JPH09134151A - Memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-yield, inexpensive device by using ionized gas to write and read data to and out of a data storage element of the memory device. SOLUTION: Plural 1st electrodes 18 are formed almost in parallel to the main surface of a 1st substrate 48, and on a 2nd substrate 54, plural grooved recessed parts 20 which cross the 1st electrodes and are almost in parallel to each other and filled with ionizable gas are formed. Then 2nd and 3rd electrodes 62 and 30 are formed in the grooved recessed parts almost in parallel to the length. A dielectric layer 46 is interposed between the 1st and 2nd substrates and data storage elements are formed at the intersections of the 1st electrodes and grooved recessed parts. Signal applying and reading means 22 and 24 apply a 1st signal selectively between the 1st and 3rd electrodes or receive a read signal. A signal applying means 26 applies a 2nd signal selectively between the 2nd and 3rd electrodes and supplies the 2nd signal selectively to ionize the gas in the grooved recessed parts having the 2nd and 3rd electrodes having received the 2nd signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory device with a data element using an ionizable gas.

[0002]

2. Description of the Related Art Systems using a data storage device, that is, a memory device include, for example, a video camera and an image display device for storing image data. Such systems have an addressing device for writing data to and reading data from the storage element. One of the devices utilizing the memory device of the present invention is a general purpose flat panel display device, the storage element or display element of which 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, which are applications of such memory devices, are desirable because they do not require a cathode ray tube to form a displayed image.
This is because the cathode ray tube has a large shape, is easily broken, and requires a high voltage drive circuit.

Since the memory device of the present invention also relates to a display device and an address device, the display device and the address device will be further described. 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 these conductors selectively apply a selection voltage signal and a non-selection voltage signal to 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" electrical elements do not cooperate to change the electro-optical properties of the liquid crystal cell. In such a display device, the number of address lines for providing video information, that is, data used to form a display image is limited (for example, about 250 lines).
There is a disadvantage that.

As a measure for increasing the number of data address lines of a liquid crystal display device, a separate electric element cooperating with each liquid crystal cell causes an electro-optical response of the liquid crystal cell to a selection voltage signal and a non-selection voltage signal. Is to use an addressing device that corrects the substantial non-linearity of. This also relates to addressing the memory device of the present invention. Some of the "two-terminal" device addressing techniques are characterized by this method. Increasing the substantial non-linearity of the display element increases the multiplexing capability in the binary display, but there are many obstacles to achieving gray scale with this technique.

To obtain a liquid crystal matrix display device with sufficient gray scale performance, an addressing device that does not rely on obtaining a non-linear function from a liquid crystal material is required. 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 is
The required non-linearity and insulation of the display element are obtained by using a solid-state element with 2 or 3 terminals associated with each liquid crystal cell. Addressing devices configured with two-terminal elements can use various types of diodes, and addressing devices configured with three-terminal elements can be used with various types of thin film transistors (TF) made from different semiconductor materials.
T) can be used.

[0006]

One of the problems with two-terminal or three-terminal active devices is that when the number of active devices is very large, it becomes very difficult to manufacture a large amount of matrix with a high yield. is there. Another problem, especially regarding the TFT element, is that it is difficult to manufacture a thin film transistor having a sufficiently high “off resistance”. When the “off resistance” is relatively low, the display element cannot hold the electric charge generated therein for a predetermined time. Further, at this time, the ratio between the “off resistance” and the “on resistance” decreases. This ratio is preferably above 10 for proper operation of the TFT matrix. TF
The T-matrix sometimes employs a separate storage capacitor (capacitance) with each display element to eliminate the effect of not having a sufficiently high "off resistance". However, the use of a separate storage capacitor allows the TF to cooperate with it.
It seems that the T-matrix becomes more complicated and the yield decreases. Another possible problem with a TFT active matrix is the need for TF due to the need to come from "on" currents.
Since the size of the T element tends to be large, the size of the TFT becomes relatively large as compared with the size of the display element. This affects the light efficiency of the device.

[0007] The active element made by the TFT element is
It is capable of producing black and white and color images. To form a color image, the active matrix uses a color filter that is spatially aligned with the display element and contains many groups of different color spots. Therefore, groups of display elements that are aligned to match different color spots therefore form a single image pixel.

The flat panel display device can also be implemented by using a display element using an ionized gas or plasma, and a light emitting region of a color determined by what kind of gas is used is formed on the 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 accelerates these electrons to collide with a phosphor to generate bright spots. Although such a flat 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 displays can be constructed with phosphors that are excited by electrons with different spectral characteristics to form a multicolor image.

Gas plasma flat panel displays have been purposely mitigated by using a plasma discharge type of plasma-sac. 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 memory device that uses an ionized gas to write or read data to or from a data storage element (storage element). Another object of the present invention is to provide a memory device that can be manufactured at low cost and with high yield. Yet another object of the present invention is to provide a memory device in which a dielectric layer cooperates with an ionized gas to form an addressable data storage device.

[0012]

A memory device according to the present invention comprises:
A first substrate having a plurality of first electrodes formed on one main surface substantially parallel to each other; formed on the main surface facing the main surface of the first substrate so as to intersect the first electrodes and substantially parallel to each other Is
A second substrate having a plurality of groove-shaped recesses in which an ionizable gas is enclosed; inside the plurality of groove-shaped recesses on the main surface of the second substrate, substantially parallel to the longitudinal direction of the groove-shaped recesses; A second and a third electrode formed on the first substrate; a dielectric layer interposed between the first substrate and the second substrate to form a data storage element at the intersection of the first electrode and the groove-shaped recess; Signal applying / reading means for selectively applying a first signal between the electrode and the third electrode or selectively receiving a read signal between the first electrode and the third electrode; and a second electrode and a third electrode Signal applying means for selectively applying the second signal between the electrodes. The signal applying means selectively supplies the second signal between the second electrode and the third electrode to ionize the gas in the groove-shaped concave portion having the second electrode and the third electrode receiving the second signal. . The signal applying / reading means selectively supplies the first signal between the first electrode and the third electrode of the storage element corresponding to the groove-shaped recess containing the ionized gas to change the charge state of the dielectric layer. The storage element stores the data corresponding to the first signal, and the read signal is selectively obtained from between the first electrode and the third electrode of the storage element corresponding to the groove-shaped recess containing the ionized gas. Then, the data stored in the storage element is read.

The first embodiment of the memory device of the present invention is applied to a high-resolution flat panel display device used for both direct-view type and projection type. This display device
It includes a display panel constituted by display elements which are data storage elements (storage 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.

The second embodiment of the present invention is a memory device itself, in which analog information is electrically written or read. The memory device includes an array of data storage elements or memory elements (storage elements), each of which includes an ionizable gas such as helium, a dielectric material such as glass or plastic, and It contains a photoconductor. The ionizable gas and the dielectric material cooperate to provide a method of addressing the memory element in order to read a signal that was previously written to the memory element in some way.

In both embodiments, the storage elements are arranged in rows and columns. In the first embodiment, the rows represent one row of video information or data, and in the second embodiment the rows represent two sets of discrete amounts of analog information or data. (The information addressed in each embodiment is referred to as "data" below.
I will call it. ) The column electrodes receive the data and the data strobe circuit addresses the column electrodes row by row by row scanning.

The memory device applied to the display panel according to the first embodiment or the memory device according to the second embodiment itself has a first substrate and a second substrate which face each other at intervals. It is equipped with 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. A large number of grooves (groove-shaped recesses) carved on the inner side of the second substrate and not overlapping with each other extend 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
They are electrically isolated from each other and extend longitudinally inside each groove to receive a data strobe signal applied thereto. Each groove is filled with an ionizable gas.

In the application example to the display panel in the first embodiment, the layer of the material having electro-optical properties and the dielectric material layer are arranged between the inner surfaces of the first and second substrates. Thus, the layer of dielectric material covering the trench forms a barrier layer between the layer of electro-optical 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 constructed as described above, and the ionizable gas for each display element is in a plasma state with conduction or in a non-conduction state according to the applied data strobe signal. It functions as a switch that electrically switches between the non-existent 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 enables a data voltage, which is representative of 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 device is non-conducting, the region of non-ionized gas allows the spatially aligned region of the liquid crystal material to hold the voltage across it for a predetermined period of time. The ionizable gas therefore serves to select the data stored in the liquid crystal material, thus providing a gray scale luminance display. Since the liquid crystal material is a dielectric, it acts as a storage element.

By switching the ionizable gas in the display panel between a conducting state and a non-conducting state, light passing through the display element can be modulated. The transmitted light is
It depends on the strength 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 with controllable color intensity can be achieved by placing a color filter in the black-and-white display that includes groups of three primary color spots spatially aligned with the display element. ． The group of three display elements that are aligned to form a group of spots results in one image pixel of a color that is determined in relation to the intensity of the spots within this group.

A display device to which the memory device of the present invention is applied can provide a fully dynamic, grayscale image over a wide range of field rates and provide a high quality display. This display device is particularly advantageous because of its simple and uneven structure,
At least 3000 data lines can be addressed at a 60 Hz field rate on the display screen.

In the memory device of the present invention, only one dielectric material layer is provided between the first and second substrates. The shape of the memory element is determined by the region where the column electrode and the groove overlap. Because the memory device is shaped as described above, for each memory element, the ionizable gas is an electrical switch that switches between a conducting state and a non-conducting state in response to an applied data strobe signal. Function as a simple switch. The amplifier supplying the data driving signal functions as an amplifier for driving the column electrode in the data writing mode and as an amplifier for detecting the column electrode in the data reading mode.

Whenever the device is conducting, the region of ionizable gas allows a data voltage with a predetermined intensity to be applied. This voltage represents the intensity of the data drive signal produced in the dielectric material in the region spatially aligned with the region of ionized gas.
This represents the data write mode of the memory device. Whenever the element is non-conducting, the region of non-ionized gas allows the spatially aligned region of the dielectric material to hold the voltage across it for a predetermined period of time. ． The column electrode sense amplifier, which is the sensing means associated with this region, applies a reference voltage to the surface of the dielectric material layer opposite the surface spatially aligned with the region of ionized gas. When it returns to the conductive state,
The region of ionized gas changes the voltage across this dielectric material. This change is proportional to the pre-written data voltage and appears at the output of the column electrode sense amplifier. This represents the data read mode of the memory device.

Other means for applying a data voltage to the memory elements of the memory device can be employed by making some modifications to the addressing device for the memory device described above. For example, when a photoconductive material is used instead of a dielectric material and a light-transmissive column electrode is used, incident light can modulate the intensity of a data voltage applied to a memory element in proportion to its intensity. Will be able to. Such an address device can be used as an image sensor or as a part of an optical processing device.

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

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a case where the memory device of the present invention is applied to a display device having a memory function will be described. FIG. 1 is a diagram showing a schematic configuration of a general flat panel display device 10, showing an addressing device and an addressing method. 1 and FIG. 2 showing the details of the panel, the flat panel display bag holder 10 comprises a display panel 12 having a display surface 14. The display surface 14 includes a pattern formed by a rectangular plane array of individual data storage elements, that is, display elements 16 which are storage elements, which are separated from each other by a predetermined distance in the vertical direction and the horizontal direction. I'm out. Each display element 1 of this arrangement
6 is a thin and narrow electrode 1 arranged along a vertical row.
8 and the elongated grooves 20 arranged in the horizontal direction overlap each other. The groove 20 is a groove-shaped recess, as can be seen from the drawing. (Hereinafter, the electrodes 18 will be referred to as column electrodes 18.) The display element 1 in each groove 20 corresponding to a row.
6 represents one line of data.

The width of the column electrode 18 and the width of the groove 20 determine the dimensions of the display element 16, which is substantially rectangular. Column electrode 18
Are arranged on the main surface of the non-conductive and optically transparent first substrate, and the grooves 20 are carved 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 a system such as a direct view or projection reflective display bag holder, either substrate may be optically transparent.

The column electrodes 18 receive an analog voltage data drive signal generated on parallel output conductors 22 'by each one of the output amplifiers 22 (see FIGS. 2-6) of the data driver 24. The data driver 24 and the output amplifier 22 form a signal applying unit. The groove 20 is
Parallel output conductors 2 by each one of output amplifiers 26 (see FIGS. 2-6) of data strobe circuit 28.
It receives a data strobe signal of a pulse voltage generated on 6 '. Data strobe circuit 28 and output amplifier 2
6 and 6 constitute a 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.

In order to form an image on the entire display surface 14, the display bag holder 10 includes a scanning control circuit 32. This coordinates the functions of the data drive circuit 24 and the data strobe circuit 28 to sequentially address all columns of the display elements 16 of the display panel 12 from row to row. Different types of electro-optical materials may be used for the display panel 12. For example, the incident light 33
If a material that changes the polarization state of is used, the display panel 12 is placed between the polarization filters 34 and 36 (see FIG. 2). The filters 34 and 36 correspond to the display panel 1
Cooperate with 2 to change the brightness of light passing through them.
If a liquid crystal cell that scatters light is used as the electro-optical material, the polarizing filters 34 and 36 are not required. Although not shown, a color filter may be arranged in the display panel 12 to form a multicolor image with controllable color intensity.
For projection display, the colors may be formed by using three separate monochromatic panels. In this case, each panel will control one primary color.

2 to 5, the display panel 12 is shown.
Comprises an addressing means, which comprises an electro-optical material layer (dielectric layer) 44 such as nematic liquid crystal and a thin dielectric material layer 46 such as glass, mica or plastic.
It includes a pair of generally parallel electrode assemblies 40, 42 separated by. The electrode structure 40 comprises a dielectric substrate 48 made of glass, on which the column electrodes 18 made of an oxide of indium and tin are provided by vapor deposition on the inner side surface 50. It is optically transparent and forms a strip pattern. Adjacent column electrode 18
Are spaced apart by spacing 52 and define the horizontal spacing between adjacent display elements 16 on a row.

The electrode structure 42 is a dielectric substrate 5 made of glass.
4, the inner surface 56 of which is provided with a plurality of grooves 20 having a trapezoidal cross section. The depth 58 of the groove 20 is measured from the inner side surface 56 to the bottom portion 60. Groove 2
0 for each of the pair of thin and narrow nickel electrodes 30 and 62 extending along the bottom 60 and the bottom 60 to the inner surface 5.
There is a pair of side walls 64 that flare toward 6.
The reference electrode 30 of the groove 20 is connected to a common reference voltage. This is fixed to the ground potential as shown. The electrode 62 of the groove 20 is connected to the data strobe circuit 28.
Output amplifiers 26 (three and five of which are shown in FIG.
And FIG. 3 respectively. ) Are connected to different ones. (The electrode 62 is hereinafter referred to as a row electrode 62.) The reference electrode 30 and the row electrode 62 are arranged on the display panel 12 as shown in FIGS. 4, 11A and 11B so that the addressing device operates reliably. On opposite sides, it is connected to the reference potential and the output 26 'of the data strobe circuit 28, respectively.

The adjacent side walls 64 of the adjacent grooves 20 have the top surface 5
6 is a supporting structure 66 supporting the dielectric material layer 46. Adjacent grooves 20 are spaced from each other by a width 68 at the top of each support structure 66. This width 68 determines the vertical distance between adjacent storage elements 16 in a column. The portion 70 where the column electrode 18 and the groove 20 overlap each other serves as the storage element 16, that is, the storage element, as shown in FIGS. 2 and 3. FIG. 3 shows the arrangement of the storage elements 16 and their horizontal and vertical distances more clearly.

The gap 52 for insulating adjacent column electrodes 18 is determined according to the magnitude of the voltage applied to the column electrodes 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 walls 64 of the adjacent grooves 20. The width 68 is typically much smaller than the width of the groove 20. The width of the column electrodes 18 and the width of the grooves 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 groove width.

Each of the grooves 20 is filled with an ionizable gas, which preferably includes helium gas as will be explained later. Dielectric material layer 46
Acts as an insulating barrier between the ionizable gas contained in the groove 20 and the layer 44 of liquid crystal material. In the absence of the dielectric material layer 46, liquid crystal material may flow into the groove 20, or ionizable gas may contaminate the liquid crystal material. Dielectric material layer 46 may not be needed in displays employing solid materials or encapsulated electro-optic materials. The principle of operation of the display panel 12 is as follows: (1) Each display element 16 functions as a sampling capacitor for an analog data voltage applied to a column electrode 18 forming a 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 plate 82 on top of it represents one of the column electrodes 18. The bottom plate 86 of this also represents the free surface 88 (FIG. 2) of the dielectric material layer 46. Capacitor model 80 represents a capacitive liquid crystal cell formed by the overlap of column electrodes 18 and trench 20. The operation method of the display device 10 will be described using the capacitor model 80.

Following the basic addressing procedure, data
The driver 24 captures the first line of data. The captured data represents individual values of the time-varying voltage of the analog data signal sampled at predetermined time intervals. The sampling of the intensity of the data signal at a particular event within this time interval is performed by the capacitor model 8 at the corresponding column position of the row electrode 62 receiving the strobe pulse.
It represents the strength of the analog voltage applied to zero. The data driver 24 produces an analog voltage on its output amplifier 22 and applies it to the column electrode 18. In FIG. 6, four representative output amplifiers 22 of data driver 24 are shown.
Is a positive analog voltage with respect to the reference electrode 30,
The voltage is applied to each of the connected column electrodes 18. Column electrode 1
Applying a positive voltage to 8 produces a voltage on the free surface 88 of the dielectric material layer 46 (FIG. 2) that is substantially equal to the applied voltage. Therefore, there is no change in the potential difference applied to the capacitor model 80, and in FIG.
2 and the bottom plate 86 are drawn on a white surface.

In this case, the gas in the groove 20 is not ionized, and the voltage generated between the plates 82 and 86 of the capacitor model 80 is equal to the potential of the reference electrode 30 in the groove. On the contrary, it is positive. When the data strobe circuit 28 produces a negative going 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,
It is indicated by a thick line in FIG. Under these conditions, the grounded reference electrode 30 and the strobed row electrode 62 act as the anode and cathode, respectively, for the plasma in the groove.

The electrons in the plasma neutralize the positive charge induced in the bottom plate 86 of the capacitor model 80.
Capacitor of the strobed row. Model 80 is
It is charged by the data voltage applied to it. In this state, in FIG. 6, the nub plate 82 is a white surface and the bottom plate 86 is indicated by a line. When the storage of the data voltage on the capacitor model 80 is completed, the data strobe circuit 28 causes the row electrode 6 of the groove 20 to be stored.
End the negative going voltage pulse of 2. 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 complete and the image field of data is stored. The voltage remains stored in each of the capacitor models 80 of the strobed row for at least the image field period. 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 the subsequent image field.

In the display device 10, when the image field is the non-interlaced type, the analog data voltage applied to the column electrode 18 in the next image field has the opposite polarity. As the image transitions from one image field to the next, it reciprocates between positive and negative polarities, resulting in a net zero DC voltage component in the long run. 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. For this reason,
The image produced is unaffected by the alternating polarity of the analog data voltage. In the display device 10, when the image field is the interlace type, the polarity of the analog data voltage applied to the column electrodes 18 of consecutive image frames is such that the DC voltage component becomes zero in the long term. It will be the opposite. Each image frame consists of two image fields, each image field consisting of half the number of addressable lines.

As will be apparent from the above description, the ionizable gas filling each groove 20 is responsive to the voltage applied by the data strobe circuit 28 between the two switching states. Functions as an electric switch 90 that changes. In FIG. 6, the switch 90 in the open position is connected to the reference electrode 30 and is driven by the 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 would therefore be non-conducting. When the switch 90 shown in FIG. 6 is closed, the switch 90 is connected to the reference electrode 30, is applied to the row electrode 62, and is driven by a strobe pulse that is strong enough to ionize the gas in the groove 20. Then, it becomes conductive. In FIG. 6, the data strobe circuit 28
The central one of the three output amplifiers strobes a row of capacitor models 80 to which the 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 and from the dielectric material layer 46 to the reference electrode. It provides a conductive path to 30. The plasma in the groove 20 having the row electrode 62 that is subjected to the strobe pulse provides a ground path to the capacitor model 80, which represents the portion of the liquid crystal material located adjacent to the plasma. As a result, the analog data voltage applied to the column electrode 18 is transferred to the capacitor model 8
0 can be sampled. When the plasma disappears, the conductive path disappears. Therefore, the sampled data is held in the display element. The voltage remains stored in the electro-optic material layer 44 until a voltage is generated in the electro-optic material layer 44 that represents a new line of data for the subsequent image field. The addressing device and its techniques described above provide a substantially 100% duty cycle signal for each of the display elements 16.

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

Data set-up time 96 represents the time that data driver 24 changes state between the data values on two adjacent data lines, causing output amplifier 22 to generate an analog voltage signal. It is applied to the column electrode 18. Data setup time 96 is
It is a function of the electronic circuitry used to configure 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 acquisition time 98 as a function of the plasma current flowing in the groove 20 between the reference electrode 30 and the row electrode 62. The curve in FIG. 8 represents the time required for the display element to acquire 90% of the voltage corresponding to the data. FIG.
Show that the ions generated by the plasma of helium gas have a shorter data acquisition time compared to the case of neon (Ne). The plasma electron flow flows from the cathode (row electrode 62) to the anode (reference electrode 30).

The preferred operating point is that which provides the shortest data acquisition time for positive ion currents. In the particular case shown in FIG. 8, at such operating points, helium
Using gas at a pressure of 40 mbar and applying a current of 7.5 milliamps achieves a data acquisition time of about 0.5 millisecond. Helium can achieve shorter data acquisition times than neon because helium is a lighter ion and more mobile. The optimum values of pressure and voltage depend on the size and shape of the groove 20.

Plasma extinction time 94 represents the time required for the plasma in groove 20 to return to its non-ionized state after the removal of the strobe pulse from row electrode 62. FIG. 9 shows the plasma extinction time as a function of the anode / cathode current in the display panel 12 where the interference does not exceed 3%. FIG. 9 shows that the plasma extinction time 94 increases as a function of the current flowing in the plasma from the row electrode 62 to the reference electrode 30. Row electrode 62
The intensity of the strobe pulse applied to the plasma determines the amount of current flowing in the plasma. FIG. 9 shows that the reduction in plasma extinction time 94 is achieved by applying a continuous bias voltage of approximately +10 OV. FIG. 9 further shows that when a bias voltage of +10 OV is applied, the plasma extinction time 94 becomes about one tenth of that when the bias voltage is zero.

The time required to address a data line is equal to the sum of data setup time 96, data acquisition time 98, and plasma extinction time 94. The number of addressable lines during the image field period is equal to the image field time divided by the time required to address the data line. For non-interlaced and 60Hz frame rate,
The number of data lines in display device 10 can exceed 9000 with the simple addressing technique described above. Note that the number of addressable data lines is not the same as the resolution of display device 10. The resolution is
It is a function of 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 the display device 10 is accomplished by passing an electric current through a priming groove (not shown). This priming groove is groove 20
Are arranged at right angles to each other and each of the grooves ends at the edge of the display panel 12. By priming,
If that were not the case, the plasma could be created without an initial statistical delay that would make the plasma creation time unpredictable.

FIGS. 1OA and 1OB show alternative circuits of the data driver 24. Corresponding components between these are shown with subscripts a and b, respectively. Figure 1O
At A, the data driver 24a samples the data signal and stores it in the buffer memory 100. The data signal is in analog or digital form. The buffer memory 100 includes a charge coupled device (CC
D) or sample and hold type, which stores analog data signals. Buffer memory 100
May be in digital form for storing digital data signals. Element 22 is a buffer amplifier or a digital-to-analog converter, depending on whether buffer memory 100 holds an analog voltage or digital data. Element 22 allows for parallel transmission of the analog voltage to the column electrodes. The data driver 24a can operate at high speed. Because CC
This is because D and the sample and hold circuit can take in at high speed, and the analog voltage is simultaneously transmitted in parallel to the column electrode 18a.

In FIG. 1OB, the data driver 24
b serially samples the analog data signal by sequentially closing and opening each of the switches 104 in the set. The switch 104 is connected to the capacitor 106. The capacitor 106 is
Stores charge from the data signal when the switch is closed. As a result, the analog voltage sample of the data signal is supplied from one end of the column electrode 18b to the other end thereof. A sampling clock signal applied to the control electrode of switch 104 sets the sampling rate. Data set-up of the circuit in FIG. 10B
Time 96 is a data setup time 9 of the circuit in FIG. 1OA, which is a multiplier equal to the number of column electrodes 18b.
Greater than 6.

For proper operation within display 10, it is necessary for data driver 24b that the row-to-row horizontal blanking time exceeds the sum of data capture time 98 and plasma extinction time 94. Is.

11A and 11B show the number of data strobe outputs required for a typical display panel 12 with each reference electrode 30 having a fixed reference voltage and nine grooves for receiving strobe signal pulses. I'm comparing. The display panel of FIG. 11A has a grounded reference electrode 30,
It has three different strobe output amplifiers 26 and a data strobe circuit 28 for driving different row electrodes 62. The display panel shown in FIG. 11B has the reference electrodes 30 arranged in three sets, and the row electrodes 62 arranged in another three sets. A groove 20 (FIG. 4) having a reference electrode forming any one of the set of reference electrodes includes an electrode 62 of any one of the row electrode sets. The display device 10 displays one of the sets of reference electrodes 30 for a predetermined time interval.
Strobe only one. During the strobe time interval,
The display device 10 addresses the display elements 16 by driving the column electrodes 18 and strobing the set of row electrodes 62 contained within the groove 20 having the reference electrode 30 receiving a strobe pulse. The row electrode 62 of the groove 20, whose reference electrode 30 has not received the strobe pulse, is therefore not activated.

Due to the configuration in which the output amplifiers 26 of the data strobe circuit 28 are electrically connected to the reference electrode 30 and the row electrode 62 in the groove 20, the number of output amplifiers 26 of the data strobe circuit 28 of the addressing device is small. I'm done. FIG.
In the exemplary 1B display panel 12, the number of data strobe output amplifiers 26 is reduced from nine to six.

FIG. 12 shows the number of addressable data lines mountable in the addressing device of the type implemented in the display panel 12 of FIG. 11B,
It is a graph which shows the minimum number of drivers required. FIG.
2 shows that a substantial reduction in drivers is achieved in a display device with a relatively large number of data lines.

The address device used in the memory device of the present invention is a self-scan (S) developed by Burroughs.
Using other techniques similar to those implemented in the elf-Scan ™ display helps reduce the number of drivers. A display device using such a technique employs a display cell that an observer can see and a scanning cell that the observer cannot see. 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.

The display panel 12 could provide an ion source that moves sequentially from one groove to the next by electrical division of orthogonal priming grooves. 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 addressing technique of applying positive and negative polarity data voltages in the alternating image field is easy to use in the embodiment of the display device 10 employing the driver reduction technique described in connection with FIGS. 11B and 12. . The addressing speed can be further increased by the alternative addressing technology that applies only the positive polarity data voltage. This alternative technology is
An erase field is introduced at the end of each image field.

In this type of addressing technique, the data strobe circuit 28 applies positive and negative pulses to the row electrode 62 of the trench 20 continuously for a relatively short period of time during scanning of the erase field. The driver 24 applies a voltage of substantially ground potential 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 is of positive polarity, the charge stored in storage element 16 causes a negative charge on surface 88 of 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, it can accumulate residual positive charge and reach a significant level. During the application of the negative pulse, the ground potential applied to the column electrode 18 causes residual positive charge to escape to ground in the same manner as it did during the writing of the image field.

If no positive pulse is used, the speed at address is limited by the positive ion charging phenomenon described above. However, this alternative addressing technique is not compatible with the driver reduction technique described in connection with FIGS. 11B and 12.

In another address technique of this type, there are two or more (for example, 10) data strobe circuits 28.
A negative pulse is applied to each row electrode 62 to erase one row of data at the same time. This technique causes a small amount of duty cycle non-uniformity across the display surface 14 of the display panel 12.

In the present invention, the flat panel display device 10 described above can be transformed into a versatile analog data memory device 110 including an array of memory elements. This is the memory device itself, and is the second aspect of the present invention.
It becomes an example. In such a modification, the polarization filter 34
And 36 are removed and the liquid crystal material layer 44 of FIGS. 2, 4 and 5 is removed.
Also, if there is, it may be removed.

FIG. 13 shows an equivalent circuit of the memory device 110 of the present invention. 6 and 1 except as described above.
The device shown in 3 is similar. Therefore, FIG. 6 and FIG.
Corresponding components in 3 have the same reference numbers. In the memory device 110, the dielectric 46 functions as a dielectric element of the capacitor model 80, which represents a memory element (storage element). Column electrode 18
Need not be made of an optically transparent material, but may be made of aluminum or another conductive material. The data driving output amplifier 22 of the memory device 110 functions as a column electrode driving amplifier in the data writing mode, and functions as a column electrode sensing amplifier in the data reading mode. The drive output amplifier 22 and the data drive circuit 24 serve as signal applying / reading means. The data strobe output amplifier of the device of FIGS. 6 and 13 is
Similar.

In FIG. 13, each output amplifier 22 of the data driving circuit 24 includes a high speed operational amplifier 112. The parallel circuit of the feedback capacitor 118 and the switch element 120 forms an inverting input terminal 114 and an output terminal 11 of the amplifier 112.
It is connected between 6 and. The amplifier 112 selectively switches the switch element 12 when in the data write mode.
It is configured as a voltage follower by driving 0 and making it conductive, and as a integrator by driving the switch element 120 and making it non-conductive in the data read mode. The non-inverting input terminal 122 of the operational amplifier 122 is connected to the movable contact 124 of the switch element 126.
Connected to. This switch element selectively connects the non-inverting input terminal 122 to the reference voltage Vr or the output signal conductor of the data driving circuit 24.

Whenever in the write mode, the output amplifier 22 provides a data drive signal to the column electrodes 18 forming the memory elements of the memory device 110. This means
The operational amplifier 112 is configured as a voltage follower, and the movable contact 124 of the switch element 126 for supplying the data driving signal is arranged from the data driving circuit 24 to the non-inverting input terminal 122 of the operational amplifier 112. Therefore, in the write mode, when the amplifier 112 becomes a voltage follower, the voltages at its non-inverting input terminal and its inverting input terminal become equal, so that the non-inverting input terminal functions as a data drive signal input terminal, and the inverting input terminal Should function as an output terminal for the data driving signal. During this period, the row strobe pulse applied to the row electrode 62 in the groove 20 forming the memory element 110 excites the ionizable gas in the groove to an ionized state. This allows the capacitor model 80 to be processed by the method described in connection with FIG.
To generate a data voltage. The magnitude of the voltage applied to the capacitor model 80 represents the data drive signal.

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

First, the movable contact 12 of the switch element 126.
4 is arranged to input the reference voltage Vr to the non-inverting input terminal 122 of the operational amplifier 112. this period,
The row strobe pulse is inactive to maintain the non-ionized state of the ionizable gas. Therefore, the reference voltage Vr is the output terminal 116 of the operational amplifier 112, the column electrode 18, and the capacitor model 80.
On the top plate 82 of the. Feedback capacitor 118
Is thus neutralized to 0.0 volts. 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 applied to the feedback capacitor 118 becomes 0.0 V, the operational amplifier 112
Is configured as an integrator whose input 114 is quasi-charged to receive the current from the column electrode 18. 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 already noted. When the row strobe pulse re-ionizes the ionizable gas,
The bottom plate 86 of the capacitor model 80 is the reference electrode 3
It is electrically connected to 0. Therefore, capacitor model 8
The voltage across 0 changes. An operational amplifier 112, configured as an integrator, senses this voltage change and provides a voltage to output 116 that is proportional to the above-described data voltage across capacitor model 80.

There are other ways to generate a data voltage on the capacitor model 80 to facilitate its function as a memory device. For example, using an optically transparent column electrode 18 to replace the dielectric material layer 46 with a photoconductive material and expose the memory device 110 to visible light results in the memory device 110.
The voltage on the capacitor model 80 is modulated in proportion to the intensity of light incident on it. The voltage change across the capacitor model 80, which is proportional to the intensity of the incident light, is restored in the data read mode, as already mentioned. A layer 46 of photoconductive material and an optically transparent column electrode 1
Therefore, 8 is an image detecting device according to the characteristics of the analog data memory.

In the image sensing device described above, providing a plurality of layers 46 of photoconductive material as electrically isolated strips 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 taken to read the data voltage across the capacitor model 80, thereby correcting data in the data read mode. The efficiency of is improved.

The image sensing device described above takes advantage of the photoconductive nature of layer 46 of photoconductive material during the data read mode. It is also possible to directly utilize the photoconductivity of the layer 46 of photoconductive material. In this case, the data element 16 would be more preferably characterized as a sensing element, and the capacitor model 80 would be even more preferably a current modulation element. This means that between the strobe electrode 62 and the reference electrode 30, a row strobe
It can be achieved by applying to the column electrodes 18 a voltage that causes a voltage gradient in the layer 46 while the pulse is being applied. The current flowing from the reference electrode 30 through the layer 46 and the column electrode 18 to the output 116 of the operational amplifier 112 is
Output signal. Replacing the feedback capacitor 118 with a resistor causes the voltage appearing at the output 116 of the operational amplifier 112 to be proportional to the current flowing through the layer 46.

Although the above has described the preferred embodiments of the present invention, those skilled in the art can easily make various modifications without departing from the gist of the present invention.

[0073]

INDUSTRIAL APPLICABILITY The present invention can store an analog voltage and can be applied to a display device using an electro-optical material layer such as liquid crystal,
An inexpensive memory device with high yield can be achieved. In addition, second and third electrodes that are substantially parallel to the longitudinal direction of the groove-shaped recess are formed inside each of the groove-shaped recesses of the second substrate.
The strobe signal (second signal) is selectively supplied between the electrode and the third electrode. This allows for a relatively low voltage,
An electric field having a uniform gradient is formed in the direction traversing the groove-like recess to cause uniform ionization of the gas, and uniform and good switching operation by the ionizable gas is obtained in each cell. Further, after ionizing the gas, a data signal (first signal) for display or storage is supplied between the first electrode and the third electrode used for the strobe signal. Therefore, since the third electrode is also used for supplying both the data signal and the strobe signal, the structure of the memory device can be simplified.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the concept of the present invention.

FIG. 2 is a partially sectional perspective view of a display panel using the present invention.

FIG. 3 is a plan view showing the display panel shown in FIG. 2 by partially cutting it off.

4 is a sectional view taken along line 4-4 in FIG.

5 is a cross-sectional view taken along the line 5-5 in FIG.

FIG. 6 is a circuit diagram showing an equivalent circuit of FIG.

FIG. 7 shows a time chart for determining the maximum number of addressable data lines used in the present invention.

FIG. 8 is a diagram comparing the data capture time relationships of neon gas and helium gas as a function of the current flowing between the electrodes provided in the grooves of the display panel shown in FIGS.

FIG. 9 is a diagram showing a relationship between a current flowing through a cathode and an anode in helium gas and a plasma disappearance time.

10 is a diagram showing an alternative circuit of the data driver shown in FIG. 1. FIG.

11 is a diagram showing an alternative circuit of the data strobe shown in FIG. 1. FIG.

12 is a diagram showing the relationship between the number of drivers and the number of addressable data lines in FIG.

FIG. 13 is a diagram showing an equivalent circuit of the memory device of the present invention.

[Explanation of symbols]

 Reference Signs List 18 first electrode 20 groove-shaped recess 22, 24 signal applying / reading means 26, 28 signal applying means 30 third electrode 44 electro-optical material layer (dielectric layer) 46 dielectric material layer (dielectric layer) 48 first substrate 54 second substrate 62 second electrode

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // H01J 17/38 H01J 17/38 H04N 5/66 102 H04N 5/66 102B (72) Inventor Paul Sea -Martin United States Oregon 97225 Portland Southwest Thurrow Drive 9950 (72) Inventor Eitch Wayne Olmsted United States Oregon 97006 Beaverton Northwest Marco La Coat 16995 (72) Inventor John Jay Horn United States Oregon 97123 Hills Suvoro Southwest Toe Handred and Thirty Ath Avenue 765

Claims (1)

[Claims] 1. A first substrate having a plurality of first electrodes formed on one main surface substantially in parallel with each other, and intersecting the first electrode on a main surface of the first substrate facing the main surface. And substantially parallel to each other and having a plurality of groove-shaped recesses in which an ionizable gas is sealed, and inside each of the plurality of groove-shaped recesses on the main surface of the second substrate. A second member formed substantially parallel to the longitudinal direction of the groove-shaped recess.
And a third electrode, a dielectric layer interposed between the first substrate and the second substrate and forming a data storage element at an intersection of the first electrode and the groove-shaped recess, and the first electrode. And signal applying / reading means for selectively applying a first signal between the third electrodes or selectively receiving a read signal between the first electrode and the third electrode, and the second electrode. And signal applying means for selectively applying the second signal between the third electrodes, the signal applying means selectively applying the second signal between the second electrode and the third electrode. Supplying and ionizing the gas in the groove-shaped recess having the second electrode and the third electrode receiving the second signal, and the signal applying / reading means includes the groove containing the ionized gas. The first of the storage elements corresponding to the circular recesses
The first signal is selectively supplied between the electrode and the third electrode to change the charge state of the dielectric layer to accumulate the data corresponding to the first signal in the storage element and ionize the same. The read signal is selectively obtained from between the first electrode and the third electrode of the storage element corresponding to the groove-shaped recess containing the stored gas to read the data stored in the storage element. A memory device characterized by the above.