JP5401019B2 - Flat panel display - Google Patents

Description

  The present invention relates to a flat panel display using a plasma display panel or the like, and more particularly to a structure suitable for high contrast.

  Plasma display panels (hereinafter referred to as PDPs) are used in large screens, thin, flat-screen televisions, and their performance is increasing. However, the bright room contrast, that is, the contrast in a bright environment (usually the brightness of the living room, ie, the illuminance of 150 to 200 lx) is still not satisfactory. That is, the PDP has the following problems.

  FIG. 4 is a diagram showing external light reflection in the PDP. The body color of the phosphor 10 is often close to white, and the phosphor film 10 reflects external light from an illumination lamp or the like incident on the PDP and lowers the contrast. It is.

  On the other hand, the following proposals have been made for improving the bright room contrast of the display.

Patent Document 1 discloses a structure of an optical filter installed on the front surface for improving the color correction function of the display. The optical filter used here is “a visible filter layer that absorbs visible light containing one or more transparent supports, a dye or pigment and a polymer binder, and at least one of an infrared shielding function and an electromagnetic shielding function. And at least one of the transparent supports has an infrared shielding function ”.
Patent Document 2 includes a “filter for plasma display including a polarization separation sheet and a polarizing plate”, and Patent Document 3 includes a filter including an absorption-type circularly polarizing plate and a selective reflection-type circularly polarizing plate. It has been published.

JP 2002-107538 A JP 11-259006 A JP 2003-202816 A

  In the method using the optical filter disclosed in the above-mentioned Patent Document 1, even if the contrast of the display can be improved, there remains a problem that the luminance is lowered. This will be described with reference to FIGS. FIG. 5 is a diagram for explaining external light reflection in a PDP (with an optical filter). Since the external light from the illumination lamp is absorbed by installing the optical filter 12, the external light reaching the fluorescent film 10 is weakened, the intensity of the light reflected from the fluorescent film to the outside of the PDP is suppressed, and the contrast is improved. To do. On the other hand, FIG. 6 is a diagram illustrating phosphor emission in a PDP (with an optical filter). Visible light emitted from the fluorescent film 10 is also absorbed by the optical filter 12. Accordingly, the contrast is improved by the light absorbing action of the optical filter 12, but the phosphor emission luminance extracted outside the PDP is lowered. In the method using the optical filter disclosed in Patent Document 1, even if the contrast of the display can be improved, there remains a problem that the luminance is greatly reduced.

In the method disclosed in Patent Document 2 and Patent Document 3, for use two polarizing plates, leaving a problem decrease in luminance is large from the phosphor.

  An object of the present invention is to improve contrast while suppressing a decrease in luminance in a plasma display device.

  The plasma display device of the present invention is characterized in that a material having a linear polarization function is provided on the light emission / emission surface side of the plasma display panel.

  With this mechanism, it is possible to suppress deterioration in image quality such as a decrease in bright room contrast due to reflection of external light illumination or the like. Furthermore, since the light emission of the fluorescent film itself has polarization, it becomes easy to separate external light and phosphor light emission, and a simple structure can suppress a decrease in luminance and improve bright room contrast.

  According to the present invention, it is possible to realize a high-contrast plasma display device that suppresses a decrease in luminance.

  Hereinafter, embodiments of a plasma display apparatus according to the present invention will be described in detail with reference to the drawings. In addition, in each drawing, what has the same function attaches | subjects the same code | symbol, and description of the description is abbreviate | omitted.

FIG. 1 shows an embodiment of a plasma display device according to the present invention.
FIG. 2 is a diagram showing a part of a typical structure of the plasma display panel (PDP). The plasma display panel (PDP) corresponds to the portions 1 to 10 and the electrodes 2, 3 and 9 have voltages. Is applied to discharge the inside of the cell, and light emitted from the fluorescent film 10 is emitted from the front glass plate 1.
The PDP 20 has a structure in which a front substrate 21 and a rear substrate 22 are bonded together, and a discharge gas is sealed between the substrates.

  The front substrate 21 has a plurality of electrode pairs each composed of a transparent electrode 2 and a bus electrode 3 (usually one electrode pair is called an X electrode) for sustain discharge (also called display discharge) on the front plate glass 1. The other is referred to as a Y electrode (only one pair is shown in FIG. 2), and these electrode pairs are covered with a dielectric 4 and a protective film 5. The back substrate 22 has address electrodes 9 on the back plate glass 6, and the address electrodes 9 are covered with a dielectric 8. Further, partition walls 7 are formed on the dielectric 8, and red, blue, and green phosphor films 10 are formed between the partition walls 7.

  The front substrate 21 and the back substrate 22 are aligned so that the electrodes on the front substrate 21 side and the electrodes on the back substrate 22 side are substantially orthogonal to each other (in some cases, simply cross each other). And the back substrate 22 are sealed, and a discharge gas is sealed in a gap between the substrates, and a plurality of cells are formed in a matrix between the substrates. By selectively applying a voltage to the sustain electrode pairs 2 and 3 on the front substrate 21 side and the address electrode 9 on the back substrate 22 side, a discharge is caused in a desired cell among the plurality of cells. By this discharge, vacuum ultraviolet rays are generated, and the generated vacuum ultraviolet rays excite each color phosphor film 10 to emit red, blue, and green light, thereby performing full color display.

  FIG. 3 is a view showing another structure of the back substrate 22. In this case, each cell has a structure partitioned by a partition wall 7 into a single chamber, and the present invention can also be applied to this case.

FIG. 7 is a diagram illustrating the structure of an embodiment according to the present invention.
Linear polarizer 11 is placed on the PDP surface. It is preferable that the linear polarizing plate main polarization axis direction, the phosphor light emission main axis direction, and the external light incident direction have the directional relationship shown in FIG.

A state when external light is incident will be described with reference to FIG. The outer light emitted from the panel upper surface direction is reflected by the surface of the linear polarizing plate 11, reflected by properties of the linear polarizing plate is reduced (external light reflection A). Further, after the external light transmitted through the linearly polarizing plate 11 is attenuated significantly, after being diffused and reflected by the fluorescent film 10, after having received a greater attenuation when passing through the linearly polarizing plate 11 again, is emitted from the PDP surface (External light reflection B).

Next, phosphor emission will be described with reference to FIG. Since the polarization axis direction of the fluorescent film main polarization axis direction and the polarizing plate are matched, it can be discharged from the PDP surface emitting less attenuation from the fluorescent film 10.

  In the present embodiment, the reflected light from the outside light is greatly reduced and the light emission from the phosphor is less blocked than in the case of the prior art (optical filter method) described with reference to FIGS. Therefore, it is possible to suppress the decrease in luminance and improve the contrast.

In the above embodiment, the panel top surface direction external light has been described effect for when illuminated, if Kaware the direction of external light, in accordance with the conditions of use, by setting the installation direction of the linear polarizer 11 Good. For example, it may be set a polarization axis direction and the phosphor film main polarization axis direction of the linearly polarizing plate to a suitable orientation if you want to block the external light from the window.

Linear polarizing plate are generally those used available.

  As the phosphor, those generally used for flat panel displays can be applied.

Red phosphors include (Y, Gd) BO ₃ : Eu, Y ₂ O ₃ : Eu, Y (P, V) O ₄ : Eu, (Y, Gd) (P, V) O ₄ : Eu, The green phosphor is Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Tb, BaAl ₁₀ O ₁₉ : Mn, and the blue phosphor is BaMgAl ₁₀ O ₁₇ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, (Sr, Ba) ₃ MgSi ₂ O ₈ : Eu, CaMgSi ₂ O ₆ : Eu can be used, and each color phosphor is not only one type, but a plurality of types are mixed Things can also be used.

  By using a phosphor paste, which is a mixture of a phosphor and a vehicle that is not perfectly spherical, and forming a phosphor film on the partition wall surface by screen printing, it is possible to align many phosphor emission main axes in one direction rather than randomly.

  Hereinafter, several embodiments of the plasma display device according to the present invention will be described (FIG. 12).

Using (Y, Gd) (P, V) O ₄ : Eu, a plasma display made of a red monochromatic phosphor shown in FIG. 2 was produced.
In FIG. 2, 1 is a front plate glass, 2 is a transparent electrode, 3 is a bus electrode, 4 is a dielectric, 5 is a protective film, 6 is a back plate glass, 7 is a partition, 8 is a dielectric, 9 is an address electrode, and 10 is fluorescent. It is a membrane.

The PDP of the present embodiment is configured by bonding the front substrate 21 and the rear substrate 22 together. After the address electrodes 9 and the barrier ribs 7 were formed on the rear substrate 22, the phosphor film 10 made of (Y, Gd) (P, V) O ₄ : Eu was formed between the barrier ribs 7 in the following procedure.

  That is, 40 parts by weight of a phosphor and 60 parts by weight of a vehicle are mixed to form a phosphor paste, which is applied by screen printing, volatile components in the paste are removed and organic substances are burned and removed by a drying and firing process. Formed. At this time, a plurality of phosphors having different phosphor particle shapes were prepared by changing the phosphor synthesis conditions, and a PDP was prepared.

The back substrate was bonded to the front substrate, and discharge gas (Ne 96%, Xe 4%) was sealed to produce the PDP shown in FIG. 2, and the drive circuit was connected. A linear polarizing plate was placed on the surface of this PDP, and the bright room contrast was measured. At that time, an example in which a normal filter was installed on the surface of the PDP was also prepared as a comparative example.

The polarization axis of the polarizing plate 10 shows the major polarization axis direction of the directional relationship of the fluorescent film emit light. The direction in which the major polarization axis direction of the fluorescent film is coincident with the polarization axis of the polarizing plate and "T direction", the direction major polarization axis direction of the fluorescent film is perpendicular to the polarization axis direction of the polarizing plate "Y direction" To do. A ratio (T / Y) of “T direction component” and “Y direction component” of phosphor emission is defined as a polarization ratio.

FIG. 11 shows changes in the bright room contrast with respect to the polarization ratio obtained by the PDP produced using phosphors having different particle shapes. For comparison, the contrast in the prior art structure shown in FIG. 5 is also shown. This patent showed that bright room contrast can be improved, and that the bright room contrast can be improved by increasing the polarization ratio.

In Example 1, a PDP was prepared using (Y, Gd) BO ₃ : Eu as the phosphor, and the bright room contrast was measured. As a result, it was possible to obtain a high contrast (93) with respect to the value 74 in the comparative example.

In Example 1, a PDP was prepared using Y ₂ O ₃ : Eu as the phosphor, and the bright room contrast was measured. As a result, a high contrast (81) was obtained with respect to the value 66 in the comparative example.

In Example 1, a PDP was prepared using Zn ₂ SiO ₄ : Mn as a phosphor, and the bright room contrast was measured. As a result, it was possible to obtain a high contrast (202) with respect to the value 160 in the comparative example.

In Example 1, as the phosphor, BaAl ₁₂ O ₁₇ : Mn
Was used to make a PDP, and the bright room contrast was measured. As a result, a high contrast (195) was obtained with respect to the value 155 in the comparative example.

In Example 1, the phosphor is YBO ₃ : Tb
Was used to make a PDP, and the bright room contrast was measured. As a result, a high contrast (190) was obtained with respect to the value 150 in the comparative example.

In Example 1, a PDP was prepared using BaMgAl ₁₀ O ₁₇ : Eu as a phosphor, and the bright room contrast was measured. As a result, it was possible to obtain a high contrast (460) with respect to the value 37 in the comparative example.

In Example 1, three-color phosphors are separately applied using (Y, Gd) BO ₃ : Eu as red phosphors, Zn ₂ SiO ₄ : Mn as green phosphors and BaMgAl ₁₀ O ₁₇ : Eu as blue phosphors. A PDP was prepared, and the bright room contrast was measured. As a result, a high contrast (114) was obtained with respect to the value 90 in the comparative example.

In Example 1, three-color phosphor using (Y, Gd) (P, V) O ₄ : Eu as a red phosphor, YBO ₃ : Tb as a green phosphor and BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor PDPs with different coatings were prepared, and the bright room contrast was measured. As a result, a high contrast (100) was obtained with respect to the value 80 in the comparative example.

In Example 1, a PDP in which three color phosphors are separately coated using Y ₂ O ₃ : Eu as a red phosphor, Zn ₂ SiO ₄ : Mn as a green phosphor, and BaMgAl ₁₀ O ₁₇ : Eu as a blue phosphor. It was prepared and the bright room contrast was measured. As a result, a high contrast (110) was obtained with respect to the value 88 in the comparative example.
In the above embodiment, in order to clarify the effect of the present invention, a single color phosphor was prepared using a phosphor having a single composition, but the same color phosphor having a different composition was mixed. May be used.

  In the above embodiment, a plasma display device using an ac-type PDP having a so-called three-electrode / surface discharge structure has been described. For example, the present invention can also be applied to a dc type PDP and a counter discharge type PDP.

  In the PDP having the above-described structure, “ultraviolet rays are generated by the main discharge, and the generated vacuum ultraviolet rays excite each color phosphor to emit red, blue, and green, and perform full color display”. It goes without saying that the present invention can be applied not only to the case where the phosphor is excited with vacuum ultraviolet rays but also to the case where the phosphors are excited with normal ultraviolet rays. Further, in the PDP having the above structure, visible light of red, blue, and green is generated by the phosphor. However, the present invention can be applied not only to such a structure but also to a structure that directly generates visible light by discharge. Needless to say. Furthermore, the visible light is not limited to red, blue, and green light, and it goes without saying that the present invention can be applied to the case of generating visible light of other colors, and further to generating monochromatic visible light. .

  In addition to the PDP, the present invention can be applied to all flat panel displays such as a field emission display (FED) in which the excitation source of the phosphor is an electron beam.

1 is a cross-sectional view showing an embodiment of a plasma display device according to the present invention. The figure which shows a part of typical structure of a plasma display panel (PDP). The figure which shows the other structure of a back substrate in FIG. The figure which shows external light reflection in the conventional PDP. The figure explaining external light reflection in PDP (with an optical filter). The figure explaining fluorescent substance light emission in PDP (with an optical filter). The figure explaining the structure of one Embodiment by this invention. The figure explaining operation | movement of the plasma display apparatus of this embodiment. The figure explaining operation | movement of the plasma display apparatus of this embodiment. It shows a polarization axis direction. The figure which shows the contrast change with respect to a polarization ratio. The figure which shows the contrast of the phosphor material of each Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Front plate glass, 2 ... Transparent electrode, 3 ... Bus electrode, 4 ... Dielectric, 5 ... Protective film, 6 ... Back plate glass, 7 ... Partition, 8 ... Dielectric, 9 ... Address electrode, 10 ... Fluorescent film, 11 ... linear polarizing plate, 12 ... optical filter, 15A, 15B ... light absorber mobile device, 20 ... plasma display panel (PDP), 21 ... front plate, 22 ... rear substrate.

Claims (1)

In a flat panel display that has a fluorescent film and emits visible light,
A linear polarizing plate having a linear polarization function is installed on the light emission / emission surface side of the flat panel display,
The main direction of the transmission field vector of linearly polarized light is the vertical direction of the flat panel display,
The flat panel display is a plasma display;
The plasma display has a structure in which a front substrate and a rear substrate are bonded together,
The front substrate has a plurality of electrode pairs consisting of a transparent electrode and a bus electrode for sustain discharge on the front plate glass,
The plurality of electrode pairs are covered with a dielectric and a protective film,
The back substrate has address electrodes on a back plate glass,
The address electrodes are covered with a dielectric;
A partition is formed on the dielectric of the address electrode,
The phosphor film is formed between the barrier ribs,
The phosphor film is prepared using a phosphor paste that is a mixture of a phosphor and a vehicle,
Flat panel display, characterized in that the polarizing axis direction of the main polarization axis direction of the phosphor film the linearly polarizing plate is consistent.

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