JPS635671A - Electron beam picture recorder - Google Patents

Abstract

PURPOSE:To faithfully record a video signal on a film by setting the average video level of video signals given to an electron gun to almost a fixed value and keeping thermal deforamtion quantity and a thermal response characteristic constant. CONSTITUTION:When an input video data VID is given, it is temporarily stored in an image memory 1, and its same horizontal scan line is read out by twice. Afterwards an output data OUT to which a read-out data READ and its inversion data INV are alternately appeared can be obtained, and given to the electron gun 7 through a digital/analog conversion circuit 5 and an electron gun drive circuit 6. In such case a horizontal deflection signal HDEF synchronizing with the output data OUT of a horizontal deflection circuit 10 is given to a deflection unit 9, and a vertical deflection signal VDEF from a vertical deflection circuit 11 is also given to said unit 9. The electron gun 7 emits an electron beam BN modulated according to the output data OUT, and the deflection unit 9 deflects said beam BM, which comes on the film 8 or a landing plate 15 to expose the film 8.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an electron beam recording device, and is particularly suitable for application to a television signal film recording device.

B. Summary of the Invention The present invention provides an electron beam recording device in which the average video level of the video signal for driving the electron gun given to the electron gun is approximately 50% regardless of the waveform of the input video signal. As a result, changes in the thermal characteristics of the electron gun can be suppressed to a small extent, and an image faithful to the input video signal can be recorded on the film.

C. Conventional Technology As is well known, there is a method of recording a video signal on a film for screen projection using an electron beam. According to this method, the amount of electron beam emitted from an electron gun is The irradiation is controlled so that it is large as the level approaches and becomes small as it approaches the white level, thereby recording a predetermined image.

Problems that invention D aims to solve: This kind of recording using a child beam makes it possible to record at a high density by reducing the beam diameter, and compared to other recording methods using laser beams, etc. Images based on video signals can be recorded with satisfactory fidelity.

However, depending on the image content, the video signal may continuously take a value near the black level, or conversely, it may continuously take a value near the white level. When a value near the black level is continuously taken, compared to a case where a value near the white level is continuously taken, a large beam current continues to flow, so the electron gun warms up. Therefore, the grid etc. may undergo thermal deformation, and even in the case of a transitional change from black level to white level, the thermal response time constant may be changed depending on the length of the period during which the previous black level was maintained.
This had a subtle effect on the recorded images.

That is, when attempting to increase the fidelity of recorded images to video signals, changes in the amount of heat generated based on the video signal level have become a problem.

The present invention has been made in consideration of the above points, and is an electron beam recording device that can faithfully record an image based on a video signal on film while eliminating the thermal effects associated with changes in the level of the video signal. This is what we are trying to provide.

E Means for Solving the Problem In order to solve this problem, in the present invention, the input video signal VID is stored in the image memory 1, and the recorded video signal is transmitted from the image memory 1 to each horizontal scanning line. The continuous video signal RE for the same read horizontal line is read out twice in succession.
The video signal of one period of AD is inverted to form an output video signal OUT that alternately includes an in-phase video signal and an anti-phase video signal for each horizontal scanning line of the input video signal VID, and this output video When the electron beam BM emitted from the electron gun 7 is controlled based on the signal OUT, and the emitted electron beam BM is controlled by the in-phase video signal (...NH, (N+2)H・
.

For the video signal VID to be recorded, the output video signal OUT was formed so as to alternately contain the video signal READ having the same phase as the video signal of each horizontal scanning line and the video signal INV having the opposite phase. As a result, the output video signal OU″
The average video level APL of T is always approximately 50%, and when the electron gun 7 is driven based on this output video signal OUT, the electron gun 7 is in a thermally stable state.

Therefore, the irradiated electron beam BM is hardly affected by thermal changes.

Moreover, since the electron beam BM is scanned onto the film 8 only when it is controlled according to the video signal component having the same phase as the input video signal VID, the image recorded on the film 8 is scanned in accordance with the input video signal VID. It will be as per your requirement.

Embodiment G An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, input video data VID consisting of digital data is given to an image memory 1 consisting of, for example, a frame memory, and the image memory 1 is connected to a system controller 2.
Based on the write clock signal WCK given from , human video data is sequentially stored in the memory area designated by the write address signal WAD.

The video data thus stored is sequentially read out from the memory area indicated by the successive address signal RAD based on the successive clock signal RCK from the system controller 2 and is applied to the switch circuit 3 and the level inversion circuit 4. Here, the controller 2 forms a successive address signal RAD so as to read the data of each horizontal scanning line of the input video data VID twice consecutively, and a second
Two consecutive horizontal scanning periods as shown in Figure (A)...
...NH and (N+1)Hl (N+2)H and (N+3
)H readout data of the same waveform is sent to the image memory 1.
Note that the horizontal scanning period here refers to the time required to scan one horizontal scanning line on the film.

This read data READ is inverted between a black level and a white level via a level inversion circuit 4, and the inverted data I
NV (FIG. 2(B)) is applied to the switch circuit 3.

The switch circuit 3 performs a switching operation every horizontal scanning period based on a switching control signal SW (FIG. 2 (C)) given from the controller 2, alternately selects read data READ and inverted data INV, and outputs the selected data. Data OUT (
2(D)) is applied to the digital/analog conversion circuit 5.

This selected output data OUT is not related to the waveform of the video signal (average video level APL is always around 50%.

Such selected output data OUT is converted into an analog signal AOUT based on the clock signal RCK in the digital/analog conversion circuit 5, and then sent to the electron gun drive circuit 6.
The signal is subjected to signal processing such as aperture compensation and gamma correction, and is applied to the grid 7G of the electron gun 7.

Thus, the video signal V after signal processing from the cathode 7K
The electron beam BM modulated based on OUT is applied to film 8.
irradiated towards.

In addition to the above configuration, it has an electron beam deflection configuration.

That is, a deflector 9 is provided, and the deflector 9 receives a horizontal deflection signal HDEF (
2(G)) and the vertical deflection signal VDEF provided from the vertical deflection circuit 11, the film 8 is scanned in rasp in synchronization with the video signal VOUT.

The horizontal deflection circuit 10 includes a sawtooth wave generation circuit 12 that generates a sawtooth wave signal 5AW (FIG. 2 (E)) whose period is one horizontal scanning period, and a sawtooth wave generation circuit 12 that generates a DC signal DC (FIG. 2 (F)) of a predetermined level.
)), and a switch circuit 14 that receives the above-mentioned switching control signal SW (FIG. 2(C)) and performs a switching operation every horizontal scanning period. The sawtooth wave signal SAW and the DC signal DC are alternately selected every horizontal scanning period and are applied to the deflector 9 as the horizontal deflection signal HDEF shown in FIG. 2(G).

The switch circuits 3 and 14 are such that when the switch circuit 3 selects the read data READ, the other switch circuit 14 selects the sawtooth wave signal SAW, and conversely, when the switch circuit 3 selects the inverted data INV, the other switch circuit 14 selects the sawtooth wave signal SAW. 14 performs a switching operation so as to satisfy the relationship for selecting the direct current signal DC.

Here, the predetermined level of the DC signal DC is such that when the electron beam BM is deflected in the horizontal direction by the DC signal DC, the landing position is F, and the arrow The landing plates 15 are arranged horizontally and have a ground potential as shown in FIG.

In the electron beam recording apparatus having the above configuration, when input video data VID is given, it is temporarily stored in the image memory 1, read out twice for the same horizontal scanning line, and then read out via the switch circuit 3. REA
Output data OUT in which D and its inverted data INV appear alternately is obtained, and is applied to the electron gun 7 via the digital/analog conversion circuit 5 and the electron gun drive circuit 6.

At this time, the horizontal deflection signal H shown in FIG. 2 (G) synchronized with the horizontal deflection circuit 10 output data OUT is applied to the deflector 9.
DEF is applied, and a vertical deflection signal VDEF is also applied from the vertical deflection circuit 11.

Thus, the electron beam BM modulated according to the output data OUT is emitted from the electron gun 7, and this beam BM is deflected by the deflector 9 and reaches the film 8 or the landing plate 15, exposing the film 8. .

Here, since the horizontal deflection signal HDEF repeats the sawtooth wave and the DC level every horizontal scanning period as shown in FIG. 2(G), the electron beam BM has the output data OUT as shown in FIG. Horizontal scanning period in which the waveform takes the same waveform as the input video data VID...NHl(N+2)
In H..., the film 8 is scanned in the horizontal direction, and in another horizontal scanning period...(N+1)Hl
At (N+3)H..., the vehicle lands on the landing plate 15.

Thus, according to the embodiments described above, the human video data V
An image corresponding to the ID can be recorded on the film 8, and the drive signal VOIJT given to the electron gun 7
Since the average video level APL (corresponding to the output data OUT) is always around 50%, thermal fluctuations are small, and there is no possibility of a situation where image fidelity decreases due to thermal deformation or changes in thermal response. can be avoided.

Incidentally, since we made it possible to irradiate the electron beam even on inverted data, it takes twice as long to record one frame on the film compared to the conventional method. In order to record without vibration, the next recording operation is performed several times (4 or 5 times) after recording one frame, so the recording time for one frame on the film is Even if the recording time is doubled, the overall recording time can be kept almost unchanged compared to the conventional method.

In the above embodiment, the electron beam BM is irradiated onto the landing plate 15 when the inverted data ■NV is given to the electron gun 7, but the amplitude etc. of the electron beam BM may be set to a predetermined value. A landing member (commonly called a Faraday cage) constituting the servo system may be irradiated for that period.

H Effects of the Invention As described above, according to the present invention, since the average image level of the video signal given to the electron gun is set to a substantially fixed value, it is possible to maintain the amount of thermal deformation and thermal response characteristics constant. Thus, an electron beam recording device capable of faithfully recording video signals on film can be easily obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the electron beam recording device according to the present invention, FIG. 2 is a signal waveform diagram of each part thereof, and FIG.
The figure is a layout diagram for explaining the landing position of the electron beam. 1... Image memory, 2... System controller, 3.14... Switch circuit, 4.
...Level inversion circuit, 7...Electron gun, 8
... Film, 9 ... Deflector, 15.
...Landing plate, BM...Electron beam.

Claims (1)

[Claims] An input video signal is stored in an image memory, and the recorded video signal is successively read out twice for each horizontal scanning line from the image memory; Inverting the video signal of one period of the continuous video signal,
An output video signal is formed that alternately includes an in-phase video signal and an anti-phase video signal for each horizontal scanning line of the input video signal, and the electron beam emitted from the electron gun is controlled based on the output video signal. , characterized in that the emitted electron beam is caused to scan over the film when controlled by the video signal of the same phase, and is caused to land outside the film when controlled by the video signal of the opposite phase. Electron beam recording device.