JPS59181327A - Diaphragm value detecting device - Google Patents

Abstract

PURPOSE:To detect exactly a diaphragm value by forming an image of an exit pupil in a line sensor arrayed linearly in the diameter direction passing through the center of an image forming surface of a conjugate position to a film. CONSTITUTION:A light passing through a photographic lens 2 passes through a semi-permeable mirror part 4a of a movable reflecting mirror, a total reflecting mirror 10, and a small lens 15 of a photodetecting part 12, and an image of a diaphragm member 3, namely, an image of an exist pupil 20 of the photographic lens 2 is formed on a line sensor 16 provided in the center of an image forming surface of a conjugate position to a film surface. A diameter D2 of its image 20A is in inverse proportion to an F-number of the photographic lens 2. Accordingly, the F-number is determined immediately from the number of photodetectors irradiated by a light, namely, an output of the line sensor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aperture value detection device, and more particularly to an aperture value detection device that can detect the aperture value of a photographic lens from the camera body side in a non-contact manner.

As is well known, automatic exposure (AID) cameras are classified into aperture-priority type A'FJ cameras, shutter-second priority type AE cameras, program AE cameras, etc. depending on their exposure control mechanism. In this camera as well, a mechanical exposure control mechanism is used to transmit the aperture value of the photographic lens to the camera body and to control the aperture aperture of the photographic lens from the camera body side. However, such mechanical exposure control mechanisms have the disadvantage that their configurations are often complicated. In addition, in a camera with an interchangeable photographic lens, the photographic lens and the camera body must be mechanically connected in conjunction with the operation of attaching the photographic lens to the camera body, and this connection mechanism is called 'bIl+'. There are drawbacks.

Therefore, in order to eliminate the above-mentioned conventional drawbacks, the present applicant has proposed that the image of the diaphragm member of the photographic lens, that is, the image of the exit pupil, be formed by a plurality of light receiving elements disposed at positions conjugate with the film surface. We have previously proposed an aperture value detection device in which an image is formed on a light receiving section and the aperture value of a photographing lens is detected based on the output of this light receiving section (Japanese Patent Application Laid-open No. 159417/1983).
. Since this aperture value detection device optically detects the aperture value of the photographic lens, it has the advantage that the aperture value is transmitted in a non-contact manner. However, since this device uses a light-receiving element with a circular light-receiving surface, it is affected by eccentricity of the light-receiving element and exit pupil. ■Exit pupil image 6-
In case things get blurry, the solution is to rely on the dog.

- Affected by the eccentricity of the imaging optical system and photodetector.

There is a problem with the cap.

Purpose of the present invention 1ZJ1 In view of the above points, means for adjusting the exit pupil of the photographing lens is disposed at a position conjugate with the film surface, and the exit pupil of the photographing lens is arranged in a position conjugate with the film surface, and the exit pupil of the photographing lens is An object of the present invention is to provide an aperture value detection device that detects the aperture value of a lens by forming an image of an exit pupil on a line sensor formed by linearly arranging a plurality of light receiving elements.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a sectional view of a main part of a reflex camera equipped with an aperture value detection device according to an embodiment of the present invention. In FIG. 1, the optical system of the -eye reflex camera 1 includes a photographing lens 2 which is made up of a combination of multiple lens groups (shown as a single lens in the figure), and A diaphragm section +A consisting of a plurality of sector blades built into the lens frame (not shown) of the lens 2
6, a movable reflection mirror 4 which is incorporated into the camera body and is arranged in the photographing optical path at an angle of 45 degrees with respect to the principal optical axis, and a photographic film 5 which is disposed at the focal position of the photographic lens 2. and a focusing glass 6 disposed above the movable reflective mirror 4 at a position conjugate with the photographic film 5;
It consists of a retacondenser lens 7 disposed directly above the focusing glass B, and a pentaprism 8 disposed on the surface of the condenser lens 70 to supply an erect image to the finder eyepiece 9. . The movable reflection mirror 4 is arranged in the diaphragm member 6 near the main optical axis.
The area corresponding to the maximum measuring aperture becomes the semi-transparent mirror part 4a,
The other area is a total reflection mirror section 4b, and a total reflection mirror 10 is disposed behind the semi-transparent mirror section 4a.

This total reflection mirror 10 is designed to interlock with the movable reflection mirror 4, and when the reflection mirror 4 jumps up, it follows the movement of the semi-transparent mirror 4 of the mirror 4. ] from below, and move it from the viewfinder optical system to the inside of camera 1 (
(Acts 1.-1 to prevent light from entering.

Then, at a position conjugate with the film surface, via the semi-transparent mirror part 4a of the reflection mirror 4 and the total reflection mirror 10,
A light receiving section 12 of an aperture value detection device is provided. As shown in FIGS. 2(A) and 2(I), the configuration of the light receiving section 12 of the aperture value detection device β' is such that a frame body 14 is fixed on a substrate 13, and a small lens 15 is mounted on this frame body 14. is supported and fixed.The upper surface of the substrate 16 is an image-forming surface conjugate with the film surface, and a large number of light-receiving elements 16 are arranged at the center of the image-forming surface.
a in a straight line ((line sensor 1 formed side by side)
6 are arranged.

Then, the center of this line sensor 16 and the small lens 1
The optical axis O of No. 5 and the optical axis O of No. 5 coincide in y.

FIG. 6 shows a state in which the image of the aperture member 3 of the photographic lens 2, that is, the exit pupil 20 of the photographic lens 2, is formed on the light receiving section 12 of the aperture value detection device in the optical system shown in FIG. FIG. The exit pupil 20 of the photographic lens 2 is imaged by the small lens 15 to form an image of @2OA.

If this image 2OA is far from the position of the line sensor 16, a blur D3 occurs on the line sensor 16.

Here, the distance from the exit pupil 20 to the small lens 15 is XI
+If the focal length of the small lens 15 is f, then image 2
The magnification (β) of OA is β=-□ (1)X, -f. Therefore, if the diameter of the exit pupil 20 is Dl, the image 2
The diameter (1)2) of the OA and the distance position (X2) from the small lens 15 are as follows. Then, if blur D occurs, this @2
0 A no Hoket (D 3) is the diameter of the small lens 15 d
, the patent is characterized by the distance from the small lens 15 to the line sensor 16. Furthermore, when the focal length f of the small lens 15 is made so small that it can be ignored compared to the above distances X and K,
The diameter (D2) of the image 2OA shown in the above equation (2) is as follows.

By the way, the 20F number of the photographic lens is, therefore,
The diameter (D2) of the image 2OA, which is not shown in equation (5) above, is D −□
...... (C2: According to the F number, the diameter of the image 2OA is 1) 2 is inversely proportional to the [・' number of the photographing lens 2, and by detecting the diameter of the image, the F number of /Z2 is inversely proportional to the [・' number of the taking lens 2] It is clear that it is possible to calculate

FIG. 4 shows a state in which the image 2OA of the exit pupil 20 is formed on the substrate 16 of the light receiving section 12 of the diaphragm 1 direct detection device, and the Ill' number of the photographic lens 2 is F2°F2
．． 8, F4, and F5-6, the area of the image 2OA formed on the substrate 16 becomes AI+A2.8, F4, and F5-6, respectively. A3. Changes to A4. Furthermore, since the light receiving elements 16a of the line sensor 16 are arranged in the radial direction passing through the center of each region, the light receiving elements 1 in each region
The number of 6a (d is proportional to the size of each area above.

In other words, among the light receiving element rows of the line sensor 16, the number of light receiving elements that receive the imaged light 1' when the image 20A of the exit pupil 20 is formed is inversely proportional to the F number of the photographic lens 20. That is, if the pitch of each light-receiving element 16a of the line sensor 16 is p, and the number of light-receiving elements 16a illuminated by light is n, then the above (force formula) is obtained, and the F number can be immediately calculated from the number of light-receiving elements 16a illuminated by light. For example, in the above equation (8), p = 0.02
mm, f = 2 mm, the relationship between the number n of light-receiving elements 16a that is illuminated by light and the F nanocouple is F
When 2, n = 50. F2. ．． When 8, n=65
．． At F4, n = 25. Ii” When 5.6, n
= 18°F 817) when n = 13. “F1
'When 1, n = 9. ' When F 16, n = 6
becomes. Of course, in addition to these F-numbers, the intermediate values thereof can also be detected incorrectly. Therefore, the line sensor 16
As shown in FIG. 5, the output state value of the light receiving element row 16a changes depending on the number of the photographing lens 2, and the smaller the II' number, the more the output of the light receiving elements 16a in a wide range becomes the "usable" level. become.

FIG. 6 shows the distance between the photographing lens 2 and the line sensor 16,
Or between the line sensor 16 and the small lens 15 ((This does not indicate the imaging state when eccentricity or inclination occurs. Due to eccentricity or inclination, the center of the line sensor 16 is 1+;
If the light 1111 of the shadow lens 2 or the small lens 15 deviates from the light 1111, the image 2OA of the exit pupil 20 is a normal imaging area A. Maybe, for example, area A. 1 or area A. The image will be formed on the substrate 16 with a shift of 2. Area A. , is the case where the line sensor 16 has healed in the longitudinal direction and shifted from side to side; in this case, area A.

and area A'01, the light receiving element 1 that receives the imaging light.
Since there is no change in the number n of 6a, the photographic lens 2
0F number can be detected. Also, area A.

2 is a case where the line sensor 16 is shifted in a direction perpendicular to the longitudinal direction, but even in this case, the area A is. By arranging the line sensor 16 near the diameter portion of 2, the number of light receiving elements 16a that receive the imaging light is 11! The photographing lens 20F number can be detected with almost no change.

By the way, when the above-mentioned blur D3 (see FIG. 6) occurs, the area of the exit pupil image 2OA formed on the substrate 16 of the light receiving section 12 of the surface detection device is as shown in FIG. There is a bright area A and an indistinct area B that gradually becomes darker toward the outside of the bright area. Therefore, the output state of the light receiving element array of the line sensor 16 is as shown in FIG.
As shown in C, the output level of the light-receiving element in the area Δ reaches a certain level I-1", but the output level of the light-receiving element in the region I3 increases outward to the level I-1". The blur changes gradually from ゛°L'' level.This kind of blur phenomenon occurs when changing lenses,
This occurs when the distance X between the exit pupil 20 and the small lens 15 changes by extending the photographing lens 2 for distance adjustment. Therefore, the focal length n of the small lens 15
By making af sufficiently small, it is possible to achieve a pan-focus configuration in which the imaging position hardly changes.

However, on the other hand, if the focal round angle flf of the small lens 15 is made small, as is clear from equation (8) above,
As the F-number increases, the detection resolution decreases, so in order to avoid this decrease in detection resolution, it is required to finely arrange the pitch of each light receiving element 16a of the line sensor 16.

For this reason, for example, as shown in FIG. 9, a line sensor 26 in which the pitch of the light-receiving elements becomes finer as it approaches the center.
You may also use The photographic lens 20F numbers are F1', 4, t12, r-2, 8.

t"'4, [-5, s, the areas of the exit pupil image 20.A formed on the substrate on which the line sensor 26 is provided are A, o, A, A, A, respectively.
A', A20 30 40
It changes to 50. The change in the diameter of the exit pupil image 2OA becomes larger as the F number decreases even at the same iEV. For example, the change in the diameter of the exit pupil image 2OA becomes larger as the F number decreases.For example, the change in the diameter of the exit pupil image 2OA becomes larger as the F number becomes smaller. . Therefore, by increasing the arrangement pitch of the light receiving elements 26a on the outer side of the line sensor 26 and decreasing the pitch toward the center, an average detection accuracy can be obtained as a whole.

Further, by using such a line sensor 26, the number of light receiving elements of the line sensor can be reduced, and the calculation time for reading out the output of this line sensor 26 can also be shortened.

Furthermore, even if the focal length f of the small lens 15 is greater than a certain value, the exit pupil @20 that is imaged on the substrate 16
Even if A has a blur area B around area A as shown in FIGS. 7 and 8, the F number may be detected based on this blur. In that case, as shown in FIG. 8, a constant level Ho may be detected at the gently changing output portion of the light receiving element in the blur area (3). An example of the ■-number (aperture value) detection means based on this blur will be explained using the electric circuit shown in FIG.

FIG. 10 is a schematic circuit diagram, not showing an example of the configuration of an electric circuit of a camera that performs aperture control using the aperture value detection device of the present invention.3 In the circuit shown in FIG. 8t) An aperture value detection circuit 63 including the line sensor 16 in a series circuit of the power supply 31 and the power switch 32.
The output of the aperture value detection circuit 33 ((therefore, the aperture control circuit 64 and back-on reset pulse generation circuit 65 that are driven are connected, and when the power switch 32 is turned on, these circuits In addition, in the series circuit of the power supply 61 and the power switch 32,
A series circuit consisting of a lens attachment switch 36 and a resistor 37 is connected, and a connection point between the lens attachment switch 36 and the resistor 67 is connected to a lens attachment detection circuit 68. The lens mounting switch 56 is, for example, a normally open switch disposed at a predetermined position inside the camera 1, as shown in FIG. e When the shadow lens is not attached, the push pin 42 provided on the body mount 41 so as to be movable along the optical axis protrudes toward the photographic lens side due to the elastic force of the coil spring 43, so that the lens cannot be attached. Although the switch 36 is in the OFF state, when a photographic lens is attached to the camera, the lens mount 44 causes 2. The pushing pin 42 is pushed and its rear end protrudes in the direction of the lens mounting switch 36, and the switch 36 is turned on.

The power-on reset pulse generating circuit 35 is a circuit that generates a short-time II'' pulse when the power switch 32 is turned on, and its output terminal is connected to the single-power input return of the OR gate 39. Furthermore, the lens attachment detection circuit 38 is a circuit that turns on the power switch 62 and generates a short 'IT' pulse after a certain period of time when the lens attachment switch 36 is turned on/'. Its output terminal is connected to the other input terminal of the OR gate 39.

The output terminal of the OR gate 39 is connected to the clear terminal CI of the aperture control circuit 54. Therefore, each time the power switch 32 is turned on or the lens is replaced, a '°H' pulse is generated from the power-on reset pulse generation circuit 35 or the lens attachment detection circuit 38, and this pulse is applied to the OR gate. 69 to the clear terminal CLI of the aperture control circuit 64 (.

guided by. 7 The aperture control circuit 64 has a clear terminal CL I
t.

When the °゛11'' pulse is led to the output terminal, the output terminal becomes uHI+ level, and a signal of the same level is sent to the digital terminals It and Ic A D of the aperture value detection circuit 33. . The aperture value detection circuit 33 is a circuit that scans the output of the line sensor 16, extracts it, processes it, and counts and detects the l number (aperture value), When a signal of 11" level is introduced to the above input terminals R, EA i), the detection output is latched and outputted to the i terminal OU i
” to the aperture control circuit 34.

The aperture control circuit 34 uses the output flow 1 of this aperture value detection circuit 63.
Aperture control is performed based on the output at the child OUT.

FIG. 12 is an electric circuit diagram showing a specific circuit configuration of the aperture value detection circuit 33 shown in FIG. 10 above. In this aperture value detection circuit 33, the line sensor 56 corresponds to the line sensor 56, and includes a row of light receiving elements 56a, a transfer gate 561), and a transfer gate 561).
6b and an analog shift register section 56c to which charges accumulated in all the light receiving elements are transferred.
(charge coupled device) line image sensor. A reset pulse φ (see FIG. 14) of the transfer lock generation circuit 55 is guided to the light receiving element portion 56a of the line sensor 56, and the charge of the light receiving element portion 56a is The storage is reset to prepare for the next charge storage. Transfer gate 561
) is led to the trigger pulse φT (see FIG. 14) from the transfer lock generation circuit 55, and at the 'rT' level of the trigger pulse φA, the transfer gate 561) is opened and the signal is accumulated in the light receiving element section 56a. The charge is transferred to the analog shift register section 56C.The analog shift register section 56CK is led to the transfer locks φ, ~φ3 (see FIG. 14) of the transfer lock generation circuit 55.
Due to this transfer lock, signals corresponding to the charges transferred to the analog shift register section 56C are sequentially derived to the output terminal VOUT of the line sensor 56. The clock pulse generation circuit 5 equipped with an oscillator 53 is connected to the clock input terminal of the transfer lock generation circuit 55.
4, a clock pulse CL K (see FIG. 14) of a constant period is derived.

The output terminals of the line sensors:, y9--56 are connected to the inverting input terminal of an analog comparator 58 via a buffer amplifier 57. Further, the output I terminal of the buffer amplifier 57 is connected to the pulse processing circuit 600 input terminal SUN via an analog switch 59. A pulse φ33 from the transfer lock generating circuit 55 is introduced to the control terminal of the analog switch 590.

The configuration of the pulse processing circuit 60 is as shown in FIG.
Input terminal 1. N is connected to the non-inverting input terminal of an operational amplifier 62 via an analog switch 61 in the same circuit, and the reset pulse φ□ is guided to the control terminal of the analog switch 61. 1
The inverting input terminal 620 is connected to the anode of the diode 63, the cathode of the diode 660 is connected to the output/terminal of the operational amplifier 62, and the anode of the diode 63 is grounded via the capacitor 64. This operational amplifier 62. A circuit consisting of a diode 63 and a capacitor 64 forms a peak value detection circuit for detecting the negative peak value of the analog output of the line sensor 56 that is input manually through the analog switch 61.

An analog switch 65 is connected in parallel with the capacitor 64. This analog switch 65 is turned on by a trigger pulse φ guided to its control terminal, and discharges the charge in the capacitor 64 to reach the peak value or cent. The anode of the diode 63 is connected to the input terminal of a buffer amplifier 66, and the output terminal of the buffer amplifier 66 is connected to the buffer amplifier 6 through an analog switch 67.
90 input terminal. buffer amplifier 690
The input terminal is grounded via a capacitor 68. The analog switch 67 and the capacitor 68 form a sample and hold circuit, and when the analog output switch 67 is turned on by introducing a pulse φ to the control terminal of the analog switch 67, the signal is accumulated in the capacitor 64 of the peak value detection circuit. The electric charge transferred to the capacitor 68 through the pan amplifier 66° analog switch 67 is transferred to the capacitor 68.
It is arranged as follows: buffer amplifier 69
The output terminal of this pulse processing circuit 60 is the output terminal SO
U i' becomes "C is here.

The output terminal 5OUT of the pulse processing circuit 60 is grounded via series-connected voltage dividing resistors 71 and 72, and the connection point between the resistors 71 and 72 is the analog comparator 5 of the pulse processing circuit 60.
It is connected to the non-inverting input terminal of 8. The analog comparator 58 compares the output of the pulse processing circuit 60 led to the non-inverting input terminal and the output of the line sensor 56 led to the inverting input terminal via the buffer amplifier 57. The outputs of line sensor 56 and pulse processing circuit 60 are at negative levels, and therefore analog comparator 58
If the level of the inverting input terminal is low, the level of the output terminal becomes the "use" level.The output of the analog comparator 58 is guided to one input terminal of the Nandt gate 73, and transferred to the other input terminal of the Nandt gate 73. The pulse φ3a from the lock generating circuit 55 is guided thereto.

The output terminal of Nant Gate 7B is 74 of the counter circuit 74.
When the above-mentioned trigger pulse φ is led to the reset terminal R, ES E ']', the previous count contents are reset, and then the output of the analog comparator 58, which is manually inputted as a serial pulse through the Nant gate 73, is counted. This pulse is led to the input terminal LIN of the latch circuit 75 as a parallel pulse. Lunch circuit 75
The output terminal LOU 'l' of this aperture value detection circuit 33
The output terminal of the aperture control circuit 64 is connected to the input terminal of the aperture control circuit 64. The output terminal of the aperture control circuit 34 is connected to one negative logic input terminal of an AND gate 76, which serves as the input terminal R, E A I) of the aperture value detection circuit 36, and the other input terminal of the AND gate 76 is connected to the output terminal of the aperture value detection circuit 36. A pulse φ8 from the transfer lock generation circuit 55 is guided to the terminal. The latch circuit 75 performs a latching operation based on the output of the AND gate 76.

Next, the operation of the aperture value detection circuit 63 will be described in 14.1.5.
This will be explained using the time chart of each part signal shown in the figure.

When the exit pupil image of the photographic lens is formed on the light receiving element portion 56a of the line sensor 56, charges corresponding to the recent state of this pupil image are accumulated in the light receiving element portion 56aVC.

The accumulated charge is transferred to the analog shift register R[i 56c K when the trigger pulse φ7 from the transfer lock generating section 55 is guided to the transfer gate 56b, which is opened. The device section 56a receives the charge transferred to the analog shift register section 56c, and is internally set by a reset pulse width that reaches the "use" level immediately after the trigger pulse φ, and is set for the next charge accumulation. Analog shift register section 56
The accumulated charge sent to transfer lock φ1. φ2. φ
3, and in synchronization with the 'TI' level of the transfer lock φ3, a negative voltage is output from the jlT next output terminal VOUT and the light receiving elements 1, 2 of the light receiving element section 56a are set to 1-.
I] is derived chronologically.

The negative voltage output 1 derived in time series from the output terminal V OUT of the line sensor 56 is passed through the buffer amplifier 57 to the inverting input terminal of the analog comparator 58, and at the same time is passed through the analog switch 59 to the When it is at the "TI" level, it is guided to the input terminal SIN of the pulse processing a circuit 60. The pulse processing circuit 60 performs 'I-1' immediately after the trigger pulse φ,
The analog switch 61 is turned on by the reset pulse φ which is a bell, and the output terminal V OU ' of the line sensor 56 is connected to the non-inverting input terminal of the operational amplifier 62 through the analog switch 59 and 61 of the buffer amplifier 57. Of the output waveform of l', pulse φ3a
of! Only the period of l Hu level is sampled and derived sequentially. Then, since the potential of the non-inverting input terminal of the operational amplifier 62 is guided to the anode of the diode 66,
The capacitor 64 is charged with the sampling waveform signal, and the terminal voltage vP of the capacitor 64 is maintained at a negative peak value. The accumulated charges of the n light receiving elements in the analog shift register section 56L) of the line sensor 56 with this peak value voltage VP are transferred and locked φ1 to φ.
3 and are sequentially sent out from the output terminal V OU E', the analog switch 67 is off, so the pulse is not sent to the next stage, and the pulse processing circuit 60
The voltage of the capacitor 68, whose peak value was held in the previous transfer cycle, is output to the output terminal S OUT of the capacitor 68 . All accumulated charges of the n light receiving elements in the analog shift register section 561) are transferred to the output terminal V OU.
The center pulse φ sent out from T. becomes L" level, the analog switch 61 is turned off, and the manual gate of the peak value detection circuit of the pulse processing circuit 60 is closed. At this time, the light receiving element section 56a K of the line sensor 56 Photoelectric conversion is performed again and charge is accumulated.

Reset pulse φ. Immediately after becoming L” Lebel, 'II
” level pulse φ is sent out, the peak value voltage VP, which had been held in the capacitor 64 of the peak value detection circuit of the pulse processing circuit 60, is held in the capacitor 68 through the analog switch 7, and is transferred through the buffer amplifier 69. The pulse processing circuit 60 outputs the reset pulse φ8 to the output terminal 5OUT.
”During the transfer cycle (Nth transfer cycle) in which the output terminal V of the line sensor 56 is connected to the input terminal SIN.
When the voltage waveform of OUT is guided, the output terminal S'O
The peak value of the voltage waveform of the output terminal V OU 1' of the line sensor 56 in the previous transfer cycle (N-1th transfer cycle) continues to be output to the UT.

The voltage at the output terminal 5OUT of the pulse processing circuit 60 is
Since the voltage is divided by the resistors 71 and 72 at a predetermined division ratio,
A voltage value VP/ which is obtained by dividing the peak value VP of the output waveform of the line sensor 56 in the N-1st transfer cycle is led to the non-inverting input terminal of the analog converter 58 as a reference voltage for comparison and determination. . Since the output voltage of the line sensor 56 in the N-th transfer cycle is sequentially led to the inverting input terminal of the analog converter 58 through the buffer amplifier 57, the analog converter 58 compares the two types of pressures. If there is no sudden change in the exit pupil image formed on the light receiving element portion 56a of the line sensor 58, the line sensor 58 in the Nth transfer cycle
Since the output waveform of No. 6 is exactly equal to the output waveform of the line sensor 56 in the N-1 transfer cycle, the N-th voltage waveform is directly chronologically derived from the line sensor 56 to the analog converter on the fifth day. There is a portion where the partial pressure is lower than the partial pressure value VP/, and in this portion, the analog comparator 58 id becomes the “I(” level. That is, the light receiving element section 5.6a of the line sensor 56 receives the exit pupil image. To do this, the clear area of the imaging light (7th,
The accumulated charge in the area A shown in Figure 8 reaches a large constant value, and the accumulated charge in the area that is unclear and blurred (corresponding to area B shown in Figures 7 and 8) is smaller than the charge in the sharp area. As mentioned above, the exit pupil image has a sloped value as it approaches the non-light receiving area, but when the output of the line sensor 56 including such a blur amount is led to the analog comparator 58, the analog comparator 58 The above peak value vI) Totally divided voltage value Vl)
Therefore, the analog comparator 58 outputs the signal ``in synchronization with the output pulse of the line sensor 56 exceeding a certain value in the area B) shown in FIGS. 7 and 8 from the analog comparator 58. 1" pulse is generated. When the output of this analog comparator 58 is led to the NAND gate 76, the "H" pulse from this analog comparator 58 and the NAND output of the Norx φ3a from the transfer lock generation circuit 55 are input to the input terminal C' of the counter circuit 74. Guided by IN, the analog controller 58
The number of pulses emitted from the machine is counted. The count contents of the counter circuit 740 are sequentially led to the latch circuit 75. Then, the light receiving element section 56 of the line sensor 56
When the transfer of all the accumulated charges for the n light receiving elements of a is completed, the transfer lock generation circuit 55 generates a pulse φ8.
is sent out, so if the output terminal of the diaphragm control circuit 64 is at L level at this time, the pulse φ is guided to the latch circuit 75 through the AND gate 76, and the count contents of the counter circuit 740 become the latch circuit 75. The signal is latched into a state where it is output from its output terminal LOUT.

As mentioned above, the aperture control circuit 64
20 is turned on, or when the lens mounting switch 3B is turned on, when the "H" cross is led to the clear terminal CLR (No. 1 (see Figure 11)), the output terminal is connected to the input terminal of the aperture value detection circuit 36. I(EAD becomes 6H" level, the AND gate 76 outputs the above node φ, the level sent to the latch circuit 75 becomes L"
Therefore, in this case, the output of the latch circuit 75 is fixed, and the output of the latch circuit 75 does not change every time the transfer cycle occurs. In this way, a count output corresponding to the size of the exit pupil image, that is, F-number information of the photographic lens is guided from the latch circuit 75 to the aperture control circuit 34. When the aperture control circuit 34 receives the F-number information of the photographic lens, it performs a well-known aperture control operation based on this information.

In the embodiment shown in FIGS. 10 to 12, the aperture control circuit 34 is operated based on the aperture detection circuit 33 reading the aperture value detection circuit 33 of the aperture value of the photographing lens 2. Of course, it is also possible to further detect the aperture diameter narrowed down by the circuit 64 using the aperture value detection circuit 6'5 to detect a predetermined aperture value.

Furthermore, the output detected by the aperture value detection circuit 65 is inputted to the aperture control circuit 34, etc., as well as to a distance measuring device, etc., which uses a plurality of receiving X element arrays by switching them according to the aperture diameter of the photographic lens. The present invention can be applied to a wide range of applications, not limited to the above-mentioned embodiments.

As described above, according to the present invention, the exit pupil image is formed on the line sensor at a position conjugate to the film surface, and the aperture value is detected from the light receiving area of the line sensor. The aperture value of the lens can be detected on the camera side, and by using a line sensor, even if the exit pupil, imaging optical system, and light receiving section are eccentric,
It is possible to obtain an output according to the exit pupil image from the line sensor without being affected by this, making it possible to accurately detect the aperture value, and even if the exit pupil image becomes blurred, countermeasures can be easily taken. Demonstrates excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a single-lens reflex camera having an aperture value detection device showing an embodiment of the present invention, and FIGS. FIG. 3 is an optical principle diagram for explaining the imaging optical system in FIG. 1, and FIG. 4 is the diagram in FIG. Figure 5 is a plan view of the light receiving section showing the image forming area of the exit pupil according to the F number of the photographing lens on the line sensor shown in Figure 4 above. Figure 6 is a plan view of the light receiving section to explain the state when the photographing lens or imaging optical system and line sensor are decentered, and Figure 7 is a diagram showing the exit pupil image blurred by the line sensor. FIG. 8 is a plan view of the light receiving unit to explain the state in which an image is formed in the above-mentioned state. FIG. 8 is a diagram of the output waveform derived from the line sensor shown in FIG. 7 above, and FIG. FIG. 10 is a plan view of a light receiving section showing an example in which the pitch is varied according to changes in the area of the exit pupil image. FIG. A schematic circuit diagram showing an example; FIG. 11 is a partial sectional view of a camera showing an example of the lens attachment switch shown in FIG. 10; FIG.
FIG. 13 is an electric circuit diagram showing the circuit configuration of the aperture value detection circuit in FIG. 12 is a time chart showing signal waveforms at various parts of the electric circuit shown in FIGS. 12 and 13. FIG. 2...Photographing lens 3...Aperture member 5...Film 12...Light receiving section of aperture value detection device 15...Small lens (imaging means) 16 .26.56... Line sensor 16a
+ 26a, 56a... Light receiving element 33... Aperture value detection circuit (means for detecting aperture value) Patent applicant
Olympus Optical Industry Co., Ltd. Agent Fuji Shichibej',,j+1
・Kawa 62nd Ward (A) O2 Ward (B)

Claims (1)

[Claims] A means for forming an image at a position where the exit pupil of a photographic lens is g-conjugate with respect to the film surface, and a means for forming an image at a position where the exit pupil of the photographic lens is g-conjugate with respect to the film surface, A line sensor is formed by linearly arranging a plurality of light-receiving elements, and the number of light-receiving elements of this line sensor that receives the imaged light of the exit pupil is counted, and the count output ((based on An aperture value detection device comprising: means for detecting an aperture value of a photographic lens;