JPH02150186A - High-definition projection tv screen - Google Patents

Abstract

PURPOSE:To clearly project a standard television signal by supplementing a display signal to a signal omission parts generated on the both sides of a screen, and covering the parts with multiple reflection absorbers. CONSTITUTION:On a frame memory 10, a prescribed supplementary signal is added to the standard television signal, read by converting an aspect ratio into 9:16, amplified by a video amplifying circuit 13, and added to the input of a projecting tube 14. The both sides of a picture at the aspect ratio 9:16 projected on a screen 5 become dark because the projected light is scattered or absorbed due to a multiple reflection absorber 6, and the aspect ratio of the picture projected on the screen becomes 3:4. Thus, the luminance level difference between the standard television signal display part and the supplementary signal display part is eliminated, the change of the luminance in the supplementary signal display part on the screen is absorbed by the multiple reflection absorber, and awkwardness is eliminated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a high-definition projection TV screen that can also project standard television signals [Summary of the Invention] The high-definition television system of the present invention and the standard television On a projection TV screen that can project both formats, in order to improve the unsightliness when projecting standard television format signals due to differences in aspect ratio, display signals are supplemented to the areas where signals are missing on both sides of the screen. At the same time, that area was covered with a multi-reflection absorber.

[Conventional technology] High-definition projection TVs display detailed images on a large widescreen screen with approximately five times as much image information as standard televisions, creating powerful, movie-like immersive images. The idea is to provide images. The high-definition television system used here was proposed by the Japan Broadcasting Corporation (NHK), and has a screen aspect ratio of 9:16, 1125 scanning lines, and a standard television signal (aspect ratio 3: 4, 525 scanning lines).

FIG. 3 shows a state in which a scan-converted standard television signal is projected onto a conventional high-definition projection TV. Standard television signals with an aspect ratio of 3:4 have different aspect ratios on a screen with an aspect ratio of 9:16, so if the screen is projected with the same vertical length,
As shown in FIG. 3, signal missing portions occur on both sides of the screen.

In such a case, conventionally, this signal missing portion was supplemented with another signal (for example, a single blue signal) during scan conversion. Examples of publicly known reference materials include JP-A-63-26173.
There is a publication.

[Problem to be solved by the invention]

However, if the standard television signal as mentioned above is
A high-quality projection TV that projects images as shown in the figure,
There is a risk that uneven burn-in may occur on the fluorescent surface of the projection tube due to the difference in signal level between the supplementary signal display area and the standard television signal display area in the center. Also, if the average brightness of the standard television signal decreases on the screen,
There is a possibility that the brightness of the supplementary signal display portions on both sides may interfere with the display and make it difficult to see.

(Means for Solving the Problems) In order to solve the above problems, the high-definition projection TV of the present invention eliminates the difference between the standard television signal display portion and the supplementary signal display portion, which may occur when projecting a standard television signal. In order to prevent the burn-in level difference between the levels, the supplementary signal level is made equal to the time average brightness of one horizontal period of the standard television signal, and the supplementary signal display area of the screen is covered with a multi-reflection absorber to reduce the reflected light from that area. scatter or absorb.

[Function] As described above, the present invention adjusts the brightness of the supplementary signal display portion generated by scan conversion of a standard television signal to a high-definition television signal by comparing it with the video signal level of one horizontal period of the immediately preceding standard television signal. Since the level is a time average, there is no difference in brightness level between the standard television signal display area and the supplementary signal display area, and there is no burn-in step on the fluorescent surface of the projection tube. In addition, there is no problem with the unsightliness caused by changes in brightness of the supplementary signal display portion on the screen because it becomes invisible due to the multiple reflection absorber.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-quality projection TV according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a screen in one embodiment of the present invention. In the figure, 5 is a high-quality projection T
V indicates a screen, and 6 indicates a multi-reflection absorber.

Further, FIG. 1 shows the state when a standard television signal is projected on the screen 5 of a high-definition projection TV. The multiple reflection absorber 6 covers an area on the screen 5 corresponding to the supplementary signal display portion. As the multiple reflection absorber 6, for example, a non-reflective velvet with many pleats is used, and it is attached to the screen 5 so that it can slide like a curtain.

When projecting a high-definition television signal, this multiple reflection absorber 6 is pushed to the edge or hangs down to the back side of the screen 5, giving the screen 5 an aspect ratio of 9:16. Figure 2 shows a high-quality projection T in an embodiment of the present invention.
FIG. 2 is a schematic circuit configuration diagram of V. In the figure, 9 is an A/D conversion circuit for standard television signals, IO is a frame memory with an aspect ratio of 9:16, 11 is an 1H line memory (H represents one horizontal scanning period), and 12 is a frame memory with an aspect ratio of 9:16. I
13 is a video amplification circuit that switches and amplifies a standard television signal and a high-definition television signal; 14 is a projection tube; 15 is a The deflection circuit is shown. Again 1
6 indicates a projection lens, and 17 indicates a screen.

The operation of the high-definition projection TV configured as described above will be explained below with reference to FIGS. 1 and 2. A standard television signal input from a standard television signal input terminal 7 is digitally converted by an A/D conversion circuit 9 and stored in a standard television display area of a frame memory (aspect ratio 9:16). Another digitally converted output is stored in the IH line memo January 1 for each IH, and then sent to the averaging circuit 12 for each IIT and calculated to determine the average brightness level for the IH period. This average species level information is stored in Fray 1 and memo January 0 in the relevant IH.
It is sent to the supplementary signal area following the line and stored as the luminance of that supplementary signal line. Subsequently, a luminance level similar to that described above is stored in the next supplementary signal area on the left side of the screen. In this way, a predetermined supplementary signal is added to the standard television signal on the frame memory 10 to adjust the aspect ratio to 9:1.
6 and read out, amplified by the video amplification circuit 13 and applied to the input of the projection tube 14. The projected light is scattered or absorbed by the multiple reflection absorbers 6 on both sides of this aspic (9:16) image projected onto the screen 5, making it darker, and the aspect ratio of the image projected onto the screen is equivalently 3.
: It becomes 4.

When projecting a high-definition television signal, input the high-definition television signal to the high-definition television signal input terminal 8, amplify it in the video amplification circuit 13, drive the projection tube 14, and send the high-definition television signal to the screen 5. Project the image. At this time, the multiple reflection absorber 6 is removed.

[Effect of the invention] When a standard television signal is projected on a high-definition projection TV that can also project a standard television signal, the signal is applied to the signal missing portions on both sides of the fluorescent surface of the projection tube caused by the difference in aspect ratio. Additionally, by making the average level of brightness in the standard television signal area and the supplementary signal area equal, no difference in burn-in occurs on the fluorescent surface of the projection tube. Furthermore, since a multiple reflection absorber is used in the supplementary signal area of the screen, the supplementary signal is scattered or absorbed and becomes invisible (the standard television signal is clearly projected).

[Brief explanation of the drawing]

FIG. 1 is a front view of a screen in one embodiment of the present invention, and FIG.
The figure is a schematic circuit diagram of an embodiment of the present invention, and FIG. 3 is a conceptual diagram of a conventional high-definition projection TV. 5---------11---Screen 6---
11-------Multiple reflection absorber 10---1---
-----...- Frame memory 1 t-----1...
-・-IH line memory 12-1-・-・-1111 addition and averaging circuit 5 screens (9:16) Front view of the screen in the one-dog example 2nd page of Puruno's 4 area map

Claims (1)

[Claims] When the signal of the current standard television system is projected completely in the vertical direction on the screen of a high-definition projection TV that can project a high-definition television system signal and a signal of the current standard television system with different aspect ratios, A high-definition projection TV screen, characterized in that display signals are supplemented to signal-missing portions that occur on both sides of the screen, and the portions are covered with multiple reflection absorbers.