JP6290837B2 - Fluorescent display tube manufacturing method, fluorescent display tube - Google Patents

Description

  The present invention relates to a fluorescent display tube having an anode having an anode electrode and a phosphor, and a filament that emits electrons for causing the phosphor to emit light, and a method for manufacturing the same.

JP 11-339699 A JP 2009-272260 A

  As a display device for displaying various information, a display device using a fluorescent display tube (VFD: Vacuum Fluorescent Display) is known. A fluorescent display tube has at least a filament (directly heated cathode) and an anode disposed in a vacuum vessel, and heats electrons by emitting direct current, alternating current, or pulse voltage to heat the filaments. A desired pattern is displayed by causing the phosphor formed in the above to emit light by collision.

  As a display device including a fluorescent display tube, for example, there is a display device used as a head-up display (hereinafter referred to as “HUD”) for a vehicle. The pattern emitted from the light-emitting surface is enlarged and projected on an object such as a windshield or a combiner, and the appearance of the display pattern actually viewed by the user is taken into consideration. Then, it is required to reduce the arrangement interval (gap between the anodes) of the anode (phosphor) as much as possible.

  However, when the gap between the anodes is narrowed, so-called “letter missing” that lowers the luminance of the outer peripheral edge of the phosphor in the anode tends to occur. This is because the electric potential of the insulator arranged so as to partition between the anodes (between the anode electrodes) is the ground potential, so the amount of electrons reaching from the filament to the outer edge of the phosphor by so-called electronic vignetting is compared with the central portion of the phosphor. This is because it decreases.

  In order to suppress chipping, it is effective to provide an electrode (peripheral electrode) as a planar grid between the anodes and drive the peripheral electrode to control the electric field around the phosphor. For example, Patent Document 1 discloses a fluorescent display tube provided with a planar grid.

  In addition, about the related prior art, the said patent document 2 can be mentioned with the said patent document 1. FIG. Patent Document 2 discloses a technique for forming an anode wiring by a photolithography method.

  Here, the fluorescent display tube can be manufactured by laminating and forming a wiring layer, an insulating layer, an electrode layer, and a phosphor on a glass substrate in a predetermined pattern. At this time, it is desirable from the viewpoint of reducing the manufacturing cost that printing formation (for example, pattern printing) is adopted for the lamination formation of the electrode layer and the insulating layer.

  However, according to the print formation, it is difficult to form a narrow gap between the anodes as compared with the case where patterning is performed by thin film formation such as sputtering or vacuum deposition. In particular, when the above-described peripheral electrode is formed between the anodes in order to suppress chipping, the gap between the anodes must be increased, and the display quality is deteriorated from the viewpoint of the fineness of the display pattern.

  Therefore, the present invention has an object to overcome the above-mentioned problems and to realize a fluorescent display tube that improves display quality in terms of both suppression of missing characters and a narrow gap between anodes at a lower cost. To do.

A method of manufacturing a fluorescent display tube according to the present invention is a method of manufacturing a fluorescent display tube having an anode having an anode electrode and a phosphor, and a filament that emits electrons for causing the phosphor to emit light. The conductive photosensitive layer formed by applying a printing paste containing a conductive material and a photosensitive agent made of powder of any one of ITO, ITO, or SnO ₂ is subjected to exposure patterning, and the periphery of the anode electrode and the anode electrode And an electrode forming step of forming an electrode.

As described above, the anode electrode and its surrounding electrode are formed by exposure patterning on the conductive photosensitive layer, and as a fluorescent display tube with the surrounding electrode provided to suppress missing characters, the layer to be the electrode is printed. The gap between the anodes can be miniaturized even if this is performed. Furthermore, since ZnO, ITO, and SnO ₂ have a relatively high transmittance with respect to ultraviolet rays used for exposure and it is difficult to inhibit the curing action by exposure, this point also contributes to the miniaturization of the gap between the anodes.

  In the above-described method for manufacturing a fluorescent display tube according to the present invention, it is desirable that the content of the conductive material in the printing paste is 40 wt% to 60 wt%.

  By appropriately setting the content ratio of the conductive material, it is possible to form a film to be an electrode while ensuring film formation accuracy.

  In the above-described method for manufacturing a fluorescent display tube according to the present invention, it is desirable that the conductive material has a powder average particle diameter of 1 μm to 10 μm.

  By appropriately setting the powder particle size of the conductive material, it is possible to achieve both good printability and patternability.

  In the above-described method for manufacturing a fluorescent display tube according to the present invention, the photosensitive agent preferably contains 5 wt% to 10 wt% of a photosensitive resin.

  By appropriately setting the content of the photosensitive resin in the photosensitive agent, it is possible to achieve both good printability and patternability.

  In the above-described method for manufacturing a fluorescent display tube according to the present invention, it is desirable to form the conductive photosensitive layer with a film thickness of 5 μm to 15 μm.

  By appropriately setting the film thickness of the conductive photosensitive layer, it is possible to ensure both good characteristics as an electrode and good patterning properties.

  According to the present invention, it is possible to realize a fluorescent display tube that is improved in display quality in terms of both suppression of chipping and a narrow gap between anodes at a lower cost.

It is a schematic sectional structure figure of the fluorescent display tube as an embodiment. It is a schematic plan view of the display part which the fluorescent display tube as an embodiment has. It is explanatory drawing about the cause of character missing. It is explanatory drawing about the character chip | tip suppression effect by a surrounding electrode. It is explanatory drawing about the manufacturing method of the fluorescent display tube as embodiment. Similarly, it is explanatory drawing about the manufacturing method of the fluorescent display tube as an embodiment. It is the figure which showed the result of having patterned the electrode using the printing paste by the composition example 1. FIG. It is the figure which showed the result of having patterned the electrode using the printing paste by the composition example 2. FIG. It is the figure which showed the result of having patterned the electrode using the printing paste by the composition example 3. FIG. It is the block diagram which showed the circuit structure of the display apparatus provided with the fluorescent display tube as embodiment.

Embodiments according to the present invention will be described below.
The description will be given in the following order.

<1. Structure of fluorescent display tube>
<2. Manufacturing method>
<3. Configuration of display device>
<4. Summary of Embodiment>
<5. Modification>

<1. Structure of fluorescent display tube>

1 and 2 are explanatory views of the structure of a fluorescent display tube 1 as an embodiment according to the present invention. FIG. 1 shows a schematic cross-sectional structure of the fluorescent display tube 1, and FIG. As a diagram illustrating the arrangement pattern of the anodes 3 formed in FIG. 1, a schematic plan view of the display unit 1a of the fluorescent display tube 1 is shown. FIG. 1 mainly shows a schematic cross-sectional structure in the display unit 1a.

The fluorescent display tube 1 is a so-called segment display type fluorescent display tube, and anodes 3 having shapes and numbers corresponding to display patterns (graphic figures such as numbers and arrows in the figure) to be realized are arranged. For example, in the numerical part illustrated in FIG. 2, seven anodes 3 are arranged for each digit so that an arbitrary numerical value can be switched and displayed by so-called seven-segment display.
In the present embodiment, the fluorescent display tube 1 is exemplified by a fluorescent display tube applied to a vehicle head-up display (hereinafter “HUD”) device.

In the fluorescent display tube 1, a structure including wiring, electrodes and the like necessary for causing the anode 3 to emit light is vacuum-sealed in the glass container 2 (see FIG. 1).
In the fluorescent display tube 1, an anode wiring 5 for supplying a driving voltage to the anode 3 is formed for each anode 3 on a glass substrate 2 a constituting the bottom of the glass container 2. Each anode 3 includes a photolithography electrode 32a, a phosphor 31 formed on the photolithography electrode 32a, and a through electrode 32b joined to the photolithography electrode 32a.
Here, in each anode 3, an electrode formed by the through electrode 32 b and the photolithography electrode 32 a is referred to as an anode electrode 32.

  Each anode wiring 5 is joined to a through electrode 32 b in the corresponding anode 3, so that a driving voltage can be applied to the photolithography electrode 32 a via the anode wiring 5. That is, the phosphor 31 formed on the anode electrode 32 can emit light.

  In addition, the fluorescent display tube 1 is formed with an insulating layer including a first insulating layer 8 and a second insulating layer 9. The first insulating layer 8 is formed so that a part thereof is in contact with the glass substrate 2 a, and the second insulating layer 9 is formed so that a part thereof is in contact with the first insulating layer 8. The insulating layers of the first insulating layer 8 and the second insulating layer 9 are formed so that the anode wiring 5 and the anode electrode 32 for each anode 3 are electrically insulated from each other.

Further, the fluorescent display tube 1 is formed with a peripheral electrode 6 surrounding the anode 3 and a peripheral electrode wiring 7 for supplying a voltage to be applied to the peripheral electrode 6. The peripheral electrode wiring 7 is formed on the glass substrate 2 a, and the peripheral electrode 6 has a photolithography electrode 6 a and a through electrode 6 b that joins between the photolithography electrode 6 a and the peripheral electrode wiring 7.
The peripheral electrode 6 and the peripheral electrode wiring 7 are formed such that an electrical insulation relationship between the first insulating layer 8 and the second insulating layer 9 is obtained between the anode wiring 5 and the anode electrode 32.
In FIG. 1, only one through electrode 6b is shown that joins between the peripheral electrode 6 and the peripheral electrode wiring 7, but the through electrode 6b may be provided at a plurality of locations.

  1 and 2, the display unit 1a includes the glass substrate 2a, the anode 3 (including the anode electrode 32), the anode wiring 5, the peripheral electrode 6, the peripheral electrode wiring 7, and the first insulating layer 8 described above. And a portion including the second insulating layer 9.

In the fluorescent display tube 1 of the present embodiment, the lack of characters can be suppressed by applying a voltage to the peripheral electrode 6 provided as described above.
This point will be described with reference to FIGS.
FIG. 3A is a schematic cross-sectional structure diagram of a display portion in a conventional fluorescent display tube, and FIG. 3B is a diagram of potential distribution (dashed line in the figure) and electron orbit (thick arrow in the figure) between the filament 4 and the anode 3. It is a schematic diagram.

As shown in FIG. 3A, in the conventional display unit, the anode electrode 32 ′ included in each anode 3 includes a through electrode 32b ′ and a printed electrode 32a ′ formed by pattern printing, for example. 32 a ′ is formed on the second insulating layer 9, and the through electrode 32 b ′ joins between the printed electrode 32 a ′ and the anode electrode 5 while being covered with the second insulating layer 9. A phosphor 31 is formed on the print electrode 32a ′.
According to such a conventional structure, since the second insulating layer 9 is formed around each anode 3, even if a voltage is applied to the anode 3 through the anode wiring 5, the filament 4 as shown in FIG. 3B. It becomes difficult for the electrons from the light to reach the outer edge portion (broken line portion in the figure) of the phosphor 31. This is because the potential of the second insulating layer 9 around the phosphor 31 is the ground potential, so that the amount of electrons reaching the outer edge of the phosphor 31 from the filament 4 by so-called electronic vignetting is compared with the central portion of the phosphor 31. This is because it decreases.
As a result, a so-called “letter loss” occurs in which the amount of emitted light at the outer edge of the phosphor 31, that is, the amount of emitted light at the outer edge of the display segment is insufficient.

On the other hand, according to the fluorescent display tube 1 of the embodiment provided with the peripheral electrode 6, as shown in FIG. It is possible to increase the amount of electrons that reach the part more than before.
Therefore, suppression of “letter missing” is achieved.

<2. Manufacturing method>

Here, as described above, especially for the fluorescent display tube 1 applied to the HUD, it is required that the arrangement interval of the anodes 3 (gap between the anodes 3) be as narrow as possible.
For forming a fine pattern, it is effective to perform patterning by thin film formation such as sputtering or vacuum deposition, but this is not desirable because it promotes an increase in manufacturing cost.

  Therefore, in the present embodiment, it is possible to apply the printing formation to the lamination formation of the electrode layer and the insulating layer in the fluorescent display tube 1, thereby reducing the manufacturing cost.

With reference to FIG.5 and FIG.6, the manufacturing method of the fluorescent display tube 1 as embodiment is demonstrated.
In the manufacturing method of the embodiment, first, the wiring forming step shown in FIG. 5A is performed. In the wiring formation step, the anode wiring 5 for each anode 3 and the peripheral electrode wiring 7 for the peripheral electrode 6 are formed on the glass substrate 2a. In this example, aluminum is used as the material of the anode wiring 5 and the peripheral electrode wiring 7, and the formation (patterning) of these is performed by, for example, sputtering or photolithography.

  Next, a first insulating layer forming step shown in FIG. 5B is performed. In the first insulating layer forming step, the first insulating layer 8 is formed on the glass substrate 2a while avoiding positions where the through electrode 32b in the anode 3 and the through electrode 6b in the surrounding electrode 6 are to be formed. The first insulating layer forming step is performed by pattern printing. In this example, glass is used as the material of the first insulating layer 8, and in the first insulating layer forming step, the glass paste is pattern-printed and then cured by baking.

  Next, the through electrode 32 b is formed on the anode wiring 5 and the through electrode 6 b is formed on the peripheral electrode wiring 7 by the through electrode forming process shown in FIG. 5C. For example, silver is used as the material of the through electrodes 32b and 6b. In the through electrode forming step, the through electrodes 32b and 6b are formed by pattern printing of a silver paste.

  Further, the second insulating layer 9 is formed not to contact the through electrodes 32b and 6b by the second insulating layer forming step shown in FIG. 5D. In the second insulating layer forming step, the paste forming material for forming the second insulating layer 9 is pattern printed. In the case of this example, glass is used as the second insulating layer 9 similarly to the first insulating layer 8, and in the second insulating layer forming step, a glass paste is pattern-printed and then cured by baking.

Next, a photolithography electrode forming step shown in FIGS. 6A and 6B is performed.
In the photolithography electrode forming process, first, as shown in FIG. 6A, the conductive paste pp is applied to the entire surface formed by the processes up to the second insulating layer forming process, for example, by screen printing (solid coating). To apply). The conductive paste pp is a printing paste containing a conductive material and a photosensitive agent. In this example, ZnO (zinc oxide) powder is adopted as the conductive material, and the photosensitive agent is a kind of ultraviolet curable resin. A certain PVA-SBQ (PVA: polyvinyl alcohol, SBQ: styryl biridinium salt addition) is employed, and these are adjusted to a required viscosity (viscosity suitable for printing) with a solvent to form a paste.

In the photolithography electrode forming step, after the solvent of the conductive paste pp applied as described above is dried, the photolithography electrode 32a to be the anode electrode 32 and the photolithography electrode 6a to be the surrounding electrode 6 are separated. Patterning is performed by a photolithography method for formation. Specifically, pattern exposure and development are performed on the conductive paste pp after drying. In this example, since an ultraviolet curable resin is used, the exposure is performed only on the portion to be the photolithography electrode 32a and the portion to be the photolithography electrode 6a (in other words, the photolithography electrode 32a and the photolithography electrode 6a). ) Is not subject to exposure). As development, for example, water development is performed.
By performing such exposure and development, as shown in FIG. 6B, a gap G is formed that partitions the photolithography electrode 32a and the photolithography electrode 6a. That is, independent electrodes are formed as the photolithography electrode 32a and the photolithography electrode 6a.

After forming each electrode as described above, the phosphor 31 is formed on each photolithography electrode 32a by the phosphor forming step shown in FIG. 6C. For example, the phosphor 31 is formed by pattern printing.
Thereby, the display part 1a in the fluorescent display tube 1 is formed.

As described above, in this embodiment, the conductive photosensitive layer is formed by applying the printing paste (conductive paste pp) containing the conductive material and the photosensitive agent, and the conductive photosensitive layer is subjected to exposure patterning to form the anode. The electrode 32 and the surrounding electrode 6 are formed.
Thereby, in manufacturing the fluorescent display tube 1 provided with the peripheral electrode 6 of the anode 3, the gap G between the anode electrode 32 and the peripheral electrode 6 and the width of the peripheral electrode 6 are adopted while adopting relatively inexpensive printing. Can be miniaturized. In other words, in manufacturing the fluorescent display tube 1 provided with the surrounding electrode 6, it is possible to reduce the gap between the anodes 3 while reducing the cost by adopting printing.
In the case of this example, the minimum value of the gap between the anodes 3 is about 30 μm to 40 μm.

Here, in this example, ZnO is used as the conductive material of the conductive paste pp, but this point also contributes to narrowing the gap between the anodes 3. ZnO has a relatively high transmittance with respect to ultraviolet rays, and it is difficult to inhibit the curing action by exposure, so that the patterning accuracy can be improved. By improving the patterning accuracy, the gap G between the anode electrode 32 and the surrounding electrode 6 and the width of the surrounding electrode 6 can be reduced, and the gap between the anodes 3 can be made narrower. It becomes.
In addition, ITO (indium tin oxide), SnO ₂ (tin oxide), and the like can also be cited as materials suitable for the conductive paste pp because of its relatively high transmittance for ultraviolet rays.

Here, suitable conditions for the conductive material used for the conductive paste pp include that it does not emit light even when a voltage is applied, does not adversely affect the vacuum characteristics in the fluorescent display tube 1, and does not adversely affect the phosphor 31 due to ion diffusion. (Specifically, the luminance of the phosphor 31 is not reduced). Examples of the conductive material satisfying these conditions include aluminum and the like in addition to the above ZnO, ITO and SnO ₂ .

For the conductive paste pp, the content (content rate) of the conductive material should be taken into consideration. If the content of the conductive material is too small, the characteristics as an electrode cannot be satisfied. On the other hand, if the amount is too large, the viscosity characteristics as a printing paste cannot be satisfied, resulting in a decrease in film forming accuracy (for example, uniformity of film pressure).
As a result of experiments from these viewpoints, it has been found that the content of the conductive material (ZnO powder in this example) in the conductive paste pp is preferably 40 wt% (wt%) to 60 wt%. More preferably, it is 50 wt%.

Also, the powder particle size of the conductive material is an element that affects the characteristics of the conductive paste pp. If the powder particle size is too large, it will be difficult to ensure a paste viscosity suitable for printing, resulting in deterioration of printability, and if it is too small, adhesion with the substrate will be deteriorated and patterning properties will be deteriorated. Note that the deterioration of the adhesion to the base is due to the fact that the specific surface area of the conductive material increases when the particle size is small, and the area that adheres to the base side becomes excessive with respect to the amount of the photosensitive agent. Guessed.
As a result of experiments from the above viewpoint, the average particle diameter of the conductive material is preferably 1 μm to 10 μm, more preferably 2 μm.

Further, for the photosensitive agent used for the conductive paste pp, the content of the photosensitive resin (PVA-SBQ in this example) is an element that affects the patterning accuracy.
If the amount of the photosensitive resin in the photosensitive agent is too small, the curing effect by exposure cannot be sufficiently obtained, resulting in deterioration of patterning properties, and if too large, the photosensitive agent itself becomes unstable and gels, It becomes difficult to maintain the viscosity of the conductive paste pp suitable for printing.
As a result of experiments from these viewpoints, the content (content ratio) of the photosensitive resin in the photosensitive agent is preferably 5 wt% to 10 wt%, and more preferably 7 wt%.

Also, the thickness of the conductive photosensitive layer formed by applying the conductive paste pp should be considered. If the thickness of the conductive photosensitive layer is too thick, the patterning property is deteriorated by photolithography, and if it is too thin, the electrical resistance value is increased and the characteristics as an electrode are deteriorated.
As a result of experiments conducted from these viewpoints, the thickness of the conductive photosensitive layer is preferably 5 μm to 15 μm, more preferably 10 μm.

The present inventors conducted an experiment on the patterning accuracy of the conductive paste pp using printing pastes according to the following [Composition Example 1] to [Composition Example 3].

[Composition Example 1]
Conductive material A = (ZnO powder, average particle size = 2 μm) ... 50 wt%
Photosensitizer A = (PVA-SBQ: 7 wt%, saccharide: 8 wt%, propylene glycol: 85 wt%) ... 30 wt%
・ Solvent = Propylene glycol ... 20wt%

[Composition Example 2]
Conductive material B = (ZnO powder, average particle size = 0.1 μm) ... 40 wt%
Photosensitizer A = (PVA-SBQ: 7 wt%, saccharide: 8 wt%, propylene glycol: 85 wt%) ... 30 wt%
・ Solvent = Propylene glycol ... 30wt%

[Composition Example 3]
Conductive material B = (ZnO powder, average particle size = 0.1 μm) ... 40 wt%
Photosensitizer B = (PVA-SBQ: 4 wt%, monomer: 4 wt%, propylene glycol: 92 wt%) ... 30 wt%
・ Solvent = Propylene glycol ... 30wt%

In the experiment, the ratio of the solvent is different between Composition Example 1 and Composition Examples 2, 3 because the difference in paste viscosity is caused by the difference in the powder particle size of the conductive material. This is intended to prevent this.

7, 8, and 9 show the results of electrode patterning using the conductive paste pp according to Composition Example 1, Composition Example 2, and Composition Example 3, respectively. In addition, each B figure is an enlarged view of the center part in corresponding A figure.
From the results shown in FIGS. 7 to 9, when the conductive paste pp of Composition Example 1 having an average particle diameter = 2 μm was used (FIG. 7), Composition Example 2 having an average particle diameter = 0.1 μm. The improvement in patterning accuracy can be confirmed as compared with the case where the conductive paste pp. 3 is used (FIGS. 8 and 9). This supports the preferable numerical value of the average particle diameter described above.

  Further, with respect to the photosensitive agent, composition example 1 in which the content was 7 wt% compared to the case where the conductive paste pp of composition example 3 in which the content of the photosensitive resin was 4 wt% was used (FIG. 9). When the conductive paste pp 2 is used (FIGS. 7 and 8), it can be confirmed that the patterning accuracy is improved. This point supports the preferable condition (5 wt% to 10 wt%) regarding the content of the photosensitive resin in the above-described photosensitive agent.

In addition, as a difference between photosensitive agents A and B, there is a difference in sugar / monomer in addition to the content of the photosensitive resin. Although it cannot be stated that these sugar / monomer differences do not affect the patterning accuracy at all, the difference in patterning accuracy between the photosensitive agents A and B is dominated by the difference in the content of the photosensitive resin. It is a thing.

<3. Configuration of display device>

FIG. 10 is a block diagram illustrating a circuit configuration of the display device 10 including the fluorescent display tube 1.
In FIG. 10, the display device 10 includes a CPU (Central Processing Unit) 11 and a power supply circuit 12 together with the fluorescent display tube 1.

The CPU 11 generates data (display data) relating to which of the anodes 3 in the display unit 1a is lit (emitted) based on data or commands input from the outside (vehicle side in this example), and the display data In order to realize the lighting operation of the anode 3 based on the above, various signals to be given to the fluorescent display tube 1 are generated. Specifically, the data signal SI, the clock CLK, and the latch signal LAT are generated.
Further, the CPU 11 generates a blank signal BK for dimming control in response to an instruction from the outside. The blank signal BK is, for example, a PWM (Pulse Width Modulation) signal whose period is about 5 msec, and specifically, a signal for controlling the extinguishing period of the anode 3. For example, the H level (on) indicates that the anode 10 is turned off, and the L level (off) indicates that the anode 10 is turned on. The CPU 11 adjusts the on-duty of the blank signal BK, that is, the duty (ratio) of the turn-off period of the anode 3 according to the dimming ratio (%) instructed from the outside. Specifically, when increasing the dimming ratio (decreasing the luminance of the anode 3), increasing the on-duty of the blank signal BK and decreasing the dimming ratio (decreasing the luminance of the anode 3). Decreases the on-duty of the blank signal BK.

The blank signal BK, the data signal SI, the clock CLK, and the latch signal LAT are supplied to the terminal portion 1b in the fluorescent display tube 1.
In the case of this example, the blank signal BK is also supplied to the power supply circuit 12.

  The fluorescent display tube 1 includes a terminal portion 1b and a driver 1c together with the display portion 1a and the filament 4 described above. The fluorescent display tube 1 includes a driver voltage terminal TVd for inputting an operating voltage of the driver 1c, a first filament terminal TF1 for inputting a driving voltage of the filament 4 (hereinafter referred to as “filament voltage Ef”), and a first filament terminal TF1. A peripheral electrode terminal TVs for inputting a peripheral electrode voltage to be applied to the peripheral electrode 6 in the display unit 1a and the two-filament terminal TF2 is provided.

The driver 1c inputs the data signal SI, the clock CLK, the latch signal LAT, and the blank signal BK generated by the CPU 11 through the terminal portion 1b, and is shown as wirings Ha1, Ha2,. Each of the anodes 3 (segments in this example) is individually connected to each of the plurality of anode wirings 5 (n number of anode wirings 5) in the display unit 1a via each wiring Ha connected to the corresponding one. A drive voltage can be applied.
The driver 1c takes in the data signal SI by serial data and performs serial / parallel conversion in accordance with the clock CLK and the latch signal LAT. On / off control of voltage application to each anode 3 via the wirings Ha1 to Han is performed based on the data for each anode 3 (binary data indicating lighting / extinction) obtained by such serial / parallel conversion. Do.
Thereby, the anode 3 in the display unit 1a is turned on by a pattern based on the display data generated by the CPU 11.

Further, the driver 1c performs on / off control of voltage application to each anode 3 via the wirings Ha1 to Han based on the blank signal BK. Specifically, on / off control of voltage application to each anode 3 is performed according to the inverted signal of the blank signal BK.
Thereby, the brightness adjustment as the dimming described above is realized.

  In this example, the drive voltage (anode voltage) of the anode 3 is a DC voltage of 5.0 V, for example.

  In the display unit 1a, an input terminal TVs is connected to the peripheral electrode wiring 7 shown in FIG. As a result, it is possible to apply a peripheral electrode voltage to the peripheral electrode 6.

The filament 4 is provided to emit electrons for causing the phosphor 31 formed for each anode 3 to emit light. The filament 4 generates and outputs an alternating drive signal (first signal sF1, second signal described later). Based on sF2), an alternating voltage as a filament voltage Ef is applied and driven.
As shown, the filament 4 has one end connected to the first filament terminal TF1 and the other end connected to the second filament terminal TF2.
In the case of this example, the filament voltage Ef is an alternating voltage with an effective value = 1V, and the average voltage value with respect to the ground (0V) level is, for example, about −35V.

  The power supply circuit 12 includes, for example, a power supply input terminal tVin for inputting a power supply voltage Vin using a vehicle-mounted battery as a supply source, a driver voltage terminal TVd, a peripheral electrode terminal TVs, a first filament terminal TF1, a second in the fluorescent display tube 1. The driver voltage generation unit includes a driver voltage terminal tVd connected to the filament terminal TF2, a peripheral electrode terminal tVs, a first filament terminal tF1, a second filament terminal tF2, and a blank signal input terminal tBK to which a blank signal BK is input. A circuit 12a, a surrounding electrode voltage generation circuit 12b, and a filament voltage generation circuit 12c are provided.

The driver voltage generation circuit 12a generates an operating voltage of the driver 1c based on the power supply voltage Vin, and outputs it through the driver voltage terminal tVd.
The filament voltage generation circuit 12c generates a first signal sF1 and a second signal sF2 for driving the filament 4 based on the power supply voltage Vin, and outputs them through the first filament terminal tF1 and the second filament terminal tF2, respectively. To do. The first signal sF1 is a pulse signal that repeats on / off in a predetermined cycle, and the second signal sF2 is an inverted signal of the first signal sF2. Note that the peak voltage values (voltage values during the ON period) of the first signal sF1 and the second signal sF2 in this example are about 1V.

The peripheral electrode voltage generation circuit 12b generates a peripheral electrode voltage for driving the peripheral electrode wiring 7 based on the power supply voltage Vin, and outputs it through the peripheral electrode terminal tVs.
At this time, the peripheral electrode voltage generation circuit 12b turns on / off the peripheral electrode voltage in synchronization with the blank signal BK. Specifically, in this example, the surrounding electrode voltage is turned on / off in synchronization with the inverted signal of the blank signal BK.
As a result, voltage application to the surrounding electrode 6 is performed only corresponding to the ON period of the anode 3 due to dimming, so that it is possible to minimize the power consumption in preventing the missing characters, and the power consumption Reduction.
It is not essential to turn on / off the surrounding electrode voltage in synchronization with the blank signal BK.

<4. Summary of Embodiment>

As described above, the method of manufacturing a fluorescent display tube according to the embodiment releases the anode (3) having the anode electrode (32) and the phosphor (31) and the electrons for causing the phosphor to emit light. And a printing paste (conductive paste pp) containing a conductive material and a photosensitizer made of any powder of ZnO, ITO, or SnO _2. The conductive photosensitive layer formed by applying the exposure patterning is subjected to exposure patterning to form an anode electrode and an anode electrode surrounding electrode (sixth).

As described above, the anode electrode and its surrounding electrode are formed by exposure patterning on the conductive photosensitive layer, and as a fluorescent display tube with the surrounding electrode provided to suppress missing characters, the layer to be the electrode is printed. The gap between the anodes can be miniaturized even if this is performed. Furthermore, since ZnO, ITO, and SnO ₂ have a relatively high transmittance with respect to ultraviolet rays used for exposure and it is difficult to inhibit the curing action by exposure, this point also contributes to the miniaturization of the gap between the anodes.
Therefore, it is possible to realize a fluorescent display tube that is improved in display quality in terms of both the suppression of missing characters and the narrow gap between the anodes at a lower cost.

  Here, according to the manufacturing method of the embodiment as described above, it is possible to narrow the gap G between the photolithography electrode 32a (anode electrode 32) and the photolithography electrode 6a (surrounding electrode 6). By narrowing the gap between the anode electrode 32 and the peripheral electrode 6 in this way, the voltage value of the peripheral electrode voltage to be applied for suppressing the chipping can be suppressed. That is, from this point, according to the manufacturing method of the embodiment, it is possible to reduce the power consumption in suppressing the lack of characters.

  Furthermore, in the manufacturing method according to the embodiment, the content of the conductive material in the printing paste is 40 wt% to 60 wt%.

  By appropriately setting the content of the conductive material, a film to be an electrode can be formed while ensuring film formation accuracy.

  Furthermore, in the manufacturing method of the embodiment, the average particle diameter of the conductive material is set to 1 μm to 10 μm.

  By appropriately setting the powder particle size of the conductive material, it is possible to achieve both good printability and patternability.

  Moreover, in the manufacturing method of embodiment, the photosensitive agent contains 5 wt%-10 wt% of photosensitive resin.

  By appropriately setting the content of the photosensitive resin in the photosensitive agent, it is possible to achieve both good printability and patternability.

  Furthermore, in the manufacturing method of the embodiment, the conductive photosensitive layer is formed with a film thickness of 5 μm to 15 μm.

  By appropriately setting the film thickness of the conductive photosensitive layer, it is possible to ensure both good characteristics as an electrode and good patterning properties.

The fluorescent display tube (1) of the embodiment includes an anode (3) having an anode electrode (32) and a phosphor (31), a filament that emits electrons for causing the phosphor to emit light, and A peripheral electrode of the anode electrode (same as 6) is formed, and the anode electrode and the peripheral electrode are made of ZnO, ITO, or SnO ₂ powder as a conductive material. It is contained.

As described above, ZnO, ITO, and SnO ₂ have a relatively high transmittance with respect to ultraviolet rays used for exposure, and it is difficult to inhibit the curing action by exposure. Therefore, the layers to be electrodes are stacked by printing, and exposure patterning is performed on the layers. In the case where the anode electrode and the surrounding electrode are formed, the gap between the anodes can be made finer.
Therefore, it is possible to realize a fluorescent display tube that is improved in display quality in terms of both the suppression of missing characters and the narrow gap between the anodes at a lower cost.

<5. Modification>

While the embodiments according to the present invention have been described above, the present invention is not limited to the specific examples described above, and various modifications can be made without departing from the scope of the present invention.
For example, in the above, a fluorescent display tube of a type that displays a segment pattern is illustrated, but the present invention can also be suitably applied to a fluorescent display tube that performs dot matrix display, for example, an active matrix fluorescent display tube.

  The present invention can also be applied to display devices other than the vehicle HUD.

  DESCRIPTION OF SYMBOLS 1 ... Fluorescent display tube, 3 ... Anode, 31 ... Phosphor, 32 ... Anode electrode, 32a ... Photolitho electrode, 32b ... Through electrode, 4 ... Filament, 5 ... Anode wiring, 6 ... Ambient electrode, 6a ... Photolitho electrode, 6b ... through electrode, 7 ... peripheral electrode wiring, 8 ... first insulating layer, 9 ... second insulating layer

Claims (5)

A method for manufacturing a fluorescent display tube, comprising: an anode having an anode electrode and a phosphor; and a filament that emits electrons for causing the phosphor to emit light.
Exposure patterning is performed on the conductive photosensitive layer formed by applying a printing paste containing a conductive material and a photosensitizing agent made of ZnO, ITO, or SnO ₂ powder, and the anode electrode and the anode electrode The manufacturing method of a fluorescent display tube which has an electrode formation process which forms a surrounding electrode. The method for manufacturing a fluorescent display tube according to claim 1, wherein the content of the conductive material in the printing paste is 40 wt% to 60 wt%. The method for manufacturing a fluorescent display tube according to claim 1, wherein the conductive material has a powder average particle diameter of 1 μm to 10 μm. The method for producing a fluorescent display tube according to claim 1, wherein the photosensitive agent contains 5 wt% to 10 wt% of a photosensitive resin. The method for manufacturing a fluorescent display tube according to claim 1, wherein the conductive photosensitive layer is formed with a film thickness of 5 μm to 15 μm.