JPH0686111A - Electronic view finder provided with projecting function - Google Patents

Abstract

PURPOSE:To allow the projector function to project a picture with a prescribed lightness onto a screen without being affected with a change in a projection distance by detecting a supplied quantity of an eyepiece lens so as to control the luminance of the light source in the projector mode. CONSTITUTION:The finder is provided with a comparator 4 discriminating the setting mode based on a setting position (supplied quantity of an eyepiece lens) of a slide switch 24 and outputting a command signal in response to the discriminated mode and a dimmer section 5 reaching a dimmer control state accordingly when a command signal based on the projector mode is received from the comparator 4 and outputting a dimmer signal based on a level of the signal in response to the supplied quantity of the eyepiece lens from the slide switch 24. That is, the dimmer section 5 decreases the luminance of a light source 10 based on the EVF mode and increases the luminance of the light source 10 based on the projector mode and outputs a dimmer signal controlling the luminance of the light source 10 so that the lightness of a projected picture is made constant based on the signal level even when a projection distance is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic viewfinder having a projection function, which is mounted on a video camera and has a liquid crystal display section.

[0002]

2. Description of the Related Art In recent years, an electronic viewfinder capable of driving a liquid crystal display portion by an image signal obtained by a video camera and allowing a photographer to observe an image displayed on the liquid crystal display portion to confirm a subject. It has been known.

Such an electronic viewfinder has a cylindrical shape with one end closed, and an image displayed on a liquid crystal display section arranged inside the cylinder can be viewed from the other end side through an optical system. It is like this.

[0004]

By the way, such an electronic viewfinder reproduces an image signal obtained by photographing in substantially real time, or reproduces an image signal from a recording medium after photographing. The number of people who can see is limited to one.

In order for a plurality of people to view the reproduced image after shooting, it is necessary to connect a video camera to an external monitor and reproduce the image on this monitor.

Therefore, in the conventional video camera, it has been difficult for a plurality of people to view and enjoy an image photographed outdoors, and to enjoy the image because of problems such as securing the power source of the monitor device and portability. For example, it was difficult to take a picture of a child's competition with a video camera at an athletic meet and to enjoy the picture of the competition at the time of lunch outdoors thereafter so that everyone can enjoy it.

In view of such circumstances, the inventors of the present application have a projector function of projecting an image displayed on the liquid crystal display portion of the electronic viewfinder onto a screen outside the finder through an eyepiece lens by illumination from a light source. Has invented an electronic viewfinder and applied for it and has already disclosed it (Japanese Patent Application No. 4-153384).

By the way, when the electronic viewfinder is used in a normal use method, even if the brightness of the illumination is kept constant, there is not much problem.

However, when this electronic viewfinder is used as a projector, the brightness of the image changes greatly depending on the projection distance from the liquid crystal display section to the screen.

That is, if the brightness of the illumination light source is kept constant, the image on the screen becomes dark when the projection distance is large, and the image on the screen becomes bright when the projection distance is small.

In particular, since the projector function is expected to be used outdoors as in the above-mentioned example,
Often, screen substitutes in place are used at appropriate distances, and it is an important issue to project an easy-to-see image on this screen.

The present invention has been made in view of the above circumstances, and allows a plurality of people to easily view a reproduced image at the same time without using an external display device and is affected by a change in projection distance to the screen. It is an object of the present invention to provide an electronic viewfinder having a projection function, which allows the reproduced image to be viewed in a state of good brightness without any need.

[0013]

An electronic viewfinder having a projection function of the present invention has a projector function of projecting an image displayed on a liquid crystal display unit onto an external screen of the finder through an eyepiece lens, It is characterized in that the brightness of the light source is controlled so as to increase as the projection distance increases, based on the detection result of the amount of extension of the eyepiece when focusing on the screen.

That is, in an electronic viewfinder equipped with a liquid crystal display unit mounted on a video camera, an image displayed on the liquid crystal display unit is illuminated by illumination light from a light source, and the image is viewed through an eyepiece lens of the viewfinder. When a projection amount detecting unit configured to have a projector function of projecting onto a screen outside the finder via the finder and detecting a projection amount of the eyepiece lens with respect to the liquid crystal display unit and using the finder as a projector In addition, based on the detection result of the feeding amount detection unit when focusing on the screen, a dimmer unit that adjusts the brightness of the light source so that the brightness of the light source increases as the projection distance increases. It is characterized by having.

Here, the electronic viewfinder is mounted on a video camera, reproduces an image photographed by the video camera in substantially real time, and reproduces an image signal from a recording medium after the photographing and this image. It has an optical system that allows an image displayed on the display unit to be viewed as a virtual image.

Further, the screen includes not only so-called projector screens but also plain screens, paper pieces, and the like that can be used as screens.

[0017]

According to the above construction, it has a projector function for projecting the image displayed on the liquid crystal display unit to the outside, and it is not only the screen for the original projector but also a plain wall or a piece of paper, for example. Since the captured image can be displayed in a desired size by using the screen substitute, a plurality of people can simultaneously view the same image at any place.

Further, in the electronic viewfinder of the present invention, when a photographed image is projected on the screen through the eyepiece lens, the amount of extension of the eyepiece lens when the focus is focused on the screen is detected. Based on the detection result, when the projection distance is large, the brightness of the illumination light source is increased, and when the projection distance is small, the brightness of the illumination light source is controlled to be small, so that the liquid crystal display unit changes according to the change of the projection distance. Since the illumination brightness of is changed, it is possible to always display a reproduced image with a brightness that is easy to see on the screen without being affected by changes in the projection distance.

Particularly in such a projector,
It is expected that the reproduced image will be displayed on the spot immediately after the video shooting in the field. In this case, since the screen substitute is often used at an appropriate distance, the change in the projected distance causes a change in the reproduced image. The finder of the present invention, which is prevented from affecting the easiness, has a very high practical value.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic view showing a general video camera equipped with an electronic viewfinder according to an embodiment of the present invention.

That is, the electronic viewfinder 1 is attached to the side portion of the video camera body 2, and an image photographed through the photographing lens 3 is recorded at approximately the same time as the photographing, or after the recording medium (such as a video tape). ) Is recorded and then reproduced. Further, the electronic viewfinder 1 has a projector function and is configured to be able to project an image once recorded on a recording medium to the outside.

FIG. 3 shows an optical system inside the electronic viewfinder 1. FIG. 3A is a schematic view showing an optical arrangement when the electronic viewfinder mode (hereinafter referred to as EVF mode) is set. FIG. 2B is a schematic diagram showing the optical arrangement when the projector mode is set.

That is, in the EVF mode, the light source 10
The light emitted from the collimator lens 12 is collimated into parallel light, the diffusion plate 14 reduces illumination unevenness, and the polarization filter 16 converts the light into linearly polarized light.
Irradiated to 18. The liquid crystal display plate 18 is driven by an image signal obtained by photographing to display an image, and the light transmitted through the liquid crystal display plate 18 carries image information.

The light carrying the image information is a biconvex lens 20.
The biconvex lens 20 is positioned so that the distance x ₁ between the image display surface of the liquid crystal display plate 18 and the biconvex lens 20 is smaller than the focal length f of the biconvex lens 20, Looking through the biconvex lens 20 in the direction of the liquid crystal display plate 18, the virtual image formed at the back of the liquid crystal display plate 18 can be seen. As a result, the image displayed on the liquid crystal display plate 18 can be viewed.

Next, when the mode is changed from the EVF mode to the projector mode, the biconvex lens 20 is moved forward by a distance x ₂ . This allows the LCD panel 18
The distance between the image display surface and the biconvex lens 20 is x ₁ + x ₂ , which is larger than the focal length f of the biconvex lens 20.
Therefore, the light carrying image information is incident on the biconvex lens 20 and then a predetermined distance X from the biconvex lens 20, that is, X = (x ₁ + x ₂ ) f / (x ₁ + x ₂ -f) (1 The image displayed on the liquid crystal display panel 18 is formed as a real image on the screen 22 that is separated by only).

The electronic viewfinder 1 is composed of an outer cylinder 1A and an inner cylinder 1B, and has a biconvex lens 20.
The other optical members such as the light source 10, the collimator lens 12, and the liquid crystal display plate 18 are attached to the outer cylinder 1A and the inner cylinder 1B, respectively. A slide switch (lens extension amount detection unit) 24 is arranged between the outer cylinder 1A and the inner cylinder 1B.
The section of the slide switch 24 moves according to the movement of the biconvex lens 20 (outer cylinder 1A), and the slide switch 24 is switched between the two modes described above. In the projector mode, the diffusion plate 14 is transferred to the outside of the optical path.

By the way, one of the features of the device of the present invention is that it has a light control mechanism for making the image displayed on the screen 22 always bright enough to be seen even if the projection distance changes in the projector mode. . In the apparatus of this embodiment, the dimming mechanism is made to function by the configuration shown in FIG.

That is, the apparatus of this embodiment determines whether the mode is set to the EVF mode or the projector mode based on the set position of the slide switch 24 (the amount of extension of the eyepiece 20) as shown in FIG. , A comparator 4 that outputs a command signal according to the determined mode, and when a command signal based on the projector mode is input from the comparator 4, the high brightness / dimming state is set accordingly, and the slide switch 24 A light control section 5 that outputs a light control signal (light source drive signal) based on the level of the signal corresponding to the amount of extension of the eyepiece lens 20 is provided. That is, the dimming unit 5 reduces the brightness of the light source 10 when the command signal based on the EVF mode is input, and the light source when the command signal based on the projector mode is input.
Outputs a dimming signal that drives the light source 10 so that the brightness of the projected image becomes constant even if the projection distance changes based on the level of the signal level input from the slide switch 24 while increasing the brightness of 10 To do.

4 to 6 show the details of the slide switch 24. In the electronic viewfinder 1, the two cylinders 1A and 1B are slid on each other to change the relative distance between the biconvex lens 20 and the liquid crystal display plate 18, and the slide switch 24 is used to switch the mode. As described above, the brightness of the light source is controlled according to the position where 24 is set.

As shown in FIG. 4, this slide switch
The reference numeral 24 includes a section 24A attached to the outer cylinder 1A and a substrate portion 24B attached to the inner cylinder 1B.

The section 24A has a conductor plate 41 attached to the outer cylinder 1A through an insulating plate 42, and a dogleg-shaped tip arranged so as to project from the conductor plate 41 in the sliding direction as shown in FIG. It consists of a multi-wire 43.

Further, as shown in FIG. 6, the board portion 24B is formed by arranging the conductor wire 44 and the resistor 45 in parallel with each other on an elongated board 46.

When the outer cylinder 1A and the inner cylinder 1B are combined, the tip portion of the multi-wire 43 of the section 24A is the substrate portion 24B.
Of the multi-wire 43 is arranged so as to abut on the conductor wire 44 and the resistor 45 of the outer cylinder 1A, and the tip of the multi-wire 43 slides on the upper surfaces of the conductor wire 44 and the resistor 45 when the outer cylinder 1A is pulled out from the inner cylinder 1B. Become.

As shown in FIG. 6, one end of each of the conductive wire 44 and the resistor 45 has a resistance detection circuit (slide switch).
(Attached to 24), the resistance value from the end of the resistor 45 to the position in contact with the multi-wire 43 is detected by the resistance detection circuit. That is, the resistor 45 is electrically connected to the conductor wire 44 through the multi-wire 43 and the conductor plate 41, so that the outer cylinder 1A is pulled out and the section 24A is removed.
The detected resistance value increases as the distance moved in the direction of the arrow increases. In this way, the slide switch 24 functions as a potentiometer.

The voltage value based on the resistance value detected by the resistance detection circuit is input to the comparator 4 and the dimming unit 5, and the larger the amount of extension of the outer cylinder 1A, the more it is input to these units 4 and 5. The voltage value to be increased becomes large.

FIG. 7 is a graph showing the relationship between the output voltage value based on the resistance value of the slide switch 24 and the illumination brightness of the light source 10.

As shown in FIG. 7, a slide switch is used when the EVF mode in which the amount of extension of the eyepiece lens 20 is small is set.
Since the output voltage from 24 is small and does not exceed the reference voltage in the comparator 4, a small dimming signal is output from the dimming unit 5, and the light source 10 is in a constant low brightness state.

On the other hand, when the amount of extension of the eyepiece lens 20 becomes large and the projector mode is set, the voltage value output from the slide switch 24 exceeds the reference voltage value of the comparator 4, whereby the signal from the comparator 4 is adjusted. The light unit 5 is set to the dimming operation state. This dimming operation changes the magnitude of the dimming signal according to the amount of extension of the eyepiece lens 20, but the closer the extension amount of the eyepiece lens 20 is, the closer to the eyepiece lens 20 the focus is. Therefore, as shown in FIG. 7, the magnitude of the dimming signal is adjusted so that the illumination brightness decreases as the amount of extension of the outer cylinder 1A increases.

Data representing the relationship between the output voltage value and the dimming signal value from the dimming unit 5 is stored in the memory of the dimming unit 5.

In this projector mode, the light source 10
The form of the dimming signal output from the dimming unit 6 for controlling the brightness of the signal may be such that the magnitude of the signal level changes, or the pulse width of a fixed cycle changes (PW
(M control).

Next, drive scanning of the liquid crystal display panel 18 in each mode when the subject 51 as shown in FIG. 8 is photographed by the video camera 52 will be described.

When the video camera 52 is set to the EVF mode, an erecting virtual image of the image displayed on the liquid crystal display plate 18 is seen, so that the liquid crystal display plate 18 is driven and scanned in the upper left corner of the screen as shown in FIG. To the lower right ((1) and (2) in the figure)
, (3) ……)).

On the other hand, when the video camera 52 is set to the projector mode, the liquid crystal display panel 18 is displayed on the screen 22.
An inverted real image of the image displayed above will be formed.

Therefore, in the case of the transmissive type screen 22a, as shown in FIG. 10 (a), the liquid crystal display plate 18 is moved from the lower right to the upper left ((1), (2), (3) ... It is necessary to invert the display image on the liquid crystal display panel 18 in the vertical and horizontal directions by driving and scanning.

Further, in the case of the reflection type screen 22b, as shown in FIG. 10 (b), the liquid crystal display plate 18 is moved from the lower left to the upper right (see (1), (2), (3) ... It is necessary to perform (in order) drive scanning to invert the display image on the liquid crystal display panel 18 only up and down.

As described above, since the driving scanning direction of the liquid crystal display plate 18 is different depending on the mode or the screen type, in the present embodiment, the liquid crystal display plate 18 is driven according to these modes or types. The drive scanning direction is switched.

FIG. 11 is a block diagram showing a control system for driving and scanning the liquid crystal display plate 18.

This control system circuit receives an X and Y scanning direction switching signal and an image signal from a detection switch 24a for detecting the mode and the type of the screen 22, and performs X scanning from either the left or the right in accordance with the switching signal. Or
A liquid crystal display panel controller 26 is provided which determines whether to perform Y scanning from above or below and sends a command signal to the X direction driver 28 and the Y direction driver 30.

Therefore, in the apparatus of this embodiment, when the mode is set to the EVF mode, the controller described above is used.
In response to a command signal from 26, X scanning is performed from the left side and Y scanning is performed from the upper side, and an image as shown in FIG. 9 is formed on the liquid crystal display plate 18.

When the mode is set to the projector mode and the screen 22 is set to select the transmissive type 22a, the X scanning is performed from the right side and the Y scanning is performed according to the command signal from the controller 26. Is performed from below, and an image as shown in FIG. 10 (a) is formed on the liquid crystal display plate 18.

When the mode is set to the projector mode and the reflective type 22b is selected as the screen 22, the X scanning is performed from the left side and the Y scanning is performed according to the command signal from the controller 26. Is performed from below, and an image as shown in FIG. 10 (b) is formed on the liquid crystal display plate 18.

In the EVF mode, a bright image can be seen when looking into the viewfinder, whereas in the projector mode, an image needs to be projected at a position away from the viewfinder. It is necessary to increase the brightness of 10 and conversely EV
In the F mode, it is necessary to reduce the brightness of the light source to a predetermined value in order to protect the eyes. Therefore, in the apparatus of this embodiment, the switching of the brightness is performed according to the switching of the detection switch 24a. The slide switch 24 described above may be used as a part of the detection switch 24a.

FIG. 11 shows a circuit for switching the luminance of the light source according to the mode switching. That is, when the detection switch 24a is set to the projector mode side, the brightness selector switch 32 is set to the high brightness side terminal 32.
It is connected to a and a large current flows through the light source 10, and the light source 10 is in a high brightness state.

On the other hand, when the detection switch 24a is set to the EVF mode side, the brightness changeover switch 32 is connected to the low brightness side terminal 32b, a small current flows through the light source 10, and the light source 10 is in the low brightness state. .

The electronic viewfinder of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made.

For example, in the above-described embodiment, the outer cylinder 1A is manually pulled out from the inner cylinder 1B. However, the outer cylinder 1A can also be fed out by an automatic feeding mechanism using autofocus. Of course, it is also possible to adopt a system in which the outer cylinder 1A is drawn out while being spirally rotated.

Further, although the slide switch 24 is provided with the multi-wire-shaped section tip portion, the form of the slide switch is not limited to this, and any constitution is possible as long as it can function as a potentiometer. It doesn't matter.

Further, the extension amount detecting portion of the eyepiece lens in the electronic viewfinder of the present invention is not limited to the slide switch as described above, and any optical system or the like can be used as long as it can detect the extension amount of the eyepiece lens. Other methods such as magnetic method may be used.

In the above embodiment, the outer cylinder 1A
Although the eyepiece 20 and the liquid crystal display plate 18 and the like are attached to the inner cylinder 1B, the optical members attached to both the cylinders 1A and 1B may be reversed.

In the above-described embodiment, the brightness of the light source 10 is changed according to the mode switching. For example, when an object such as human eyes approaches the viewfinder, it is sensed. The brightness of the light source 10 may be reduced.

In the projector mode, the light source
10 may be replaced with a high-brightness one, and since the amount of heat generated is large in this projector mode,
A fan for discharging the air around the light source 10 to the outside may be attached.

Further, if a television tuner unit is built in the electronic viewfinder 1 or the camera body 2, a television image can be projected on the screen by the projector function of the electronic viewfinder. You can enjoy watching the program. Further, the TV tuner section may be of an adapter type which can be attached at the time of use.

If a small screen for a projector is attached to the electronic viewfinder 1 or the camera body 2, it is convenient not to carry these separately.

In the electronic viewfinder of the present invention, a projector function is provided so that a photographed image can be projected on the screen. However, an image signal and an audio signal are output to a terminal of the camera body like a normal video camera. If the signal can be output, the taken image and sound can be reproduced by a television receiver or the like, for example, indoors.

[0066]

As described above, according to the electronic viewfinder of the present invention, it has a projector function, and furthermore, an image of good brightness can be projected on the screen regardless of the projection distance. Even in a place where there is no television receiver such as outdoors, it is very convenient for a plurality of people to enjoy a bright and easy-to-see reproduced image at a proper distance with a screen substitute or the like.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a light control mechanism of an electronic viewfinder according to an embodiment of the present invention.

FIG. 2 is an external view of a general video camera equipped with an electronic viewfinder according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining an optical system of the electronic viewfinder shown in FIG.

FIG. 4 is a schematic diagram for explaining a part of the slide switch shown in FIG.

5 is a perspective view showing the section shown in FIG.

FIG. 6 is a perspective view showing a state in which a section section is in contact with the board section shown in FIG. 4;

7 is a graph showing the relationship between the output voltage value from the slide switch shown in FIG. 1 and the illumination brightness value of the light source.

FIG. 8 is a schematic diagram for explaining how the driving scan of the liquid crystal display panel differs depending on the mode in the electronic viewfinder shown in FIG.

9 is a diagram showing an electronic viewfinder shown in FIG.
Schematic diagram for explaining drive scanning of the liquid crystal display panel in the VF mode

FIG. 10 shows an electronic viewfinder shown in FIG.
Schematic diagram for explaining drive scanning of the liquid crystal display panel in the projector mode

11 is a block diagram showing a circuit system for driving a liquid crystal display panel of the electronic viewfinder shown in FIG.

[Explanation of symbols]

 1 electronic viewfinder 1A outer cylinder 1B inner cylinder 2 camera body 4 comparator 5 light control unit 10 light source 12 collimator lens 18 liquid crystal display plate 20 biconvex lens 22, 22a, 22b screen 24, 24C slide switch 24A section 24B substrate section 41 conductor Board 43 Multi-wire 44 Conductor 45 Resistor 46 Board

Claims (1)

[Claims] 1. An electronic viewfinder equipped with a liquid crystal display unit mounted on a video camera, wherein an image displayed on the liquid crystal display unit is illuminated with illumination light from a light source, and the image is viewed through an eyepiece of the viewfinder. A projection amount detecting section configured to have a projector function of projecting on a screen outside the finder via the finder, and detecting a projection amount of the eyepiece lens with respect to the liquid crystal display section, and using the finder as a projector To
And a light control unit that adjusts the brightness of the light source so that the brightness of the light source increases as the projection distance increases, based on the detection result of the extension amount detection unit when the focus is adjusted on the screen. An electronic viewfinder equipped with a projection function.