JPS5891438A - Indicating device for focus adjustment state - Google Patents

Abstract

PURPOSE:To obtain a stable indication while providing a stepwise focusing area, by displaying a focusing state stepwise by the use of a focusing state indicating means. CONSTITUTION:From sharpness signals F1, F2, and F3 of images on photodetection parts 3a, 3b, and 3c, F1-F3 is obtained through arithmetic 12 and decision 14-17 on the value are made. Further, decisions 18 and 19 which is greater, F1 or F2 and F1 or F3, are executed and on the basis of those decision results, outputs of gates 20-26 are determined to turn on or off a focusing state indicating means (LED) 28 and out-of-focus state indicating means (LED) 27 and 29. Namely, all LEDs turn off in areas D and E where discrimination is impossible; and the LEDs 27 and 29 turn on in front-focus and rear-focus discrimination areas B and C, and the LED 28 turns on in a focusing discrimination area A. Specially when a switch 33 is connected to the output of the gate 21, the LED 28 flashes in a high-precision focusing area A'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a focus adjustment state indicating device, and more particularly to a focus adjustment state indicating device equipped with means for respectively indicating an in-focus state and an out-of-focus state. Focus,
A focus adjustment state indicating device is known that uses light emitting elements such as LEDs to indicate each state of the front bin and rear bin, respectively. , the out-of-focus instructions for the rear bin are usually clearly different - i.e., this is necessary in the first place, but on the other hand, the user of such a device is not aware that the instructions are clear. It is easy to get stuck in the illusion that the current state is definitely different from other states because of the difference in the camera. Although this is fine, it is easy to have a slightly erroneous understanding that you should never take a picture when out-of-focus is instructed. However, the focus adjustment state of the optical system changes continuously, so for convenience,
This is simply a matter of drawing lines as appropriate on the premise of permissible ranges so that the states can be distinguished. Also,
A common problem with such devices is that they are difficult to use due to instability of the state indication when the focusing state coincides exactly with the transition of the state distinction. Regarding lenses, as is well known, each lens has an allowable focusing range, and this also differs depending on the optical characteristics of each lens. Considering these things together, rather than simply focusing and defocusing instructions as in the past,
More rational, easy-to-use, and stable instructions should be pursued.

The present invention was made in view of such circumstances, and focuses on &4.
As a status indicating device, it has a very simple configuration, especially:
The aim is to make it possible to provide more rational, easy-to-use, and stable instructions by making very small changes to the conventional configuration, rather than simply giving instructions for focusing and defocusing as in the past. With such an object in mind, the present invention provides a focus adjustment state indicating device that is provided with means for indicating an in-focus state and an out-of-focus state, respectively! is characterized by comprising means for instructing the focus state in stages by means for instructing the focus state or by a combination of the means for instructing the focus state and a different means. It is something to do.

According to a preferred embodiment of the present invention described below,
When instructing the in-focus state step by step using only the in-focus state instructing means, the in-focus state instructing means is a light emitting body, and the in-focus state is determined by distinguishing between continuous light emission and intermittent light emission. Instructing the focus state step by step, or when using different means together, use a sounding body as the different means. A configuration has been proposed that includes means for selectively enabling use.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram for explaining the principle of focus detection of an example of a focus detection device to which the present invention is applicable;
is an imaging lens whose optical axis is 1', and 2 is the same lens 10.
This is a beam splitter having semi-transmissive parts 2& and 2b and a total reflection part 26 arranged in the optical path. A beam of light from the imaging lens 1 enters the semi-transmissive section 2a of the Φ Sugeritter 20, and the semi-transmissive section 2a and other semi-transmissive sections 2
b and total reflection part 2C, 5 beams of light, L, and,
It is shown how it is divided into. The semi-transmissive part 2a has a characteristic of transmitting about 1A of the incident light flux and reflecting the remaining part, and the other semi-transmissive part 2b transmits about 1/2 of the incident light flux and reflects the remaining part of the light flux. If it is given the characteristic of reflecting 2, the energy of the above-mentioned 5-divided light beam, -L, is equalized by a photoelectric conversion element such as an element. Here, the center light receiving m
51s is placed with respect to the beam sgelitter 2 at a position equivalent to the planned focal plane of the lens 20 (film plane in the case of a camera). The positional relationship with respect to the lens 1 is isometrically shown in FIG. They will be placed in accordance with their respective positions.

The optical arrangement of such a detection system is particularly similar to that shown in FIG.
), when the lens 1 is in focus, the sharpness of the images on the light receiving sections 5a and 6C is approximately the same, and the image on the light receiving section 6b is the maximum, and the sharpness of the image on the light receiving section 6b is the highest. In the bin state, the clarity of the image on the light receiving section 5a is higher than that on the light receiving section 50, and on the contrary, in the rear bin state, the clarity of the image on the light receiving section 5a is higher than that on the light receiving section 50.
The sharpness of the image on C is higher than that of the image on light receiving section 3a. In this way, from the outputs of the light receiving sections 6 to 5b, 5o, the respective light receiving sections 5&,! The focusing state of the lens 1 can be discriminated by determining the sharpness of the image on the lens 5'' and comparing them appropriately.

Next, Fig. 2 shows the configuration of an electric circuit system of an embodiment in which the present invention is applied to a focus detection device according to the principle of focus detection as explained in Fig. @1. Elements denoted by the same reference numerals as in the above are exactly the same as those already explained. Incidentally, the charging conversion element 6 here has three twin-shaped sensor arrays 5451 and 5C (3CD7 auto. Senna.In Figure 2,
The output of the photoelectric conversion element 3, that is, the six image signals obtained by the light receiving sections 5&, 511, and 36 are
The variation therein is extracted through a high pass filter 5 consisting of & and a resistor 6b, and then squared by a squaring circuit 7. The squaring circuit 7 converts the output of the i-pass fill #5 into an absolute value and emphasizes the absolute value signal according to its level, and the level of the absolute value signal increases as the image clarity increases. While further emphasizing the image, it also suppresses the absolute value signal at a low level when the sharpness of the image decreases. Note that such a circuit can be easily realized by utilizing the nonlinear characteristics of input and output of semiconductors. Therefore, the square circuit 7
The output level reflects the sharpness of the image extremely sharply. Reference numeral 8 denotes an integrating circuit which integrates the enhanced signal of the image receiving area corresponding to 6 to 5% of each light receiving portion of the photoelectric conversion element 3, that is, the entire field of view. Therefore, the output of the integrating circuit 8 is transmitted to the six light receiving sections 6 obtained in this way to retain the signal regarding the sharpness of the image on 5b150 until the next image. 9 is a temple hold circuit for receiving light, 10 is a light receiving part 5brc, and 11 is a temple hold circuit for receiving a sharpness signal corresponding to a light receiving angle of 115 degrees. Incidentally, here, the light receiving section 5&, 31
1.50 is obtained respectively and the number is this - ~ de circuit 9
．． 10. The sharpness signal subjected to IIK number hold is transferred to the husband ^r1. Fs, Fs (as shown in FIG. 4). 12 is a differential amplifier for obtaining Fz -Fs (Fig. 4 (→ diagram)), 15 is =i:Vo and U ±
V& (However, +Va>+V'o -m 4 Figure tb
), 14 is a comparator for comparing F, -F, which is the output of the differential amplification l1112, with +vo, and 15 is the same <Fl-F.
Comparator for comparing m against −Vo, 16
is a comparator for comparing the same <Fl-Fl with respect to +v'o, 17 is a comparator for comparing the same <Fl-Fs with respect to -V', 18 is a comparator for comparing Fl and Fl
19 is a comparator for comparing F and Fl, 50 is F, and the focus adjustment degree
A predetermined voltage Vt (
The comparator for comparison with Fig. 1g4 (&) shown in the figure is an AND gate that receives the output of the MUND game) 20 and the output of the comparators 18 and 19, and 25 is a combiner #18-
and a NAND gate receiving the outputs of 50, 24 is a muND
Gate 22. A NAND gate 25 receives outputs from a comparator 50 and a NAND gate 26, which will be described later. 21 is an inverter cam ND gate that receives the outputs of comparators 16 and 17; 51 is a condenser 521.
An oscillation circuit consisting of a resistor 52b and an inverter 526152+1 connected as shown; 26 is a NAND gate that receives the output of the oscillation circuit 51 and the output of the AND gate 21 selected by the switch 55; The outputs of gate 22 and combiner #50 are applied to NAND gate 24'. 27, 28 and 29 are the husband kNAND gates) 25. The display LEDs connected to the output terminals of 24 and 25 are the display LEDs 54, 55 and 56 are respective holding resistors. In addition, 4 is a photoelectric conversion element 6. The control circuit for controlling the integrating circuit 8 and the temple hold circuit 9.10 and 11 is the control circuit for controlling the integration circuit 8, temple hold circuit 9, 10 and 11.
9. 5m light receiving section temple held at 10 and 11
, 5b and 6C, image sharpness signals Fh, Fm and F,
First, if Fl≧Vt, the comparator 50
The output G is high, but at this time F, -F > +V
・If =, the output of the inverter 14 becomes high, and therefore the output of the NAND gate 23 becomes low, causing l4D27 to light up.On the contrary, F, ≧vt
Under the condition that F* −Fl < −V.

When %Fl≧Vt, the output of the comparator 15 becomes NO, and therefore the output of the NAND gate 25 becomes a, causing the LED 29 to light up.On the other hand, %Fl≧Vt
Under the condition of IF deF, +≦■O, the outputs of comparators 14 and 15 both become negative, so the
The output of the D gate 20 becomes high, but in this state the F
If m > F z and F, > F, the outputs of comparators 1B and 19 will both be high. Therefore, if the output of the NAND gate 26 is high in this state, then N
The output of AND game) 24 becomes low, and I and KD 28 are lit.

If Hly, <Vt &, the output of the comparator 50 is
As a result, none of the LEDs can be turned on.

The above is, so to speak, the operation when the switch 63 is connected to the enclosure ground side and inputted to the NAND gate 26 to force its output to I/I. When connected to the output side of the AND gate 21, IFx-F1+≦■.

The outputs of the comparators 16 and 17 both become NO, so that the output of the AND gate 21 becomes low, and therefore, this In this case, the four pulses generated by the oscillator circuit '51 are outputted through the NAND gate 26, so that the N
Since the output of the AND gate 24 becomes intermittently low at the oscillation frequency of the oscillation circuit 61, the LED 28 lights up intermittently, that is, blinks.

In other words, if we summarize the above and explain with reference to Fig. 4, when the lens 1 is moved from the close focus position to the infinity focus position with respect to the object at the distance, the image sharpness signal is generated. F
,, F, , If F traces the change as shown in Figure 4 (-), then in the waveform of Figure 4 (b) showing Fl-Fl, the areas D and E will change as shown in Figure 4 (-). As can be seen from the comparison, Fs<Vt and no LED can be turned on, so to speak, it is a state indistinguishable region, and the region of G is F1≧v
Under the condition of t, Fz-1's > vo and LKD2
7 is lit, which is basically the front bin state discrimination area, and the area B is F, ≧Vt<-V・, and llCD29
is lit, so to speak, in the rear bin state discrimination area,
The region of the film is F under the condition of ≧Vt.
vo, and only 4, Fs>Fx and Fs>Fi, and the LICD 2B is turned on, so to speak, this is the in-focus state discrimination area, but especially the area H'-
4I K I Fz−Fs I ≦”@ (<V@)
"C" 6W This is the area where the LBD 28 is switched from continuous lighting to flashing. Now, here, switch 65 in the circuit system shown in Figure 2 is set to NAN.
When connected to the output side of the D gate 21, in the area M excluding A', that is, in the range M1 and M2, l4
D2B lights up continuously and blinks in the range of area A', thus indicating the in-focus state in stages. The range A' represents an acceptable but somewhat coarse focusing area, whereas the range A', where LICD2B is blinked, represents a more accurate focusing area. Of course, when the switch 56 is connected to the circuit ground side, the stepwise instruction of the focused state described above is invalidated, and the LED 28 is lit continuously in the entire area A.

It goes without saying that each II 'jm': A, 'I qQ E no range II HaV'o, v,, vt can be set as appropriate by selecting the values. FIG. 3 shows only the parts of another embodiment of the present invention, particularly the parts that are different from the structure of the embodiment shown in FIG. 2. In this embodiment, the output of the HAND gate 26 is
Game) A sounding body 67 such as a piezoelectric buzzer instead of being attached to 24
By adding to LEIl12 within the range of A' mentioned above,
Instead of blinking 8, it is kept on continuously and the sound is emitted from the sounding element 57.In the case of the embodiment shown in FIG. 2, the oscillation frequency of the oscillation circuit 31 is 2 It is better if the blinking is relatively low so that it can be clearly identified! ! In the case of the embodiment shown in FIG. 3, the oscillation frequency should be set high enough so that the sound from the sounding element 57 can be heard for a sufficient period of time.As described in detail above, according to the present invention, the focus adjustment state indicating device In particular, it has a very simple configuration, and is a major improvement over the conventional configuration, going beyond simple focusing and defocusing instructions as before.
This makes it possible to provide more rational, easy-to-use, and stable instructions, and is extremely useful as a focus adjustment state indicating device for optical equipment such as cameras.0 Needless to say, the present invention is not limited to the embodiments. The present invention is not limited to this configuration, and various modifications can be made within the scope of the spirit of the present invention. As a very familiar example, for example, in the embodiment shown in Figure 2, instead of blinking the LED 28 in the range A', it may be made to blink in the range Mu 0 and Mu 1; In the embodiment shown in FIG. 6, the sounding body 67 is
Instead of pronouncing ``,'' it may be possible to pronounce it in the range of ``mul'' and ``mukarasu,'' which may be more convenient.

[Brief explanation of drawings]

FIG. 10 is a schematic diagram for explaining focus detection llAl1 of an example of a focal point detection device to which the present invention can be applied, and (-)
is the optical arrangement of the focus detection device, and (b) is (&)
(O) shows the configuration of the light receiving section of the photoelectric conversion element in (a). FIG. 2 is a block diagram showing the configuration of an electric circuit system in one embodiment when the present invention is applied to a focus detection device according to the principle explained in FIG. 1, and FIG. 6 is a block diagram showing another embodiment of the present invention. This is a partial circuit diagram showing only the configuration of the parts that are different from the example shown in FIG. These diagrams show how the discrimination is performed, and (1) shows how the sharpness of the image changes at the five points in FIG. 1b), and (b) shows how the focus adjustment state is discriminated based on these changes. 1...Lens, 6...Fist photoelectric conversion element, 28
... Focus state indicating means (LED), 27
．． 29...Out-of-focus state indicating means (LED), 5
7... Different type of means (pronunciation body), 1h22.24
．． 26,51@0... Component for step-by-step instruction of focus state, 550.0 selection means (switch switch). Patent applicant Canon Co., Ltd.

Claims (1)

Scope of Claims: (1) In a focus adjustment state indicating device equipped with means for respectively indicating an in-focus state and an out-of-focus state, the in-focus state instructing means 1. A focus adjustment state indicating device characterized by comprising means for instructing a focus state step by step when used in combination with a means for one purpose and a means different from the above. (2) When the focusing state indicating means is a light emitting body, the focusing state is indicated in stages according to continuous light emission and intermittent light emission. The focus adjustment state indicating device described in . (5) The focus adjustment state indicating device according to claim (1), wherein a sounding body is used as the differentiating means. (4) Claim (1) or (2), or Same number (
5) The focus adjustment state indicating device described in XJ.