JP3689075B2 - Fluorescent display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluorescent display device, and in particular, includes a light emitting display unit in which a plurality of anodes coated with phosphors are arranged in a matrix, and an anode substrate integrally formed with a drive circuit that controls light emission of the light emitting display unit. The present invention relates to an active matrix fluorescent display device.
[0002]
[Prior art]
In a fluorescent display device, electrons emitted from a cathode collide with a phosphor coated on the anode in a vacuum vessel (envelope) at least one of which is transparent to cause the phosphor to emit light, thereby forming a desired pattern. An electron tube to be displayed. In general, this fluorescent display device is most commonly used in a triode structure having a grid for controlling the action of electrons. In one of such fluorescent display devices, an anode substrate in which a light emitting display unit in which a plurality of anodes coated with phosphors are arranged in a matrix and a drive circuit for controlling light emission of the light emitting display unit are integrally formed is provided. There is an active matrix fluorescent display device having a light-emitting display surface obtained by disposing on an insulating substrate.
[0003]
One configuration example of a conventional active matrix fluorescent display device is composed of a semiconductor integrated circuit formed on a polycrystalline silicon film whose driving circuit is arranged on the surface of a glass substrate which is an anode substrate, and the light emitting display portion is polycrystalline. An anode electrode arranged in a matrix on a passivation film (insulating film) covering the surface of the silicon film and connected to a drive circuit, and a phosphor applied on each anode electrode (for example, JP-A-2002) -8771.) In this case, since the drive circuit is constituted by a thin film transistor made of a so-called low-temperature polycrystalline silicon film formed on a glass substrate, it is possible to increase the size and cost.
[0004]
[Problems to be solved by the invention]
However, the above-described conventional active matrix type fluorescent display device has a problem in that the light emission in the peripheral portion of the light emitting display portion is non-uniform and the display quality is lowered.
The present invention has been made to solve this problem. A light emitting display unit in which a plurality of anode electrodes coated with a phosphor are arranged in a matrix and an anode electrode are selectively driven to control light emission of the light emitting display unit. An object of the present invention is to make light emission of a light emitting display portion uniform in an active matrix fluorescent display device including an anode substrate integrally formed on a substrate with a driving circuit including a thin film transistor made of crystalline silicon.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is based on a light emitting display unit in which a plurality of anode electrodes coated with a phosphor are arranged in a matrix and polycrystalline silicon that selectively drives the light emitting display unit to control light emission of the light emitting display unit. An anode substrate integrally formed on the substrate, a plurality of filamentary cathodes disposed opposite to the light emitting display portion mounting surface of the anode substrate, and the anode substrate and the filamentous cathode In the fluorescent display device including the arranged grid electrode and the vacuum envelope having at least one surface containing the anode substrate, the filamentary cathode, and the grid electrode having translucency, the anode substrate is arranged on each anode electrode forming surface. Characterized by having an auxiliary electrode surrounding the electrode.
[0006]
In this case, the auxiliary electrode is grounded. By auxiliary electrode surrounding the anode electrode is grounded, the auxiliary electrode to absorb excess electrons that do not contribute to light emission. Thereby, the insulating film around the anode electrode is prevented from being charged by surplus electrons, and the disturbance of electrons incident on the anode electrode is eliminated, so that the light emission of the light emitting display unit is made uniform. One configuration example of the auxiliary electrode is black. By making the auxiliary electrode black, the contrast of the display pixel is improved. As an electrode material constituting the black auxiliary electrode, for example, carbon is used.
[0007]
In one configuration example of the fluorescent display device, the vacuum envelope is made of a member having the same expansion coefficient as that of the anode substrate. In another configuration example of the fluorescent display device, the substrate of the anode substrate is accommodated in a recess formed in the vacuum envelope. One configuration example of the anode substrate includes a plurality of connection terminals arranged along an edge of one side of the substrate formed in a rectangle. In this case, in one configuration example of the fluorescent display device, a plurality of anode substrates are arranged in a matrix. In another configuration example of the fluorescent display device, the connection terminal of the anode substrate is connected to a lead terminal that penetrates the vacuum envelope.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1A and 1B show the configuration of a fluorescent display device according to a first embodiment of the present invention, in which FIG. 1A is a perspective view showing the overall configuration, and FIG. 1B is a light-emitting display section of FIG. (C) is the sectional view on the AA line of (b). 2 is a cross-sectional view showing a cut surface including a light emitting display portion of the anode substrate of FIG. 1 and lead pins connected to the anode substrate. In this fluorescent display device, an anode substrate 110, a grid electrode 130, and a plurality of filament cathodes 140 are accommodated in an envelope made of a plate glass 101, a spacer glass 102, and a windshield 103.
[0009]
The plate glass 101 has a rectangular shape, a predetermined number of anode substrate wirings 106 having one end connected to the lead connection terminal 105 and the other end connected to the bonding pad 107, and a grid electrode having one end connected to the lead connection terminal 105. Wiring 133 is formed on the surface. These lead connection terminals 105 are arranged along the edge of one side on the plate glass 101, and are connected to the lead pins 104 for the anode substrate and the lead pins 134 for the grid electrode, respectively. In this embodiment, in order to simplify the manufacturing process, the lead connection terminal 105, the bonding pad 107, and the wirings 106 and 133 are made of the same material, such as aluminum, so that they can be manufactured in one process. Yes.
[0010]
On the plate glass 101, an anode substrate 110 in which an anode electrode 114 coated with a phosphor 115 is arranged in a matrix and a drive circuit that controls light emission of the light emitting display unit 120 is integrally formed; A pair of grid supports 131 that hold the grid electrode 130 above the anode substrate 110 at a predetermined distance and a pair of filament supports 142 that hold the plurality of filament cathodes 140 above the grid electrode 130 at a predetermined distance. And are arranged.
[0011]
The anode substrate 110 includes a predetermined number of bonding pads 117 along the edge of one side of the light-emitting display unit 120 mounting surface, and the side where the bonding pad 117 is arranged is arranged with the lead connection terminal 105 of the plate glass 101. It is arrange | positioned so as to oppose the edge. Each bonding pad 117 is connected to the bonding pad 107 of the anode substrate wiring by a bonding wire 108. The anode substrate 110 is fixed by bonding the surface opposite to the light-emitting display unit 120 mounting surface to the plate glass 101. Here, adhesion to the plate glass 101 is performed with a heat resistant resin such as a polyimide resin.
[0012]
One grid electrode 130 is disposed above the anode substrate 110 so as to cover the light emitting display unit 120, and a plurality of filament cathodes 140 are disposed above and parallel to the grid electrode 130. The grid electrode 130 has a mesh shape, and is stretched between a pair of grid supports 131 arranged outside two sides orthogonal to the side where the bonding pads 117 of the anode substrate 110 are arranged. It is fixed with an insulating paste containing a low melting point frit glass.
[0013]
The grid support 131 is a glass plate whose thickness is larger than the anode substrate 110 by a predetermined height and whose length is longer than the width of the grid electrode 130, and the two grid supports 131 are parallel to the anode substrate 110. And is adhered to the plate glass 101. In this case, the grid support 131 is fixed to the plate glass 101 with an insulating paste containing a low melting point frit glass. The grid electrode 130 is fixed to the grid wiring 133 formed on the plate glass 101 with a part of the mesh drawn out from one grid support 131 by a conductive paste.
[0014]
Each filament cathode 140 is stretched between a pair of anchors 141 arranged to face each other so as to sandwich a pair of grid supports 131, and is attached to the anchor 141 by welding. The anchor 141 is attached by welding to a filament support 142 having a leg portion that also serves as a cathode lead pin 144. The cathode lead pin 144 formed integrally with the filament support 142 is arranged on one edge of the plate glass 101 on which the plurality of lead pins 104 are arranged. In addition to the anchor 141, other parts such as a getter ring (not shown) are attached on the filament support 142.
[0015]
A rectangular transparent windshield 103 is disposed above the filament cathode 140 so as to face the plate glass 101. The spacer glass 102 and the windshield 103 disposed around the plate glass 101 and the plate glass 101 are arranged. An envelope is formed by bonding with frit glass, and the inside is kept in a vacuum. The lead pins 104, 134, and 144 are arranged on one side of the plate glass 101 and are drawn out from between the plate glass 101 and the spacer glass 102. The leg portion of the filament support 142 is also sandwiched between the plate glass 101 and the spacer glass 102 and bonded and fixed with frit glass. Here, the bases of the plate glass 101, the spacer glass 102, the front glass 103, and the anode substrate 110 are composed of members having the same expansion coefficient in order to prevent distortion and breakage due to differences in thermal expansion coefficient. In this embodiment, borosilicate glass which is a base of an anode substrate 110 described later is used for the glass member constituting the vacuum envelope.
[0016]
Next, the anode substrate 110 will be described in detail with reference to FIG. The anode substrate 110 is an active matrix substrate in which a light emitting display unit 120 and a drive circuit that controls light emission of the light emitting display unit 120 are integrally formed. The anode substrate 110 has a glass substrate 111 as a base, and a polycrystalline silicon film 112 is formed on the surface of the glass substrate 111. A semiconductor integrated circuit including a thin film transistor (TFT) is formed on the polycrystalline silicon film 112, and a drive circuit is constituted by the semiconductor integrated circuit. The thin film transistor formed on the polycrystalline silicon film 112 has high performance characteristics that are two to three orders of magnitude higher than those of the thin film transistor formed on the amorphous silicon film. It is effective for.
[0017]
Here, as the polycrystalline silicon film 112, a so-called low-temperature polycrystalline silicon film formed at a processing temperature equal to or lower than the strain point of the glass substrate 111 is used. This low-temperature polycrystalline silicon film is usually formed at 450 ° C. to 600 ° C., and is formed by a known technique such as chemical vapor deposition (CVD). The glass substrate 111 is made of borosilicate glass that does not contain sodium or the like that adversely affects transistor characteristics. The semiconductor integrated circuit formed on the polycrystalline silicon film 112 is manufactured by a known manufacturing process using a low-temperature polycrystalline silicon film.
[0018]
The surface of the polycrystalline silicon film 112 is covered with a passivation film (insulating film) 113, and the light emitting display portion 120 is formed on the passivation film 113. The light emitting display unit 120 surrounds the anode electrodes 114 arranged in a matrix at a predetermined pitch on the passivation film 113, the dot-like phosphors 115 applied on the anode electrodes 114, and the anode electrodes 114. And a grid-like auxiliary electrode 116 disposed on the passivation film 113.
[0019]
A thin film transistor forming portion 112a of an anode driving portion that forms a part of a driving circuit is formed immediately below each anode electrode 114, and is connected to the anode electrode 114 through a through hole 113a provided in the passivation film 113. . The auxiliary electrode 116 is connected to one of the bonding pads 117. In this case, the anode electrode 114, the auxiliary electrode 116, and the bonding pad 117 are made of aluminum, and the phosphor 115 is made of a phosphor material used in a conventional fluorescent display device. The material of the auxiliary electrode 116 is not limited to aluminum. For example, the auxiliary electrode 116 may be made of carbon. When the auxiliary electrode 116 is made of carbon, the color of the auxiliary electrode 116 is black, and each pixel is surrounded by a black grid. Therefore, there is an advantage that the contrast of the display screen is improved. A known conventional technique can be used to form the passivation film 113, the anode electrode 114, the phosphor 115, the auxiliary electrode 116, and the bonding pad 117.
[0020]
FIG. 3 is a block diagram showing a circuit configuration of the anode substrate, and shows an example of a drive circuit that controls lighting of display pixels arranged in a matrix of vertical N dots × horizontal M dots (N and M are natural numbers). This drive circuit has the number of display pixels (N × M) of anode drive units 201 having a memory function for driving the anode electrode 114 provided for each display pixel for a predetermined period, and displays on each anode drive unit 201. And a data input control unit for inputting and driving data.
[0021]
The anode drive unit 201 has a column input a for inputting a drive signal, a row input b for inputting display data, and an output for driving the anode electrode 114. In this case, as illustrated in FIG. 4, the anode driving unit 201 includes a memory transistor 211, a capacitor 212, and a driving transistor 213, and the lower side of the light emitting display unit 120 corresponding to each anode electrode 114. The polycrystalline silicon film 112 is formed. In this case, the memory transistor 211 and the drive transistor 213 are configured by field effect transistors, and a column input a for inputting a drive signal is connected to the gate of the memory transistor 211, and display data is connected to the source of the memory transistor 211. Is connected to the line input b.
[0022]
The drain of the memory transistor 211 is connected to one terminal of the capacitor 212 and the gate of the driving transistor 213, and the source of the driving transistor 213 is connected to a connection terminal (not shown) of VDD which is an anode voltage. The drain of the driving transistor 213 is connected to the anode electrode 114. Further, the other terminal of the capacitor 212 is grounded via a ground connection terminal (not shown). Thus, when the display data is lit and a drive signal is input, the memory transistor 211 charges the capacitor 212, and the charged capacitor 212 keeps the drive transistor 213 in an ON state for a predetermined period. 114 is driven.
[0023]
An auxiliary electrode 116 surrounding the anode electrode 114 is grounded via a ground connection terminal (not shown). Since the auxiliary electrode 116 is grounded, light emission is uniform in the peripheral pixels of the light emitting display portion, and the display quality is improved . The reason why the light emission in the peripheral portion of the light emitting display portion is made uniform by grounding the auxiliary electrode 116 is not to prevent the insulator around the anode electrode 114 from being charged and to prevent disturbance of electrons incident on the anode electrode 114. It is thought.
[0024]
The data input control unit receives display data for each column for one column, and inputs the data to the anode driving unit 201 of each row one column at a predetermined timing, and the anode driving unit 201 for each row at a predetermined timing. And an output control unit for outputting display data input for each column. The data input unit is composed of N D flip-flop circuits 202 connected in cascade and N latch circuits 203 connected to the data output Q of each D flip-flop circuit 202, and the output control unit is connected in cascade M Each D flip-flop circuit 204 and M latch circuits 205 connected to the data output Q of each D flip-flop circuit 204.
[0025]
In the data input section, the signal terminal of the vertical synchronization clock VCK is connected to the clock input CK of each D flip-flop circuit 202, and the vertical data VDA which is display data of each pixel is connected to the data input D of the head D flip-flop circuit 202. The signal terminal is connected, and the data output Q of the preceding D flip-flop circuit 202 is connected to the data input D of the succeeding D flip-flop circuit 202 and the input IN of the preceding latch circuit 203. Further, the signal terminal of the vertical N dot enable signal VWR is connected to the clock input C of each latch circuit 203, and the output OUT of each latch circuit 203 is connected to the row input b of each anode driving unit 201.
[0026]
In the output control unit, the signal terminal of the horizontal synchronization clock HCK is connected to the clock input CK of each D flip-flop circuit 204, and the signal terminal of the horizontal data HDA as a drive signal is connected to the data input D of the head D flip-flop circuit 204. The data output Q of the preceding D flip-flop circuit 204 is connected to the data input D of the subsequent D flip-flop circuit 204 and the input IN of the preceding latch circuit 205. Further, the signal terminal of the horizontal M dot enable signal HWR is connected to the clock input C of each latch circuit 205, and the output OUT of each latch circuit 205 is connected to the column input a of each anode drive unit 201.
[0027]
Since the anode substrate 110 has such a circuit configuration, it is possible to perform horizontal scanning (display data vertical rewriting) drive by inputting a signal shown in FIG. FIG. 5 is a timing chart showing control waveforms of the fluorescent display device. 5, (a) is a vertical synchronization clock VCK, (b) is vertical data VDA, (c) and (d) are horizontal M dot enable signals HWR, (e) is a horizontal synchronization clock HCK, and (f) is horizontal. Data HDA, (g) is a vertical N dot enable signal VWR.
[0028]
In this case, by inputting N pieces of vertical data VDA as display data in synchronization with the vertical synchronization clock VCK, the display data for one column is held in the corresponding latch circuit 203 of the data input unit, and the horizontal M dot enable signal A driving signal is output from the latch circuit 205 of the corresponding column of the output control unit by the HWR, and the anode driving unit 201 connected to this column is driven to rewrite display data simultaneously in one vertical column. Selection of the corresponding column of the output control unit is performed by transferring the horizontal data HDA sent prior to the display data for one screen to each D flip-flop circuit 204 of the output control unit by the horizontal synchronization clock HCK.
[0029]
Since the anode substrate 110 includes a control circuit that performs active matrix driving, six signal lines (VCK, VDA, VWR, HCK, HDA, HWR) and a power source are used regardless of the number of rows and columns of the display screen. Each anode 114 can be driven only by connecting a supply line (VDD, ground). For this reason, since connection points are reduced, connection reliability is improved. In addition, since the number of connection locations is small, the connection location of the bonding wire 108 can be only one side of the anode substrate 110. Therefore, the routing of the anode substrate wiring 106 formed on the plate glass 101 is simplified and the manufacture is facilitated. Become.
[0030]
In this fluorescent display device, the thermoelectrons emitted from the heated and heated filament cathode 140 are diffused and accelerated by the positive voltage applied to the grid electrode 130 and are continuously irradiated to the anode substrate 110, and the irradiated electrons are The light enters the anode 114 to which a positive voltage is applied by active matrix driving to cause the phosphor 115 to emit light, and the input data is displayed on the screen. On the other hand, the electrons irradiated on the anode 114 to which no positive voltage is applied or on the anode 114 in the column that is not driven until the next driving cycle is incident on the auxiliary electrode 116 and absorbed. Thus, since the auxiliary electrode 116 absorbs surplus electrons that do not contribute to light emission, charging of the passivation film 113 and the like by surplus electrons is prevented.
[0031]
Fluorescent display device according to this embodiment has a lattice-like auxiliary electrode 116 anode substrate 110 for active matrix driving surrounds each anode electrode 114 to the anode electrode formation surface, the auxiliary electrode 116 is grounded Therefore, even in the peripheral pixels of the light emitting display portion, the light emission is uniform and the display quality is improved. In this anode substrate 110, a plurality of connection terminals connected to the drive circuit and the auxiliary electrode 116 are arranged along one edge of the rectangular substrate, so that the plurality of anode substrates are arranged in a matrix. It is possible to form a larger screen by closely contacting the screen.
[0032]
FIG. 6 is a perspective view showing the configuration of the fluorescent display device according to the second embodiment of the present invention. 7 is a cross-sectional view showing a cut surface including a light emitting display portion of the anode substrate of FIG. 6 and lead pins connected to the anode substrate. 6 and 7, the same reference numerals as those in FIGS. 1 and 2 denote the same parts. The fluorescent display device according to this embodiment is different from the fluorescent display device according to the first embodiment in that the glass plate 111 constituting the vacuum envelope accommodates the glass substrate 111 which is the substrate portion of the anode substrate 110. A recess (groove) having a possible depth is provided, and the glass substrate 111 is bonded to the bottom of the recess, and a lead connection terminal 119 is disposed on the anode substrate 110 instead of the bonding pad. The lead pin 104 for the anode substrate is directly connected to 119.
[0033]
According to this embodiment, since the substrate portion of the anode substrate 110 is accommodated in the groove of the plate glass 101, the height of the grid electrode 130 and the filament cathode 140 can be lowered by the thickness of the glass substrate 111. For this reason, it becomes possible to use the support member of the general fluorescent display tube which uses plate glass for an anode substrate for the support member of a grid electrode or a filament cathode. Further, since the lead pins 104 are directly connected to the anode substrate, it is not necessary to form anode substrate wiring on the plate glass 101 and connection of bonding wires. For this reason, in addition to the effect obtained in the first embodiment, it is possible to expect the effect of improving the reliability by reducing the number of connection points and the effect of reducing the production cost by reducing the manufacturing process.
[0034]
In these embodiments, borosilicate glass is used in order to give the glass member constituting the vacuum envelope the same thermal expansion coefficient as that of the anode substrate. Glass may be used. In this case, in order to prevent distortion and breakage due to the difference in thermal expansion coefficient, it is preferable to fix only one side of the anode substrate on which bonding pads and lead connection terminals are formed with an adhesive. At that time, in order to prevent the substrate from being inclined due to the thickness of the adhesive, for example, a groove for filling the adhesive may be provided.
[0035]
【The invention's effect】
As described above, the fluorescent display device of the present invention is a polycrystalline silicon in which a plurality of anode electrodes coated with phosphors are arranged in a matrix and a light emitting display unit and anode electrodes are selectively driven to control light emission of the light emitting display unit. since a driver circuit including a thin film transistor of having an auxiliary electrode each anode is enclosed Mikatsu ground the anode electrode formation surface of the anode substrate that is integrally formed on a substrate, a pixel in the periphery of the light emission display unit In this case, the light emission is uniform and the display quality is improved. Further, since the anode substrate surrounds the anode electrode connected to the thin film transistor with the auxiliary electrode which is a conductor, the effect of preventing the electrostatic breakdown of the thin film transistor during the manufacturing process can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a fluorescent display device according to a first embodiment.
2 is a cross-sectional view showing a cut surface including a light emitting display portion of the anode substrate of FIG. 1 and lead pins connected to the anode substrate.
FIG. 3 is a block diagram showing a circuit configuration of an anode substrate.
4 is a circuit diagram of the anode driving unit of FIG. 3;
FIG. 5 is a timing chart showing control waveforms of the drive circuit of FIG. 3;
FIG. 6 is a perspective view showing a configuration of a fluorescent display device according to a second embodiment.
7 is a cross-sectional view showing a cut surface including a light emitting display portion of the anode substrate of FIG. 6 and lead pins connected to the anode substrate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 101 ... Plate glass, 101a ... Groove, 102 ... Spacer glass, 103 ... Windshield, 104, 134, 144 ... Lead pin, 105, 109, 119 ... Lead connection terminal, 106 ... Wiring for anode substrate, 107, 117 ... Bonding pad 108 ... bonding wire 110 ... anode substrate 111 ... glass substrate 112 ... polycrystalline silicon film 112a ... thin film transistor forming part 113 ... passivation film (insulating film) 113a ... through hole 114 ... anode electrode 115 ... Phosphor, 116 ... auxiliary electrode, 120 ... light emitting display unit, 130 ... grid electrode, 131 ... grid support, 133 ... grid wiring, 140 ... filament cathode, 141 ... anchor, 142 ... filament support, 201 ... anode drive unit, 202 , 204 ... free Flop circuit, 203 and 205 ... latch circuit, 211 ... memory transistors, 212 ... capacitor, 213 ... driving transistor.

Claims (7)

A light emitting display unit in which a plurality of anode electrodes coated with phosphors are arranged in a matrix and a driving circuit including a thin film transistor made of polycrystalline silicon for selectively driving the anode electrode and controlling light emission of the light emitting display unit are provided on a substrate. An integrally formed anode substrate, a plurality of filamentary cathodes disposed opposite to the light emitting display portion mounting surface of the anode substrate, a grid electrode disposed between the anode substrate and the filamentary cathode, and the anode In a fluorescent display device comprising a vacuum envelope in which at least one surface containing a substrate, the filamentary cathode, and the grid electrode has translucency,
The anode substrate is
Fluorescent display device characterized by having an auxiliary electrode each anode is enclosed Mikatsu grounded to the anode electrode formation surface. The fluorescent display device according to claim 1,
The fluorescent display device , wherein the auxiliary electrode is black . The fluorescent display device according to claim 1 or 2,
The vacuum envelope is
The fluorescent display device, wherein the anode substrate is made of a member having the same expansion coefficient as that of the substrate . The fluorescent display device according to any one of claims 1 to 3,
The substrate of the anode substrate is
A fluorescent display device, wherein the fluorescent display device is accommodated in a recess formed in the vacuum envelope . The fluorescent display device according to any one of claims 1 to 4,
The anode substrate is
A fluorescent display device comprising a plurality of connection terminals arranged along an edge of one side of the substrate formed in a rectangular shape . The fluorescent display device according to claim 5, wherein
A fluorescent display device , wherein a plurality of the anode substrates are arranged in a matrix . The fluorescent display device according to claim 5 , wherein
The connection terminal of the anode substrate is
A fluorescent display device, wherein the fluorescent display device is connected to a lead terminal penetrating the vacuum envelope .

Images