JPS5926720A - Device for exposure information digital display in common use as overexposure and underexposure warning display of camera - Google Patents

Abstract

PURPOSE:To allow simple constitution which uses common light emitting elements to display both exposure information and overexposure/underexposure warning by displaying the exposure information digitally and flashing the display at specific cycles in case of overexposure or underexposure. CONSTITUTION:Digital exposure information from a photometric circuit 1 is displayed on solid-state light emitting elements of a display device 3 through a gate 2. When this exposure information shows overexposure or underexposure, an AND gate 4 is opened through a warning signal generating circuit 5 and the gate 2 is turned on and off by a rectangular wave with a specific period supplied from a rectangular wave oscillator 6 through the gate 6 to flash the display of the device 3 as the warning display of the overexposure or underexposure. Therefore, the simple constitution which uses the common light emitting elements displays both exposure information and warning information corresponding to the overexposure or underexposure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that digitally displays exposure information in a camera finder and also displays a warning about overexposure or underexposure.

As camera exposure control advances, various warning displays have become necessary, and in recent automatic exposure adjustment cameras, various warning displays have come to be performed using rungs and the like.

Particularly as automatic exposure control advances, overexposure and underexposure warnings are important when exposure is not performed properly. Furthermore, it has been proposed or proposed to provide a warning lamp in the viewfinder of the camera to display a warning when the shutter speed falls below the camera shake limit. On the other hand, with automatic exposure devices, it is also necessary to display exposure information such as the shutter speed and aperture value that are actually being controlled in the viewfinder so that the photographer can know the actual shooting conditions. Therefore, this type of display device has to be installed in a complicated manner in the limited space around the viewfinder, which greatly complicates the mechanism of the camera, increasing the number of failures and creating manufacturing difficulties.

Recently, digital display devices using solid-state light-emitting display elements (light-emitting diodes, etc.) have come into use in various devices, and these can be used to display exposure information in the viewfinder of a camera. However, in this case, as described above, a device for displaying overexposure/underexposure warning information and a digital device for displaying exposure information would be installed at the same time, which would pose serious manufacturing problems. Particularly in this type of digital display device, the fewer the number of pins drawn out from the digital light emitting element, the better in terms of cost. Therefore, if the warning information is displayed together with the exposure information using the digital light emitting element, the cost will increase. This is undesirable in terms of manufacturing.Therefore, cameras equipped with this type of digital display (
In this case, ordinary lamps have to be used for warning indications, which causes more complicated problems in terms of structure and is inconvenient in practice.

The present invention displays image information without complicating the internal structure of the camera by displaying overexposure/underexposure warning information and displaying exposure information using a common light emitting element (including a lamp). The object of the present invention is to provide a display device that makes it possible to display images.

In order to achieve this object, the present invention inputs an overexposure/underexposure warning signal and a square wave to a device that digitally displays exposure information of a camera through an AND circuit, so that when the warning signal is generated, the square wave is sent to the device that digitally displays the exposure information of the camera. The digital display is interrupted at the cycle of a rectangular wave.

The principles and embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram representing the concept of an embodiment of the present invention, and is intended to explain an example of the basic idea of the present invention. An exposure meter or photometering circuit 1 that includes a photoelectric element such as CdS as a photoreceptor receives information from a subject and outputs Kameyama information corresponding to the brightness of the subject.

A gate circuit 2 is connected to this photometric circuit 1, which always transmits the output from this photometric circuit 1 to a display device 3 as it is.
L, this output is input to a display device 3 that displays exposure information (for example, appropriate shutter speed, aperture value, etc.) by emitting light. The means of display may be a lamp or a light-emitting device such as a light-emitting diode, as long as it emits light using an electric current.
. An overexposure/underexposure warning signal generator 5 and a rectangular wave oscillator 6 are connected to the gate circuit 2 via an AND circuit 4 as a warning gate circuit. This AND circuit 4 is for transmitting the rectangular wave from the rectangular wave oscillator 6 to the gate circuit 2 to turn off the gate circuit 2 that is ON at the cycle of the rectangular wave when a warning signal is generated. . As a result, the light emitting display of the light emitting display device 3 is interrupted at the period of the rectangular wave,
This system is designed to warn the photographer of overexposure or underexposure by flashing the exposure information display. Therefore, the period of this rectangular wave needs to be long enough to allow the human eye to perceive the blinking of this display. Theoretically,
This period can be set to about 0.1 seconds, since the length of time the light-emitting element is turned off should be at least 1/20 second, which is the afterimage time of the human eye, but in reality, the warning is clear. It is desirable to set the time to about 0.05 to 1.0 seconds so that it can be recognized as such.

FIG. 2 shows an embodiment of the present invention based on the above concept whose basic configuration is shown in FIG.

The configuration shown in FIG. 2 is an example in which a device for digitally displaying exposure information also serves as a warning display. In FIG. 2, the photometry circuit 21 is a silicon photocell or C
A photoreceptor 21a made of a photoelectric element such as dS, and a photoreceptor 21a connected to the photoreceptor ■a and receiving light from the subject.
Reference numeral 520 is a digital display device, which is equipped with an amplification circuit 21t) which amplifies the output of the amplification circuit 21t and outputs exposure information according to the brightness of the light from the subject as an analog quantity.
Receive analog output from 1b and convert to digital quantity 1
'-A-I) converter 27, which converts the digital display light-emitting element 2 according to the digital output of this A-D converter 27.
3, a decoder 28 which acts to selectively emit light according to a predetermined code; a first plurality of digital display light emitting elements 23 such as light emitting diodes connected to the decoder 28; and between the element 23 and the decoder 28; It includes an interposed gate circuit 22 and an AND circuit 24 connected to the gate circuit 22. This AND circuit 24 is connected to an overexposure/underexposure warning signal generator 25 and a rectangular wave oscillator 26 so as to AND signals from each.

Specifically, the gate circuit 22 is an ANI circuit that is always in an OPEN state, and the AND circuit 24 is a NAND circuit. From the overexposure/underexposure warning signal generator 25,
When the exposure control results in proper exposure and there is no warning condition, no signal is generated and the output to the AND circuit 24 is at 0 level. The rectangular wave oscillator 26 constantly oscillates a rectangular wave with the above-mentioned period, and the AND circuit 2
4, and an output that repeats 0 level and level is output (・However, when there is no warning signal, the AND of the NAND circuit is always 6, that is, 1, so the gate circuit 22 is 0
Continue the PEN (ON) state. Therefore, light emitting element 2
3 remains lit.

When the result of exposure control is not a proper exposure (i.e., over or under, or shutter speed below the camera shake limit), an overexposure/underexposure warning signal is generated, and the output of the warning signal generator 25 changes from O level to level. , the output of the logic circuit 24 repeats 1.0 (0, 1) in accordance with the period of the rectangular wave. This output changes the gate circuit 22 to CLO8E (O
FF), the light emitting element 23 blinks at the above period. For example, if this cycle is set to 1 second, it will blink once per second, so the light emitting element that normally displays exposure information such as shutter speed will blink clearly to the photographer's eyes. visible and can give warnings. Exposure information and overexposure/underexposure warning information can take various forms. For example, if we take shutter speed as exposure information and overexposure as warning information, specifically, we can use a camera as a subject. When you aim at the camera and lower the shutter button slightly, 500 will be displayed in the viewfinder as a light-emitting diode display.

Kosai 1 indicates that if you press the shutter as it is, the shutter will be down for 1/500th of a second. At this time, if the character "500" starts blinking, 5
This indicates that the exposure is overexposed at 1/00th of a second, and that the aperture should be made even smaller to obtain a proper exposure.

The embodiment of the present invention is not represented only by the block diagram shown in FIG. 1, but various modifications are possible. Next, one example of the modification will be explained with reference to FIG.

The embodiment shown in FIG. 3 is applied to a digital display device like the one shown in FIG. 2, but uses something like the gate circuit 22 used in the example of FIG.
The square wave is transmitted between the light emitting element and the decoder (to one terminal of the light emitting element).

In Fig. 3, a photometric circuit 31 corresponding to the photometric circuit 21 in Fig. 2 includes a photoreceptor 31a and an amplification circuit 31b. converter,
Each decoder is shown in which a large number of light emitting elements 33 are connected in parallel to a decoder 38 (.) This light emitting element 33, such as a light emitting diode, is connected to an AND circuit 34 at the other end 32 (.. Here, the AND circuit 34 is an AN I) circuit, and the overexposure/underexposure warning signal generation circuit 35
A signal of O level is given in a non-warning state, and a level signal is given in a warning state. This AND circuit 34 is also connected to the aforementioned rectangular wave oscillator 36, and a rectangular wave repeating the 1.0 level is provided and ANDed with the warning signal. Since the output of the overexposure/underexposure warning signal generator 35 is always at the O level, the logical product (AND) becomes O, and the other end (lower end in the figure) of the element 32 is kept at the O level potential. On the other hand, as in the embodiment shown in FIG. 2, the exposure information is digitized and selectively transmitted to the light emitting element 33 through the decoder 38, and the upper end of the light emitting element 33 is selectively set at Lebel's potential, so that a predetermined level is reached. In combination, the element 33 emits light and displays exposure information (shutter speed, aperture value, etc.). When the warning signal (LEBEL) is generated (1-), the LEVEL is inputted to one side of the AND circuit 34, so that the AND with the rectangular wave that repeats 1 and 0 becomes 1 and 0 repeatedly. As a result, the potential at the lower end 32 of the light emitting element changes from the potential at the upper end of the rube 33 to Lebel (
(in the element to be selected and lit),
The potential difference between both ends of this light emitting element 33 becomes 0 periodically,
As a result, the light emitting element 33 will blink. Since this period is equal to the period of the above-mentioned rectangular wave, the light-emitting display element for exposure information blinks to display a warning about overexposure or underexposure, as in the example of FIG.

Overexposure/underexposure warning signal generating device 25 in the above embodiment.
Although various types of 35 can be considered, any type can be used as long as it provides a level output at the time of a warning and a zero level output at other states. Various known methods can be used to convert the warning content into a 0° level output, but information on overexposure and underexposure can be obtained using the measurement circuits 1, 21, and 31.
can be easily obtained from the output of an exposure control circuit containing

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one example of the basic configuration of the display device of the present invention, FIG. 2 is a schematic circuit diagram showing an embodiment I that embodies the basic configuration shown in FIG. 1, and FIG. 2 is a schematic circuit diagram showing another embodiment of the present invention not based on the configuration shown in FIG. 1. FIG. 1.21.31...Photometering circuit 2,22...
...Gate circuit 6.26,36...Square wave oscillator

Claims (1)

[Claims] In a camera, a digital conversion circuit that converts exposure information into a digital signal, a digital display means having a large number of solid-state light emitting elements that selectively emit light according to the output of this digital conversion circuit, and an over/under exposure obtained from the exposure information. A warning signal and a rectangular wave are inputted to the solid-state light emitting element of the digital display means through an AND circuit, and when a warning signal is generated, the solid-state light emitting element selectively generated is set to 0.5 to 0.5. An exposure information digital display and overexposure/underexposure warning display device comprising a flashing warning means that flashes at a cycle of 10 seconds.