JP2008258067A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device having high display capability. <P>SOLUTION: The image display device comprises an enclosure 10 including a first board 11 which has an outer surface and an inner surface, the inner surface being provided with a fluorescent screen 16 having fluorescent layers of three or more colors including red, green, and blue, and a second board 12 which is disposed to be opposite to the first board 11 across a gap and carries an exciting source that excites the fluorescent layers. The image display device also comprises a color filter 30 disposed between the inner surface of the first board 11 and the fluorescent screen 16. The color filter 30 has filter layers 30G that are arranged opposite to green fluorescent layers 16G of the fluorescent screen 16, respectively, and that have a high transmission factor to light having a wavelength within a range of ±20 nm to a maximum emission spectrum wavelength among light emitted from the green fluorescent layers 16G. This transmission factor is higher than a transmission factor of light having a wavelength of 300 to 400 nm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device including a phosphor screen having phosphor layers of three or more colors.

  2. Description of the Related Art In recent years, various flat-type image display devices have attracted attention as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). For example, a surface conduction electron emission display (hereinafter referred to as SED) is being developed as a kind of field emission device (hereinafter referred to as FED).

  The SED includes a first substrate and a second substrate that are arranged to face each other at a predetermined interval, and these substrates form a vacuum envelope by joining peripheral portions to each other through rectangular side walls. ing. A phosphor layer of three colors and a metal back are formed on the inner surface of the first substrate, and a large number of electron-emitting devices corresponding to each pixel are arranged on the inner surface of the second substrate as electron-emitting devices that excite the phosphor. Has been.

  In the SED, in order to improve bright spot contrast and color purity, a color filter provided between the phosphor and the inner surface of the substrate has been proposed (for example, Patent Document 1). Transmit efficiently and absorb unnecessary components of external light. Therefore, it is possible to efficiently reduce the diffuse reflectance while suppressing a decrease in luminance, and to improve the bright place contrast. In addition, since the color filter absorbs light whose color purity is deteriorated, the color purity is also improved.

In the SED, when displaying an image, an anode voltage is applied to the phosphor layer, and the phosphor emits light by accelerating the electron beam emitted from the electron-emitting device by the anode voltage and colliding with the phosphor layer. Display an image. In order to obtain practical display characteristics, it is necessary to use a phosphor similar to a normal cathode ray tube and set the anode voltage to several kV or more, preferably 5 kV or more.
JP 2003-215327 A

  In the SED described above, when a phosphor excited at a wavelength of 300 to 400 nm is used, the phosphor emits light by external light such as indoor lighting or sunlight, so that light is emitted even during black display and the contrast of the bright place is reduced. I will let you. In particular, green has high visual sensitivity, so even a small amount of light emission reduces the bright place contrast. As a result, the display quality of the image display device is lowered.

  The present invention has been made in view of the above points, and an object thereof is to provide an image display device having high display performance.

  In order to achieve the above object, an image display device according to an aspect of the present invention is provided with a phosphor screen having an outer surface and an inner surface, and having phosphor layers of three or more colors including red, green, and blue on the inner surface. An envelope comprising: a first substrate disposed opposite to the first substrate; and a second substrate on which an excitation source for exciting the phosphor layer is disposed. A color filter provided between an inner surface of one substrate and the phosphor screen. The color filter is disposed to face the green phosphor layer of the phosphor screen, and transmits light having a wavelength in the range of ± 20 nm of the maximum emission spectrum wavelength among the light emitted from the green phosphor layer. The filter layer has a higher rate than the transmittance with respect to the wavelength of light having a wavelength of 300 to 400 nm.

  According to the above configuration, since light having a wavelength of 300 to 400 nm of external light is absorbed by the color filter, excitation of the phosphor due to external light can be suppressed, and transmission around the maximum wavelength of the green emission spectrum can be suppressed. Since the rate is high, there is almost no decrease in luminance. As a result, it is possible to obtain an image display apparatus with improved bright place contrast and high display performance.

  Hereinafter, an embodiment in which the present invention is applied to an SED as a flat-type image display device will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, this SED includes a front substrate 11 and a rear substrate 12 each made of a rectangular glass plate as insulating substrates, and these substrates have, for example, a gap of 1 to 3 mm. Are opposed to each other. The front substrate 11 and the back substrate 12 functioning as the first substrate and the second substrate are joined to each other through a rectangular frame-shaped side wall 13 and the inside of the flat rectangular vacuum outside is maintained in a vacuum state. The envelope 10 is configured. The side wall 13 functioning as a bonding member is sealed to the peripheral edge portion of the front substrate 11 and the peripheral edge portion of the rear substrate 12 by, for example, a sealing material 23 such as low melting glass or low melting metal, and these substrates are bonded to each other. is doing.

  A plurality of plate-like support members 14 are provided inside the vacuum envelope 10 in order to support an atmospheric pressure load applied to the front substrate 11 and the rear substrate 12. These support members 14 extend in a direction parallel to one side of the envelope 10 and are arranged at a predetermined interval along a direction orthogonal to the one side. Both ends in the longitudinal direction of each support member 14 are opposed to the side wall 13 with a gap. The support member is not limited to a plate shape, and may be a column shape.

As shown in FIGS. 2 and 3, a phosphor screen 16 that functions as a display surface is formed on the inner surface of the front substrate 11. The phosphor screen 16 includes red, green, and blue phosphor layers 16R, 16G, and 16B, and a black light shielding layer 20 that is positioned between the phosphor layers. The phosphor layers 16R, 16G, and 16B of three colors of red, green, and blue are formed alternately with a gap in the first direction, and the phosphor layers of the same color are in the second direction orthogonal to the first direction. Are arranged with a gap in between. Each of the phosphor layers 16R, 16G, and 16B constitutes a subpixel with single colors of red, green, and blue, and constitutes one pixel by combining the subpixels of three colors.
The phosphor layers 16R, 16G, and 16B are not limited to dot shapes, and may be stripe shapes.

  A metal back layer 17 made of an aluminum film or the like is formed on the phosphor screen 16, and a getter film 19 is formed on the metal back. According to the present embodiment, the metal back layer 17 has a plurality of divided regions that are divided in the vertical direction and the horizontal direction and are electrically separated from each other. The electrically separated metal back layer 17 is provided so as to overlap the phosphor layers 16R, 16G, and 16B.

  As shown in FIG. 2, a color filter 30 is provided between the phosphor layers R <b> 12, G <b> 13, B <b> 14 and the inner surface of the front substrate 11. The color filter 30 has red, green, and blue filter layers 30R, 30G, and 30B, and these filter layers are formed corresponding to the phosphor layers 16R, 16G, and 16B, respectively.

  The plurality of green filter layers 30G arranged to face the green phosphor layer 16G of the phosphor screen 16 have a light emission from the green phosphor layer 16G within a range of ± 20 nm of the maximum emission spectrum wavelength. The transmittance for light having a wavelength is higher than the transmittance for light having a wavelength of 300 to 400 nm. The green phosphor layer 16G of the phosphor screen 16 is excited by light whose maximum intensity is in the wavelength range of 300 to 400 nm.

  On the inner surface of the rear substrate 12, a number of surface conduction electron-emitting devices 18 that emit electrons are provided as excitation sources for exciting the phosphor layers 16 R, 16 G, and 16 B of the phosphor screen 16. These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. Each electron-emitting device 18 includes an electron emitting portion (not shown) and a pair of device electrodes for applying a voltage to the electron emitting portion. Further, a large number of wirings 21 for supplying a potential to the electron-emitting device 18 are provided on the inner surface of the rear substrate 12 in a matrix shape, and end portions thereof are drawn out of the vacuum envelope 10.

  In such an SED, when displaying an image, an anode voltage is applied to the phosphor screen 16 and the metal back layer 17, and electrons of a predetermined current amount are emitted from the electron emitter 18. Then, the electrons emitted from the electron emitter 18 are accelerated by the anode voltage and collide with the phosphor screen. As a result, the phosphor layers 16R, 16G, and 16B of the phosphor screen 16 are excited to emit light, and a color image is displayed.

  FIG. 4 shows a light absorption spectrum of the green filter layer 30G in the color filter 30. FIG. 5 shows a green emission spectrum when the color filter 30 is not used, and FIG. 6 shows a green emission spectrum when the color filter 30 is used. 5 and 6, D1 indicates the maximum light emission intensity during white display, and D2 indicates the maximum light emission intensity during black display. As the ratio D1 / D2 between D1 and D2 is larger, the contrast of the display image is improved. Comparing FIG. 4 and FIG. 5, it can be seen that by providing the color filter 30 as in the present embodiment, green light emission due to external light is suppressed, and as a result, the bright place contrast is improved.

  According to the SED configured as described above, since the light having a wavelength of 300 to 400 nm of the external light is absorbed by the color filter 30, excitation of the phosphor due to the external light can be suppressed, and the green emission spectrum can be suppressed. Since the transmittance of the filter layer near the maximum wavelength is set high, there is almost no reduction in luminance. As a result, since the emission of the green phosphor due to external light can be suppressed, the luminance during black display can be suppressed, and as a result, an image display device that has high contrast in the bright place and can maintain high display performance over a long period of time. can get.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can embody by modifying a component in the range which does not deviate from the summary. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  The present invention is not limited to SED, and may be applied to other image display devices such as FED and PDP. Moreover, the color filter should just have the green filter layer provided facing at least the green fluorescent substance layer, and may omit the red and blue filter layers.

FIG. 1 is a perspective view showing an SED according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the SED along line AA in FIG. FIG. 3 is a plan view showing the phosphor screen of the SED. FIG. 4 is a diagram showing an absorption spectrum of a green filter in a color filter provided in the SED. FIG. 5 is a diagram showing an emission spectrum when a conventional color filter is used. FIG. 6 is a diagram showing an emission spectrum when the color filter according to the embodiment is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope, 11 ... Front substrate, 12 ... Back substrate, 13 ... Side wall, 14 ... Support member,
16 ... phosphor screen, 16R, 16G, 16B ... phosphor layer,
17 ... Metal back layer, 18 ... Electron-emitting device, 20 ... Light shielding layer,
30 ... Color filter, 30R, 30G, 30B ... Filter layer

Claims (2)

A first substrate having an outer surface and an inner surface and a phosphor screen having phosphor layers of three or more colors including red, green, and blue on the inner surface is disposed opposite to the first substrate. A second substrate on which an excitation source for exciting the phosphor layer is disposed, and an envelope,
A color filter provided between the inner surface of the first substrate and the phosphor screen, disposed opposite to the green phosphor layer of the phosphor screen, and emitting light from the green phosphor layer Among them, a color filter having a filter layer whose transmittance for light having a wavelength in the range of ± 20 nm of the maximum emission spectrum wavelength is higher than that for light having a wavelength of 300 to 400 nm,
An image display device comprising:   2. The image display device according to claim 1, wherein the green phosphor layer of the phosphor screen is excited by light having a maximum intensity in a wavelength range of 300 to 400 nm.

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