JPS61246792A - Image display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a single image display device, and more particularly to an image display device that displays image information to be displayed in a simple manner.

[Prior art]

2. Description of the Related Art Conventionally, a television receiver is an example of an image display device. In this case, the video signal sent via radio waves is the image display information.

FIG. 7 shows a known television receiver.

Here, the received television radio wave is a video signal VI
The signal is separated into a D and ID interperiod signal HOR and a vertical synchronization signal VER, and an image is displayed on a picture tube (braun tube). This cathode ray tube applies an electron beam from an electron gun to a fluorescent display surface in accordance with a video signal VID, and also generates magnetic fields from both a horizontal deflection coil to which a horizontal synchronization signal HOR is supplied and a vertical deflection coil to which a vertical synchronization signal VER is supplied. Depending on the intensity, the electron beam is deflected horizontally and vertically (electromagnetic deflection).

With this, the image of the video signal is displayed.

Although oscilloscopes and the like that display signal waveforms use electrostatic deflection, the principle of image display using a cathode ray tube (electron beam emission, light emission on a fluorescent surface) is the same.

However, regardless of the above-mentioned electromagnetic deflection and electrostatic deflection, as long as a cathode ray tube is used, the device inevitably becomes larger due to its structure. A high-voltage circuit is essential for emitting the electron beam and supplying it to the fluorescent surface. Due to the structure of the cathode ray tube, in order to deflect the electron beam, a distance from the electron gun to the phosphor surface is required, which inevitably increases the depth, and a deflection means is required, making it larger. Put it away.

Because electron beams are affected by magnetic and electric fields.

Without shielding, images will be distorted by external magnetic and electric fields. Furthermore, since the electron beam itself has a current flowing through it, a current also flows through the deflection means, resulting in a correspondingly large amount of power consumption.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image display device that is small, lightweight, highly reliable, and has low power consumption.

〔Example〕

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 shows a video signal density control circuit VSCN in an image display device according to an embodiment of the present invention. It is assumed that this embodiment is a television receiver.

In FIG. 1, a video signal VID is input to an input terminal T1, and is commonly supplied to non-inverting input terminals of a plurality of (here, four) comparators VCP1 to VCP4. These comparators VC
DC voltages (threshold voltages) 1 to 4 having different voltage values are separately applied to the inverting input terminals of P1 to P4, respectively. Here, the voltage relationship between these is Vl>V2
>V3>V4 and &ru! It is set to 5. Comparator VC
From the output terminals of P1 to 4.

Output signals VD1 to VD4 expressed in binary levels of "high" (bright) or °low" (dark) are generated and supplied to a comparator selection circuit CO5. A selection order generation circuit that receives a vertical synchronization signal VER1. GO3 supplies the selection order signal SSO to the comparator selection circuit CO5.
A video grayscale control signal vCD is output from the output terminal To.

Figure 2 shows the video signal density control circuit VSCN shown in Figure 1.
This shows the video signal VID input to the .

3(a)-(e7) show temporal changes in the output signals VD1-4 of the comparators VCP1-4 in the video signal density control circuit VSCN shown in FIG. 1 and the duty ratios represented by them.

FIG. 4 shows a display device used in an apparatus according to an embodiment of the present invention. Here, this display device DSP has a dot matrix configuration of nXm vertically and horizontally.

It is assumed that each matrix dot is provided with an LCD. In other words, in the LCD dot matrix display format, s
b. The common side was synchronized with a vertical synchronizing signal, and the segment side was synchronized with a horizontal scanning signal. Video signal density control circuit outputs corresponding to 5E01 to SEGm are respectively supplied.

FIG. 5 (at to (d) are drive signals for displaying an image on the LCD dot matrix shown in FIG. 4).

FIG. 6 shows a television receiver to which the present invention is applied. Here, DSP is the LCD dot matrix display shown in FIG. 4, and VSCN is the video signal density control circuit shown in FIG. The portion shown by the dotted line is the circuit component of the present invention, and the rest is the same as the configuration described above in connection with FIG. 7.

The operation of the above configuration will be explained below.

As shown in FIG. 6, in the same manner as conventionally known.

A video signal VID is generated from a video amplifier VIDA, and a horizontal synchronization signal HOR and a vertical synchronization signal VER are generated from a sync separation amplifier CIA.

The video signal VID is introduced into the video signal gradation control circuit VSCH also shown in FIG. 1, and the gradation control signal DC is supplied to the horizontal scanning signal control circuit CNTHK.

The horizontal synchronization signal HOR is introduced into the horizontal synchronization signal conversion circuit C0NH and converted into a new horizontal synchronization signal HOR1.
It is commonly supplied to the horizontal scanning signal control circuit CNTH and the vertical scanning signal control circuit 0NTV.

The vertical synchronization signal VER is introduced into the vertical synchronization signal conversion circuit C0NV and converted into a new vertical synchronization signal VER1.
It is commonly supplied to the video signal density control circuit vSCN and the vertical scanning signal control circuit CNTV.

Also, based on the vertical synchronization signal VER1, an AC signal 5LCD for driving a liquid crystal display element (LCD) is outputted by a liquid crystal drive AC signal generator LCDR and supplied to the horizontal signal drive circuit DRH and the vertical signal drive circuit VDR. be done.

The horizontal signal drive circuit DRH sequentially activates the display of the dot matrix LCD in one display DSP in the horizontal direction (SEG1→SEGm) based on the horizontal scanning signal H8C. Further, the lighting of the dot matrix LCD in the vertical direction (COM1→COMn) is performed by the vertical signal drive circuit VDR based on the vertical scanning signal SC.

It is now assumed that the video signal VID changes as shown in FIG. 2 according to time t, and that this is to be displayed on one screen.

As shown on the horizontal axis, one hour t is divided into 10 (=m). As shown on the vertical axis, it is assumed that the signal level (gradation, brightness) is divided into five voltage levels (=n) of voltage levels v4 to v1.

When such a video signal VID is commonly supplied to comparators VCP1 to VCP4 each having a threshold value at voltages v1 to V4 (see Fig. 1), the output signal of each comparator is The voltage signals VD1 to VD4 change as shown in FIGS. (a) to (d). The signal VD1 is at time t.
The "high" level is maintained only during periods 5 and t6, and the density exceeds the density defined by the threshold voltage v1 (bright).

11, the signal VD 2nd period fal (t 4 , t
6) The signal VD3 is at a bright level throughout the period [t3. t8), the signal vo4 takes on a bright level during the period (t2.t9).

If we combine the four signals VD1 to VD4 representing such shading and look at the level, the output duty ratio changes as shown in FIG. 3(e) for one hour t. This is the LCD
An image is displayed by scanning the dots and sequentially driving the display. The driving method will be explained below.

Each time the vertical synchronizing signal VER1 shown in FIG. 5(a) becomes a "high" level, one screen of display is defined.

After this vertical synchronization signal VER1 reaches the 1 high level,
Each time the horizontal synchronizing signal HOR1 shown in fb) in the same figure becomes a "high" level, the common side C0M of the LCD dot matrix
The lines corresponding to each of 1 to C0Mn are switched line by line and energized (turned on). In addition, in response to the horizontal scanning signal HSC shown in FIG. 4C, the columns corresponding to the segment sides 5EG1 to SEGm of the LCD dot matrix are outputted and energized at the same time at the timing of the horizontal synchronizing signal. That is, n pulses are generated in the horizontal synchronization signal HOR1 during one pulse generation period of the vertical synchronization signal VER1, and horizontal scanning signals H3CFiSEG1 to SEGm are generated during one pulse generation period of the horizontal synchronization signal HOR1.
data are output simultaneously.

As the lines are sequentially energized as shown in FIG. 5 (dl K), the output signals VD1 to VD4 shown in FIG.
are sequentially output from the video signal density control circuit VSCN.

A dot is displayed for each line of the LCD dot matrix according to the "high" or "low" level state of this output signal vDc.
Switching of IJ columns is performed by a clock CLK generated from a shift clock generator SHC.

For example, in an LCD dot matrix, depending on the threshold voltage that is switched at the timing of the vertical synchronization signal, first, on the first screen, the output signal vD1 of the comparator vCP1 is switched depending on whether the level exceeds the threshold voltage v1 or not. The period (t5, t6) during which is at the 1 high level is displayed as a dot.Next.

On the second screen, periods (t4, t6) during which the output signal D2 of the comparator VCP2 is at a "high" level are displayed as dots, depending on whether the level exceeds the threshold voltage v2 or not. Similarly, on the third screen, the first period (t3.t8) is displayed as dots depending on whether the level exceeds the threshold voltage v3.

Furthermore, on the fourth screen, a 1 period [t2. t9) is displayed as dots. Therefore, one screen with shading (depending on the duty ratio) is displayed using a total of four screens. This means that the area indicated by diagonal lines in FIG. 3(e) is displayed as a dot.

Even if the above dot display is performed quickly, the human eye cannot follow it, so it can be monitored as an image display on each screen.

Note that if the number of comparators VCP of the video signal density control circuit VSCN is increased to increase the number of stages for determining the density level,
You can get very natural images.

Furthermore, the present invention can be applied to image display devices other than television receivers.

Furthermore, the display of dots on the LCD dot matrix may be reversed from the above embodiment. It's just a matter of whether you look at the white level or the black level.

With this configuration, low power consumption and low voltage drive L
Since the one-time circuit for CD can be constructed from a low voltage circuit,
This eliminates the need for the rare high-voltage circuit required for cathode ray tubes. The LCD display is small, lightweight, and thin, making it easy to combine with other 1L devices. Since the LCD is not affected by magnetic fields, the display is not disturbed by external magnetic fields.

Since an LCD display does not require a deflection coil, a high voltage generating transformer, etc., unlike a cathode ray tube, there is no source of magnetic field, so it does not adversely affect other devices. LCD
Since it is not self-luminous, it is possible to monitor the displayed image even under direct sunlight.

〔Effect of the invention〕

As described in detail above, according to the present invention, by employing an LCD dot matrix display device as a single image display means, low voltage driving and low power consumption can be achieved.

A small, lightweight, and highly reliable image display device can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a signal density control circuit in an image display device according to an embodiment of the present invention, FIG. 2 is a level change diagram showing a video signal to be displayed as an image, and FIG.
) to (e) are diagrams showing the signal waveform representing the gray level of the video signal and the duty ratio of the signal, and Fig. 4 is the LC
An explanatory diagram showing the configuration of the D dot matrix display, FIG. 5 1a) to (d) are timing diagrams showing signals when displaying images on the LCD dot matrix display, and FIG. 6 is a television to which the present invention is applied. FIG. 7 is a block diagram showing the structure of a conventionally known television receiver. VSCN...Video signal density control circuit VID...
......Video signal VCP1-4・Old...Comparator ■1-4...Threshold voltage DSP...
...LCD CD Dora Tomato 92 indicator VER1, VE
R...Vertical synchronization signal HOR1, HOR...
...Horizontal synchronization signal H3C...Horizontal scanning signal Fig. 1 v4 Symbol 4 words Dark 5 Flame control circuit VSCN Fig. 2 Figure 3 Figure 4 (Mizuko scan) Figure 7 Procedural amendment (1) July 8, 1985 Director General of the Patent Office Mr. Michibu Uga 1, Indication of the case 1985 Patent Application No. 58556 2, Invention Name of image display device 3, relationship with the person making the amendment Patent applicant name (230) Stanley Electric Co., Ltd. 4, agent address Tamuracho Building 5, 3-3-14 Shinbashi, Minato-ku, Tokyo, amendment order Date: June 25, 1985 (shipping date) 6. Subject of amendment: Specification (brief explanation column of drawings) 7. Contents of amendment - Attached document 0.7゜ Contents of amendment (1) On page 13, line 6 of the specification, “Figures 3 (a) to (e)
) is the darkness of the video signal," which has been corrected to read "the darkness of the video signal 1" in Figure 3.

Claims (1)

[Claims] (1) An LCD dot matrix display means, a comparison means having a plurality of threshold levels, the level of the signal to be displayed is compared with the threshold level by the comparison means, and the LCD dots are displayed according to the level comparison result. means for controlling the display of each matrix dot of the matrix display means;
and means for scanning the comparison results of the comparison means based on the plurality of threshold levels.