JPS60144711A - Auto-facus camera - Google Patents

Abstract

PURPOSE:To photograph without being out of focus on a target object by making it possible to select a normal mode, where only one light emitting element is driven to obtain one distance measuring information, and a wide-visual field mode where plural light emitting elements are driven to obtain plural distance measuring information. CONSTITUTION:If a wide-visual field mode selecting switch 131 is turned on, the output of an inverter 132 is at the high level, and therefore, the Q output of a flip-flop 111 is at the high level when a clock input is given to a shift register, and consequently, a signal line 41 is set to the high level, and a light emitting element 1 is driven to start the distance measuring operation. Next, when a clock pulse is inputted, the Q output of the flip-flop 111 is set to the low level, and the Q output of a flip-flop 112 is set to the high level, and therefore, the signal line 41 and a signal line 42 are set to the low level and the high level respectively, and a light emitting element 2 is driven instead of the light emitting element 1, and the visual field of distance measurement is changed. If the switch 131 is turned off, only a signal line 43 is at the high level, and only a light emitting element 3 is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the reflected light of light emitted from a light emitting element to a subject by a light receiving element that is separated by a certain baseline length from the light emitting element, and calculates the distance to the subject. The present invention relates to a so-called active type automatic point location (hereinafter abbreviated as AF) camera that measures distance, and particularly to an AF right camera that can widen the distance measurement range and perform wide-field distance measurement.

As shown in FIG. 1, the conventional AF right camera has a distance measuring field mark 7a for capturing the main subject at approximately the center of the field frame 6a in the camera's finder.
It is fixed relative to the camera, which means -1:,'fJ! The I-alternator must be captured within the distance measurement field mark 7a, and the screen configuration is fixed against the photographer's intention.

That is, in FIG. 2, the AF mechanism of the IJ camera is based on the Song Dynasty's AF system, in which the light emitting lens 1a and the light receiving lens 2a are placed apart by a certain baseline length, and the light emitting element 3 is placed at each focal position.
A (for example, an infrared light emitting device (iRED)) and a light receiving device (PSD) 4a are arranged.
Using the F mechanism, it is possible to measure the distance to the subject 58 located on the projection axis "2" of the projection lens 1a, but it is possible to measure the distance to the subject 58 located at the same distance from the photographer and slightly to the left or right from the projection axis "2". A distant object such as 5aL or 5an will not be measured because it is outside the projection field of view. In other words, the size of the distance measurement field of view -7-ri7a in the finder is the projected light uu
This corresponds to the i angle, and the mechanism was such that it was not possible to measure the distance of an object that was outside the distance measurement field of view mark 7a.

Therefore, we developed this technology to make it possible to take in-focus photos without changing the screen configuration, and even with subjects that are off the projection axis - 5ar or 5a++. Several cameras have been proposed and implemented. However, with these cameras, for example, the camera is linked with a selfie mechanism, the camera is set to selfie mode, the distance measurement field mark is aligned with the main subject, and the distance measurement is performed. In some cases, the distance is measured with the first stroke of the release button, and the distance is measured with the first stroke of the release button.
The disadvantage is that the camera direction is changed while the camera is held in the stroke state, and the release is performed on the second stroke, making the operation very cumbersome and making it easy to make mistakes in shooting. It had

To improve this, an AF mechanism as shown in FIG. 3 has been proposed. This includes multiple light emitting elements (3a
, 3aR, 6ar, ) are arranged so that the optical axes of the respective light emitting elements intersect at the principal point of the projection lens 1a, and the light emitting elements 3a + 3an + 3a+ are sequentially turned on in chronological order. and the resulting multiple pieces (
In this case, the distance measurement value is determined from the three pieces of distance measurement information. That is, the light emitting elements 3a+3an.

The light projected from 3ab through the projection lens 1a is
Three subjects 5 each located at the same distance from the photographer
a, 5aR, 5aI, and each reflected light passes through the light receiving lens 2a and is detected by the light receiving element 4a,
By being calculated, three measurements v1-! Information can be obtained.

Using the principles described above, when an AF mechanism capable of so-called wide-field distance measurement is incorporated into a camera, one light-emitting element is used.
Compared to the conventional AF mechanism that uses only one light-emitting element, it has a major drawback in that it consumes more current than the conventional AF mechanism because it turns on multiple light-emitting elements sequentially in chronological order. . Also, if you constantly perform wide-field distance measurement, if there are a large number of unspecified objects on both sides, the target object may not always be in focus, resulting in out-of-focus photos being taken. There was also the drawback that there was a risk of

The present invention was made in order to eliminate the above-mentioned drawbacks, and includes a single field of view AF mode in which only a specific subject is detected by the distance measurement field mark in the viewfinder, and a relatively wide field of view in the screen. The first objective is to make it possible to arbitrarily select wide-field A and F modes that enable distance measurement +JJ function, and to take pictures of the target object without blurring it out of focus.

Hereinafter, embodiments of the present invention will be described without reference to the drawings.
Be happy.

First, in FIG. 4, 1, 2, 3. ．． Numeral 4.5 is a light emitting element formed on the same chip and constitutes a light emitting element array 6, and 7 is a light receiving element (PSD). The light beam projected from the light emitting element array 6 reaches the subject through the light projection optical system 9, and the light beam reflected by the subject passes through the light receiving optical system 11 and is received by the psD 7. Now, when the subject is at the distance DJ, the light beam projected from the light emitting element 1 is received by the part A of the PSD 7, and similarly the light beam projected from the light emitting elements 2, 3, 4.5 is , are received by portions B, C, D, and F of the PSD 7, respectively. Similarly, the subject distances are D2 and D3.

The relationship between the light emitting and light receiving positions of the light emitting element and the PSD when the light emitting element is in the D4 position is illustrated in FIG. 5 together with the case of D1.

FIG. 6 is a circuit configuration diagram of an embodiment of the present invention. In the figure, 13 is a light receiving position detection circuit in P and SD 7, 27 is a light emitting element drive circuit for driving the light emitting element array 6, and 47 is a measuring circuit for measuring the light receiving position signal phase obtained from the light receiving position detection circuit 16. 107 is a distance measurement signal conversion circuit for converting into a distance signal phase; 107 is a distance measurement signal evaluation circuit for obtaining an optimal distance measurement signal from a plurality of distance learning signals; and 109 is a distance measurement control circuit.

Next, the operation of each circuit will be explained.

FIG. 7 shows the configuration of the light receiving position detection circuit 13. In the same figure, bias voltage Vc is applied to PSD7.
The photocurrent is 1h from terminal 7^+7B,
In is output. "15 is the PSD signal (IA,
I++) processing circuits, specifically MOS amplifiers, bypass filters, preamplifiers, adders, subtracters, and sample-and-hold circuits.

Including low-pass filter etc., photocurrent IA, IB
is manually operated, and a voltage k(lAmIn)/(IA4-IB) (where k is a constant) is output to the signal line 21 according to the light receiving position of the PSD 7. 17 is an A/D converter, and the voltage k(LIB)/(IA+I[I)'
is input, and a digital light receiving position signal corresponding to the light receiving position on the PSDZ is output to signal lines 23, 24, and 25.

In this case, the correspondence between each digital output of the signal lines 23, 24, and 25 and the light receiving position of the PSD 7 is set as shown in FIG.

Next, FIG. 9 shows the configuration of the light emitting element drive circuit 27, and in the same figure, the control signal from the distance measurement control circuit 109 is inputted from the signal lines 41.42, 43°44.45, Drive circuit 61°32.33, 34.35 respectively
The light emitting elements 1, 2, 3, 4, 5 are driven through. Each drive circuit includes a drive transistor, a constant current circuit, etc., and blinks each light emitting element according to an oscillation cycle from an oscillation circuit (not shown).

Next, FIG. 10 shows the configuration of the ranging signal conversion circuit 47.

In the figure, reference numeral 49 denotes a binary to octal conversion circuit, which converts the digital light receiving position signal manually input from the light receiving position detection circuit 16 through the signal lines 23, 24, and 25 into A and B in the relationship shown in FIG. ,C.

Converts into D, E, F, G, and H light receiving position signals.

51-60 is a two-person or gate, and 61-70 is a two-man or gate.
A human-powered AND gate, and 71.72 are five-human OR gates, and the combination of these gate elements converts the eight light receiving position signals A-H into two distance measurement signals. Output on lines 73 and 74.

For example, the light emitting element 3 is selected by the signal line 43 from the ranging control circuit 109 (that is, the signal line 46 is
” level.) The distance to the subject at this time is D2
If so, the light receiving position signal output from the binary number-octal number conversion circuit 49 in FIG. 10 will be D (the fifth
(see figure). In this case, there are four or gates 51.53.
The outputs of the gates 6 and 57 become "H" level, and the outputs of the other six OR gates 52, 54, 55, 58, 59.60 become "°L" level.Here, due to the assumed conditions, the signal line 46 is at H” level, and the other four signal lines 41°4
Since 2.44.45 is at the "L I+ level", only the output of the AND gate 66 becomes "'H" and becomes a "bell", and the other nine AND gates 61, 62.64.65.
The output of 66.67.6B and 69.70 is "'L"H"
becomes le. Therefore, the output of the OR gate 71 is “H”
level, the output of OR gate 72 becomes 'L' level.Similarly, signal lines 41 to 45 and signal lines 23, 24 .
25, the OR gate 71.7
The output of 2 is determined.

FIG. 11 shows the relationship between the output of (or game) 71.72 at this time and the distance to the subject shown in FIG.

Next, the configuration of the ranging signal evaluation circuit 107 is shown in FIG. 76.77s78 and 79.80 are shift registers, which take in the data inputs of Dl and D2, respectively, when the P input is at "H" level, and clock inputs T6', T
7, T8, T9, and TIO transfer data from the Q output, so-called 2-bit parallel input.
Perform serial out operation. 81.82.83,84
．． 85 is an AND gate, and distance measurement control circuit 109
Signal lines 41, 42, 43, 44 carrying control signals from
By the combination of 45 and 75, the shift register 76
~80 parallel input signals are provided. Signal lines 41-45
and 75 timing charts are shown in FIG. This parallel input signal causes shift registers 76 to 80 to
Distance measurement signals based on the light beams of the light emitting elements 1.2, 3, and 4.5 are stored in the respective areas. The 13 signals T1 to T13 shown in FIG. 12 are timing signals generated by a timing circuit (not shown), and the timing chart of each of these timing signals and the reference clock pulse (cp) is shown below. It is shown in FIG. Next, 86°87.8
8, 89.90 are AND gates, each of which receives a timing signal T1. T2. ;T3. T4. When T5 is at the "H" level, each of the ranging signals stored in the shift registers 76 to 80 is sequentially output by passing the OR gate 91. Next, reference numeral 93.95 denotes a 2-bit shift register that takes in data from 0 inputs in accordance with clock inputs Tll and T12, respectively, and each 2-bit output is input to a digital comparator 97. Digital comparator 97 is shift register 9
The data B (Bl and B2) manually input from the shift register 95 is compared with the data A (AI and A2) manually input from the shift register 95, and when the condition A<13 is satisfied, A (“H” from the B terminal) is compared. A level output is performed. 99 is a D-type flip-flop that stores the A (B output) of the digital converter 97.

101 and 103 are AND gates, and 105 is an OR gate, and these three gate elements constitute a select gate for applying a human input signal to the D input of the shift register 95. That is, when the Q output of the flip-flop 99 is at the "H" level, the data transferred from the shift register 96 is inputted to the shift register 95, and conversely, when the Q output is at the "H" level, the data from the shift register 95 itself is transferred. In FIG. 12, all shift registers and flip-flops 99 are reset in advance by a power-up clear circuit (not shown) before starting operation.

With the above configuration, the shift register 93 sequentially inputs the data of the shift registers 76, 77, 78, 79, 80, compares it with the data of the shift register 95, and only when the data of the shift register 9B is large, the shift register 9
6 is transferred to the shift register 95, and at other times, the data in the shift register 95 is held. Therefore, at the end of the timing chart in FIG.
The shift register 95 includes shift registers 76°, 77.
Among the ranging signals stored in 78, 79, and 80, the largest data is stored. The largest data in this case is the distance measurement signal indicating the closest distance D4, as is clear from the relationship shown in FIG.

Next, FIG. 15 shows the configuration of the measurement control circuit 109. 1
Reference numerals 11, 112, 113, 114, 115° and 116 are D-type flip-flops forming a shift register. A NOR gate 117 manually outputs the six Q outputs of the flip-flops 111 to 116, and gives an H' output to the zero output of the flip-flop 111 when all the Q outputs are at the "L" level. Reference numeral 119 denotes a counter, which receives a reference clock pulse (cp) as a clock input.

121 is an AND gate, and a flip-flop 116
The output of the counter 119 and the Q4 output of the counter 119 are input manually, and while the output of the flip-flop 116 is at the 11H'' level, the Q4 output of the counter 119 is output as the clock output of the shift register. 12
6 is an acid gate, which receives the Q2 and Q3 outputs of the counter 119 and the output of the inverter 125 as inputs.

The inverter 125 uses the Q4 output of the counter 119 as human power.

161 is a switch for selecting wide field of view mode.

Further, 132 is an inverter, and when the switch 161 is off, the human power is pulled up to the power supply Vcc by the resistor 166, so the output becomes 'L' level, and conversely, when the switch 161 is on, the human power is grounded. Therefore, the output becomes HI+ level.AND gates 134, 135
, 136, 137 are the flip-flops 11, respectively.
1.112,114°115 Q output and inverter 16
When the switch 161 is off, the output of the inverter 162 is at the "L I+" level, so the outputs of the AND gates 134, 135, 136, and 137 are all at the "L" level. When is on, the output of the inverter 162 becomes "Hn level" and the AND gates 134, 135, 136°16
7 is flip flop 111,112°114.11
Pass the Q output of 5. Also, and gate 134
．． 135 output, the Q output of flip-flop 116,
The outputs of the AND gates 166.degree. 167 are output to signal lines 41, 42, 43.degree. 44.45, respectively. The counter 119 and all flip-flops are first reset by a power-up clear circuit (not shown), and since the Q outputs of the flip-flops are all °゛L'L' level, the output of the NOR gate 117 is °゛HH. Rubel Ru. Furthermore, since the four outputs of the flip-flop 116 are at the "I" level, the Q4 output of the counter 119 is applied to the shift register through the AND gate 121 as a clock input.

Now, let us consider the case when the switch 161 is on, that is, when the wide field of view mode is selected. At this time, 1° inverter 1
Since the output of the flip-flop 62 becomes "H" level, when the clock input is returned to the shift register, the Q output of the flip-flop 111 becomes "H" level, and therefore the signal line 41
becomes 11 H11 level -, and the light emitting element 1 is driven to start the distance measuring operation. Also, since the Q output of the flip-flop 111 is at the "HI+" level, the output of the NOR gate 117 is at the "L'" level.Next, when a clock pulse is input manually, the Q output of the flip-flop 111 is at the 'L' level.
level, the Q output of flip-flop 112 is “HI+
Therefore, the signal line 41 becomes the L'' level and the signal line 42 becomes the ``H'' level, the light emitting element 2 is driven instead of the light emitting element 1, and the distance measurement field of view is changed. From then on, clock pulses continue to be input in the same way, and the flip
When the Q output of the flop 116 becomes "H'" level,
The signal lines 41 to 45 are all at the ``L'' level, and conversely, the output is at the ``L'' level, so the AND gate 12
The output of 1 becomes L'' level, and the clock pulse is no longer applied to the shift register.

Output Q2 of counter 119 when switch 161 is on
, Q3, Q4, and signal lines 41, 42, 43°4
A timing chart of signal line 75, which is the output of 4.45 and AND gate 126, is shown in FIG.

Next, when the switch 161 is off, the signal line 41.4
2.44.45 remain at “L” level, and signal line 4
Only light emitting element 6 is at II HI+ level, and only light emitting element 3 is selected. Furthermore, since the signal lines 41, 42° 44.45 maintain the +1 LI+ level, the AND gate 81.82.84.85 remains at the LIT level in FIG. 12, and the shift register 76.77° 79 .80
Since the reset state is maintained by the power-up clear circuit, 0'' is stored as data.In other words, the distance measurement signal 'i' which gives priority to short-range data, that is, to prioritize large number of data. In the evaluation circuit 107, the data stored in the shift register 78 is stored in the shift register 95 as the final ranging signal.

Therefore, as explained above, the switch 161 is placed on the camera.
By providing this, it is possible to select between the conventional normal single field of view AP mode and the wide field of view AF mode of the present invention.

Next, the configuration of another embodiment (designated 109a) of the distance measurement control circuit 109 is shown in FIG. 6 D-shaped flips
Flops 111-116. Noah Gate 117. Counter 119. AND gate 126 and inverter 125
Regarding this, since it is the same as that of the embodiment shown in FIG. 15, the explanation will be omitted.

First, 151 is a switch for switching between wide-field AF mode and single-field AF mode; when it is off, it is in wide-field AF mode, and when it is on, it is in single-field AF mode. 155 is an inverter, the input of which is pulled up to the power supply Vcc by a resistor 156. 1
57 is an OR gate, and 158 and 159 are AND gates, which constitute a select gate. 161
In the single field of view AF mode, there is a switch for changing the distance measurement field of view according to the photographer's will. 165 is an inverter, which is pulled up to the power supply Vcc by a resistor 163. Reference numeral 167 denotes a known chattering absorption circuit, which absorbs chattering of the signal input to the i terminal and outputs it to the 0 terminal. 169 is a liquid crystal device (LCD) driving circuit, which includes five flip-flops 111 to 115.
Each Q output of the inverter 155 is input, and the output of the inverter 155 is HI
The liquid crystal device (LCD) 171 is driven when it is at I level.

A switch 176 is linked to the second stroke of the release button, which is normally off and turned on when the release button is pushed to the second stroke. Reference numeral 179 denotes a known monostable multivibrator (hereinafter referred to as a one-shot circuit), which outputs an "H" level from the 0 terminal for a certain period of time when the human power goes from the "L" level to the "H" level. 180 is an AND gate, and an inverter 155
The output of the one-shot circuit 179 and the 0 output of the one-shot circuit 179 are input. 181 is an OR gate, 182 and 183 are acid gates, and these three gates constitute a select gate. Similarly, three gates each
185-187.189-191,193-195
and 197 to 199 constitute a select gate. That is, there are five select gates.

First, the wide-field AF mode will be explained.

In the wide-field AF mode, the switch 151 is off, and the input of the inverter 155 is at the "H" level, so the output of the inverter 155 is at the "L" level.

Therefore, the AND gate 159 side of the select gates 157, 158, and 159 is selected. Therefore 6
Since the Q4 output of the counter 119 is inputted to the clock input of the shift register consisting of the flip-flops 111 to 116, the same operation as in the previous embodiment is performed. On the other hand, since the output of the inverter 155 is at the "L I+" level, the output of the AND gate 180 is also at the "L" level, and in the five select gates mentioned above, the AND gates 182.18'6, 190°194.19
8 side is selected, flip-flop 111.112,
The Q outputs of 113, 114, and 115 are 11111th order “H”
In response to the I+ level, the signal line 41°42.43
, 44, and 45 are sequentially output at "H" level, that is, the wide-field AF mode is set.

Next, the case of single field of view AF mode will be explained.

First, the photographer turns on the switch 151.

Then, the output of the inverter 155 becomes 11 HI+ level, and the AND gate 158 side of the select gates 157, 158, and 159 is selected.

When the photographer turns on the switch 161 to move the distance measurement field of view, the output of the inverter 165 becomes "H" level, and the "°H" level is input to the AND gate 158 through the chi-v taring absorption circuit 167. be done. Therefore, each of the six flip-flops 111-116 is provided with a clock input, and flip-flop 1
The Q output of No. 11 becomes II HI+ level. The LCD drive circuit 169 causes the LCD 171 to display the distance measurement field -7- corresponding to the Q output of the flip-flop 111 in the finder. For example, as shown in FIG.
Display one of e. The photographer presses switch 161
is turned on and off repeatedly, and when the desired distance measuring field -7- is selected, the release button is pushed to the second stroke and the switch 176 is turned on. switch 17
3 turns on, the output of the inverter 177 becomes 'H' level, and the one-shot circuit 179 outputs '' for a certain period of time.
An H'' level output is output through the AND gate 180 to the aforementioned five select gates (AND gates 183, 187, 191, 195, and 199 sides), and at this time, the five flip-flops 111 to Depending on which of the 11 Q outputs is at the "H" level, one of the signal lines 41 to 45 is output at the "H" level, that is, single field of view AF is performed. The distance measurement result at this time is output from the distance measurement (+-? "";' conversion circuit 47.

Therefore, by providing switches 151 and 161 in the camera, when switch 151 is on, single field of view AF
mode, and when it is off, it is possible to select wide field of view A or F mode. Further, in the single field of view AF mode, by appropriately operating the switch 161, it is also possible to select a desired distance measurement field of view. Note that in the wide-field AF mode, the distance measurement field mark is not displayed in the finder.

As explained above, the present invention improves the conventional single field of view A and F in which a plurality of light emitting elements are arranged and only one of them is driven.
This is because it is configured so that it is possible to select both the AF method and the wide-field AF method, which sequentially controls multiple light emitting elements in a time-series manner to measure distances over a wide range and obtain multiple pieces of distance measurement information. ,
If only a specific subject is in the frame, you can switch to wide-field AF mode, or if there are an unspecified number of sub-liquid objects in the frame (including two) in addition to the main subject. In some cases, by selecting the conventional single field of view AF mode and aligning the distance measuring field mark with the main subject, you can take a photograph with the subject in focus in any case, and the operability is very improved. There are also advantages such as:
In F mode, only one light emitting element is driven, so it has the advantage of reducing power consumption, and in one-way field of view AF mode, the main subject does not have to be in the center of the screen. These advantages make it possible to select and use each mode as desired, making it an extremely valuable AF camera for photographers.

[Brief explanation of the drawing]

Figure 1 shows the inside of the viewfinder of a conventional A'F camera, Figure 2 shows the principle of the conventional A1 mechanism, and Figure 6 shows the A1 mechanism using multiple light emitting elements. FIG. 4 is a diagram showing an embodiment of the present invention, and FIG. 4 is a diagram showing the principle of the 7AF mechanism. FIG. 5 is a diagram showing the relationship between light emitting and light receiving positions according to FIG. FIG. 6 is a circuit configuration diagram of an embodiment of the present invention. FIG. 7 is a configuration diagram of the light receiving position detection circuit in FIG.
Figure $8 is a correspondence diagram between the output of the light receiving position detection circuit and the light receiving position, Figure 9 is a configuration diagram of the light emitting element drive circuit in Figure 6, and Figure $10 is the distance measurement signal conversion circuit in Figure 6. Fig. 11 is a diagram showing the relationship between the output of the ranging signal conversion circuit and the distance to the subject, Fig. 12 is a block diagram of the ranging signal evaluation circuit in Fig. 6, and Fig. 16 and the fourteenth
15 is a configuration diagram of the ranging control circuit in FIG. 6, FIG. 16 is a timing chart, and FIG. 17 is a circuit showing another embodiment of the ranging side 601 circuit. 18 shows information in the finder. 1 +2+3+3a+3aR+3aL+4+5""・'
Light emitting element. 4a, 7... Light receiving element. 5 a + 5 art + 5 aL ・・・・・・+
subject. 7a, 8a, sb, 8c, 8d,
8t+・- Distance measurement field mark. 109.109a... Curved distance measurement control circuit. 131.151.161... Song switch. 1'h Applicant: Canon Co., Ltd. 1 - R piece (DI>02>D3>D4) Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Procedural amendment document April 9, 1985 Patent Director-General of the Office 1, Indication of the case 1981 Patent Application No. 813 2
, Name of the invention Auto-focus camera 3, Relationship with the person making the correction Patent applicant: Canon Co., Ltd. 4 Address of agent: Drawing of the 8th floor of Kowa Building, No. 16, 1-9-20 Akasaka, Minato-ku, Tokyo. 6 Contents of amendment

Claims (2)

[Claims] (1) In an autofocus camera that measures multiple distances to a target object by controlling multiple light emitting elements in time series, only one of the light emitting elements is driven and one i11'
l b"1] An autofocus camera characterized in that it is possible to select both a normal mode for obtaining information and a wide field of view mode for obtaining a plurality of distance measurement information by driving a plurality of light emitting elements. (2) A plurality of ranging field marks displayed at different positions in the viewfinder and a plurality of corresponding light emitting elements j'
- and (1, and 1- of the distance measurement field marks)
When is displayed, only the corresponding light emitting element is fully activated.
i) An autofocus camera according to claim 1, characterized in that it has the following functions: