KR100299529B1 - Dichroic mirror for plasma display panel - Google Patents

Abstract

PURPOSE: A dichroic mirror for a plasma display panel is provided to increase the utilization efficiency of an ultraviolet light by reflecting the ultraviolet light lost at a front plate of a PDP(Plasma Display Panel) electrode cell among the ultraviolet light generated by a gas discharge therein. CONSTITUTION: A high-refractive index material LaF3 and a low-refractive index material MgF2 are layered on a glass substrate at least 11 times by using an electron beam evaporator. A thickness(H) of the high-refractive material LaF3 is 207.2 angstrom and a thickness(L) of the low-refractive index material MgF2 is 260 angstrom. A peak wavelength in an impermeable band is 156 nm. LaF3 has a refractive index of 1.85 over at 135-230 nm and MgF2 has a refractive index of 1.4-1.6.

Description

Dichroic mirrors for plasma display panels

The present invention relates to a dichroic mirror for a plasma display panel (hereinafter referred to as a 'PDP'), and more particularly, to reflect ultraviolet rays lost toward the front plate of ultraviolet rays generated by gas discharge in a PDP electrode cell. The present invention relates to a dichroic mirror for PDP that can maximize UV utilization efficiency and a dichroic mirror for PDP that can improve PDP brightness by maximizing visible light utilization efficiency by reflecting the converted visible light absorbed by the ultraviolet light. .

PDP is a device that displays characters or graphics by using ultraviolet rays emitted from plasma generated during gas discharge. Among the various flat panel displays currently being discussed, it is easy to enlarge and colorize and secure a wide viewing angle. As a high-definition wall-mounted TV and multimedia display device, it is a device that has been intensively researched in recent years.

In the conventional AC reflective PDP electrode cell structure, as shown in FIG. 1, a front plate and an address electrode in which a discharge sustaining electrode 10, a bus electrode 11, a dielectric layer 12, and a protective layer 13 are sequentially stacked. (21) and the dielectric layer 22 in order to keep the back plate, the front plate and the back plate laminated in sequence at a certain interval, and to prevent the cross-talk between the cells and the phosphor layer coated on the partition and back plate It consists of 41.

In the conventional electrode cell structure as described above, the ultraviolet rays generated by the gas discharge in the cell are absorbed by the phosphor coated on the back plate and the partition wall so that visible light of blue, green, and red comes out, wherein the ultraviolet rays generated from the gas discharge are emitted to the phosphor. It is pointed out that the amount of loss that is not absorbed and goes out to the front panel lowers the brightness of the PDP.

In order to solve such a problem, conventionally, an organic material filter in which organic materials are dyed as a color separation filter has been mainly used, but a conventional organic material filter has a low light utilization rate and a problem in heat resistance.

In order to solve the above problems, the present inventors reflect ultraviolet rays generated from gas discharge to the front plate toward the rear plate to maximize the utilization efficiency of ultraviolet rays and absorb them in a high-efficiency heat-resistant dichroic mirror and phosphor to improve PDP brightness. In order to maximize the utilization efficiency of the converted visible light, a highly efficient heat resistant dichroic mirror reflecting most of the visible light was developed.

It is an object of the present invention to provide a highly efficient heat resistant dichroic mirror, ie an ultraviolet reflecting mirror, which transmits 90% or more of visible light while reflecting most of the ultraviolet light.

Another object of the present invention is to provide a highly efficient heat resistant dichroic mirror that reflects most of the visible light.

The object of the present invention is a dichroic mirror in which a dichroic mirror in which LaF ₃ , which is a high refractive index material, and MgF _{2, which} is a low refractive index material is alternately stacked, a TiO ₂ , which is a high refractive index material, and SiO _{2, which} is a low refractive index material, are alternately stacked. Achieved by a mirror.

1 is an exploded perspective view of a conventional AC reflective PDP electrode cell;

2 is a cross-sectional view of a dichroic mirror (ultraviolet ray reflecting mirror) according to Embodiment 1 of the present invention;

3 is a cross-sectional view of a dichroic mirror (visible light reflecting mirror) according to a second embodiment of the present invention;

4 is a measurement and reflection characteristics of the dichroic mirror according to the first embodiment of the present invention,

5 is a dichroic mirror reflection characteristic measurement method according to a second embodiment of the present invention.

Hereinafter, the configuration of the present invention will be described in detail by way of examples, but is not limited to this embodiment.

<Example>

Example 1

UV reflecting mirror

로 표시될 수 있고, λo 는 다이크로익 미러의 비투과대 중심파장이다.On the glass substrate, 11 layers of LaF ₃ , a high refractive index material, and a layer of MgF ₂ , a low refractive index material, were alternately deposited using an Electron Beam Evaporator. The substrate temperature was set at 250 ° C., and the evaporator was fixed at 4 Kv and supplied with low current to low power deposition. At this time, the laminated structure is a structure in which the (H / 2, L, H / 2) configuration is stacked five times as shown in FIG. H represents the optical layer thickness of LaF ₃ , a high refractive index material, and L represents the optical layer thickness of MgF ₂ , a low refractive index material.

Can be represented by λo Is the non-transmissive center wavelength of the dichroic mirror.

In this embodiment, the thickness H of the high refractive index material layer is 207.2 kPa, the thickness L of the low refractive index material layer is 260 kPa, and the center wavelength of the non-transmissive band is shown. λo Is 156 mm. In general, the material that can be used as a thin film material of dichroic mirror should have absorption coefficient less than 10 ^-3 , mechanical and chemical stability are required, and stability against radiation and temperature is required. The present inventors selected BaF ₂ and LaF ₃ as the thin film materials having the above requirements and having high refractive index characteristics. In particular, LaF ₃ has the highest refractive index among the fluoride-based materials having a refractive index of 1.85 or more from 135 mm to 230 mm. Absorption rate was smaller than BaF ₂ , and the high refractive index material of this example was used. However, it is not even with different objects of the present invention and to replace the LaF ₃ using BaF ₂ as a refractive index materials, of course.

In the present embodiment, MgF ₂ was selected as the low refractive index material, and MgF ₂ has a refractive index of about 1.4 to 1.6 and is known to have the lowest absorption coefficient of 0.01 to 10 ⁻⁶ in ultraviolet light.

The dichroic mirror according to the present embodiment has a structure in which the (H / 2, L, H / 2) configuration is stacked five times, and the laminated structure filter of five or more laminations increases UV reflectance, but of course, Application of the filter for the PDP is not preferable because of its complicated structure.

Example 2

Visible light reflecting mirror

A layer of TiO ₂ , a high refractive index material, and a layer of SiO ₂ , a low refractive index material, were alternately deposited on a glass substrate using an electron beam evaporator. In this case, as shown in FIG. 3, the structure (L / 2, H, L / 2) was stacked five times, and the lamination conditions were performed in the same manner as in Example 1.

TiO ₂ selected by the present inventors as a high refractive index material of the visible light filter has excellent chemical stability and excellent adhesion, which is advantageous for film formation, and SiO ₂ selected as a low refractive index material can form a chemically and mechanically stable film.

The dichroic mirror according to the present embodiment has a structure in which (L / 2, H, L / 2) configurations are stacked five times, and more complicated laminated mirrors tend to have a larger bandwidth and better reflection characteristics. It is not preferable to apply for actual PDP because the structure is complicated.

In order to apply the ultraviolet reflective filter according to the first embodiment for the PDP, the ultraviolet reflective filter must be inserted between the MgO protective film and the dielectric material, and the ultraviolet ray lost to the front plate by mounting the ultraviolet reflective filter is attached to the rear plate and the partition wall. It is to maximize the ultraviolet reflectance by reflecting to the phosphor layer applied to. The MgO protective film for optimizing the ultraviolet reflectance of the ultraviolet reflector is about 100 mW.

In addition, in order to apply the visible light reflecting filter according to the second embodiment for the PDP, the visible light reflecting filter must be inserted between the phosphor and the dielectric, and the ultraviolet light absorbed by the phosphor due to the mounting of the visible light reflecting filter is converted into the visible light. As a result, the visible light lost to the back plate is reduced and the amount of visible light reflected toward the front plate is ultimately improved to improve the brightness of the PDP.

4 shows the reflection characteristics and the transmission characteristics of the ultraviolet reflection filter composed of the LaF ₃ layer and the MgF ₂ layer according to the first embodiment. Reflectance (R) was measured under a vacuum degree of 10 ^-5 or less using a reflectometer, and the light emitted from the deuterium lamp was incident at an angle of 10 ° C. According to the measurement results of FIG. 4, the ultraviolet reflectance by the ultraviolet reflector according to the present invention shows a maximum of 70% or more at around 147 nm and 173 nm, which is the most at around 147 nm and 173 nm out of the discharged plasma. Recalling that it is strong, the ultraviolet reflector filter according to the present invention effectively prevents the loss of ultraviolet rays to maximize the ultraviolet utilization efficiency. In addition, the wavelengths of blue, green, and red, which are three primary colors of visible light, are 450 nm, 550 nm, and 630 nm, respectively, and more than 90% of the blue, green, and red wavelengths are transmitted without being reflected by the ultraviolet reflection filter. have.

The reflection characteristics of the visible light reflection filter including the TiO ₂ layer and the SiO ₂ layer according to the second embodiment are shown in FIG. 5. Reflectance measurement conditions are the same as described above, and as can be seen in FIG. 5, the reflectance in the range of 400 nm to 650 nm including the three primary wavelengths of visible light is almost 90% or more.

The present invention relates to a high-efficiency heat-resistant UV reflective filter for PDP that reflects most of the ultraviolet light and transmits 90% or more of visible light, wherein at least 11 or more layers of LaF ₃ , which is a high refractive index material, and an MgF ₂ layer, which is a low refractive index material, are laminated. By using the dichroic mirror, the ultraviolet rays lost to the entire surface of the PDP without being converted into the visible light by the phosphor are reflected while the visible light is transmitted without reflecting, thereby maximizing the utilization efficiency of the ultraviolet rays and contributing to the improvement of the brightness pointed out as a PDP problem.

In addition, the present invention relates to a highly efficient heat-resistant visible light reflection filter for PDP that reflects most of the visible light, the dichroic mirror in which at least 11 layers of TiO ₂ layer of high refractive index material and SiO ₂ layer of low refractive index material are laminated As a result, the visible light lost to the back surface of PDP can be effectively reflected to maximize the utilization efficiency of visible light, thereby contributing to the improvement of brightness pointed out as a PDP problem.

Claims (1)

PDP composed of at least five layers of high refractive index material of LaF ₃ and BaF ₂ and a low refractive index material of MgF ₂ (H / 2, L, H / 2), interposed between MgO protective film and dielectric Ultraviolet Reflective Dichroic Mirror. Where H is the optical stack thickness of the high refractive index material

Where L is the optical stack thickness of the low refractive index material

Is indicated by λo Is the non-transmissive center wavelength of the dichroic mirror.

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