JPH04322300A - Display device - Google Patents

Abstract

PURPOSE:To prevent an automatic pedestal circuit part from malfunctioning even if a video signal which is provided with a black level at an excessive part is supplied. CONSTITUTION:The video signal supplied to an input terminal 1 is supplied to an RGB output circuit 3 through the automatic pedestal circuit 2 and the signal from the output circuit 3 is supplied to a cathode-ray tube 4 to make a display; and dynamic pulses from a microcomputer 5 are supplied to the automatic pedestal circuit 2. Then the microcomputer 5 outputs the dynamic pulses in the period of the excessive part of the video signal and in this period, the automatic pedestal circuit 2 interrupts the detection of the most black level.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device such as a monitor receiver.

0002

[Prior Art] For example, in a display device such as a monitor receiver using a cathode ray tube, an optical reproduction system (cathode ray tube) is used.
The dynamic range of is narrower than ideal. Therefore, so-called autopedestal circuits are often used to compensate for this. In other words, in FIG. 5, when a video signal as shown in A in the same figure is supplied, the blackest level of this video signal is detected, and that level is transferred to the actual cathode ray tube as shown in B in the same figure. Reduce the black level to the level played above. According to this, it is possible to obtain a good display for a signal in which so-called black appears a little off.

However, in such a device, there are cases where a signal, such as movie software, whose aspect ratio of the image is different from that of the video signal is displayed. In this case, in the above-mentioned movie software, the surplus portions without images are usually set to a black level. That is, FIG. 6 shows a so-called vista-sized movie software screen, in which the aspect ratio is 1:1.33 for a video signal screen.
An 85 Vista size image is displayed in the center, and the upper and lower surplus areas are set to black level.

Therefore, when such a video signal is supplied, the autopedestal circuit described above detects the black level of the upper and lower surplus portions as the highest black level. Therefore, even if black floating occurs in the original image part, it will not be possible to reduce it to the black level, and the purpose of the autopedestal circuit, which is to effectively utilize the dynamic range of the cathode ray tube, will not be achieved.

[0005]

[Problem to be solved by the invention] The problem to be solved is that if the surplus part of the video signal is set to the black level,
This means that the purpose of the autopedestal circuit cannot be achieved.

[0006]

[Means for Solving the Problems] The present invention provides an automatic system that detects the blackest level in a video signal (input terminal 1) and adjusts the blackest level so that it matches the black level reproduced on a display. In a display device provided with the pedestal circuit 2, when displaying an image of a video signal configured with an aspect ratio different from the original aspect ratio and with a black level signal provided in the surplus portion, it is necessary to This is a display device in which detection of the lowest black level is stopped (microcomputer 5) during the period of the surplus portion.

[0007]

[Operation] According to this, the detection of the highest black level is stopped during the period of the surplus portion, so that the autopedestal circuit does not malfunction due to erroneous detection of the black level of this surplus portion. Good display can always be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes an input terminal to which a video signal is supplied. The video signal supplied to this input terminal 1 is supplied to an RGB output circuit 3 through an autopedestal circuit 2, and a signal from this output circuit 3 is supplied to a cathode ray tube 4 for display. 5 is a control microcomputer (μ
-COM), the dynamic pulse from this microcomputer 5 is supplied to the autopedestal circuit 2, and the display pulse from this microcomputer 5 is supplied to the RGB output circuit 3. For example, a signal from the manual input terminal 6 is supplied to the microcomputer 5, and the formation positions of the above-mentioned dynamic pulses and display pulses are manually controlled.

In other words, in this device, when a video signal with a black level is supplied to the surplus portion as shown in A in FIG. Dynamic pulse is output,
During this period, detection of the blackest level in the autopedestal circuit 2 is stopped. Further, the microcomputer 5 outputs display pulses located at the leading and trailing edges of the dynamic pulse as shown in C in the figure.

[0010] As a result, the cathode ray tube 4 has, for example,
An image as shown in FIG. 1 is displayed, in which, for example, a white line 7 is displayed at portions corresponding to the leading and trailing edges of the dynamic pulse. For example, by adjusting the signal supplied to the manual input terminal 6 so that the white line 7 is positioned at the boundary between the video portion 8 and the surplus portion 9, detection of the blackest level in the autopedestal circuit 2 is stopped. The range can be defined accurately.

For example, when a video signal with a black level is supplied to the surplus portion 9 as shown in A in FIG. 4, the microcomputer 5 outputs a dynamic pulse as shown in B in the same figure. As a result, the autopedestal circuit 2 detects the lowest black level only in the video portion 8.
As shown in C in the figure, an adjustment is made to lower the maximum black level to the black level reproduced on the actual cathode ray tube 4. Therefore, when black floating occurs in the original video portion 8, adjustments are made to lower it to the black level of the cathode ray tube 4, and a display is performed that effectively utilizes the dynamic range.

[0012] Thus, according to the above-described device, the surplus portion 9
Detection of the lowest black level is stopped during the period (microcontroller 5
), the autopedestal circuit 2 will not malfunction due to erroneous detection of the black level of this surplus portion, and a good display can always be obtained.

Note that the above-mentioned white line 7 is erased after the boundary is set. Furthermore, when the display position of the video portion 8 is accurately determined based on the vista size or the like, the microcomputer 5 may automatically output a predetermined dynamic pulse.

[0014]

[Effects of the Invention] According to the present invention, since the detection of the highest black level is stopped during the period of the surplus portion, there is no possibility that the black level of the surplus portion will be erroneously detected and the autopedestal circuit will malfunction. Now you can always get a good display without any problems.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an example of a display surface of a display device according to the present invention.

FIG. 2 is a time chart diagram for explaining the same.

FIG. 3 is a diagram showing an example of a screen.

FIG. 4 is a waveform diagram showing the autopedestal of the present application.

FIG. 5 is a waveform diagram showing a conventional autopedestal.

FIG. 6 is a diagram showing an example of a screen.

[Explanation of symbols]

1 Input terminal to which a video signal is supplied 2 Auto pedestal circuit 3 RGB output circuit 4 Cathode ray tube 5 Control microcomputer (μ-COM) 6 Manual input terminal 7 White line 8 Video portion 9 Surplus portion

Claims (1)

[Claims] Claim 1: In a display device equipped with an autopedestal circuit that detects the blackest level in a video signal and adjusts it so that this blackest level matches the black level reproduced on the display, When displaying an image of a video signal that is configured with an aspect ratio different from the ratio and in which a black level signal is provided in the surplus portion, detection of the lowest black level in the video signal is stopped during the period of the surplus portion. A display device designed to be displayed.