece 42. The conductive pattern is partially P ₀
Is connected to P ₁₀ and the common GND _{and, P 1, P 2, P} 3 are respectively connected to one input terminal of the AND gate 43, 45 and 47 of the gate circuit _{39, P 11, P 12,} P 13 Is AND gate 44,4 respectively
It is connected to one input terminal of 6,48. And Gate 4
A gate control signal CS sent from a counter (not shown) is input to the other input terminals of 3, 45 and 47, and the gate control signal CS is input to the other input terminals of AND gates 44, 46 and 48.
Is input via an inverter 49.
The outputs of the AND gates 43 and 44 are input to the ROM address decoder X via the OR gate 50. The outputs of the AND gates 45 and 46 output the OR gate 51 and the AND gate 47.
And 48 are input to a ROM address decoder X through OR gates 52, respectively. When the gate control signal CS is “1”, an output signal of the distance information encoder 320 is output. When the gate control signal CS is “0”, an output signal of the focal distance information encoder 310 is output from the ROM through the gate circuit 39.
Input to the address decoder X. Output signals ₈ , ₉ , and ₁₀ sent from a counter (not shown) are input to the ROM address decoder Y. For example, the No. 4 code is PFDUTYH1 and the No. 5 code is PFDUTYH.
The address information specified by the output signal and the signal from the encoder input to the ROM address decoder X is output from the ROM 38 through the output buffer. Table 2 below shows an example of the correspondence between codes, distances, and focal length data based on encoder outputs. The signal EN controls the main buffer and EN =
When it is "0", it serves to switch the ROM to low power consumption. [Effects of the Invention] As described above, according to the present invention, the photographing lens is moved at an optimum driving speed according to the focal length, the focal position, and the like. Can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an electric circuit mainly for supplying power to a camera system to which the present invention is applied, and FIG. 2 is a diagram focusing on an AF block in FIG. FIG. 3 is a block diagram showing transmission and reception of signals, FIG. 3 is a flowchart showing a program operation centered on the AF CPU shown in FIG. 2, and FIG. 4 is a flowchart showing a program operation in a power focus mode. FIG. 5 is a block diagram showing a flow of a signal of a read power focus duty factor, and FIG. 6 is a block diagram showing an example of an electric circuit of an interchangeable lens having a built-in lens ROM. . 31 ... Lens drive motor 300 ... Lens ROM

Continuation of front page                   (56) References JP-A-61-196214 (JP, A)                 JP-A-60-53908 (JP, A)                 JP-A-62-58212 (JP, A)

Claims (1)

(57) [Claims] Storage means provided in the interchangeable lens and storing information on the lens drive speed at the time of power focus corresponding to the focal length or the photographing distance; and information on the lens drive speed at the time of power focus is read from the storage means. Reading means, power focus operation means for instructing power focus, and information on the lens drive speed at the time of power focus read from the storage means provided in the interchangeable lens at the time of power focus operation by the power focus operation means. Control means for changing the rotation speed of the motor to change the driving speed of the photographing lens in accordance with the focal length or the photographing distance based on the information. 2. The above information is a coefficient according to the focal length,
2. A power focusing apparatus for an interchangeable lens camera according to claim 1, wherein said reading means reads the coefficient according to focal length information of the photographing lens. 3. 2. The information processing apparatus according to claim 1, wherein the information is a coefficient corresponding to a photographing distance of the photographing lens, and the reading unit reads the coefficient according to photographing distance information of the photographing lens. Power focus device for interchangeable lens cameras. 4. 2. The power focusing device for a lens-interchangeable camera according to claim 1, wherein the information is information for setting a duty ratio of a driving pulse current supplied to the motor.