JPH0566068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electronic camera having an optical viewfinder or an electronic viewfinder, a VTR camera, a broadcasting use
Related to electronic imaging devices used as VTR cameras, ITV cameras, various microscopes, various endoscopes, etc.

Finders in conventional electronic image pickup devices of this type include optical finders and electronic finders. In an optical finder, light passes through an imaging lens and is split by an optical image splitting means such as a mirror into a focusing glass and two-dimensional photoelectric conversion means such as a CCD or image pickup tube, and the optical image formed on the focusing glass is Single-lens reflex cameras that lead to the eyepiece optical system are common. In this finder-type electronic imaging device, the object viewed through the finder is an optical image formed on a focusing glass. Therefore, the image quality is good, and since it does not have an electronic display means such as a CRT, it has the advantage of not requiring as much power.
However, on the other hand, it also had the following drawbacks. Normally, in dynamic photography such as a VTR camera, the light image splitting means is a fixed half mirror, and the light passing through the imaging lens is split into an eyepiece optical system and a two-dimensional photoelectric conversion means, so that it can be viewed from the viewfinder. The disadvantage is that the amount of light in the optical image is small and it is difficult to see the optical image in a dark place. Furthermore, when a movable total reflection mirror is used in static photography with an electronic camera, etc., the mirror is raised the moment the shutter is turned off, which reduces the optical image from the viewfinder and causes image breakage. . Another major drawback was the reliability problem during recording. In other words, with an optical finder, the image viewed through the finder is the image on the focusing glass, and the image output signal actually acquired is the image focused on the light focusing surface of the two-dimensional photoelectric conversion means. The disadvantages include that it is not possible to check the resulting focus shift, that the photographer cannot check the image output status during recording, and that a separate electronic image display device is required to check the reproduced image. It was hot. On the other hand, an electronic finder is an example of a second finder format. In an electronic finder, light that passes through an imaging lens forms an image on the condensing surface of a two-dimensional photoelectric conversion means, and the photoelectrically converted electrical information is converted into a video signal to generate an electronic image on a CRT or other device installed inside the finder. A method was used to display the information on a display means. According to this finder format, the reliability problem described above has been solved. In other words, the images that are actually being recorded can be checked directly from the viewfinder, and since the viewfinder is equipped with an electronic image display means such as a CRT, the reproduced images can be checked on the spot where they are taken. be. However, in the case of an electronic viewfinder, the clarity of the image displayed on an electronic image display means such as a CRT is incomparably lower than that of an optical viewfinder, and the effects of scanning lines, flicker, etc. can cause eye strain during shooting. ,
Electronic image display means usually display black and white, which has drawbacks such as not being able to see beautiful colors.Furthermore, there are many improvements to be made, such as the need for extra power to drive the electronic image display means. It also included issues that need to be addressed.

As described above, both optical finders and electronic finders have their advantages and disadvantages, so users often have difficulty selecting a finder format, and it has been difficult to construct a finder format that can satisfy the general public.

The purpose of the present invention is to compensate for the above-mentioned drawbacks of both in a simple manner, to provide good image quality and easy viewing, to check colors, and to reduce power consumption compared to conventional electronic viewfinders. An object of the present invention is to provide an electronic imaging device equipped with a finder that does not reduce the reliability of the electronic image and can also evaluate a recorded electronic image by comparing it with an optical image.

In order to achieve the above object, the present invention, in addition to the structure of the optical viewfinder, matches the optical axis of the eyepiece optical system with the projection axis of the electronic image from the electronic image display means in the electronic viewfinder, so that the viewfinder allows the optical viewfinder to It is characterized in that recording and reproducing means, electronic image display means, optical image splitting means, etc. are provided so that the image and the recorded electronic image can be viewed simultaneously.

First, a basic configuration example according to an embodiment of the present invention will be explained as follows.
This will be explained with reference to FIGS. FIG. 1 is a sectional view showing the mechanical configuration of a cine camera type electronic imaging device according to the present invention. In FIG. 1, a half mirror 1 is provided at a position to separate light that has passed through an imaging lens 2 and an aperture 3 in the direction of a relay lens 4 and a relay lens 5. relay lens 4
The light that has passed through is further reflected by a mirror 6, passes through a relay lens 7, and forms an image on a focusing glass 8. Therefore, the photographer can visually observe the optical image on the focusing glass 8 through the eyepiece lens 9 and the half mirror 10. On the other hand, the light that has passed through the relay lens 5 forms an image on a two-dimensional photoelectric conversion element 11 (hereinafter simply referred to as an image sensor), and after being photoelectrically converted, it becomes a video signal by an electronic circuit (not shown) and is displayed as an electronic image. On the means 12 (hereinafter simply referred to as a display), an electronic image, etc., which is equivalent to the optical image on the focusing glass 8 or whose brightness can be adjusted by adding arbitrary information such as exposure white balance around the optical image, is formed. do. This electronic image is filtered by color toning filter 1.
3. Finder section 1 via half mirror 10
4, it is still visible. Therefore, the optical image on the focus glass 8 and the display 12
The electronic images above are simultaneously superimposed to form a visible composite image. FIG. 2 shows the finder section 14.
FIG. 2 is a diagram showing a visually visible composite image, a state in which the composite image is separated into an optical image and an electronic image, and an electronic image to be recorded. 15 is an optical image on the focusing glass 8; 16 is the display 12;
17 is various information such as exposure and white balance displayed on the display 12; 18 is a composite image visible from the viewfinder section 14; 19 is an electronic image to be recorded. be.

According to the above configuration example, the optical image and the electronic image are simultaneously overlapped and visible, and at the same time, the brightness of the electronic image can be easily controlled electrically. The photographer can select the desired image quality by adjusting the level to the optimum level and, if necessary, by turning off the power to the display 12. Furthermore, even if the electronic image is black and white, the color balance of the screen can be checked using a visible optical image, and distortion correction of the electronic image can also be performed at a glance. Furthermore, by displaying the display 12 only during shooting, or by increasing the brightness, it is easier to use than with electronic viewfinders, which conventionally required the display to be displayed even during setup before shooting. This makes it possible to check the video signal output status while significantly reducing power consumption. In addition, in FIG. 1, by disposing the half mirror 10, display 12, and color toning filter 13 between the relay lens 7 and the focusing glass 8, both the optical image and the electronic image are displayed on the focusing glass 8 at the same time. It is also possible to construct a viewfinder that allows a composite image with less noticeable scanning lines to be seen.

FIG. 3 shows an embodiment of the present invention, in which a pentaprism 2 is attached to the mirror 6 portion in the basic configuration example described above.
1 is a cross-sectional view showing the mechanical configuration of a single-lens reflex electronic camera using a digital camera. In FIG. 3, 21 is a rotatable mirror, 22 is an image sensor such as a CCD,
23 uses a display such as a liquid crystal or a light emitting diode to reduce the size. Referring to FIG. 3, first the mirror 21 is moved to the mirror down position 2.
The state of the optical path when it is at position 1a will be explained. The light that has passed through the imaging lens 24 and the aperture 25 forms an image on a focusing glass 26 by the mirror 21. The optical image formed on the focusing glass 26 further passes through a half mirror 27, a pentaprism 20, and an eyepiece 28, and becomes visible through a viewfinder section 29.
Next, the optical path when the mirror 21 is at the mirror up position 21b will be explained. Imaging lens 24, aperture 2
Since the mirror 21 is at the mirror up position 21b, 100% of the light that has passed through the mirror 5 reaches the image sensor 22. After the optical image on the image sensor 22 is photoelectrically converted, it is converted into a video signal by an electronic circuit (not shown).
It is displayed on the display 23. Further, the electronic image displayed on the display 23 can be visually viewed from the viewfinder section 29 via a color toning filter 30, a half mirror 27, a pentaprism 20, and an eyepiece 28.

According to the above embodiment, when the mirror 21 is raised up to 21b, it is possible to image with nearly 100% TTL light intensity, unlike when using a fixed half mirror. Furthermore, during imaging, that is, when the mirror is raised, the optical image that is removed by the viewfinder section 29 to block the optical path of the optical image formed on the focusing glass 26 is equivalent to or equivalent to the optical image instantaneously displayed on the display 23. Replace the optical image with an electronic image with information marks such as exposure status added around the periphery. Therefore, not only can you visually check the image at the moment it was taken, but you can also check the recording status at the same time. Also, normal mirror 2
1 is in the mirror down position 21a, the optical image is visible. Therefore, by reproducing the already recorded electronic image on the display 23, the current optical image and the electronically reproduced image can be compared within the same finder. Therefore, by comparing the reproduction state with the actual optical image, it becomes easy to evaluate the recording conditions and reset the conditions.

FIG. 4 is a diagram showing a modification of the above embodiment. In other words, FIG. 4 is the display 1 in FIG.
FIG. 2 is a block diagram showing an electronic circuit for adding a function to display a poor exposure video signal representing overexposed and underexposed areas. Note that the same parts as in FIG. 1 are denoted by the same symbols, and detailed explanations will be omitted. Now, if the aperture 3 in FIG. 1 is set to a certain value and the image quality confirmation switch (not shown) is turned on under that exposure condition, the image sensor 11 in FIG.
The imaging device driving circuit 31 converts the optical image formed on the condensing surface into a serial electrical signal and sends it to the composite video signal converting circuit 32. The composite video signal converting circuit 32 adds a synchronization signal from a synchronization signal generator 33 to the electrical signal and converts it into a recordable video signal. Further, a comparator 34 having a white level setting value V _S near the saturation level detects an overexposed portion of the video signal, and at the same time a comparator 35 having a black level setting value V _D near the light shielding level detects an overexposed portion of the video signal. Detect missing parts. Next stage AND gate 36
has the function of performing an AND operation between the signal from the synchronizing signal generator 33 and the overexposure detection signal to stop detection when the synchronizing signal is generated. Similarly, AND
The gate 37 stops the underexposure detection when the synchronization signal is generated. The overexposure signal from the AND gate 36 and the underexposure signal from the AND gate 37 may be used independently, but
Here, the OR gate 38 further performs the logical sum of the two to obtain an exposure failure signal. Further, the composite video signal converting circuit 39 outputs an exposure failure imaging signal by adding a synchronization signal to the exposure failure signal.

FIG. 5 is a timing chart showing the process from the video signal to obtaining the poor exposure imaging signal. Here, (A) is the video signal output from the composite imaging circuit 32, (B) is the overexposure signal output from the AND gate 36, (C) is the underexposure signal output from the AND gate 37, and (D) is the OR The exposure defect signal output from the gate 38 and (E) show the exposure defect imaging signal output from the composite video signal converting circuit 39, respectively.

By repeating horizontal scanning, the poor exposure visualization signal can be displayed as it is on the display 12 by the display device drive circuit 40 as a pattern display of the poor exposure portion, but it can also be displayed by the video signal synthesis circuit 41. Therefore, it is also possible to display a pattern of a poorly exposed portion superimposed on a video signal. 42 is a display brightness adjustment circuit that adjusts the brightness of the display 12.

FIGS. 6a and 6b are diagrams respectively showing an electronic image 43 based on a video signal of a subject standing by a window through which the setting sun shines, and an electronic image 44 based on a poor exposure imaging signal.

With the above configuration, the electronic image and the optical image based on the poor exposure imaging signal can be viewed simultaneously through the viewfinder. Therefore, there is an advantage that it becomes easy to set the optimum exposure conditions so that the subject can be placed in any position within the latitude of the electronic imaging device. This will be very effective in backlit photography, photography in sunlight, etc.

As described above, according to the present invention, the drawbacks of both conventional optical viewfinders and electronic viewfinders are compensated for in a simple manner, and the image quality is good and color confirmation is possible, and the power consumption is lower than that of conventional electronic viewfinders. In addition, the image quality can be selected according to the individual user's preference by adjusting the electronic image display mode, brightness adjustment, etc. It becomes possible to provide an electronic imaging device equipped with a finder that can evaluate a target image by comparing it with an optical image.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the mechanical configuration of a cine camera type electronic imaging device, which is an example of the basic configuration according to an embodiment of the present invention, and FIG. An explanatory diagram showing how the composite image is separated into an optical image and an electronic image, and an electronic image to be recorded; FIG. 3 is a sectional view showing the mechanical configuration of a single-lens reflex electronic camera according to an embodiment of the present invention; FIG. 4 is a block diagram showing an electronic circuit having a function of displaying a poor exposure imaging signal, which is a modified example of the embodiment of the present invention, and FIG. 5 is a block diagram showing the video signal, overexposure signal, and underexposure signal in the modified example. FIGS. 6a and 6b are explanatory diagrams showing electronic images based on the video signal and the good exposure imaging signal in the above modification. 1, 10... Half mirror, 2, 24... Imaging lens, 3, 25... Aperture, 6, 21... Mirror, 8... Focusing glass, 9... Eyepiece, 1
1, 22...Image sensor, 12, 23...Display, 13, 30...Toning filter, 17...
Various information, 20... Pentaprism, 34, 35
... Comparator, 45 ... Underexposure signal, 46 ... Overexposed portion, 47 ... Recording and reproducing section.

Claims (1)

[Scope of Claims] 1. An imaging lens; a two-dimensional photoelectric conversion means; a light image splitting means interposed on an optical axis connecting the imaging lens and a condensing surface of the two-dimensional photoelectric conversion means; an eyepiece optical system that makes it possible to visually see the optical image divided by the image dividing means; a recording and reproducing means that records and reproduces the electric signal from the two-dimensional photoelectric conversion means; and a recording and reproducing means that corresponds to the electric signal reproduced from the recording and reproducing means. comprising an electronic image display means for projecting and displaying a visible electronic image; and means for aligning a projection axis of the electronic image in the electronic image display means with an optical axis of the eyepiece optical system; An electronic imaging device characterized in that an optical image and a reproduced electronic image can be viewed simultaneously. 2. an imaging lens, a two-dimensional photoelectric conversion means, a light image splitting means interposed on an optical axis connecting the imaging lens and a condensing surface of the two-dimensional photoelectric conversion means, and a light image divided by the light image splitting means. an eyepiece optical system that allows the optical image to be visually viewed; a poor exposure area determining means for obtaining an exposure defect signal representing an overexposed area or an underexposed area based on the electrical signal from the two-dimensional photoelectric conversion means; electronic image display means for projecting and displaying a visible electronic image corresponding to the exposure failure signal from the defective part determination means; and a projection axis of the electronic image in the electronic image display means aligned with the optical axis of the eyepiece optical system. an electronic image pickup device, comprising means for causing an optical image to be visible at the same time through the eyepiece optical system.