JPS5916482A - Electronic view finder - Google Patents

Abstract

PURPOSE:To convert simply a monaural picture displayed on an electronic view finder into a color picture, by observing a screen of a cathode ray tube through a view window and one of each color filter of a rotary filter device. CONSTITUTION:A color video signal SA is separated into a luminance signal and three chrominance signals, and the chrominance signals are transmitted selectively by switching sequentially the signals at each field. The color signals transmitted and the luminance signal are mixed and applied to a monaural cathode ray tube 8. A light shield plate 2 having a view finder 3 is provided in opposing to the screen of the cathode ray tube. Each color filter is inserted sequentially and selectively between the view finder 3 and the cathode ray tube, by driving synchronizinly a filter 4 having the three color filters corresponding to the chrominance signals to a vertical synchronizing signal of the video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic viewfinder device used in a color TV camera, VTR, etc., and particularly to a means for easily colorizing a monochrome image displayed on a monochrome cathode ray tube.

Conventionally, portable color TV cameras and the like have generally been provided with a finder function. In this case, if you use an electronic bee finder as a finder, you can display images recorded outdoors as playback images on the 2-viewer on the spot, which has the advantage of allowing you to confirm or check the recorded images. be. If the image that can be monitored with the electronic viewfinder is a color image, more accurate confirmation and checking will be possible.

However, the 'electronic viewfinder' used in the conventional bow-pull type color TV camera often uses a monochrome cathode ray tube in order to reduce the cost and size of the entire device.

The present invention has been made in consideration of these circumstances, and its purpose is to easily convert a monochrome image displayed on an electronic viewfinder into color without hindering cost reduction and miniaturization. An object of the present invention is to provide an electronic viewfinder device that can accurately confirm or check a fit image.

Hereinafter, the present invention will be clarified by examples shown in the drawings.

FIG. 1 is a diagram showing the configuration of a finder mechanism in an electronic viewfinder device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 indicates the eyes of a person who performs monitoring activities. The image displayed on the image display screen) 9 can be viewed. The cathode ray tube 8 is a monochrome cathode ray tube, and the base plate 2 is installed at least 100 degrees away from the tube surface 9 of the cathode ray tube 8. The viewing window 3 provided on the shield plate 2 has a diameter of at least 1 m+, and its center is aligned with the center of the tube surface 9 of the cathode ray tube 8. Also color filter 5.6.
7 is a cy color filter + Mg color filter IYe filter, respectively, which are attached to three fan-shaped areas obtained by dividing the disk portion of the rotary filter device 4 into 1200 pieces, and the one-rotation filter device 4 rotates together with the disk portion.
The center of the disk portion is connected to the rotating shaft of the motor 10, and is rotationally driven by the motor 1θ. A hole 11 is provided at the periphery of the disk portion, and the photosensor 12 is turned on through this hole 11 to generate all pulses. Thus, the rotational frequency and rotational phase of the rotary filter device 4 are detected by the pulses from the 7-point sensor 12.

FIG. 2 is a block diagram showing the configuration of a drive control system connected to the finder mechanism shown in FIG. 1. A color TV camera or V applied to terminal 21 in FIG.
The color signal SA which is the output of TR etc. is LPF 2
2 and BPF 23, respectively. LPF
22, the luminance signal component is separated and extracted using BPF 2 g
Then, the carrier color signal (chroma signal) is separated and extracted. B.P.
The chroma signal 1r separated and extracted by F23 is supplied to the chroma decoder 24. The color signal C'l r Mc
, Y@. A color subcarrier SC applied to a terminal 25 is supplied to the color decoder 24 . Note that this color subcarrier SC is phase-synchronized with the chroma signal. Each color signal C3' separated by the color decoder 24
+ MO* Y@ are analog gates 25 and 26'.

8 analog gates 25°2 each supplied with 27VC
6.27 is to analog gate the color signal CY + MOrYe by sequentially turning on gates by a ring counter 35 to be described later, corresponding to the rotation of the color filters 5, 6, and 7 shown in FIG. For example, when viewing the image on the cathode ray tube 8 through the cy color filter 5,
The application of the color signal Cy is gated. Similarly, when viewing through the M and color filters 6, only the color signal MG is gated, and when viewing through the Ye color filter, only the color signal Ys is gated. The output of each analog gate 25, 26, 27 becomes one input of mixer 28. The other input of the mixer 28 is supplied with the luminance signal separated and extracted by the LPF 22. Therefore, each color signal and the luminance signal are mixed in the mixer 28, and the output is sent to the grid 8 of the cathode ray tube 8.
Supplied to G. As a result, the intensity of the beam is modulated by the output of the mixer 28, and an image is displayed on the tube surface 9 of the cathode ray tube 8. If the subject is monochrome, no color signals are obtained, so the color decoder 24 does not output any color signals. However, no image is formed on the cathode ray tube surface 8 only by outputting the color signals. However, since the luminance signal from the LPF 22 is supplied to the mixer 28, an image is formed even in the case of a monochrome subject. In addition,
The mixing ratio in the mixer 28 is set at 50 degrees.

On the other hand, the vertical synchronizing signal SV given to the terminal 29 is 1/3
The signal is supplied to a frequency dividing circuit 30 and frequency-divided by 1/3°.

The output frequency-divided by this frequency dividing circuit 30 is given to a sampling pulse generator 31 as a trigger signal. When triggered, the pulse generator 3 delivers a sampling pulse which is applied to one input of the phase comparator 32. The other input terminal of the phase comparator 32 receives a signal from a sawtooth wave generator 33 which is triggered by the output of the photo sensor 12, that is, one pulse generated every time the rotary filter device 4 rotates. Waves are supplied.

As a result, the phase comparator 32 outputs a voltage proportional to the phase difference between the vertical synchronization signal Sv and the output beam SP of the photo sensor 12, which is amplified by the current amplifier 34 to control the motor 10. do. In this way, the rotating blade device 4 rotates once in phase synchronization with the vertical synchronizing signal 3v. As a result, each color filter (j
The time it takes for '+MG+7e to pass through the viewing window 3 shown in FIG. 1 is 1/60 second. That is, the rotating filter device 4
The rotation period of each color filter is 1/2o second.

Since Mo*Ys is attached to the rotary filter device 4 in 120° divisions, the time it takes for one color filter to pass is 1760 seconds. This time corresponds to 1/6o seconds of one field period of the video signal SA, so
C3' r Mo +Y for each field in viewing window 3
The corresponding color filters are sequentially switched in the order of e.

The vertical synchronization signal SV is supplied to the ring counter 35 as a clock signal, and the sampling pulse sent out from the sampling pulse generator 3) is supplied to the ring counter 35 as a reset signal. After being reset, the ring counter 35 counts the clock signals and outputs a three-phase output signal S1*S2+Ss. Each phase output pulse S1+82 of this counter 35
+83 becomes each gate input of the analog gates 25 and 26127. Thus analog gates 25, 26 .
27 repeats the gate ON in the order of 25, 26, 27→25.26.27...>.

3. 100 in FIG. 3 is the waveform of the vertical synchronization signal SV, and 191
．． 102 and 103 are output waveforms of the outputs S1+S2 HS3 of each phase of the ring counter 35. xoi,'
-Turn OFF when at rtJ level. 10 more
4 is the output waveform of the frequency dividing circuit 30, 105 is the output waveform of the sawtooth wave generator 33, and 106 is the sampling pulse waveform generated by the sampling pulse generator 31. Figure 3 Chuunin.

Point A is a sampling point during phase synchronization, and point B is a reset trigger point by a sampling pulse. The ring counter 35 is forced to 102i1 at the above point B.
'-HJ level, and 101°103t 'L' level. That is, color filter 5.6.7 switching 1
and the switching order of analog gates 25, 26, and 27 are made to match. In addition, each color filter of Cye Ye + MG is B and G.

Although it can be achieved with R three primary color filters, B.

When G and R color filters are used, there is a drawback that 7 filters are noticeable. That is, in the case of a red subject, for example, a red light will be displayed on the screen only once every three fields, resulting in flicker. In this regard, if a Cy * Ye + Ma color filter is used as in this example,
Since Cy = G0B, Ye = G+R = Ma = R+B, even if the Cy, Ye, and MO color filters are switched once for each field, a red light (R) will appear on the screen over two fields. Therefore, flicker is significantly reduced compared to the previous R, G, and B images. The same applies to other colors.

Note that the present invention is not limited to the one embodiment described above. For example, by linearly moving a plurality of color filters using a plunger or the like, predetermined color filters may be sequentially and selectively positioned on the tube surface of the cathode ray tube. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

As described above, according to the present invention, it is possible to display color video signals in color using a monochrome cathode ray tube. Therefore, for example, when the present invention is applied to an electronic viewfinder of a color TV camera, etc., it is possible to perform one round adjustment such as color balance adjustment while monitoring the color image, and to avoid recording mistakes when recording the image on a VTR, etc. It is possible to provide an electronic viewfinder device that can significantly reduce costs.

[Brief explanation of drawings]

1 to 3 are diagrams showing the configuration of an embodiment of the present invention,
FIG. 1 is a perspective view showing the structure of the finder mechanism of an electronic viewfinder device, FIG. 2 is a block diagram showing the configuration of the drive control system connected to the mechanism, and FIG. 3 is each part of the drive control system. It is a signal waveform diagram. 2... Shield plate, 3... Peep window, 4... Rotating filter device, 5, 6.7... Color filter, 8...
Monochrome cathode ray tube, 12...photo sensor. Kazuo Wakasugi, Commissioner of the Patent Office1. Indication of the case Japanese Patent Application No. 57-126135 2, Name of the invention Electronic View Fine Nose Device 3, Person making the amendment Relationship to the case Patent applicant (037) Olino ξ Optical Industry Co., Ltd. 4, Agent

Claims (2)

[Claims] (1) Means for separating a color video signal into a luminance signal and three color signals, and selectively transmitting the three color signals by sequentially switching each field, and selectively transmitting the three color signals by this means. A monochrome cathode ray tube that is supplied with a mixture of the respective color code and the luminance signal, a front plate installed opposite to the tube surface of the cathode ray tube, and a viewing window provided on the front plate. and a filter device having three color filters corresponding to the three color signals, and by driving this filter device in synchronization with the vertical synchronization signal of the video signal, the color filters are connected to the viewing window and the cathode ray tube. An electronic viewfinder device comprising means for sequentially and selectively inserting the electronic viewfinder device between the electronic viewfinder device and the electronic viewfinder device. (2) The electronic viewfinder device according to claim (1), wherein the 74/'tar device is a disk-shaped arrangement of Cy 1Mar 7e three-color filters.