JP2718976B2 - AF point display finder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ranging point display finder that displays ranging points in a finder field of view.

[Conventional technology]

In the conventional active AF camera, the subject is detected with a single infrared beam, so that the range that can be measured is narrow, and the subject has to be captured with a small AF target mark displayed in the center of the viewfinder field of view.

Also, as a method of focusing on a subject located at a position deviated from the center of the viewfinder visual field, a method of once focusing on the center is used.
It is known to use the AF target mark to capture the subject, measure the distance, and then immediately release the viewfinder by shifting the field of view. However, it is difficult for inexperienced people to operate it.

On the other hand, in the case where distance measurement is performed by irradiating different portions of the subject with, for example, five infrared beams, in most cases, one of the infrared beams is radiated to the main subject. It is possible to focus on the main subject with a high probability.

[Problems to be solved by the invention]

However, conventional cameras that measure the distance to a plurality of locations of a subject presuppose that the main subject is located at the shortest distance, and when multiple ranging information is obtained, the distance to the closest distance is determined. Focusing is performed based on the corresponding ranging information. For this reason, if there is a foreground object at a position closer to the main subject, the foreground object is often in focus and the main object is often out of focus.

[Object of the invention]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a distance measurement point display finder which can easily focus on a subject located off the center as intended by a photographer.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a mark display means for displaying a display mark in a viewfinder field corresponding to each of a plurality of ranging points set on a subject side, and any one of the ranging points. And a mark clarifying unit that clarifies and displays the display mark corresponding to the distance measuring point selected by the selection operation member with respect to other display marks. In configuring the ranging point display finder, a diffusely-transmissive daylighting window, a mask plate provided behind the daylighting window and having openings formed corresponding to each of the display marks, A mirror for reflecting light passing therethrough, and a mirror provided between the finder objective lens and the finder eyepiece, which reflects the light reflected from the mirror toward the finder eyepiece. The mark comprises a half mirror that transmits light from a finder objective lens, and a lens that is provided between the half mirror and the mirror and adjusts diopter so that an image of the opening can be observed as a display mark through a finder eyepiece. A display means is provided, and further provided outside the optical path between the finder objective lens and the finder eyepiece in correspondence with the number of the distance measuring points, and illuminating light is superimposed on the image of the display mark reflected by the mirror. A plurality of light emitting elements, and switching means for selecting one of the plurality of light emitting elements in response to operation of the selection operation member, and driving the selected light emitting element in response to half-pressing of a shutter button. This constitutes the mark clarifying means.

[Action]

Since a plurality of display marks are displayed in the field of view when viewed through the viewfinder, the selection operation member is operated in accordance with the desired composition, and the position of the main subject (may be off the center of the field of view) on one display mark. ). At this time, the display mark is clarified, and it can be confirmed that the ranging point exists at that position. Thereafter, the light emitting means is operated by a well-known operation to measure a distance at a distance measuring point and focus on a main subject. In the range finder display finder of the present invention, a plurality of light emitting elements used for clearly displaying the range finder are provided outside the finder optical path, and light is emitted from the lighting window to the half mirror in the finder optical path. Since the illumination light from the element is superimposed on the display mark, a clear distance measurement point can be displayed without affecting the subject image observed through the viewfinder at all.

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

〔Example〕

Multipoint beam AF with built-in finder according to the present invention
In FIG. 3 showing the appearance of a camera, a movable lens barrel holding a taking lens 12 having an optical axis 11 on the front surface of a camera body 10.
Thirteen are arranged. The movable lens barrel 13 focuses on a subject by moving back and forth along the optical axis 11. A finder objective lens 1 is provided above the movable lens barrel 13.
4. In addition to the daylighting window 16, a light emitting window 18 for autofocus and a light receiving window 17 are arranged. A shutter button 19 is provided on the upper surface of the camera body 10, and a selection lever 20 for selecting a distance measuring point is provided on the rear surface. This selection lever
The reference numeral 20 is connected to a control circuit 45, which will be described later.

As shown in FIG. 1, the finder objective lens 14 constitutes a finder optical system together with the rear half mirror 21 and the eyepiece 22. On the other hand, a mask plate 23 is provided behind the lighting window 16 having diffuse transmission. The mask plate 23 is made of a thin light-shielding sheet, and has a slit 25 for displaying a field frame indicating an imaging range and openings 26, 27, and 28 for displaying AF target marks in the viewfinder. A mirror 24 is disposed behind the mask plate 23, and the light passing through the slits 25 and the openings 26 to 28 of the mask plate 23 is reflected by a convex lens 34.
Through the half mirror 21.

The mirror 24 is provided with half mirror portions 29, 30, and 31 corresponding to the openings 26 to 28. Therefore, when the finder image is observed with the eyepiece 22, as shown in FIG. 2A, the field frame 25a by the slit 25 is clearly displayed in the finder field 25, and the AF target by the apertures 26 to 28 is displayed. The marks 26a to 28a are displayed darker than the field frame 25a. The convex lens 34 is connected to the field frame 25a and the AF target marks 26a to 28 through the eyepiece 22 as is well known.
When observing a, the diopter is adjusted so that the virtual image is located at a position that is easy to observe.

Behind the mirror 24, a light shielding plate 36 having three openings formed corresponding to the half mirror portions 29 to 31 is provided, and LEDs 37, 38, and 39 are arranged corresponding to the three openings. Then, when any of the LEDs 37 to 39, for example, the LED 37 emits light, the light is guided to the finder optical system through the half mirror section 31 of the mirror 24, so that the corresponding AF target mark 28a is located within the finder field of view. It is displayed brightly.

Behind the projection window 18 for auto focus, a lens 41
And LEDs 42, 43, 44. These LEDs 42, 43, 44
Are connected to the drivers 46, 47 and 48. Infrared light L ₁ from LED42,43,44 this driver operates, L _2, L ₃ is irradiated. The LEDs 42 to 44 are selected by the control circuit 45 in accordance with the switching of the selection lever 20, and only the selected LED emits light and emits infrared light. This light is emitted by the shutter button 19
This is performed when is pressed halfway.

On the other hand, a filter 40, a lens 51, and CCDs 52, 53, 54 that cut natural light and transmit only infrared light are provided behind the light receiving window 17. The lens 51 collects the reflected lights of the infrared lights L ₁ , L ₂ , L _{3 on} the light receiving surfaces of the CCDs 52, 53, 54, respectively. CCD52-54
Receives the light reflected by the object among the infrared lights emitted from the LEDs 42 to 44, and outputs distance measurement data corresponding to the light receiving position to the distance calculation circuit 56. Distance calculation circuit 56
Calculates the set position of the taking lens 12 based on the distance measurement data, and drives the lens driving device 57 in accordance with the calculated position.

Incidentally, for example, if the LED42 is infrared light L ₁ toward the subject is irradiated with light, light reflected from an object CCD52
To 54 are received. The distance measurement data output from the CCDs 52 to 54 is different from each other. However, since the correct one of the distance measurement data is from the CCD 52, the distance measurement data from the CCDs 53 and 54 is invalidated. For this reason, the control circuit 45 outputs a calculation selection signal for validating any one of the distance measurement data from the CCDs 52 to 54 according to which of the LEDs 42 to 44 is turned on. To supply.

Half-press signal generator 58 connected to shutter button 19
Is connected to the control circuit 45 and the AND circuits 61, 62, 63. The half-press signal generator 58 supplies a half-press signal to the control circuit 45 while the shutter button 19 is half-pressed, and also supplies an “H” signal to one input terminal of the three AND circuits 61 to 63. .

The light emission signal generation circuit 64 connected to the control circuit 45 receives the signal from the control circuit 45 and outputs an “H” signal (light emission signal) for lighting the LEDs 37 to 39. The switching unit 66 indicated by a broken line performs a switching operation in accordance with the operation of the selection lever 20, and the output side of the light emission signal generation circuit 64 and the three AND circuits 61 to 63 are connected.
The switching is performed between the input side and the input side.

Hereinafter, the operation of the above embodiment will be described with reference to the flowchart of FIG.

The control circuit 45 is initialized when the power switch is turned on or when the film is wound up after photographing. When the finder observation is performed after this initialization, as shown in FIG. 2A, in addition to the subjects T ₁ , T ₂ , and T ₃ , the field frame 25a and the AF target marks 26a, 27a, and 28a are observed. You. In this case, AF
Each of the target marks 26a, 27a, 28a is
It is slightly darker than before, and informs the photographer that the distance measurement position has not yet been determined.

When the shutter button 19 is half-pressed, a constant switching signal determined by the initialization is supplied to the switching unit 66, and the LED 38 is turned on. Light from LED38 is half mirror part
30 and transmitted through the viewfinder as shown in Fig. 2 (B).
The AF target mark 27a is displayed brightly. When photographing an object T ₂ which is aimed by the AF target mark 27a as the main subject may be directly press the shutter button 19 all.

With this full press, the control circuit 45 sets the AF target mark.
A light projection signal is output to the driver 47 corresponding to 27a, and a calculation selection signal is output to the distance calculation circuit 56 so that only the distance measurement data from the CCD 53 is handled as a valid signal. Thus, only the infrared light L ₂ from LED43 is radiated toward the subject, the set position of the taking lens 12 is determined on the basis of the distance measurement signal obtained by CCD 53. Then, after the taking lens 12 is set at the in-focus position, the shutter is opened and closed to perform photographing, and after this photographing, the LED 38 is turned off. Thereafter, upon completion of the film winding, the control circuit 45 is initialized again, and enters a standby state for the next photographing operation.

If you want to shoot a subject T ₁ shown in FIG. 2 (A) as the main subject may be performed a distance measurement by selecting the AF target mark 26a that is aimed to the object T _1. When performing this selection operation, the selection lever 20 may be pressed once to the left. When the selection signal is input to the control circuit 45, a switching signal is supplied from the control circuit 45 to the switching unit 66, and the signal from the light emission signal generation circuit 64 is supplied to the LED 39. Therefore, when the shutter button 19 is half-pressed in this state, the lighting of the LED 39 clearly displays the AF target mark 26a as shown in FIG. 2 (C).

When the shutter release button 19 is fully pressed after selecting the distance measurement position in this way, the control circuit 45 outputs a light projection signal to the driver 48 in response to the selection signal from the selection lever 20, and the CCD 54 The AF target mark 26
so focusing is performed on an object T ₁ which is aimed at a.

Incidentally, AF target mark 26a that is aimed to the object T ₁
After selecting the distance measurement position by, when making the change of the distance measurement position on the object T ₃ may be twice pressing the selection lever 20 to the right. When the half-press of the shutter button 19 is released after the selection operation of the distance measurement position, the clear display of the selected AF target mark is turned off, and the state shown in FIG. 2A is obtained. However, when the shutter button 19 is half-pressed again, since the control circuit 45 has not been initialized, the AF target mark set by the previous selection operation is clearly displayed.

The above has been described in accordance with the illustrated embodiment.
Instead of operating the selection lever 20, it is also possible to change the distance measurement position by pressing the shutter button 19 halfway. In this case, every time the shutter button 19 is half-pressed, the AF target mark displayed clearly is changed from 26a → 28a →
It suffices to circulate from 27a to 26a and to input a selection signal to the control circuit 45 in response to this. Of course, the number and arrangement of the distance measurement positions are not limited to the above-described embodiment. Also, for the clear display of the AF target mark corresponding to the selected distance measurement position, for example, a method such as blinking an LED can be used. Furthermore, if a liquid crystal display panel is used instead of the light shielding plate 36 and only a portion corresponding to the distance measurement position is made transparent by a switching signal from the control circuit 45, one LED for illuminating the AF target mark can be used. It is also possible to make individual.

As shown in FIG. 5, a diffusing plate 67 is provided on the object side of the mask plate 23 to make the AF target mark shine more clearly.
There is also a method of arranging ~ 69 and illuminating each with LEDs 37 ~ 39. The diffusing plates 67 to 69 are members that allow incident light from the lighting window to pass therethrough and illuminate the LEDs 37 to 38. In addition, light-shielding paints 68a, 69a are applied to the right side surfaces of the diffusion plates 68, 69,
Light from other LEDs is prevented from entering.

〔The invention's effect〕

As described in detail above, the present invention provides a method for clearly displaying a display mark corresponding to a selected ranging point in a viewfinder, among a plurality of ranging points set on the subject side.
The display mark corresponding to each ranging point is guided into the finder optical path through the lighting window and the mask plate, and a plurality of light emitting elements for clearing the display mark corresponding to the selected ranging point are located outside the finder optical path. When a specific light emitting element is selected from these light emitting elements in response to a selection operation of a distance measuring point and driven in response to half-pressing of a shutter button, the illumination light is transmitted from a lighting window to a finder optical path. In the viewfinder optical path composed of the viewfinder objective lens and the viewfinder eyepiece, there is no other than the half mirror because the clear display is performed by superimposing it on the predetermined display mark up to the half mirror inside. Need not be provided at all. Therefore, even though the finder has a function of displaying a plurality of distance measuring points in the finder, it does not affect the subject image observed through the finder at all, and when the shutter button is half-pressed, the subject image is displayed. Both the display of the distance measuring point and the distance measurement point can always be clearly observed.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an embodiment according to a distance measuring point display finder of the present invention. FIG. 2 is an operation explanatory view when the subject is observed through the range finder display finder in FIG. FIG. 3 is an external view of an active AF camera provided with the distance measuring point display finder of FIG. FIG. 4 is a flowchart showing the flow of the operation of the embodiment of FIG. FIG. 5 is a schematic view showing another embodiment of the present invention. 14 Finder objective lens 16 Lighting window 17 Light-receiving window 18 Light-emitting window 19 Shutter button 20 Selection lever 21 Half mirror 23 Mask plate 24 Mirror 26-28 ... opening 26A～28a ...... AF target mark 37~39,42~44 ...... LED 61~63 ...... AND circuit 66 ...... switching unit _{L 1, L 2, L 3} ...... infrared light T _1, T ₂ , T ₃ …… Subject.

Claims (1)

(57) [Claims] 1. A camera having a built-in light projecting means for projecting distance measuring light toward a plurality of distance measuring points on a subject side, and displaying a display mark corresponding to each of the distance measuring points in a finder field of view. Mark display means, a selection operation member for selecting any of the distance measurement points, and a display mark corresponding to the distance measurement point selected by the selection operation member among the display marks with respect to other display marks. In a distance measuring point display finder provided with a mark clarifying means for clarifying and displaying the mark, the mark displaying means is provided with a light-transmitting window having a diffuse transmittance disposed adjacent to a finder objective lens, and behind the light-receiving window. A mask plate provided with a light-transmitting opening corresponding to each of the display marks, a mirror for reflecting light incident from a lighting window and passing through the opening, a finder objective lens, and a finder A half mirror that is provided to be inclined between the eyepiece and the mirror that reflects the light reflected from the mirror toward the finder eyepiece and transmits the light from the finder objective; And a lens for diopter adjustment so that the image of the aperture can be observed as a display mark through a finder eyepiece.The mark clarifying means is provided outside the optical path between the finder objective lens and the finder eyepiece. A plurality of light emitting elements provided corresponding to the number of the distance measuring points, for superimposing the certification light on an image of the display mark reflected by the mirror; and the plurality of light emitting elements in response to an operation of the selection operation member And switching means for driving the selected light emitting element in response to half-pressing of the shutter button. AF point display finder.