JPS59201006A - Camera - Google Patents

Abstract

PURPOSE:To suppress an influence of a near infrared-ray area component in an external light component, and to obtain a correct exposure by placing a visibility correcting filter on the front of a photodetecting means at the time of photometry, in a camera which combines a photodetecting means of an auto focus device of an active type, and a photometric photodetector. CONSTITUTION:In case when luminance of an external light is comparatively high, and a photometric changeover switch SW50 is switched to a K1 side, when the second release is pushed, a switch SWD becomes on, a plunger PM is driven, and a visibility correcting filter DCE is inserted between a differential type CCD SPE and an object to be photographed. An output signal from an external component output terminal VFG2 is inputted to an operational amplifier OP13, an operation is executed, and a shutter second time signal is displayed on a meter MT. At the photographing time when the third release is pushed, the shutter second time signal is expanded by a real time by a transistor TR50, and a shutter magnet Mg is controlled by a Schmitt trigger circuit SHK.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a photoelectric conversion means for controlling the exposure amount of a camera using a photoelectric conversion means of a distance measuring device that projects light onto a subject and detects distance by receiving light reflected by the subject. Regarding correction of the sensitivity characteristics of.

Conventionally, in distance measuring devices that detect distance by projecting light onto a subject from a light projecting device and receiving reflected light from the subject by a light receiving device, the projecting device uses a light emitting diode, a laser diode, etc. that emits near-infrared rays with high energy efficiency. Since a photodetector is used, the light receiving means of the distance measuring device uses an element with high sensitivity in the near-infrared region, and in order to further improve the efficiency of the photodetector, a narrow band filter that transmits only near-infrared light is used. However, when the light receiving means of the distance measuring device is used for controlling the exposure amount, as described above, the light receiving means uses a narrow band filter in the near infrared region. When the component is large, such as under an incandescent lamp, the near-infrared component is large, even though the actual level of outside light is not very high. The drawback was that it sometimes resulted in under-lit photos. Also, when the near-infrared region component of the external light component is small, even though the actual level of external light is not very low, the near-infrared region component is small, so the exposure is determined based on the output of the light receiving means and the photograph is taken. This had the disadvantage that it could result in over-the-top photographs.

In view of this point, the present invention includes a narrow band filter that transmits only near-infrared light of the wavelength of the projected light in front of the light receiving means when operating a distance measuring device that projects light onto a subject and detects distance by receiving light reflected by the subject. The above-mentioned drawbacks are solved by disposing a visibility correction filter in front of the light receiving means when detecting the exposure amount control signal of the camera.

The present invention will be explained in detail below using the drawings.

FIGS. 1(a), 1(b), and 1(0) are explanatory diagrams of a priori conversion means used in a differential type COD to which the present invention is applied.

FIG. 1(a) shows that when light is emitted from a light source, two photoelectric conversion units A4. B.

The amount of charge A, B generated by the ambient light and the amount of charge A generated by the ambient light when light emission is stopped. , Bo are conceptually shown.The sum A+Ao and B+Bo of the charge amount of each photoelectric conversion unit A1 . B, to the first and second charge storage sections A2.
B2 respectively, and when no light is emitted, the photoelectric conversion units A1. B,
The charge A generated on , Bo are the sixth and fourth charge storage parts A5
．． B, respectively. Since the difference between these accumulated charges is taken by a differential circuit, only the charge amounts A and B of the reflected light components due to the projection of light are detected, as shown in Fig. 1 (1)), and as a result, the first As shown in figure (C), when the amount of charge A and B is A=B, for example, the lens system of the distance detection system determines that it is the in-focus position. In addition, if the charge amount A-1-BO value is kept constant at this time, the slope near the focus position of A-B will be almost constant, and the focusing accuracy will be maintained constant. This is preferable because it can be done.

FIG. 2 is an explanatory diagram of an embodiment of the differential type 00D according to the present invention, and As and BS are the first and second photoelectric conversion sections, AL
, BL are first and second charge storage units that accumulate the sum of reflected light from light emission and ambient light when light is emitted, and AD and BD are sixth and fourth charge storage units that accumulate ambient light when no light is emitted. Charge storage section, engineering C! G
1. Engineering tm! When φIcG is at a high level, G2 is an integral clear gate for clearing the charge generated from the photoelectric conversion section As and BS; SHL and OR2 are charge transfer gates; when φIcG is at a high level, the photoelectric conversion section As , BS and the generated charges are stored in the charge storage unit AL.

Accumulates in BL, and when φsH is low level, inverter N1
If su2 is at a high level through the photoelectric conversion section As.

Charges generated from BS are stored in charge storage sections AD and BD. TG1 to TG4 are charge transfer gates, and when φTG is at a high level, the charges stored in the charge storage section are transferred to the charge voltage conversion sections BO1 to BO4, and signal reading is performed. BOl contains the A + Ao signal in Figure 1 (a), and the B
B + Bo signal to o2, A to Bo6. signal,
B for Bo4. A signal is output, and the differential amplifier circuit DA1
Through the differential amplifier circuit DA2, (A+Ao)-(Ao): A, through the differential amplifier circuit DA2 (B+Bo)-(Bo) = B
, A-B signal ■A-B via differential amplifier circuit DA3
is output. Also, charges (A + Ao) + (B+Bo) and A accumulated in AL and BL and AD and BD. 10B0 is a floating goo) FG1, which is non-destructively read out via F()2 and is read out via the differential amplifier circuit DA4 as (A0A.)+(B+Bo)-(Ao+Bo)=:A+
B signal ■A+B is output. When the output of ①A+B reaches the reference value, the signal is read out. After signal reading is detected, φRB is set to high level and unnecessary signals are reset.

FIG. 3 shows an example of an electric circuit for driving the differential fi COD 8PE shown in FIG. 2, and FIG. 4 is a timing chart of the main parts of FIG. Time t. When the power switch SW is turned on, the power E1 is applied to each part, the oscillator OSC starts oscillating, and the constant voltage power REQ becomes V
Output C. At the same time, in synchronization with the rising pulse of OSC, for a short time determined by capacitor C20' and resistor R2o,
Since the output of AND is inverted to high level, one-shot circuit ON1 generates a one-shot pulse, which is passed through OR gates OR3, OR4, and OR5 at time t.

During -t2, unnecessary charges in the differential CCD are cleared. At time t1, the R197 flip-flop RF1 is reset in synchronization with the rising υ pulse of OSC. Also, due to the high level signal of OSC, C) transistor Tr1
is turned on, the light emitting element LD emits light with the current regulated by the resistor R1, and is projected onto the object OB via the light projecting lens LN1, and the reflected light passes through the light receiving lens LN2 to the differential CC.
The image is formed on D. When a reflected light image is formed at the center of the photoelectric conversion units A1 and B, the outputs from the photoelectric conversion units A1 and B are equal, which is the in-focus position. Time t2
When the output of one-shot 0IJ1 is inverted to low level, when OBC is high level, the reflected light signal at the time of light emission is transferred to the charge storage parts AL and BL, and when OSC is low level, the signal during non-emission is charged. The storage units AD and BDVc9 store each other. R
When the signal at time t, TEvA+, exceeds the reference voltage determined by the resistors R2, R, the output of the comparator OP1 is inverted to the high level side. is set, one-shot ON2 generates one-shot pulse, and φIO
Set G to high level to complete storage of image information in the differential W COD. At the same time Antogame) ANl, Orgate O
φTG is set to a high level through R5 to read out the stored information, and the sample and hold circuit BED is set at time t4 to t.
The information of vA-B is sampled and held during the period of 5. Between time t5 and t6, inverter N2 and AND gate AN
2. Since φ is set to a high level via the OR gate OR3, unnecessary charges stored in the charge-voltage converter are reset, and new image information storage starts from time t6. Note that at time t5, J
RF, and is configured to be set.

Time t6-t. Between times t and t6, image information is detected in the same manner as between times t and t6, and new image information is sampled and held between times t and t. The information sampled and held in the pHD is used to drive the photographing lens to the in-focus position via the control circuit CKT.

FIG. 5 is a circuit diagram of the first embodiment of the present invention, and FIG. 6(a)
is a diagram showing the sensitivity characteristic DSE of the differential type 00D, the spectral characteristic DCE of the visibility correction filter, and the spectral characteristic DRE of the near-infrared bandpass filter. Fig. 6 <b) is a schematic diagram of an embodiment of the present invention, Fig. 6 (0) is a top view of the switch SWA for switching between distance measurement and ANl light, and Fig. 6 (d) is linked to the shutter button. Fig. 6 (Ej
) is a circuit diagram of the switch shown in FIG. In Figure 5, TOK is the clear gate signal φ of the differential type 00D SPE. . OH2 is a timer circuit that operates in synchronization with the fall of TCK and inverts its output from L level to R level after a predetermined period of time. The one-shot circuits that generate pulses, AG and OtAGll, are analog gates made of PET, and each has a differential CCD S.
PB Q'>terminal vA-)B, connected to terminal vm2 and ψ. The capacitors C1° and C1 are supplied with 1 when the analog gates AG and AG are turned on, respectively.
0 Accumulates a charge of 1. BP, o, BPl are capacitors C
10°C buffer amplifier' R10pR11 and R12
tRlg is a comparator CP, respectively. , CPl, is a voltage dividing resistor that sets the input voltage of the non-inverting input terminal of the comparator cp,. ■1 when the potential of the capacitor C10, which stores the signal at the terminals vA+B of the differential CCD SPK corresponding to the reflected light when the light is projected toward the subject, is lower than the level set by the resistor R10°R. Outputs the level signal. The converter cp1.degree. outputs an A level signal when the potential of the capacitor C1.degree. is higher than the level set by the resistor "121" S5. Buffer amplifier BP1. The output terminal of is connected to an operational amplifier OF through a resistor R15. and Yuioto.

L.D. is applied to a logarithmic compression circuit constructed by

5P1o is a central focus photometry type photometry element provided for determining exposure of the camera. Photometric element 8P. The output signal of operational amplifier OP1. and is applied to a logarithmic compression circuit constituted by a diode LD11. switch 5w5o
is the photometry switch, and when it is switched to the K1 side, spot photometry is performed using the differential COD BPK.
When switched to the 2 side, the photometry-element 8P,. center-weighted metering is performed.

OP, 2 calculates the photometric value output via the ASA or aperture setting resistor VR5° and the switch 5W5o,
This is an operational amplifier that outputs a shutter speed signal.

The transistor Trso forms a real time expansion circuit together with the second time count start switch 5W51, which is turned on in conjunction with the shutter opening of the capacitor 050%, and the Schmitt trigger circuit 5FiK, and calculates the shutter time obtained by the operational amplifiers OP and 2. Magnets for shutter control)
Drive Mf.

E2 is the power supply battery for the strobe device EIT, 8W8T is the power switch for the strobe device BT, VRIF is the thyristor 8CR [resistor R23゜R24, which outputs the reference voltage]
Together with the capacitor C31 and the transformer IDC, it constitutes a known strobe trigger circuit. TB is a xenon tube.

Light receiving element 5P2o is resistor R24j R25PH10PH
27e R28e R29# R50%″77 differential 32
1 CAst C54 and thyristors 8R2 and SR3 constitute a known automatic light control circuit. Comparator C
P, 2 is the voltage obtained by dividing the terminal voltage of capacitor C3o by resistor R2G, resistor R21t, R2□, and the terminal voltage of sensor C30, which is divided by resistor R20t, R21, and resistor "22,"
Compare the voltages divided from the reference voltage VoK resistor "18 p R19. The AND gate AND outputs the AND of the output signals of the comparators CP14 and CF2.
ANDGATE AHD1. is the comparator CI'1. by the inverter N1o. and the inverted signal of comparator cp,
Outputs the AND of 2. Tr, , Tr, 2 are connected to an AND gate AN, through a resistor R1617, respectively. ,A)I
J4. This is a transistor driven by the output signal of.

In FIG. 6(a), DSEj is a differential type ClCD, S
PE sensitivity characteristic curve, DCE is visibility correction filter D
The spectral characteristic curve C3 and DRIii are the spectral characteristic curves of the near-infrared bandpass filter DRE.

In Figure 6 C1)), LD is a light emitting element, OB is the subject, SWD is a switch that is switched for distance measurement and photometry, RD is a resistor, PM is a plunger, and LN2 collects the reflected light from the subject OB. It is a condensing lens.

In FIG. 6(Q), E3WA is a photometry changeover switch, which switches between center-weighted photometry side A and spot photometry S.

In Figure 6(d), the 8HB turns on the camera and measures the distance in the first stroke, performs photometry in the second stroke, and performs distance measurement in the second stroke.
The shutter button drives the shutter movement with the stroke, and when it is not pressed, the camera's power switch SW
, photometry changeover switch SWB, and 8WO1 filter changeover switch SWD, switch SWC is on, switches sw and SWB.

The SWD is off, and if the release is pressed from the first off to perform distance measurement (sw H, p 7), the switch SWC remains on and the switches SWB and SWD remain off. To perform photometry, when the second release is pressed, SW remains on, switch SWC changes from on to off, and switches SWB and SWD change from off to on/off.
become. When the third release is pressed, a shutter (not shown) operates, and a light emission signal is outputted by a light emission signal generation circuit in the case of a strobe device.

FIG. 6 (θ) is a detailed circuit of 5w5o shown in FIG. Even when the photographer presses the first stroke of the shutter button EIHB to measure distance, and the switch SWB is off and the switch SWC is off, the metering changeover switch 8W
If A is switched to the center-weighted photometry side, photometry can be performed using the center-weighted photometry element spi-o.

ΔNext, the operation of the first embodiment of the present invention constructed as above will be explained.

If the shutter release button 8HB is not pressed, the power switch SW shown in
The 1ml CD 8PK does not operate, the switch swc is on, the 8WB is off, and the outputs of the operational amplifiers 0P10 and 0P11 are not input to the resistor 50. Outer band filter DRFI! only is placed in front of the differential part ClCD 8PK.

When the photographer presses the second release of the shutter button SHB, the power switch SW is turned on and the differential W QC! D-
8PF- starts the operation described above.

After a certain period of time has elapsed, the output VA-) of the differential OCD SPK
- When vB reaches a certain value, comparator C shown in Figure 3
P1 is inverted, flip 7p tube RFI, one shot pulse is output by one shot circuit DN2)
Timer circuit T via OR4. Operate 1.

After a certain period of time set in the timer circuit Tck, the output is inverted from the L level to the R level, and the one-shot circuit ON3 outputs a one-shot pulse.

As a result, analog game) AGIQ and AGll are turned on, and differential fi QC! D BPK said timer 'l"c
Differential type 00D 8P]lC% at a certain time set to k
The accumulated surface charges are output from terminals A-)-B and VFG2, and are stored in capacitors 010 and 011, respectively.

The electric charge of the capacitor is transferred to the comparator 0P via the buffer amplifier BP10 and the buffer amplifier BP11, respectively.
10 Q'ry valley p 0P11, resistor 15, diode LD10, operational amplifier 0P10.

When the brightness of the outside light is relatively high, the photographer is not using a flash, the flash power switch 5W8T is turned off, and the metering switch 8W50 is set to 1, the shutter button 8IIB is When the second stroke of is pressed, switch SWO is off and 8
Since WB is turned on and switch 8WD' is turned on, plunger PM is driven and filter DCIC inputs to differential mClCD SPE 0P13, and calculations are performed with variable resistor VR5α for shooting information setting and resistor R50. ,
Shutter second time signal is displayed on camera MT. During photographing when the sixth release of the shutter button 8HB is pressed, the shutter time signal is extended in real time by the transistor Tr50, and the shutter magnet Mf is controlled by the Schmitt trigger circuit 8HKK.

When the light metering changeover switch 8W50 is switched to the t-[1, side and the first stroke of the shutter button is pressed, the switch 8WD is off and the visibility correction filter DOFi is not driven by the plunger PM. , differential fi C! (:!D Since the 8PK detects only near-infrared components, it is possible to perform photometry when the photometry switch is set to the 5w5o or 2 side with the first stroke, but it is If the photometry switch 5w5o is switched to the 2nd side, the SWB will be turned off as soon as the SWA is on the 1st side, making photometry impossible.Also, if the photometry selector switch 5w5o is switched to the 2nd side, the center-weighted photometry type light receiving element will be turned off. B.P.
10 and operational amplifier 0P11. fi number compression diode LD
When the shutter button SHB is pressed to the third release, the photometric value from 11 is input to the operational amplifier 13 via the switch 5w5o, and calculations are performed with the shooting information setting resistor VR50 and resistor R50, and the shutter time signal is sent to the meter MT. During shooting when the shutter button is pressed up to the third release, the shutter time signal is extended in real time by the transistor 'rrso, and the shutter magnet Mf is controlled by the Schmitt trigger circuit 8HK.

When the brightness of the outside light is relatively low and the photographer turns on the power switch 8W8T to perform strobe photography, the reference voltage source VEM' generates the reference voltage VC, and at the same time, a circuit (not shown) displays the scimeter MT. is turned off for flash photography)
The shutter speed will also be set automatically. When the first stroke of the shutter button 8HB on the camera side is pressed, the power camera is driven, and as described above, the generating element LD shown in FIG. Differential type 00D SPI! Terminals A-1-B of i are synchronized with the clear gate signal φ-aa, and are output as charges accumulated in the differential type (30D SPF!) at a fixed time set by the timer circuit Tck, and are output by the output of the one-shot circuit ON3. Analog gate AG10 turns on and capacitor 01
Stored at 0. The potential of capacitor 010 is applied to comparators 0P10 and 0P1 via buffer amplifier BP10.
1 is compared. Since the level of external light is low and most of the light reflected from the subject is φ, the potential of capacitor 010 is lower than the input level of the non-inverting input terminal of comparator cpio set to resistors R10 and R11, and resistors R12 and RI
When the level is lower than the inverting input terminal of the comparator (3P11) set by B. The photographer is informed that the light reflected from the subject by the light emitting element LD shown in Figure 3 is weak and cannot be photographed even if the strobe light is emitted.If the subject is far away, the light reflected by the light emitting element LD shown in Figure 3 When the light level is relatively weak, the output of BPlo is connected to resistors R10 and R1.
If the level is higher than the level of the non-inverting input terminal of the comparator 0P10 set in 1, and higher than the level of the inverting input terminal of the comparator ap, , set by the resistors R12 and R15, the comparator OF, o is at L level. A signal is output, the transistor Tr1o is turned off, and the light emitting diode LE1o is turned on. Also comparator CPs
1 mode level signal is output, and the signal inverted by inverter N1o is input to AND gate AN11. Therefore, resistor 11a, R1? Comparator set with (
The level of the non-inverting input terminal of 3P12 and the capacitor C3
0 resistor R20 and resistors R21, R22 until the divided voltages become equal) ANll outputs an H level signal, the transistor Tr12 turns on, and the booster circuit D
The terminal ST of OO becomes the same potential as the ground, and the booster circuit DC
C performs an action. Also, if the subject is relatively close,
When the level of light reflected by the subject of the light emitting element LD shown in the figure is high or the brightness of external light is high, the differential type COD
Capacitor 0 due to the output signal of terminals A and B of EIPB
When the voltage of 10 is higher than the level set by the resistors R10 and R11, it is input to the comparator (3P11 also outputs a signal of the ■ level first and inputs it to the analog game) ANlo. Therefore resistance R18
The level of the non-inverting input terminal of the controller (lator C!P11) set by 1R19 and the resistor R2 of the capacitor (3so)
0, the AND gate ANIQ outputs an H level signal until the divided voltages by R21 and resistor R22 become equal, transistor Tr11 is turned on, and terminal S of external pressure circuit DCO
T becomes the same potential as the ground, and the booster circuit DCC operates.

FIG. 7 is a schematic diagram of a second embodiment of the invention. 7th
In the figure, LK1 and LK2 are guest-host type liquid crystals, respectively, and the lens LN2 and differential W shown in Figure 6 are
C! (It is placed between the 3D SPE.

When the switch 8WD is off, an electric field is applied to the liquid crystal LK2, and the liquid crystal LK2 has the same spectral characteristics as the near-infrared band filter DRE. When the switch BWD is on, an electric field is applied only to the liquid crystal LK1 by the inverter ND, and the liquid crystal LK2 has the same spectral characteristics as the near-infrared band filter DRE. LK1 has the same spectral characteristics as the filter DOE for visual sensitivity correction, and in the case of distance measurement, it is used as a differential mcaDSP.
It has the same effect as when the bandpass filter DRE is placed in front of E. In the case of photometry, it has the same effect as the visibility correction filter Di.

In the above-mentioned embodiment of the present invention, a switch linked to the switch SWB linked to the second stroke of the release button SHB is used as the detection means for detecting whether the photometry state is present, but other means for detecting the photometry state may be used. The photometry state may be detected from a circuit. In this embodiment, a plunger PM driven by a switch EIWD interlocked with a switch 8WB is used as a control means for disposing a visibility correction filter in front of the light receiving means during photometry based on a signal from the detection means. Differential type C (
! It goes without saying that a=D8PIn may be used as another storage type photoelectric conversion element, or may be used as another light receiving element. In addition, in the first embodiment, the filter D is used as a visual correction filter.
i. In the second embodiment, the liquid crystal LK1 is used, but other electrochemical devices may be used.

As described above, according to the present invention, in a camera in which the light receiving means of an active autofocus device is also used as a light receiving element for photometry, there is provided a detection means for detecting that the camera is in a photometry state, and a signal from the detection means is used when measuring light. Since the control means for disposing a visibility correction filter in front of the light receiving means is provided, it is possible to obtain a photograph with incorrect exposure that occurs when the light receiving means of an active autofocus device and a side light receiving element are used together. can be prevented and is highly effective.

[Brief explanation of drawings]

FIGS. 1(a), (1)), and (C) are explanatory diagrams of storage-type photoelectric conversion means used in the storage-type photoelectric conversion device according to the present invention, and FIG. 2 is an illustration of an accumulation-type photoelectric conversion means used in the present invention. FIG. 3 is an explanatory diagram of an embodiment of an electric circuit for driving the photoelectric conversion means used in the present invention. FIG. 4 is a timing chart of the main part of FIG. 3. FIG. An electric circuit diagram of an exposure amount control device to which the present invention is applied. )) is a schematic diagram of an embodiment of the present invention, FIG.
d) is a sectional view of a switch linked to the shutter button, FIG. 6 (θ) is a detailed circuit diagram of the switch EIWso shown in FIG. 5, and FIG. 7 is a schematic diagram of a second embodiment of the present invention. . SPE...Differential type C0D 8WD...Switch I, 1...Liquid crystallinity for near-infrared band filter

Claims (1)

[Claims] In a camera in which the light-receiving means of an active autofocus device also serves as a light-receiving element for photometry, there is a detection means for detecting that the camera is in the photometry state, and a sensor that detects the presence of light in front of the light-receiving means during photometry based on a signal from the detection means. A camera characterized by comprising a control means for arranging a sensitivity correction filter.