JP2000056725A - High-definition image display device - Google Patents

Abstract

(57) [Problem] To solve the problem of high cost due to the increase in the number of wirings and circuit points due to the increase in the number of pixels and the inability to operate the circuit due to the decrease in the pulse width of a control signal, thereby realizing a high definition image display device. SOLUTION: Non-overlapping frequency signals (f0 to f3 and f4 to f) are generated by two voltage controlled oscillators (1, 2).
7) is swept and output. A modulator (MOD) is arranged at the intersection of the voltage-controlled oscillator and the vertical wiring (H00 to H71) which divides the input signal into two. The modulator modulates the amplitude of the frequency signal from the voltage controlled oscillator with an input signal for pixel control. The cycle of the frequency sweep of the voltage controlled oscillator is made to match the input signal cycle of the wiring (H00 to H71). Two wirings having the same N in the wiring HNn (N = 0 to 7, n = 0, 1) are combined, and the wiring HN (N = 0 to 7)
Through the image display unit. In each pixel, only a desired frequency component is extracted from the vertical wiring by a band-pass filter (BPF) and guided to a liquid crystal driving circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a high-definition image display apparatus, and more particularly to a control signal wiring technique for inputting a control signal to each of a plurality of pixels arranged on a two-dimensional plane.

[0002]

2. Description of the Related Art With the spread of personal computers and the development of computer networks represented by the Internet, image acquisition, transmission, storage,
Computerization of storage and display is progressing. As described above, as the digitization of images in various fields progresses, image display devices for displaying electronic images have become increasingly important.
At present, a typical computer display is CR
It is a T display.

A CRT display encloses an electron gun in a vacuum tube. The CRT display deflects an electron beam emitted from the electron gun by applying a voltage to electrodes placed opposite to each other to scan the display surface. I have. A fluorescent paint is applied to the display surface, and when an electron beam collides, visible light corresponding to the intensity is emitted to the outside. An image can be displayed on the image display surface by changing the electron beam intensity in synchronization with the scanning of the beam. CRT displays are widely used from general television use to computer display use. With the progress of multimedia in various fields, almost all people have one or more CRT displays. This is no longer an exaggeration.

The CRT display has a problem that a certain depth is required because the deflection angle cannot be increased during scanning of the electron beam. This depth increases in proportion to the size of the display screen. Further, since a vacuum tube sealed with glass is used for the CRT display, there is also a problem that the weight increases.

[0005] Recently, various flat displays have been proposed and commercialized to overcome these drawbacks of CRT displays. A typical flat display is a liquid crystal display.

A liquid crystal display is a backlight that radiates uniform light in a normal direction of a two-dimensional plane, a polarizing plate that allows only a single polarized light to pass, and a liquid crystal layer that can control the polarization angle of incident light according to an applied electric field. , And a polarizing plate. Light emitted from the backlight in the direction perpendicular to the two-dimensional plane is converted into single polarized light by the polarizing plate and input to the liquid crystal layer. The liquid crystal layer rotates the polarization of the incident light according to the electric field applied to the liquid crystal layer. The output light of the liquid crystal layer is
The light passes through the second polarizer and is emitted into space. The polarization direction of the transmitted light of the polarizers placed above and below the liquid crystal layer is made orthogonal to each other in advance, and the amount of transmitted light is controlled by rotating the polarization angle of the transmitted light in the liquid crystal layer from 0 to 90 degrees according to the applied electric field. it can. The liquid crystal layer has a structure in which liquid crystal layers divided into minute regions called pixels are densely arranged on a two-dimensional plane. Transparent electrodes are provided above and below each pixel, and an electric field is applied to the liquid crystal layer by applying a voltage between the electrodes. An image can be displayed by individually controlling the voltage applied to the electrode corresponding to each pixel.

FIG. 8 shows a conventional example of a method of applying a voltage to each pixel using a liquid crystal display device as an example. FIG. 8 shows a case where the number of pixels is eight in each of the vertical and horizontal directions.
In a normal display device, the number of pixels is several hundred to several thousand in each of the vertical and horizontal directions. Eight (H0 to H7) lines in the vertical direction and eight (V0 to V7) lines in the horizontal direction are provided in the image display unit according to the number of pixels. A voltage is sequentially applied to the horizontal wirings from V0, and when V7 is reached, a voltage is again applied sequentially from the uppermost wiring V0. By the way, the voltages to be applied to each pixel are arranged in time series on each of the vertical wirings, and are guided to the image display unit. FIG. 8 also shows an enlarged view of a portion where vertical and horizontal wirings intersect on the image display surface. The intersection of the wirings is composed of a switch composed of a transistor or FET, a liquid crystal driving circuit (that is, an electrode sandwiching the liquid crystal layer), a capacitor for holding a voltage applied to the liquid crystal layer, and the like. The vertical wiring is connected to the liquid crystal driving circuit via a switch, and the horizontal wiring is connected to the gate of the switch. When a voltage is applied to the horizontal wiring, the gate opens, and a control signal for the pixel is applied to the liquid crystal driving circuit via the vertical wiring.

FIG. 9 shows the wirings and signals applied to the wirings with respect to the time axis in the configuration of FIG. Each wiring is connected to the vertical wiring (H0 to H7).
One control signal to be input to one pixel is arranged in each time slot. On the other hand, a switch control signal is divided into eight time slots and applied to the horizontal wirings (V0 to V7). When a voltage is applied to the horizontal wiring, the switches of eight pixels connected to the wiring are turned on, and a control signal input from the vertical wiring is applied to the liquid crystal layer to control the transmitted light intensity. Is done. By sequentially applying the applied voltage to all the horizontal wirings, the control signal is applied to all the pixels. By repeating the above signal control periodically, the image display device (including moving images)
Images can be displayed.

[0009]

With the development of multimedia technology, image display devices are required to have higher and higher definition. In order to increase the definition of the image display device, it is necessary to increase the number of pixels and to shorten the rewrite cycle of each pixel. However, when the number of pixels is increased in order to increase the definition of the image display device, the number of wirings and the number of circuits for sweeping the gate signal are increased, resulting in a problem that the cost is increased. Further, there is a problem that the pulse width of the control signal pulse of each pixel is reduced due to the increase in the number of pixels and the shortening of the rewriting cycle, and the liquid crystal driving circuit does not respond.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems associated with an increase in the number of pixels for higher definition of an image display device, and to realize a higher definition image display device.

[0011]

According to the present invention, there is provided a high-definition image display apparatus which controls a light intensity distribution on a two-dimensional plane by an external control signal. It is composed of a plurality of pixels arranged on a plane, means for controlling the intensity of light emitted from the plurality of pixels by an external control signal, and means for externally inputting a control signal to the plurality of pixels. In the high-definition image display device, the means for inputting the control signal to each pixel from the outside includes wiring connected to the plurality of pixels, and means for generating frequency signals of the same number as the number of pixels connected to the wiring. Means for modulating each of the plurality of generated frequency signals with a control signal of a pixel connected to the wiring, wherein each of the pixels connected to the wiring is modulated with a control signal of the pixel. Frequency component It characterized by having a band pass filter for passing. This is the basic form of the present invention.

The means for inputting the control signal from the outside to each pixel may be a means for generating a frequency signal of the same number as the number of pixels connected to the wiring, a means for generating a periodically swept frequency signal. And a means for periodically arranging control signals to a plurality of pixels connected to each wiring of the image display unit on a time axis, the cycle of the swept frequency signal and the control signal And the period is made equal. This uses a voltage-controlled oscillator or the like as a frequency signal source in the above basic type.

The means for inputting the control signal from the outside to each pixel may include generating a plurality of periodically swept frequency signals as means for generating the same number of frequency signals as the number of pixels connected to the wiring. Having a means for making a control signal to a plurality of pixels connected to each wiring of the image display unit a means for setting the same number of parallel periodic signals as the number of sweep frequency signals,
The cycle of the swept frequency signal is equal to the cycle of the parallel periodic signal. This uses a plurality of voltage controlled oscillators or the like as the frequency signal generation source in the above basic type.

The means for inputting the control signal to each pixel from the outside may include, as means for generating a plurality of frequency signals for the wires connected to the plurality of pixels, the same number of pixels as the number of pixels connected to each wire. As means for modulating each of the plurality of generated frequency signals with a control signal of a pixel connected to the wiring, the oscillator having an oscillator that generates different frequency signals,
Means for independently modulating frequency signals from the plurality of oscillators by control signals to a plurality of pixels connected to each wiring of the image display unit; and connecting the frequency signals modulated by the modulating means to the pixels. And a means for multiplexing and inputting the wiring. In the basic form, a plurality of oscillators are used as a frequency signal generation source to enable parallel access to pixels.

Further, the wiring connected to the plurality of pixels is constituted by an optical waveguide, and the means for generating the same number of frequency signals as the number of pixels connected to the wiring generates the optical frequency signal as the frequency signal. Means for modulating each of the plurality of generated frequency signals with a control signal of a pixel connected to the wiring, the light modulating the optical frequency signal with a control signal of a pixel connected to the wiring. Wherein each of the pixels connected to the wiring has a light receiving element for converting an optical frequency signal modulated by the control signal into an electric signal, and is modulated by the control signal of the pixel as the band-pass filter. And a band-pass filter disposed downstream of the light-receiving element. This utilizes the wavelength multiplexing type optical interconnection in the above high definition image display device.

According to the present invention, a plurality of carrier frequencies are prepared, each carrier frequency is modulated by an input signal to a pixel, and the plurality of modulated signals are multiplexed on one line and input to an image display area. By controlling only the pixels by extracting only the desired frequency components with a filter, the number of wirings in the image display unit and the number of peripheral circuits are reduced,
A high-definition image display device is realized economically. Further, by using a plurality of sweep frequency signals, the pulse width of the pixel control signal is increased, and the problem of the pulse width of the pixel control signal, which has been a bottleneck in realizing a high definition image display device, is avoided. Further, the degree of freedom of image display control is increased by preparing in advance frequency signals for the number of pixels connected to the wiring in the image display unit and independently controlling each pixel.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a diagram for explaining a first embodiment of the present invention. In the present embodiment, a vertical wiring, a voltage controlled oscillator (VCO), and a modulator (MOD) that modulates the output of the voltage controlled oscillator with an input signal
And a band-pass filter (BPF) arranged in each pixel.

FIG. 2 shows a state of a time signal of each wiring in this embodiment. A sawtooth control signal is applied to the voltage-controlled oscillator (VCO in), and a frequency signal whose frequency is temporally swept is output from the voltage-controlled oscillator (VCO out). A modulator is arranged at the intersection of the voltage-controlled oscillator and the vertical wiring. The modulator modulates the amplitude of the frequency signal with an input signal for pixel control. Each pixel has a configuration in which only a desired frequency component is extracted from a vertical wiring by a band-pass filter and guided to a liquid crystal driving circuit. In some cases, a low-pass filter is provided after the band-pass filter to convert the extracted signal into a DC signal. The frequency sweep cycle of the voltage controlled oscillator is made to match the control signal cycle for the number of pixels connected to the vertical wiring. With the operation as described above, it is possible to guide a control signal to each pixel in the configuration of the present embodiment.

According to the present embodiment, since the wiring in the horizontal direction, which is conventionally required, is not required, the number of wirings required for the image display unit can be halved and the number of peripheral circuit points can be reduced. be able to. This has the advantage that a high-definition image display device can be constructed economically. Further, in the conventional example, an active element having a switch function is required for each pixel. However, in the present embodiment, since only a passive element called a band-pass filter is used for signal separation, a simple configuration and a highly reliable A high definition image display device can be realized.

[Embodiment 2] FIG. 3 is a diagram for explaining a second embodiment of the present invention. In the present embodiment, a plurality of (two in the figure) voltage-controlled oscillators (VCOs) for generating a sweep frequency are input to the vertical wirings in the configuration of the first embodiment of the present invention. The pixel signal is divided into two and inputted in parallel.

FIG. 4 shows a state of a time signal of each wiring in this embodiment. Each voltage controlled oscillator (1,
2), a sawtooth control signal (1, 2) is applied, and a frequency signal whose frequency is temporally swept is output from the voltage-controlled oscillator accordingly. Here, the oscillation of the oscillator is performed so that the frequencies of the signals output from the two voltage-controlled oscillators do not overlap each other (such as f0 to f3 in the voltage-controlled oscillator 1 and f4 to f7 in the voltage-controlled oscillator 2). The control signal (1, 2) is adjusted in the frequency band. At the intersection of the voltage-controlled oscillator and the vertical wiring,
A modulator (MOD) is arranged as shown in FIG. The modulator modulates the amplitude of the frequency signal output from the voltage controlled oscillator with an input signal for pixel control. Each pixel has a configuration in which only a desired frequency component is extracted from a vertical wiring by a band-pass filter (BPF) and guided to a liquid crystal driving circuit. The cycle of the frequency sweep of the voltage controlled oscillator is made to match the input signal cycle of the wiring (H00 to H71). Two wirings having the same N in the wiring HNn (N = 0 to 7, n = 0, 1) are combined, and the wiring HN (N = 0 to 7)
Through the image display unit. Wiring HN (N = 0 to
To 7), a pixel control signal having frequency components (f0 to f7) of eight connected pixels is frequency-multiplexed and applied. With the operation as described above, it is possible to guide a control signal to each pixel in the configuration of the present embodiment.

According to the present embodiment, a plurality of sweep frequency signal generating circuits are provided, and control signals of pixels connected to respective wirings on the image display surface are frequency-multiplexed in parallel, so that control signals of respective pixels are added to the control signal of each pixel. The number of time slots assigned can be increased (the number of time slots is eight in the first embodiment, but can be four in the present embodiment, so that the time width of the time slot can be doubled). it can). This corresponds to the fact that the pulse width of the pixel control signal, which has been a bottleneck in realizing a high-definition image display device by increasing the number of pixels, can be increased. Therefore, according to the present embodiment, a high definition image display device can be easily realized. Further, by increasing the number of sweep frequency generation circuits, it is possible to further increase the time slot allocated to the control signal, and to realize a high-definition image display device using inexpensive and low-speed peripheral circuits.

[Embodiment 3] FIG. 5 is a diagram for explaining a third embodiment of the present invention. In this embodiment, the number of oscillators is the same as the number of pixels connected to each wiring, and the output frequency signal is individually modulated by a control signal for each pixel.

FIG. 6 conceptually shows the state of the control signal in the embodiment. Each of the oscillators (f0, f2,... F
7) Set. A modulator (MOD) is arranged at the intersection of the oscillator and the wiring of each input signal as shown in FIG. The modulator modulates the amplitude of the frequency signal output from each oscillator with an input signal for controlling each pixel. The outputs of these modulators are combined to form a vertical wiring HN to each pixel.
(N = 0 to 7). Each pixel has a configuration in which only a desired frequency component is extracted from a vertical wiring by a band-pass filter (BPF) and guided to a liquid crystal driving circuit. In this way, the pixel control signal having the frequency components (f0 to f7) of eight connected pixels is frequency-multiplexed and applied to the wiring HN (N = 0 to 7). With the operation as described above, it is possible to guide a control signal to each pixel in the configuration of the present embodiment.

In this embodiment, since it is not necessary to sweep the frequency corresponding to each pixel, it is possible to control each pixel regardless of time. This indicates that the pulse width of the control signal to each pixel can be increased to about the frame period of the display circuit (33 milliseconds in a normal television). In the conventional method, since the pulse width of the control signal is about 67 microseconds, the pulse width can be increased by about three digits according to the present embodiment. Therefore, according to the present embodiment, a high-definition image display device can be realized using low-cost and low-speed peripheral circuits. Furthermore, according to the present embodiment, since each pixel can be controlled independently, for example, it is possible to rewrite only a part of the image display unit without affecting other pixels. Although the number of wirings in the image display unit can be reduced to half of that in the related art, the number of wirings outside the image display unit is increased in this embodiment. However, since there is no physical (spatial) restriction on the wiring as compared with the inside of the image display unit, it can be easily realized without affecting the performance of the entire device.

[Fourth Embodiment] FIG. 7 is a diagram for explaining a fourth embodiment of the present invention. In this embodiment, the first
In the embodiment, the sweep frequency generating circuit is a variable wavelength light source, the wiring HN (N = 0 to 7) is an optical waveguide, the modulator (MOD) is an optical modulator, and each pixel has a wavelength in order from the optical waveguide. It differs from the previous embodiments in that a filter and a light receiving element are arranged to guide a control signal to the liquid crystal drive circuit.

According to the present embodiment, since the control signal of each pixel is transmitted by an optical signal, there is an advantage that it is possible to avoid a frequency band, noise, and the like which have conventionally been problems in the wiring section.

FIG. 7 shows a case where the first embodiment of the present invention is converted to light, but the second embodiment can also be converted to light by using a plurality of variable wavelength light sources. Further, by preparing light sources for the number of pixels having different wavelengths from each other, a configuration similar to that of the third embodiment can be easily realized. Here, the light sources having mutually different wavelengths may be realized by, for example, combining an LED or a white light source having a large output spectrum width with a plurality of optical filters having different passing wavelengths. The wavelength filter shown in FIG. 7 can be replaced with a band-pass filter for an electric signal disposed after the light receiving element.

The present invention can also be used in combination with a display screen space division method which has been conventionally performed for high definition pixels. In that case, the number of pixels can be further increased, and an ultra-high definition image display device can be easily realized.

[0031]

As described above, according to the image display apparatus of the present invention, a plurality of carrier frequencies are prepared, each carrier frequency is modulated by an input signal to a pixel, and the plurality of modulated signals are converted into one signal. Multiplexed to the wiring and input to the image display area, each pixel extracts only the desired frequency component with a filter to control the pixels, so the number of wirings in the image display unit and the number of circuit points of peripheral circuits can be reduced, There is an effect that a high-definition image display device can be realized economically. Further, since a plurality of sweep frequency signals are used, the pulse width of the pixel control signal can be increased, so that the problem of the pulse width of the pixel control signal, which has been a bottleneck in realizing a high-definition image display device, is avoided. Can be. Furthermore,
Since the frequency signals for the number of pixels connected to the wirings in the image display unit are prepared in advance and each pixel is controlled independently, the degree of freedom in image display control can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing signal waveforms according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing signal waveforms according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 6 is a diagram illustrating signal waveforms according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 8 is a diagram illustrating a conventional example.

FIG. 9 is a diagram showing a signal waveform of a conventional example.

Continued on the front page F term (reference) 2H093 NA20 NC06 ND20 ND34 ND40 ND52 ND54 NE06 5C006 AA11 AC11 AC21 AF46 BB15 BC13 BF21 FA27 FA51 5C080 AA10 BB05 DD07 DD09 DD27 EE01 EE17 EE19 FF11 GG02 GG04 JJ04 JJ04 JJ01

Claims (5)

[Claims] 1. A high-definition image display device for controlling a light intensity distribution on a two-dimensional plane by a control signal from outside, comprising: a plurality of pixels arranged on the two-dimensional plane; A high-definition image display device comprising: means for controlling the intensity of emitted light by an external control signal; and means for externally inputting a control signal to the plurality of pixels. Means for inputting to the plurality of pixels, a means for generating the same number of frequency signals as the number of pixels connected to the wiring, and means for connecting each of the generated plurality of frequency signals to the wiring Means for modulating with a control signal of the pixel, wherein each of the pixels connected to the wiring has a band-pass filter for passing only a frequency component modulated by the control signal of the pixel. High-definition image display device. 2. A means for externally inputting the control signal to each pixel, wherein the means for generating a frequency signal of the same number as the number of pixels connected to the wiring includes a means for generating a periodically swept frequency signal. A means for periodically arranging control signals to a plurality of pixels connected to each wiring of the image display unit on a time axis, wherein the period of the swept frequency signal and the control signal 2. The high-definition image display device according to claim 1, wherein a period of the high-definition image is made equal. 3. A means for inputting the control signal to each pixel from the outside generates a plurality of periodically swept frequency signals as means for generating the same number of frequency signals as the number of pixels connected to the wiring. Means for converting a control signal to a plurality of pixels connected to each wiring of the image display unit into a parallel periodic signal having the same number as the number of sweep frequency signals. 2. The high-definition image display device according to claim 1, wherein a period of the signal is made equal to a period of the parallel period signal. 4. A means for inputting the control signal to each pixel from the outside, wherein the means for generating a plurality of frequency signals for wiring connected to the plurality of pixels includes a means for generating a plurality of frequency signals, the same number as the number of pixels connected to each wiring. An oscillator that generates different frequency signals; and as a means for modulating each of the generated plurality of frequency signals with a control signal of a pixel connected to the wiring, a plurality of frequency signals connected to each wiring of the image display unit. A means for independently modulating the frequency signals from the plurality of oscillators with a control signal to the pixel, and a means for multiplexing and inputting the frequency signal modulated by the modulating means to a wiring connected to the pixel 2. The high-definition image display device according to claim 1, wherein: 5. Wiring connected to the plurality of pixels is constituted by an optical waveguide, and means for generating the same number of frequency signals as the number of pixels connected to the wiring generates an optical frequency signal as a frequency signal. Means for modulating each of the plurality of generated frequency signals with a control signal of a pixel connected to the wiring, light modulates the optical frequency signal with a control signal of a pixel connected to the wiring. Wherein each of the pixels connected to the wiring has a light receiving element for converting an optical frequency signal modulated by the control signal into an electric signal, and is modulated by the control signal of the pixel as the band-pass filter. The high-definition image display device according to any one of claims 1 to 4, further comprising an optical filter that passes only the light frequency component or a band-pass filter provided at a stage subsequent to the light receiving element.