JP2601713B2 - Display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a display device using an ionizable gas (gas).

2. Description of the Related Art A system using a data storage device includes, for example, a video camera and an image display device. Such systems have an addressing device for writing data to and reading data from the storage element. A system of this type to which one embodiment of the present invention is particularly concerned is a general purpose flat panel display,
The storage element or display element stores light pattern data. Flat panel displays include a number of display elements arranged in a viewing area on a display surface. Flat panel displays are desirable because they do not necessarily require a cathode ray tube to form a display image. Cathode ray tubes are large and fragile and have high voltage drive circuits, which is undesirable.

Some types of flat panel display devices employ an addressing device in which a large number of liquid crystal cells or display elements are arranged and multiplexed directly. Each of the liquid crystal cells is disposed between a pair of conductors, and selectively applies a selection voltage signal and a non-selection voltage signal to these conductors and the liquid crystal cell to change the optical state of the liquid crystal cell. Thereby, the luminance can be changed and an image can be formed. Display devices of this type can be said to be "passive". This is because "active" electronics are not cooperating in changing the electro-optical properties of the liquid crystal cell. Such display devices have the disadvantage that the number of address lines for providing video information, ie, data, used to form the display image is limited (eg, about 250).

As a measure to increase the number of data address lines of the liquid crystal display device, a separate electric element cooperating with each liquid crystal cell requires that the liquid crystal cell's electro-optical response to the selection voltage signal and the non-selection voltage signal be substantially reduced. The use of an addressing device that modifies the dynamic nonlinearity. Some of the "two-terminal" element addressing techniques are characterized by this method. Increasing the substantial non-linearity of the display element increases the multiplexing capability in binary display, but this technique has many difficulties in achieving gray scale.

To obtain a liquid crystal matrix display device with sufficient gray scale performance requires an addressing device that does not depend on obtaining a non-linear function from the liquid crystal material. To accomplish this, addressing devices using a matrix of electrical "active" elements employ electronic switches that are separate from the liquid crystal material for each pixel. This active matrix uses two or three terminal solid state elements associated with each liquid crystal cell,
The required nonlinearity and insulation of the display element are obtained. Addressing devices configured with two-terminal devices can use various types of diodes, and addressing devices configured with three-terminal devices use various types of thin film transistors (TFTs) made from different semiconductor materials. be able to.

[Problem to be Solved by the Invention] One of the problems related to the two-terminal or three-terminal active element is as follows.
When the number of active elements becomes very large, it becomes very difficult to produce a large number of matrices with high yield. Another problem, particularly for TFT devices, is that it is difficult to manufacture thin-film transistors with sufficiently high “off-resistance”. "Off resistance"
Is relatively low, the display element cannot hold the charge generated there for a predetermined time. Further, at this time, the ratio between the “off resistance” and the “on resistance” decreases. This ratio is
It is desirable to have more than 10 for the proper operation of the TFT matrix. TFT matrices sometimes employ separate storage capacitors with each display element to eliminate the effect of "off resistance" not being sufficiently high. However, it cooperates with the use of separate storage capacitors
It is expected that the TFT matrix will become more complex and the yield will decrease. Another potential problem with TFT active matrices is the need for TFTs to come from the "on" current.
Since the size of the element tends to be large, the size of the TFT is relatively large as compared with the size of the display element. This affects the light efficiency of the device.

Active devices made by TFT devices are capable of forming black and white and color images. In order to form a color image, they are arranged so as to spatially match the display elements,
The active matrix uses a color filter that contains many groups of spots of different colors. Thus, a group of display elements aligned to match differently colored spots thus form a single image pixel.

The flat panel display device can be implemented by using a display element using ionized gas or plasma, and forms a light emitting region of a color determined by what kind of gas is used on a display surface. These light emitting areas are selectively driven to form a display image.

Other flat panel display devices employ plasma that emits electrons, and these electrons are accelerated and collide with a phosphor to generate a bright spot. Such a flat
Although the panel display device has improved luminance efficiency, it is difficult to form a wide display surface, and a complicated drive circuit is required. Such flat panel display devices have different spectral characteristics to form multicolor images,
It can be constituted by a phosphor excited by electrons.

Gas plasma flat panel displays have been intentionally mitigated by using a plasma-sac type gas discharge display. In such a display device, the plasma sack generated on the cathode side of the insulator provided with the opening moves from one opening to another opening and affects raster scanning. The production process of this plasma sack type gas discharge display device is complicated, and the yield is likely to decrease.

Therefore, an object of the present invention is to provide a display device that can be manufactured at a high yield at a low cost.

Yet another object of the present invention is to provide a display device having a high addressing speed, high contrast characteristics, and a storage or display element comprising a liquid crystal material which is an electro-optical material and an active addressing device. is there.

It is yet another object of the present invention to provide such a display in which the electro-optic material cooperates with the ionized gas to form an addressable data storage element.

Still another object of the present invention is to provide a display device having good color, gray scale, and luminance characteristics.

[Means for solving the problem]

The display device of the present invention includes a first substrate having a plurality of first electrodes formed on one main surface substantially in parallel with each other;
A second substrate having a plurality of groove-shaped recesses formed on the main surface facing the main surface of the substrate so as to intersect with the first electrode and to be substantially parallel to each other, and filled with an ionizable gas; Second and third electrodes formed in each of the plurality of groove-shaped recesses on the main surface substantially parallel to the longitudinal direction of the groove-shaped recess;
A liquid crystal material layer interposed between the first substrate and the second substrate and forming a display element at an intersection of the first electrode and the groove-shaped recess; and a first first electrode selectively provided between the first electrode and the third electrode. A first signal applying means for applying a signal; and a second signal applying means for selectively applying a second signal between the second electrode and the third electrode. The second signal applying means selectively supplies the second signal between the second electrode and the third electrode, and ionizes the gas in the groove-shaped recess having the second electrode and the third electrode which has received the second signal. I do. The first signal applying means selectively supplies a first signal between the first electrode and the third electrode of the display element corresponding to the groove-shaped recess containing the ionized gas to change the optical state of the liquid crystal material layer. Then, display is performed by the display element.

According to an embodiment of the present invention, there is provided an addressing device for a high resolution flat panel display device used in either a direct view type or a projection type. The display device includes a display panel constituted by data storage elements or display elements arranged over the entire visual area. Each display element includes one in which a predetermined amount of an ionizable gas such as helium is sealed, and one in which a predetermined amount of an electro-optical material such as nematic liquid crystal is sealed, and the display elements are provided in cooperation with each other. Modulate the light that propagates through the electro-optic material where it is and emits outward.

In this embodiment, the storage elements are arranged in rows and columns,
A row represents one row of video information or data. (The information addressed in the embodiment is referred to hereinafter as "data.") The column electrodes receive the data, and the data strobe circuit addresses the column electrodes row by row by row scanning.

An embodiment of the display device (display panel) of the present invention includes first and second substrates which are spaced from each other and face to face. A number of non-overlapping conductive paths extending in a first direction along the inner surface of the first substrate form column electrodes for data drive signals applied thereto. Numerous non-overlapping grooves (groove-shaped recesses) carved inside the second substrate
Extends inward along a direction substantially transverse to the first direction.
The first and second directions are preferably vertical and horizontal, respectively. The reference voltage electrode and the row electrode are electrically insulated from each other, extend along the longitudinal direction inside each groove, and receive a data strobe signal applied thereto. Each groove is
Filled with ionizable gas.

In a display panel according to an embodiment of the present invention, a layer of a material having electro-optical properties and a layer of a dielectric material are disposed between inner surfaces of the first and second substrates, and a dielectric layer covering the groove is provided. The body material layer forms a barrier between the layer of electro-optic material and the ionizable gas. The shape of the display element is determined by the area where the column electrode and the groove overlap, and appears as a spot on the display screen. The spots are small enough and close together that they are indistinguishable under normal viewing conditions.

The display panel is configured as described above, and the gas that can be ionized for each display element is in a conductive plasma state according to the applied data strobe signal,
It functions as a switch that electrically switches between a non-conductive and non-ionized state. The strength of the data drive signal of the column electrode corresponds to the brightness of the display image.

Whenever the device is conducting, the region of ionized gas allows a data voltage representing the voltage of the data drive signal to be applied to the liquid crystal material region. The liquid crystal material region is spatially aligned with the ionized gas region. Whenever the element is non-conducting, the region of the non-ionized gas is
The spatially aligned area of the liquid crystal material allows the voltage across it to be maintained for a predetermined time. The ionizable gas therefore serves to select the data stored in the liquid crystal material, thus providing a gray scale luminance display.

By switching the ionizable gas between a conductive state and a non-conductive state in the display panel, light passing through the display element can be modulated. The transmitted light depends on the intensity of the applied data drive signal. A monochrome or black-and-white display device having a gray scale luminance function can be used for the display panel. A full-color display device with controllable color intensity can be realized by disposing a color filter including a group of spots of three primary colors spatially aligned with the display element in a monochrome display device. The group of three display elements aligned to form a group of spots will be one image pixel of a color determined in relation to the intensity of the spots in this group.

The display device of the present invention is capable of providing an entirely dynamic, gray-scale image over a wide range of field rates, providing a high quality display. This display device is particularly advantageous because of its simple and uneven structure, with a 60 Hz field screen on the display screen.
At a rate, at least 3000 data lines can be addressed.

Other objects and advantages of the present invention will become more apparent from the following description with reference to the drawings.

〔Example〕

Figure 1 shows a typical flat panel display (10)
1 is a diagram illustrating a schematic configuration of an address device and an address method according to the present invention. In FIG. 1 and FIG. 2 showing details of the panel, a flat panel display (10)
Comprises a display panel (12) having a display surface (14).
The display surface (14) includes a pattern of a rectangular planar array of individual data storage elements or display elements (16) spaced from one another at predetermined intervals along the vertical and horizontal directions. Each display element (16) in this arrangement is an overlapping intersection of thin, narrow electrodes (18) arranged along a vertical column and elongated grooves (20) arranged in a horizontal direction. . The groove (20) is a groove-shaped recess as can be seen from the figure. (Hereinafter, the electrodes (18) will be referred to as column electrodes (18).) Each groove (20) corresponding to a row
The middle display element (16) represents one row of data.

The width of the column electrode (18) and the width of the groove (20) are
, Which is approximately rectangular. Column electrode (18)
Is disposed on the main surface of the non-conductive and optically transparent first substrate, and the groove (20) is cut on the main surface of the non-conductive and optically transparent second substrate. This will be described later in detail.
Those skilled in the art will appreciate that in systems such as direct-view or projection-type reflective displays, only one of the substrates may be optically transparent.

The column electrode (18) is connected to the analog voltage generated on the parallel output conductor (22 ') by each one of the output amplifiers (22) of the data driver (24) (see FIGS. 2 to 6). Receiving a data drive signal. The data driver (24) and the output amplifier (22) constitute first signal applying means. The groove (20) is connected to the output amplifier (2) of the data strobe (28).
6) receive a data strobe signal of a pulse voltage generated on a parallel output conductor (26 ') by each one of FIGS. 2 to 6; Data strobe (28)
And the output amplifier (26) constitute second signal applying means.
A reference electrode (30) (FIG. 2) passes through each groove (20), and a reference voltage (ground voltage) common to each groove and the data strobe circuit (28) is applied to the reference electrode (30). Is done.

The display device (10) includes a scan control circuit (32) for forming an image over the entire display surface (14). This adjusts the function of the data drive circuit (24) and the data strobe circuit (28) to address all columns of the display elements (16) of the display panel (12) sequentially from row to row. Different types of electro-optical materials may be used for the display panel (12). For example, if a material that changes the polarization state of the incident light (33) is used as the material, the display panel (12) will be composed of the polarizing filters (34) and (36).
(See Fig. 2). The filters (34) and (36) cooperate with the display panel (12) to change the brightness of light passing therethrough. If a liquid crystal cell that scatters light is used as the electro-optic material, the polarizing filters (34) and (36) are not required. Although not shown, a color filter may be disposed in the display panel (12) to form a multicolor image whose color intensity can be controlled. 3 for projection display
The colors may be formed by using individual discrete color panels, each panel controlling one primary color.

2 to 5, the display panel (12) comprises addressing means, which comprises a layer of electro-optic material (44) such as a nematic liquid crystal and a thin dielectric such as glass, mica or plastic. It includes a pair of generally parallel electrode assemblies (40), (42) separated by a layer of material (46). The electrode assembly (40) comprises a dielectric substrate (48) made of glass, on which a column electrode (18) made of an oxide of indium and tin is provided by vapor deposition on an inner surface (50). I have. It is optically transparent and forms a strip pattern. The next column electrode (18)
It is separated by an interval (52) and defines a horizontal interval between adjacent display elements (16) on a row.

The electrode assembly (42) includes a dielectric substrate (54) made of glass, and a plurality of grooves (20) having a trapezoidal cross section are provided on the inner surface (56). The depth (58) of the groove (20)
It was measured from the inside surface (56) to the bottom (60). Each of the grooves (20) has one extending along the bottom (60).
A pair of thin and narrow nickel electrodes (30) and (62), and divergently extending from the bottom (60) to the inner surface (56) 1
There are twin side walls (64). The reference electrode (30) of the groove (20)
Connected to common reference voltage. This is fixed to the ground potential as shown. Groove (20) electrode (62)
Is the output amplifier (26) of the data strobe circuit (28)
(Three and five of these are shown in FIGS. 2 and 3, respectively). (The electrode (62) is hereinafter referred to as the row electrode (62).) To ensure that the addressing means operates, the reference electrode (30) and the row electrode (62) are shown in FIGS. 4, 11A and 11B. As shown in
Opposite sides of the display panel (12) are connected to the reference potential and the output (26 ') of the data strobe circuit (28), respectively.

Adjacent side walls (64) of adjacent grooves (20) are support structures (66) whose top surface (56) supports a dielectric material layer (46). Adjacent structures (20) are spaced from each other by the width (68) of the top of each support structure (66). This width (6
8) Determine the vertical distance between adjacent storage elements (16) in the row. The portion (70) where the column electrode (18) overlaps the structure (20) becomes a storage element (16) as shown in FIGS. 2 and 3. FIG. 3 more clearly shows the arrangement of the storage elements (16) and their horizontal and vertical distances.

The gap (52) for insulating the adjacent column electrode (18) is determined according to the magnitude of the voltage applied to the column electrode (18). The spacing (52) is typically much smaller than the width of the column electrode (18). The width (68) is determined according to the inclination of the adjacent side wall (64) of the adjacent groove (20). The width (68) is
It is typically much smaller than the width of 0). Column electrode (18)
And the width of the groove (20) are typically the same and are a function of the desired image resolution. This depends on the application to the display. The gap (52) and the width (68) should be as small as possible. In the current model of the display panel (12), the groove depth (58) is half the width of the groove.

Each of the grooves (20) is filled with an ionizable gas, which preferably includes helium gas, as described below. The dielectric material layer (46) functions as an insulating barrier between the ionizable gas contained in the groove (20) and the liquid crystal material layer (44). Without the dielectric material layer (46), the liquid phase material may flow into the groove (20), or the ionizable gas may contaminate the liquid crystal material. The layer of dielectric material (46) may not be needed in displays employing solid or encapsulated electro-optic materials. Display panel (1
2) The principle of operation is as follows: 1) Each display element (16)
It functions as a sampling capacitor for the analog data voltage applied to the column electrode (18) that forms part of the display element. 2) The ionizable gas functions as a sampling switch.

FIG. 6 is an equivalent circuit for explaining the operation of the display device (10). In FIG. 6, each of the display elements (16) of the display panel (12) can be regarded as a capacitor (80) (hereinafter, referred to as a capacitor model (80)). The top plate (82) of this is one of the column electrodes (18).
Represents one. Also, its bottom plate (86) represents the free surface (88) of the dielectric material layer (46) (FIG. 2). The capacitor model (80) represents a capacitive liquid crystal cell formed by the overlap of the column electrode (18) and the groove (20). Description of the operation method of the display device (10)
This is performed using the capacitor model (80).

Following the basic addressing procedure, the data driver (24) captures the first line of data. The captured data represents individual values sampled at predetermined time intervals of the voltage of the analog data signal that changes over time. The sampling of the intensity of the data signal at a particular event during this time interval is performed by a capacitor model (8) at the corresponding column position of the row electrode (62) receiving the strobe pulse.
0) represents the intensity of the analog voltage applied to the signal. The data driver (24) generates an analog voltage at its output amplifier (22) and applies it to the column electrode (18). In FIG. 6, four representative output amplifiers (22) of a data driver (24) apply a positive analog voltage to a reference electrode (30) to a column electrode (18) connected thereto. Apply to each. By applying a positive voltage to the column electrode (18),
At the free surface (88) of the dielectric material layer (46) (FIG. 2), a voltage substantially equal to the applied voltage is generated. For this reason,
There is no change in the potential difference across the capacitor model (80), and in FIG. 6 the top plate (82) and the bottom plate (86) are drawn with white surfaces.

In this case, the gas in the groove (20) is not ionized, and the plate (82) of the capacitor model (80) is not ionized.
And (86) are positive with respect to the potential of the reference electrode (30) in the groove. When the data strobe circuit (28) generates a negative voltage pulse on the row electrode (62) in the groove (20), the gas in the groove (20) becomes ionic. The groove (20) whose row electrode is receiving the strobe pulse is indicated by the thick line in FIG. Under such conditions, the grounded reference electrode (30) and the strobed row electrode (62) function as the anode and cathode, respectively, for the plasma in the trench.

The electrons in the plasma neutralize the positive charge induced on the bottom plate (86) of the capacitor model (80). The capacitor model (80) of the strobed row is charged by the data voltage on it. This state is shown in FIG. 6 in which the top plate (82) has a white surface and the bottom plate (86) has a line. When the storage of the data voltage on the capacitor model (80) is completed, the data strobe circuit (28) sets the row electrode (6) in the groove (20).
2) End the negative voltage pulse. This terminates the strobe pulse and also extinguishes the plasma.

Each of the row electrodes (62) is strobed in a similar manner until the entire addressing of the display surface (14) is completed and the image field of data is stored. The voltage remains stored in each of the capacitor models (80) of the strobed row, at least during the image field. And it is unaffected by subsequent changes in the data voltage applied to the top plate (82) of the capacitor model (80). The voltage stored in each of the capacitor models (80) varies according to the analog data voltage representing the display data of a subsequent image field.

In the display device (10), when the image field is non-interlaced, the analog data voltage applied to the column electrode (18) in the next image field has the opposite polarity. When transitioning from one image field to the next, the DC voltage component is net zero in the long run by reciprocating between positive and negative polarities. This is particularly required for long-term use of liquid crystal materials. The liquid crystal material produces a gray scale effect depending on the effective value of the applied analog data voltage. Thus, the created image is not affected by the extreme alternating changes in the analog data voltage. In the display device (10), when the image field is interlaced, the analog data voltage applied to the column electrodes (18) of successive image frames is such that the DC voltage component is net zero in the long term. Then, the polarity is reversed. Each image frame consists of two image fields, each image field consisting of half the number of addressable lines.

As can be seen from the above description, the ionizable gas filling each groove (20) changes the contact position between the two switching states according to the voltage applied by the data strobe circuit (28). Functions as an electrical switch (90). In FIG. 6, the switch (90) in the open position is connected to the reference electrode (30) and is driven by a strobe pulse applied to the row electrode (62). Without the strobe pulse, the gas in the groove (20) would be in a non-ionized state, and thus would be non-conductive. When the switch (90) shown in FIG. 6 is closed, the switch (90) is connected to the reference electrode (30) and is applied to the row electrode (62) and only enough to ionize the gas in the groove (20). And a conductive state. In FIG. 6, the middle one of the three output amplifiers of the data strobe circuit (28) strobes a row of capacitor models (80), to which a display data voltage is applied and stored. .

To function as a switch, the ionizable gas contained in the groove (20) below the glass electrode assembly (40) cooperates with the dielectric material layer (46) to form a dielectric material layer ( A conductive path is provided from 46) to the reference electrode (30).
The plasma in the groove (20) with the row electrode (62) subjected to the strobe pulse is a capacitor model (80) representing the portion of the liquid crystal material located next to the plasma.
Provides a ground passage to This allows the capacitor model (80) to sample the analog data voltage applied to the column electrode (18). When the plasma disappears, the conductive path disappears. Therefore, the sampled data is held in the display element. The voltage that represents the data for the new line in the subsequent image field is
Until a voltage is generated in the electro-optic material layer (44), the voltage remains stored in the electro-optic material layer (44). The addressing apparatus and techniques described above provide a signal of substantially 100% duty cycle for each of the display elements (16).

FIG. 7 is a time chart for determining the limit of the number of lines of data that can be addressed by the display device (10) during the image field period. In FIG. 7, after a row electrode (62) of a strobed groove (20) receives a strobe pulse, a representative data line n requires time (92) to generate a plasma. It is. This plasma generation time (92) is not substantially a factor limiting the number of addressable lines in the image field by initiating a strobe pulse prior to the period of the previous line n-1. . In a preferred embodiment,
The plasma generation time in helium gas is nominally 1.0 microsecond.

The data setup time (96) represents the time when the data driver (24) changes state between the data values on two adjacent data lines, and the output amplifier (22).
, An analog voltage signal is generated and applied to the column electrode (18). The data setup time (96)
It is a function of the electronics used to construct the driver (24). Setup times of less than 1.0 microsecond are achievable.

The data acquisition time (98) depends on the conductivity of the ionizable gas in the groove (20). FIG. 8 depicts the data capture time (98) as a function of the plasma current flowing between the reference electrode (30) and the row electrode (62) in the groove (20). The curve in FIG. 8 is 90% of the voltage corresponding to the data.
Represents the time required for the display element to acquire. FIG. 8 shows that the ions generated by the helium gas plasma have a shorter data acquisition time compared to the neon case. In the plasma, the electron flow flows from the cathode (row electrode (62)) to the anode (reference electrode (30)).

The preferred operating point is to achieve the shortest data acquisition time for positive ion current. In the specific case shown in FIG. 8, at such an operating point, using helium gas at a pressure of 40 mbar and applying a current of 7.5 mA, a data acquisition time of about 0.5 ms is achieved.
Helium can achieve shorter data acquisition times than neon because helium is a lighter ion and more mobile. The optimum values of the pressure and current depend on the size and shape of the groove (20).

The plasma extinction time (94) represents the time required for the plasma in the groove (20) to return to a non-ionized state after removal of the strobe pulse from the row electrode (62). FIG. 9 shows the plasma extinction time with no more than 3% interference as a function of the anode / cathode current in the display panel (12). Figure 9 shows the plasma extinction time (94)
Shows that it increases as a function of the current flowing in the plasma from the row electrode (62) to the reference electrode (30).
The intensity of the strobe pulse applied to the row electrode (62) determines the amount of current flowing in the plasma. Fig. 9
The reduction in plasma extinction time (94) is shown to be achieved by applying a continuous bias voltage of about + 100V. FIG. 9 further shows that when a bias voltage of +100 V is applied, the plasma disappearance time (94) is reduced to about one tenth as compared with the case where the bias voltage is zero.

The time required to address a data line is equal to the sum of the data setup time (96), data acquisition time (98), and plasma extinction time (94).
The number of lines addressable during an image field is equal to the image field time divided by the time required to address the data line. Display device (10) for non-interlaced and 60Hz frame rate
Can be over 9000 with the simple addressing technique described above. Note that the number of addressable data lines is not the same as the resolution of the display (10). The resolution is the width of the groove (20),
And the width of the column electrode (18).

The use of priming techniques has the advantage of ensuring the ability to address a relatively large number of lines in an image frame. Priming involves introducing ions to initiate a gas discharge. Priming of the display device (10) is achieved by passing a current through a priming groove (not shown). The priming grooves are arranged at right angles to the grooves (20), each of which ends at the edge of the display panel (12). Priming allows the plasma to be generated without an initial statistical delay which would otherwise lead to unpredictable plasma generation times.

10A and 10B show an alternative circuit of the data driver (24), and the corresponding components among them are indicated by subscripts a and b, respectively.

In FIG. 10A, a data driver (24a) samples a data signal, and samples it in a buffer memory (100).
To accumulate. The data signal is in analog or digital form. The buffer memory (100) is a charge-coupled device (CCD) or a sample-and-hold type, which stores analog data signals. The buffer memory (100) may be in a digital format for storing digital data signals. The element (22) becomes a buffer amplifier or a digital / analog converter depending on whether the buffer memory (100) holds an analog voltage or digital data. The element (22)
The parallel transmission of the analog voltage is performed to the column electrodes. The data driver (24a) can operate at high speed. This is because the CCD and the sample / hold circuit can take in data at high speed, and the analog voltage is simultaneously transmitted to the column electrode (18a) in parallel.

In FIG. 10B, the data driver (24b) samples the analog data signal serially as each of a set of switches (104) is sequentially closed and opened. The switch (104) is connected to the capacitor (106). The capacitor (106) stores charge from the data signal when the switch is closed. As a result, an analog voltage sample of the data signal is supplied from one end to the other end of one column electrode (18b). The sampling clock signal applied to the control electrode of the switch (104) sets the sampling rate. Data setup of the circuit in Figure 10B
Time (96) is greater than the data setup time (96) of the circuit in FIG. 10A by a multiplier equal to the number of column electrodes (18b).

For proper operation within the display (10), the horizontal blanking time from line to line is reduced by the data acquisition time (98).
It is necessary for the data driver (24b) to exceed the sum of the time and the plasma extinction time (94).

Figures 11A and 11B show the respective reference electrodes (30)
Compare the number of data strobe outputs required for a typical display panel (12) having a fixed reference voltage and nine grooves receiving strobe signal pulses. The display panel of FIG. 11A has a grounded reference electrode (30), nine different strobe output amplifiers (26), and a data strobe circuit (28) driving different row electrodes (62). ing. The display panel shown in FIG. 11B has three sets of reference electrodes (30) and another three sets of row electrodes (62). The groove (20) with the reference electrode forming any one of the set of reference electrodes (FIG. 4) includes any one electrode (62) of the row electrode set. The display (10) strobes only one of the sets of reference electrodes (30) during a predetermined time interval. During the strobe time interval, the display (10) drives the column electrodes (18) and sets the row electrodes (62) contained in the grooves (20) with the reference electrodes (30) receiving strobe pulses. To address the display element (16).
The row electrode (62) of the groove (20) whose reference electrode (30) has not received a strobe pulse is thus not activated.

Output amplifier (26) of data strobe circuit (28)
Is electrically connected to the reference electrode (30) and the row electrode (62) in the groove (20), so that the number of output amplifiers (26) of the data strobe circuit (28) of the address device can be reduced. In the exemplary display panel (12) of FIG. 11B, the number of data strobe output amplifiers (26) is reduced from nine to six.

FIG. 12 is a graph showing the minimum number of drivers required with respect to the number of addressable data lines that can be mounted in an addressing device of the type implemented in the display panel (12) of FIG. 11B. . FIG. 12 shows that a substantial reduction in drivers is achieved in a display having a relatively large number of data lines.

The addressing device of the present invention facilitates reducing the number of drivers by using other techniques similar to those implemented in the Self-Scan ™ display developed by Burroughs. Such a display device employs a display cell that can be seen by an observer and a scan cell that cannot be seen by an observer. The scan cell controls the state of the display element by sending activated priming particles to a cell of ionizable gas. In the grooves of the scan cells, the plasma discharge sequentially moves to the next display cell and generates priming particles that activate the adjacent display cell.

In the display panel (12), the electrical division of the orthogonal priming grooves could provide an ion source that moves sequentially from one groove to the next. With respect to the techniques described above, wall charge coupling or other known techniques could be employed to further reduce the number of drivers.

The address technique of applying data voltages of positive and negative polarities in an alternating image filament is easier to use in a display device employing the driver reduction technique described in connection with FIGS. 11B and 12 (in the embodiment in FIG. 10). The addressing speed can be further increased by an alternative addressing technique that applies a data voltage of only positive polarity, such as introducing an erase field at the end of each image field.

In this type of addressing technique, when scanning the erase field, the data strobe circuit (28) applies a relatively short period of positive and negative pulses to the row electrode (62) of the groove (20) continuously. The data driver (24) applies a substantially ground potential voltage to the column electrode (18). During the application of the positive pulse, the reference electrode (30) and the row electrode (62) act as the cathode and anode of the plasma, respectively. Since the previously required data voltage was of positive polarity, the charge stored on the storage element (16) creates a negative charge on the surface (88) of the dielectric material layer (46). Therefore, it functions as a cathode. The cathode is surrounded by a relatively high concentration of ions, which rapidly neutralizes the negative charge on the dielectric material layer (46). Since the potential of the dielectric material layer (46) approaches that of the anode, residual positive charges can accumulate and reach significant levels. During the application of the negative pulse, the ground potential applied to the column electrode (18) forces the residual positive charge to ground in a manner similar to that applied during image field writing.

If a positive pulse is not used, the speed at the address is limited by the positive ion charging phenomenon described above. However, this alternative addressing technique is
This is not the same as the driver reduction technique described with reference to FIGS. 11B and 12.

In another addressing technique of this type, a data strobe circuit (28) applies a negative pulse to two or more (eg, 10) row electrodes (62) to simultaneously erase a row of data. Would. This technique causes a small duty cycle non-uniformity across the display surface (14) of the display panel (12).

The flat panel display (10) may be modified to form a versatile analog data memory device (110) including an array of memory elements. this is,
An address device is embodied as a second embodiment of the present invention. Such polarized light is applied to the polarizing filters (34) and (3
6) and removing the liquid crystal material layer (44) of FIGS. 2, 4 and 5 if present.

Next, a memory device that can be realized by using the principle of the display device of the present invention will be described. FIG. 13 shows an equivalent circuit of the memory device (110). Except as noted above, the devices shown in FIGS. 6 and 13 are similar. Therefore, corresponding components in FIGS. 6 and 13 have the same reference numerals. In the memory device (110), the dielectric (46) functions as a dielectric element of the capacitor model (80), which represents a memory element. The column electrode (18) does not need to be made of an optically transparent material, but may be made of aluminum or another conductive material. Data Driven Output Amplifier of Memory Device (110) (2
2) functions as a column electrode drive amplifier in a data write mode, and functions as a column electrode detection amplifier in a data read mode. The data strobe output amplifiers of the devices of FIGS. 6 and 13 are similar.

In FIG. 13, each output amplifier (22) of the data drive circuit (24) includes a high-speed operational amplifier (112). The parallel circuit of the feedback capacitor (118) and the switch element (120) is connected to the inverting input terminal (114) and the output terminal (11) of the amplifier (112).
6) is connected between. The amplifier (112) selectively switches the switch element (12) in the data write mode.
0) to form a voltage follower by driving and conducting, and in a data reading mode, drive the switch element (120) to form a non-conducting state to form an integrator. The non-inverting input terminal (122) of the operational amplifier (122) is connected to the movable contact (124) of the switch element (126). The switch element selectively connects the non-inverting input terminal (122) to the reference voltage Vr or the output signal conductor of the data drive circuit (24).

Output amplifier (22) whenever in write mode
Supplies a data drive signal to a column electrode (18) forming a memory element of the memory device (110). This means that the operational amplifier (112) is configured as a voltage follower, and the movable contact (124) of the switch element (126) for supplying the data drive signal is moved from the data drive circuit (24) to the operational amplifier (1).
12) to the non-inverting input terminal (122). During this period, the row strobe pulse applied to the row electrode (62) in the groove (20) constituting the memory element (110) excites the ionizable gas in the groove to an ionized state.
This causes a data voltage to be generated in the capacitor model (80) by the method described with reference to FIG. The magnitude of the voltage on the capacitor model (80) represents the data drive signal.

In the data read mode, the data amplifier (22)
Detects a current in a column electrode (18) constituting a memory element of the memory device (110). This is achieved through a two-step procedure.

First, the movable contact (124) of the switch element (126) is connected to the non-inverting input terminal (122) of the operational amplifier (112) by the reference voltage Vr.
Is arranged to enter. During this time, the row strobe pulse is inactive to maintain the non-ionized state of the ionizable gas. Therefore, the reference voltage Vr is applied to the output terminal (116) of the operational amplifier (112).
And column electrodes (18) and the top plate (82) of the capacitor model (80). The feedback capacitor (118)
Therefore, it is neutralized to 0.0 volt. However, the memory device (110) can be configured to operate with an offset voltage between the input and output of each operational amplifier (112).

Second, after the voltage across the feedback capacitor (118) is at 0.0 volts, the operational amplifier (112) is ready to have its input (114) receive current from the column electrode (18). Configured as an integrator. The potential difference between the bottom plate (86) of the capacitor model (80) and the reference electrode (30) is a function of Vr and the data voltage across the capacitor model (80) described above. When the row strobe pulse again ionizes the ionizable gas, the bottom plate (86) of the capacitor model (80) is electrically connected to the reference electrode (30). Therefore, the voltage applied to the capacitor model (80) changes. The operational amplifier (112) configured as an integrator detects this voltage change and supplies a voltage proportional to the above-mentioned data voltage applied to the capacitor model (80) to the output terminal (116).

Generate a data voltage on the capacitor model (80)
There are other ways to promote the function as a memory element. For example, by using an optically transparent column electrode (18), replacing the dielectric material layer (46) with a photoconductive material and exposing the memory device (110) to visible light, the light incident on the memory device (110) is reduced. The voltage applied to the capacitor model (80) is modulated in proportion to the light intensity. The change in voltage across the capacitor model (80), which is proportional to the intensity of the incident light, is recovered in the data read mode, as described above. The layer of photoconductive material (46) and the optically transparent column electrode (18) thus constitute an image sensing device according to the characteristics of the analog data memory.

In the image sensing device described above, providing a plurality of layers of photoconductive material (46) as electrically isolated bands would avoid conduction between adjacent capacitor models (80). . Providing a metal strip or other conductive material along the edge of the optically transparent electrode reduces the time required to read the data voltage across the capacitor model (80), thereby reducing the time required to read the data voltage. The efficiency of data correction is improved.

The image sensing device described above utilizes the photoconductive properties of the layer of photoconductive material (46) during the data readout mode. It is also possible to directly utilize the photoconductivity of the layer of photoconductive material (46). In this case, the data element (16)
Will be more preferably characterized as a sensing element, and the capacitor model (80) will also be more preferably a current modulating element. This applies a voltage to the column electrode (18) that creates a voltage gradient in the layer (46) during the application of the row strobe pulse between the strobe electrode (62) and the reference electrode (30). This can be achieved by applying. The current flowing from the reference electrode (30) through the layer (46) and the column electrode (18) to the output terminal (116) of the operational amplifier (112) becomes an output signal. Feedback capacitor (11
Replacing 8) with a resistor makes the voltage appearing at the output (116) of the operational amplifier (112) proportional to the current flowing through the layer (46).

For those skilled in the art, it is easy to make various modifications without departing from the gist of the present invention.

〔The invention's effect〕

In the display device of the present invention, second and third electrodes substantially parallel to the longitudinal direction of the groove-shaped concave portion are formed inside each of the groove-shaped concave portions of the second substrate, and a selection is made between the second electrode and the third electrode. And a strobe signal (second signal). As a result, at a relatively low voltage, an electric field having a uniform gradient is formed in the direction across the groove-shaped concave portion, and uniform gas ionization occurs, and a uniform and good switching operation by the ionizable gas in each cell is obtained. After ionizing the gas, a data signal (first signal) for display by the liquid crystal material layer is supplied between the first electrode and the third electrode used for the strobe signal. Therefore, since the third electrode is also used to supply both the data signal and the strobe signal, the structure of the device can be simplified.

[Brief description of the drawings]

FIG. 1 is a conceptual view showing the concept of the present invention, FIG. 2 is a perspective view partially showing a cross section of a display panel according to the present invention, and FIG. 3 is a view showing the display panel shown in FIG. FIG. 4 is a partially cut away plan view, and FIG.
5, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, FIG. 6 is a circuit diagram showing an equivalent circuit of the display device of the present invention, and FIG. 7 is a display diagram of the present invention. FIG. 8 shows a time chart for determining the maximum number of data lines that can be addressed by the device. FIG. 8 shows the current flowing between the electrodes provided in the groove of the display panel shown in FIGS. FIG. 9 is a diagram comparing the relationship between the data acquisition time of neon gas and helium gas as a function, FIG. 9 is a diagram showing the relationship between the current flowing through the cathode and anode and the plasma disappearance time in helium gas, and FIG. 10B is a diagram showing an alternative circuit of the data driver shown in FIG. 1, FIGS. 11A and 11B are diagrams showing an alternative circuit of the data strobe shown in FIG. 1, and FIG. Number of drivers and number of addressable data lines in Figure 11 FIG. 13 is a diagram showing an equivalent circuit of a memory device utilizing the principle of the display device of the present invention. In these, (18) is a first electrode, (20) is a groove-shaped recess, (22) and (24) are first signal applying means, (26) and (2)
8) is a second signal applying means, (30) is a third electrode, (44) is an electro-optic material layer, (46) is a dielectric material layer, and (48) is a first.
A substrate, (54) is a second substrate, and (62) is a second electrode.

Continued on the front page (72) Inventor Thomas S. Buzak 97007 Oregon United States Beaverton Southwest One Hand Red and Fifth Second 7344 (72) Inventor Paul Sea Martin United States of America Oregon 97225 Portland Southwest Sirlow Drive 9950 (72) Inventor H. Wayne Olmsted United States 97006 Oregon Beaverton Northwest Marco La Court 16995 (72) Inventor John Jay Horn United States Oregon 97123 Hillsboro BW Southwest Tow Hundred and Thirty Eights A Venue 765 (56) References JP-A-59-155880 (JP, A) JP-A-49-84780 (JP, A) JP-A-55-150524 (JP, A) US Patent 2,476,615 (US, A)

Claims (1)

(57) [Claims] A first substrate having a plurality of first electrodes formed substantially parallel to each other on one main surface, and intersecting the first electrode on a main surface of the first substrate facing the main surface. A second substrate formed substantially parallel to each other and having a plurality of groove-shaped recesses filled with an ionizable gas; and inside the plurality of groove-shaped recesses on the main surface of the second substrate. A second groove formed substantially parallel to the longitudinal direction of the groove-shaped concave portion;
And a third electrode; a liquid crystal material layer interposed between the first substrate and the second substrate to form a display element at an intersection of the first electrode and the groove-shaped recess; First signal applying means for selectively applying a first signal between the third electrodes; and second signal applying means for selectively applying a second signal between the second electrode and the third electrode. The second signal applying means selectively supplies the second signal between the second electrode and the third electrode, and receives the second signal and the third electrode. Ionizing the gas in the groove-shaped recess having an electrode, wherein the first signal applying means is configured to detect the first electrode and the third electrode of the display element corresponding to the groove-shaped recess containing the ionized gas; In the meantime, the first signal is selectively supplied to change the optical state of the liquid crystal material layer. By the display device and performing display by the display device.