JPS63128331A - Finder display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a finder display device for a camera, and particularly to a distance measurement display thereof.

<Description of Prior Art> The viewfinder display device of conventional autofocus built-in cameras, such as Albada type finder or mark type bright frame finder, reflects the mark indicating the distance measurement range with a half mirror and shows it within the field of view. That's what I do.

However, when the photographer is focused on the subject, he or she hardly looks at the distance measurement mark and misses the distance measurement point of the subject. The subject was often in focus, resulting in so-called out-of-focus photos.

For example, FIG. 2(b) shows an example of this. That is, FIGS. 1 and 2 show a conventional example in which 1 is a light emitting element for autofocus light projection, IRED 2 is a light receiving sensor for autofocus and is a PSD or CCD, 3 is a light projection lens that focuses the light projection IRED, 4 is a light receiving lens that collects the light projected by the light projecting lens 3; 5, 6.7 are objects to be photographed; and 8 is a mark indicating a distance measurement range.

In the above configuration, first, in FIG. 1(a), the I RED for light emission is
1 is projected onto the subject 5 using the light emitting lens 3, and the reflected light is imaged onto the light receiving sensor 2 using the light receiving lens 4, and the distance to the subject 5 is calculated based on the position of the image. be. This distance measuring method, which is conventionally known, projects fairly focused light in order to increase the power of the projected light. Therefore, the distance measurement range within the photographic field of view is limited to the range of the distance measurement mark 8 shown in FIG.

However, this distance measurement mark 8 is difficult to see compared to the photographic field of view, so it is sufficient if the subject 5 is located in the center of the photographic field of view as shown in Fig. 2(a). (
As shown in b), there are distance measurement marks in the center of the subjects 6 and 7, and if the photographer is paying attention to the subject, he or she is often not looking at the distance measurement mark 8. If you take a picture with a frame like that shown in Figure 2 (b) in this state, the projecting light will go to infinity as shown in Figure 1 (b), and the subject 6.7 will not be in focus. Subject 6,
It will match the background of 7. To prevent this,
Most cameras have a prefocus mechanism, or as mentioned above, when you are focusing on the photographer or the subject, you may not notice the distance measurement mark as shown in Figure 2 (b). <Objective of the Invention> The purpose of the present invention is to provide a display device that actively displays the range measurement range in order to eliminate the drawbacks of the above-mentioned passive range measurement range setting. do.

For this purpose, in a finder display device that displays the distance measurement range in a part of the finder field of view, when measuring the distance to a subject, the brightness of the distance measurement range and the finder field of view other than the distance measurement range is This is because a means for changing the hue of the pod, etc. is provided.

<Example> The present invention will be described in detail below with reference to the drawings from FIG. 3 onwards.

FIG. 3 is a perspective view showing the main parts of the optical system of the photographic finder. 11 is an objective lens, 13 is an eyepiece lens, and 12 is a half mirror disposed between the objective lens 11 and the eyepiece lens 13.

15 is a diffuser plate which is a window for letting in light; 16 is a liquid crystal (LCD) display plate that turns on and off the distance measurement range for focusing; and 14 is a half mirror that converts the light emitted from the display plate 16. -12, and is a mirror that reflects light of a predetermined wavelength, for example, yellow light.

Further, FIG. 4 shows a drive circuit for driving a finder display device according to the present invention. 25 is the battery which is the power source,
SWI is a switch that transmits a signal to a circuit to be described later, and 26 is a one-shot circuit, which outputs a one-shot pulse to the set terminal of flip-flop 29 when switch SWI is turned on. 27 is an LCD driver that blocks light from the distance measurement range 9, which is a distance measurement point that specifies the focus range of LCD 18; 28 is a CD driver that blocks light from the area other than the field of view frame 22 of LCD 16;
32 is a light-receiving sensor such as a PSD that receives the light reflected from the object 33. In FIG. 30 is an arithmetic circuit that calculates and calculates the distance to the subject based on the output of the light receiving sensor 32, and stores the measured distance; 35 is a lens that receives the output of the arithmetic circuit 30 and moves a photographing optical system (not shown); This is a drive circuit.

SW2 is a switch that triggers the exposure control circuit 36 and the lens drive circuit 35; 37 is a motor drive circuit that drives a motor for feeding the film; and 38 is a power supply 25.
This is a power supply latch circuit that latches the voltage.

Next, the operation will be explained based on the above configuration.

First, when the switch SWI is turned on, the transistor Tr,
The pulse is input as a set signal to the flip-flop 29 through the one-shot circuit 26, and the flip-flop 29 outputs the rHJ level. This signal causes the output of the inverter IN to go to rLJ level, drives the LCD driver 27, and puts only the distance measurement range 9 in a light-shielded state, so that the incident light from the diffuser plate 15 transmits light other than the distance measurement point 9. Next, as mentioned above, the mirror reflects only yellow light, and when this light is re-reflected by the half mirror 12, it overlaps with the field of view light of the finder that entered from the objective lens 11, and the photographic field of view as seen from the eyepiece lens 13. As shown in Fig. 5(a), the distance measurement point 9 is similar to the normal photographing field light, or the other parts appear yellowish, which may be a problem for photographers who are not paying attention to the distance measurement point. You can also judge whether the distance measurement point captures the subject. Then, the photographer points the distance measurement point 9 toward the object 7 to be photographed and presses the SWI button again. The light emitting element 31 emits light toward the object, and the drive circuit 30 measures the distance to the object.

When the distance measurement calculation is completed, the calculation circuit 30 outputs an end signal to the reset terminal of the flip-flop 29, and the flip-flop becomes rLJ level and the LCD driver 27 turns off the display of the distance measurement point 29, but the LCD driver 28
is placed in a driving state, and the area other than the viewing field frame 22 is in a light-shielded state. A perspective view of the finder optical system at this time is shown in Figure 3(a).
This is shown below. The state in which the incident light from the diffuser plate 15 passes through only the four locations indicating the field frame, is reflected by the reflection mirror 14, passes through the half mirror 12, and is seen from the eyepiece is the fifth point.
As shown in Figure (b).

In other words, the field of view light can be seen sufficiently, allowing free framing. Next, by pressing SW2, the lens drive circuit latches the distance measurement calculation value stored in the calculation circuit 30, drives the lens, and also controls the exposure amount control circuit 3.
6, a film (not shown) is exposed to light. When the exposure is completed, the motor drive circuit 37 feeds the film. In addition, SW
The power supply latch circuit 38 latches the voltage of the battery I due to I, but when the film feeding is completed, the motor drive circuit outputs a feeding completion signal, and by releasing the power supply latch, all displays are turned off.

According to the above explanation, the hue of the distance measurement range and other viewfinder field of view is changed by SWI, and when the distance measurement calculation is completed, the original state is returned and the photographer can focus on the subject to be photographed. At the same time, it is possible to judge whether the distance has been measured accurately, and also to frame freely.
It becomes possible to take pictures according to the photographer's intention, even if the subject is not necessarily within the distance measurement range.

The above-mentioned switches may be switched independently, or may be switched sequentially as the release button is pressed.

In the above, the distance measurement point and other parts are distinguished by color.Next, an embodiment in which the visual field light other than the distance measurement point is attenuated will be described with reference to FIG. 6.

20 is the objective lens of the finder, 17 is the eyepiece lens,
Reference numeral 18 denotes a frame plate on which a mark indicating the photographing field frame of the finder is vapor-deposited. Reference numeral 19 denotes a half mirror 121 that reflects the mark on the frame plate 18, and an LCD plate that turns on and off other than the distance measurement point.

The driving circuit of this example is achieved by replacing the LCD plate 16 of the above-described example and removing the LCD driver 28 that drives the viewing frame. That is,
By pressing SWI, the field of view becomes as shown in Figure 5 (a), and the photographer can detect the focus on the object to be photographed because the distance measurement point is equal to the normal brightness and other parts are darkened. You can quickly decide whether or not to proceed. When the distance measurement calculation is completed, the field of view frame becomes as shown in Fig. 5(b),
In addition to being able to frame freely, pressing SW2 allows accurate distance measurement to the subject.

In the above embodiments, either the entire distance measurement range is made to have the same brightness as the normal subject image, or only the edge of the mark that sets the distance measurement range is set to the same brightness as the normal subject image, or as shown in FIG. It is also possible to make a difference in brightness between the parts.

Note that if the LCD is used for checking the battery of the camera, no other device for checking the battery is required.

<Effects> According to the present invention described above, during distance measurement, by changing the appearance of the distance measurement range and the field of view of the finder outside the distance measurement range, the photographer can This has the effect of making it possible to judge whether or not distance measurement is accurate.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram for explaining the conventional technology, Fig. 2 is a viewfinder display device for explaining the conventional technology, Fig. 3 is the finder optical system of the present invention, and Fig. 4 is a drive circuit diagram of the present invention. , FIG. 5 shows an embodiment of the display in the finder of the present invention, and FIG. 6 shows a finder optical system according to another embodiment of the present invention. 9... Distance measurement range, 11... Objective lens, 13... Eyepiece lens, 16...
LCD, Figure 1 (α) Section 10 (b)

Claims (1)

[Claims] In a finder display device that displays a distance measurement range in a part of the viewfinder field of view, when measuring a distance to a subject, a drive means that changes the visual sensation between the distance measurement range and the finder field of view other than the distance measurement range is provided. A finder display device characterized by being provided.