JPS6324768A - Picture display - Google Patents

Abstract

PURPOSE:To execute automatically the luminance adjustment for a picture by measuring the luminance of the picture displayed actually on a monitor with a photodetecting element and feeding back the result through a comparator and an adder. CONSTITUTION:A photodetecting element 4 is arranged on the glass surface of a monitor 2 and the light of a fluorescent substance 41 of the inner surface of the glass is photodetected. A comparator 53 compares the output from the photodetecting element 4 amplified by an amplifier 51 with a reference value set beforehand and outputs an error signal in proportion to the difference in the reference value. An adder 55 adds the signal from the comparator 53 impedance-converted by an impedance converter 54 to a video signal inputted from a video signal input terminal 3, and the signal from the adder 55 is fed back to a monitoring cathode 56 as an electric potential change. Thus, the luminance adjustment for the picture is automatically executed.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an image display device.

(Prior Art) Conventionally, for example, in a medical image display device, when the subjects and shadow conditions of each image to be observed are different,
As shown in FIG. 1, due to the difference in the shadow conditions of the display images a, b, and c, the individual video signal levels often have different display brightness levels as shown in FIG.

(Problem to be Solved by the Invention) However, if the brightness levels of the displayed images vary as in the past, the output brightness of the images will differ each time the images are displayed one after another, causing a great deal of damage to the visual system of the viewer. It was causing fatigue. In this case, the observer can adjust the brightness each time to make it easier for him to see, but this work is very complicated. In addition, in the case of digital image display, it is possible to set the average brightness in advance, so the brightness can be adjusted by changing the window and level conversion table, but since the input/output characteristics of the monitor display device have nonlinear components, it is extremely difficult to adjust the brightness. It was difficult.

Furthermore, even if the video signals are the same, there is a problem in that when displaying on two or more different monitors, the brightness will not be equal due to differences in the input/output characteristics of each monitor.

An object of the present invention is to solve the above-mentioned problems and to enable automatic brightness adjustment for each image.

[Structure of the Invention] (Means for Solving the Problems) To achieve the above object, the present invention provides a light receiving element formed on a part of a monitor screen to measure the brightness of a displayed image, and a light receiving element formed on a part of a monitor screen to measure the brightness of a displayed image. The configuration includes a comparator that compares the output of the comparator with a preset reference value, and an adder that adds the error output from the comparator to the input video signal.

(Function) In recent years, as shown in Figure 5, the MTF characteristic of the monitor output has
1 measurement, it became clear that the MTF phenomenon in the low frequency range of the monitor (*f + 1) was significant. From this, scattered light almost spatially close to the direct current component is always present when displaying an image. The level of blur is a function of the average brightness of the displayed image.

Therefore, since the present invention has the above configuration, it operates as follows.

That is, the light receiving element measures the brightness of the image displayed on the monitor, and its output is compared with a preset reference value by the comparator. Then, the comparator outputs a signal proportional to the difference, which is negative if the output from the light receiving element is larger than the reference value, and positive if it is smaller, and the output from the comparator is added to the input video signal by an adder. will be added.

Therefore, according to the present invention, the brightness of the image actually displayed on the monitor is measured by the light receiving element, and the result is fed back through the comparator and adder, so that the brightness adjustment for each image is automatically performed. It will be carried out.

(Example) The illustrated embodiment will be described below.

In FIG. 1, 1 is a terminal for inputting the output from the light receiving element 4 (see FIG. 2).

The light receiving element 4 is connected to the monitor 2 as shown in FIG. 2(a), for example.
It is provided in a thin film form in a very small area around the area.

For example, as shown in FIG. 3, the light-receiving element 4 is constructed using amorphous silicon 44 sandwiched between In (syndium) 45 and Cr (chromium) 43, and is placed on the glass surface 42 of the monitor 2. The light from the fluorescent material 41 is received. The light-emitting surface of the monitor 2 corresponding to the light-receiving surface of the light-receiving element 4 is blanked to cut off the luminance signal, so that only scattered light enters as a method for measuring average luminance. That is, in an actual monitor, the light emitted by the fluorescent material 41 is scattered within the glass 42 that protects the fluorescent material 41 and reaches the surrounding area.
Only this scattered light is received. Such a light receiving element 4 absorbs Cr-In produced by the incidence of scattered light.
The change in potential at both ends is measured and the measured value is output to the terminal 1. Incidentally, the video signal level when the light receiving element 4 is provided is shown in FIG. 2(b).

In FIG. 1, 51 is an amplifier, which amplifies the output from the light receiving element 4.

53 is a comparator, which compares the output from the light-receiving element amplified by the amplifier 51 with a preset reference value 52; if the output is larger than the reference value, it becomes negative; if it is smaller, it becomes positive; It outputs an error signal proportional to the difference.

54 is an impedance converter, which converts the output from the comparator 53 into impedance.

Reference numeral 55 denotes an adder, which adds the signal from the comparator 53 whose impedance has been converted by the impedance converter 54 to the video signal input from the video signal input terminal 3. The signal from this adder 55 is
Similar to the conventional monitor output method, the voltage is applied to the monitor cathode 56 as a potential change.

In addition, the above standard (+1Tt52), if you have multiple monitors, display the same image on all monitors and change the standard 1st shift individually with the volume so that the brightness of all monitors is the same. Set and open.

According to the above-described device, the brightness of the image actually displayed on the monitor 2 is measured by the light receiving element 4, and the result is fed back via the comparator 53 and the adder 55, so that the brightness of the image actually displayed on the monitor 2 is Brightness adjustment is done automatically.

Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above embodiment, and can be modified as appropriate within the scope of the gist of the present invention.

For example, the arrangement of the light-receiving element 4 is not limited to the above-mentioned embodiment, and any configuration may be used as long as the light-emitting surface facing the light-receiving surface has a black level and only scattered light is received. Therefore, for example, light receiving elements with arcuate light receiving surfaces may be placed at the four corners of the glass surface 42 of the monitor 2 to perform averaging, or only on one edge of the glass surface 42 of the monitor 2. May be placed.

[Effects of the Invention] As detailed above, according to the present invention, the brightness of the image actually displayed on the monitor is measured by the light receiving element, and the result is fed back through the comparator and the adder. , Moderation lLl for each picture @! , I-attack is performed automatically.

Therefore, the viewer does not have to make irritating brightness adjustments.
Furthermore, even if there are multiple monitors, the brightness of all monitors can be made equal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an image display device according to the present invention, and FIG.
Figure (a) is a front view showing an example of installing the light receiving element, Figure 2 (b)
) is a diagram showing the video signal level in the same case as above, FIG. 3 is a partial sectional view of the same as above, FIGS. 2... Monitor, 4... Light receiving element, 53... Comparator, 55... Adder.

Claims (3)

[Claims] (1) A light-receiving element formed on a part of the monitor screen to measure the brightness of the displayed image, a comparator that compares the output from the light-receiving element with a preset reference value, and an error output from the comparator. 1. An image display device comprising: an adder for adding the input video signal to an input video signal. (2) The image display device according to claim 1, wherein the light-receiving element is arranged with its light-receiving surface facing a blanking area of the monitor, and receives scattered light within a glass surface. (3) The image display device according to claim 1 or 2, wherein a plurality of the light-receiving elements are arranged around the periphery of a monitor screen, and the average output of the plurality of light-receiving elements is compared by the comparator.