JP2001034183A - Filter plate, image display element and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter which is disposed on the front side of the display plane of an image display element and on which eaves-like light-shielding bodies to improve the contrast of a visible image are formed. SOLUTION: Linear eaves-like light-shielding bodies 1 to be arranged in parallel to each other along the vertical direction D1 in the display plane 7S are formed on the surface 6S1 in the observer's side of a transparent filter substrate 6 disposed in the front of the display plane 7S. The vertical pitch S of the light-shielding bodies 1 is controlled so that the vertical pitch S and the pixel pitch Q of the image display element 1 satisfy the condition of Q/S=n+1/2 (wherein n is a positive integer). Thereby, the moire wavelength is 2Q as the minimum and the moire wavelength is made short enough so that the moire pattern is hardly visible on the obtained filter plate to improve the contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cathode ray tube (CR)
T), plasma display panel (PDP), liquid crystal display (LCD) panel, FED (Field Emi)
ssion display) and a filter plate placed in front of the display surface of an image display device such as an electroluminescent display (ELD) panel to improve the contrast of the viewed image and the electromagnetic radiation characteristics. is there.

[0002]

2. Description of the Related Art Generally used image display devices include:
In many cases, an optical filter function to increase the contrast of an image to improve display quality and an EMI (Electromagnetic interference) filter function to reduce electromagnetic radiation and prevent electromagnetic interference to the outside of the image display device are provided. , Has been added.

First, regarding the optical filter function,
Although it is common to use an ND (Neutral Density) filter which is less expensive than the conventional one, a filter plate for improving contrast, in which eaves-like projections are arranged, is disclosed in Japanese Patent Laid-Open No. 4-298936. I have. Therefore, a structure of a conventional filter plate of this type will be described below with reference to a longitudinal sectional view of FIG. As shown in the figure, a filter plate 6 having a three-dimensional structure (light shield) 1 arranged on a front surface of a plasma display panel 7 at a vertical pitch equal to a pixel interval and in parallel with each other along a vertical direction of the panel. Is arranged. As a result, incident light from the outside of the panel, that is, illumination light or natural light, is blocked to improve the bright room contrast of the displayed image. still,
10 is a front substrate of the plasma display panel 7, 11
Denotes a rear substrate, and 9 denotes a pixel.

As described above, the filter plate having the eave-like structure shown in FIG. 14 selectively blocks incident light from above. By the way, since ordinary illumination light and natural light enter from above, this filter plate effectively improves the contrast as compared with a normal neutral density filter (ND filter) that simply lowers the transmittance of visible light. The effect can be achieved. In the filter plate of FIG. 14, the light shields 1 as three-dimensional structures are arranged at a pitch equal to the pixel pitch of the plasma display panel 7, and the light shields 1 are arranged on the non-light emitting portions of the pixels.
Therefore, this configuration does not block display light emission from the plasma display panel 7 at all, and can be said to be an ideal configuration for improving bright room contrast. However, as shown in FIG.
This is effective only when the thickness of “0” is smaller than the arrangement pitch of the light shields 1 and therefore the pixel pitch. This is because, if (thickness of the substrate 10) ≧ (pixel pitch), the light shielding body 1 comes closer to the observer side. This is because they are blocked by the light and the viewing angle becomes narrow.

On the other hand, regarding the EMI filter function,
A conductive substance is applied or formed on the display surface (front panel surface) of the image display element, or an external EMI
It is customary to install a filter plate. As the latter external EMI filter plate, those in which a transparent conductive film such as an ITO (indium tin oxide) film is provided on a transparent substrate such as a glass substrate and those in which a metal mesh is embedded in the transparent substrate are generally used. It is used.

[0006]

The filter plate with a light shielding member shown in FIG. 14 can be said to have an ideal configuration, but has the following problems in practice.

(1) The first problem is that the pixel pitch and the vertical pitch of the light-shielding member must be accurately matched. A commonly used image display device has about 480 pixels in the vertical direction, and in recent years the number of pixels in both the horizontal direction and the vertical direction has been increasing more and more. It is not easy to exactly match the pitches of the pitches, and it is unavoidable that a shift occurs between the pitches. Furthermore, when the respective processes of the two types of structures include a high-temperature heat treatment, expansion or shrinkage of the substrate due to heat is inevitably caused, which also causes an error between the two and causes a pitch shift or deformation. The reality is inevitable. As a result, moiré occurs, and it is difficult to avoid display defects.

(2) The second problem, which can be said to be an essential problem of the eaves structure, is that a vertical (vertical) viewing angle is interposed. Usually, the front substrate of the image display element needs a thickness of about 1 mm to several mm due to the strength of the material such as glass used as the substrate, and this thickness is about several times as large as the pixel pitch. It is common that Therefore, even if the pitch of the light shields is designed to match the pixel pitch in design, the light shields may block the pixels depending on the observation angle, as described later, and a situation may occur in which the viewing angle is narrowed. That is, when the position of the observer in use is almost constant, such as a desktop personal computer display, it is unlikely to cause a problem in terms of the viewing angle. In so-called public display applications in public places such as those described above, an unspecified number of people observe the screen from various positions, and in such a case, the viewing angle is particularly problematic. That is, if the vertical viewing angle is limited, visibility changes for observers of various heights or when standing and sitting on a bench or the like. Furthermore, the problem that the viewing angle is narrowed causes a problem that the installation height and the installation angle of the display device are restricted.

(3) The third problem is that the structure of the filter plate shown in FIG. 14 has a precise structure as described above, so that it is compared with the case where the neutral density filter is simply arranged in front of the front panel. This tends to be expensive and increases the cost of the image display device.

(4) The fourth problem is that since the filter plate shown in FIG. 14 does not have an EMI filter function itself, it is necessary to separately take EMI countermeasures. In this regard, conventionally, a transparent conductive film such as an ITO film is used as a measure against EMI. However, since the ITO film and the like are somewhat expensive materials (the manufacturing apparatus is also expensive), FIG. In addition to the filter plate of ITO
The use of the film causes a problem that the cost of the image display device is further increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to increase the bright room contrast of a displayed image without causing moire and at low cost. .

A second object is to provide a filter plate having a wide viewing angle in the vertical direction.

A third object is to improve the bright room contrast while suppressing the cost of the entire image display device.
An object of the present invention is to make it possible to simultaneously perform EMI countermeasures and simultaneously perform blue enhancement.

[0014]

The invention according to claim 1 is
A filter plate installed in front of a display surface of an image display element to improve a contrast of an image to be viewed, comprising: a light-transmitting substrate; A plurality of eave-shaped light shields arranged in parallel with each other at a vertical pitch S in a vertical direction in the plane, and each of the plurality of light shields extends in a horizontal direction on the display surface orthogonal to the vertical direction. The condition that Q / S = n + ／ is satisfied between the vertical pitch S and the pixel pitch Q of the image display element and a positive integer n.

According to a second aspect of the present invention, there is provided a filter plate installed in front of a display surface of an image display element to improve the contrast of an image to be viewed, wherein the substrate is a light-transmitting substrate; A plurality of eave-shaped light shields formed on the surface on the observation side and arranged in parallel with each other at a vertical pitch S in the vertical direction in the display surface, wherein each of the plurality of light shields is in the vertical direction , And extends in the horizontal direction in the display surface orthogonal to the vertical direction, and the vertical pitches S between the light shielding bodies adjacent to each other in the vertical direction are unequal intervals.

According to a third aspect of the present invention, there is provided the filter plate according to the first or second aspect, wherein a plurality of light shields are arranged in the horizontal direction.

According to a fourth aspect of the present invention, there is provided the filter plate according to any one of the first to third aspects, wherein each of the plurality of light shields is formed by observing the substrate through a thick film layer containing ceramic powder. Is formed on the surface on the side.

According to a fifth aspect of the present invention, there is provided the filter plate according to any one of the first to fourth aspects, wherein one side surface of each light shield, which is an upper surface with respect to a direction perpendicular to the screen, is provided with the side surface, The other side that is inclined downward from the surface on the observation side of the substrate and that is a lower surface with respect to the vertical direction of the screen of each light shield is orthogonal to the surface of the substrate on the observation side. It is characterized by being.

The invention according to claim 6 is the filter plate according to any one of claims 1 to 5, wherein the substrate is made of a gray material having no wavelength characteristics.

The invention according to claim 7 is the filter plate according to any one of claims 1 to 6, wherein the substrate contains neodymium oxide.

According to an eighth aspect of the present invention, in the filter plate according to any one of the first to seventh aspects, each of the plurality of light shields contains a conductive material.

A ninth aspect of the present invention is the filter plate according to the eighth aspect, wherein the conductive material is a metal powder.

According to a tenth aspect of the present invention, there is provided the filter plate according to the eighth aspect, wherein the conductive material is carbon powder.

The invention according to claim 11 is the invention according to claims 1 to 1
0, wherein the transparent conductive film is formed on at least one of the surface on the observation side and the surface on the image display element side of the substrate. I do.

The twelfth aspect of the present invention relates to the first to fifth aspects.
The filter plate according to any one of claims 7 to 11, wherein the substrate is colored blue.

The invention according to claim 13 is the invention according to claims 1 to 1
3. The filter plate according to any one of 2), wherein at least one side surface of both side surfaces of each light shielding body is colored blue.

[0027] The invention according to claim 14 is the invention according to claims 1 to 1
3. The filter plate according to claim 3, wherein the filter plate is disposed in front of a front surface of the panel.

According to a fifteenth aspect of the present invention, there is provided the image display device with the filter plate according to the fourteenth aspect.

[0029]

Embodiment 1 FIG. 1 is an enlarged vertical cross-sectional view of a plasma display device (corresponding to an image display device) according to the present embodiment. However, in FIG. 1, in order to clarify the characteristic portion of the present invention, the illustration of the IC driving section and the housing of the panel is omitted, and
The panel and its filter plate are schematically depicted. In FIG. 1, reference numeral 1 denotes a striped light-shielding body made of, for example, glass, 6 denotes a filter substrate (also simply referred to as a substrate) for supporting the light-shielding body 1, and 7 denotes a plasma display panel (hereinafter also referred to as a PDP) as an image display element. Name), 2
Numeral 0 denotes a filter plate composed of the filter substrate 6 and the plurality of light shields 1, 8 denotes a gap provided between the filter plate 20 and the image display element 7, and 9 denotes one pixel of the image display element 7. D1 is a vertical direction in the display surface or the front surface 7S of the image display element 7, D2 is a horizontal direction in the display surface 7S orthogonal to the vertical direction D1, and S is an eave-shaped light shield 1 adjacent to the vertical direction D1. The vertical pitch of the light shield 1 corresponding to the center-to-center distance between them, Q is the pixel pitch of the image display element 7,
This is the center-to-center distance between adjacent pixels 9 in the vertical direction D1. Here, the pixels 9 are arranged along the horizontal direction D2 corresponding to the display line direction, and one pixel 9 is arranged in the horizontal direction D2.
Are arranged in the following order, for example, and are composed of unit light emitting regions of three colors of R (red), G (green), and B (blue). Note that one pixel 9 may be composed of four colors of RGB + W (white) in addition to the three colors of RGB. Alternatively, it may be composed of six unit light emitting regions of two R colors, two G colors, and two B colors arranged in the vertical direction D1.

FIG. 2 is a top view of the filter plate 20 centered on a light shield group consisting of a plurality of light shields 1 extending linearly in a stripe shape, and FIG. FIG. 4 is a longitudinal sectional view showing a state where the peripheral portion is attached to a housing 30 of the plasma display device.

As shown in FIGS. 1 and 2, a plurality of eave-shaped light shields 1 are formed on the observer-side surface 6S1 of the filter substrate 6 and have a predetermined (fixed) shape along the vertical direction D1. Are arranged parallel to each other at a vertical pitch S). Moreover, each light shield 1 extends linearly along the horizontal direction D2, whereby a light shield group including a plurality of light shields 1 forms a stripe structure.

Here, a gap 8 is provided between the surface 6S2 of the filter substrate 6 on the image display element side and the display surface 7S. This means that if the filter plate 20 is
This is because, when it is arranged on the display surface 7S so as to be in contact with the surface, it is possible to prevent a Newton's ring from being seen due to a minute gap. Therefore, as shown in FIG. 3, by mechanically fixing the peripheral edge of the filter substrate 6 to the inner peripheral edge of the opening 30 </ b> H of the housing 30, the filter plate 20 is positioned in front of the display surface 7 </ b> S of the image display element 7. Has been placed.

The feature of the structure shown in FIG. 1 is that both pitches S and Q are different from each other (Q> S), and the vertical pitch S and the pixel pitch Q and the positive integer n are different from each other.

[0034]

(Equation 1)

The point is that the vertical pitch S is set so that the above condition is satisfied. When the relational expression shown in Expression 1 is satisfied, the moiré wavelength L takes a minimum value 2Q as disclosed in Japanese Patent Publication No. Hei 7-117818, and the moiré wavelength L becomes sufficiently short. A natural moire pattern is hardly visible. Moreover, even if the vertical pitch S slightly deviates from the condition of Equation 1 due to a manufacturing error, an increase in the moiré wavelength L does not deteriorate image quality. For example, as shown in FIG. 2 of Japanese Patent Publication No. 7-117818, L / Q is 2.3 with respect to the horizontal axis of 1.05 / 1.5. Even if the pitch S causes an error of 5%, the moire wavelength L
Increases to about 0.3Q, which is only about 15% of the minimum value 2Q.

As described above, when the vertical pitch S of the light shield 1 does not match the pixel pitch Q (Q> S) and the relationship satisfying the expression 1 is satisfied, the light shield 1 becomes a part of the pixel 9. Will be blocked. This point is not preferable because it is one factor in lowering the luminance of the display image. However, as shown in FIG. 4, the width of each light shield 1 is changed from width W1 to width W2 (<W
If it is narrowed to 1), the aperture ratio will increase accordingly,
Since sufficient transmittance can be obtained even when using an external light-blocking filter (ND filter) conventionally used, the above point is not necessarily a disadvantage when compared with a neutral density filter. I can say.

As shown in FIG. 1, the light shield 1 is arranged on the surface (outer surface) 6S1 on the viewer side of the filter substrate 6, but this point is different in direction as compared with the case of FIG. . The light shield 1 is usually black for the purpose, and therefore the top of the light shield 1 is also black. Therefore, in the case of the present filter plate 20, since the top portion is in contact with the outer space, external light incident on the top portion is absorbed there, which can contribute to an improvement in bright room contrast. In addition, as schematically illustrated in FIG. 5, external light reflected on the observer-side surface 6S1 of the filter substrate 6 or external light reflected on the surface 6S2 facing the same surface 6S1 and transmitted through the filter substrate 6 again. Is the upper side surface 1 of the light shield 1
The light is absorbed by S1 or the lower side surface 1S2, thereby further improving the bright room contrast. On the other hand, in the conventional filter plate shown in FIG.
As shown in FIG. 1, since the light shielding body 1 is disposed on the surface of the transparent substrate 6 on the image display element side, incident light is reflected on the front and back surfaces of the transparent substrate 6 (reflected lights La and L).
b). The reflectivity at this time is usually about 4% when the transparent substrate 6 is made of glass, and the reflection of the external light Lb occurs on the back surface of the transparent substrate 6 regardless of the presence or absence of the light shield 1. The bright room contrast must be reduced. Therefore, it is more advantageous to arrange the light shield 1 on the surface 6S on the display element side of the filter substrate 6 from the viewpoint of the contrast improvement effect.

The light shield 1 needs to have a mechanical strength in addition to the function of absorbing external light. In addition, the material needs to be an inexpensive material excellent in workability. Therefore, as the material of the light shielding body 1, a mixture of fine particles of a ceramic material or the like and a low melting point glass powder is used.
More specifically, the powder is kneaded into a paste using an organic solvent or the like, and the paste is uniformly applied on the surface 6S1 of the filter substrate 6, and then processed into a slit by a sandblast method. Alternatively, a photosensitive hardening material may be mixed with the paste, the paste may be uniformly applied on the surface 6S1 of the filter substrate 6, and then pattern processing may be performed by photolithography. Alternatively, it is also effective to mold the light shielding body 1 on a surface 6S of the filter substrate 6 with a mold or the like using a plastic material. A general plastic material is generally transparent when it is amorphous, and opaque when it is crystalline, and usually has no absorption characteristics. Therefore, a black pigment may be added to the plastic material to form the light-shielding body 1.

As described above, according to the present embodiment, FIG.
It is possible to improve the contrast at a lower cost than in the case of (1) and without generating moiré.

Second Embodiment In the first embodiment, the vertical pitch S of the light shield is a constant value.
Bright room contrast while preventing moiré patterns
Other filter plate configurations that can be improved at low cost
The vertical pitch S between the light shields is set to be unequal.
In addition, it is possible to arrange the linear light shields 1 in the vertical direction D1.
it can. For example, the basic vertical pitch S ₀(This is a picture
± 1 relative to the elementary pitch Q)
%, ± 2%, ± 3%, ..., ± k% (k is a positive integer)
2k kinds of reduced vertical pitch S₁~ S_2kAdd
(2k + 1) kinds of vertical pitches are set.
Vertical pitch by randomly selecting each vertical pitch from
The arrangement pitch between the light shields for the direction D1 is adjacent to it
Set to always differ from the array pitch. like this
Random light shield 1 with no regularity in vertical direction D1
Of photolithographic masks to realize the arrangement of
Inevitably, it is actually a random number on the computer
What should I do to determine the arrangement pitch between the light shields using
The technical problems are small. In this case, when drafting
If we can use the ideal random number without bias
If the average pitch between the light shields is the basic vertical S₀Very
Value, and the light-shielding body group is formed over the screen size.
Can be

As described above, since the light-shielding body group randomly arranged in the vertical direction D1 does not have regularity, it does not easily cause a moire pattern by interfering with the pixels of the image display element 7, thereby reducing the manufacturing cost. It is possible to drastically improve the bright room contrast while reducing the cost and suppressing the occurrence of moire. This effect is, of course, increased as the value of k increases (the number of types of increase / decrease).

Also in this embodiment, the material of the light-shielding body 1 and the method of forming the same are as described in the first embodiment.
Except that the vertical pitch S is set at random,
Other configurations are the same as in the first embodiment.

Embodiment 3 In Embodiments 1 and 2, each light shield 1 has a configuration extending linearly in the horizontal direction D2, whereby the light shield group forms a stripe structure. In the present embodiment, the case where the light shields 1 are arranged at a predetermined pitch or at irregular intervals (corresponding to a horizontal pitch SA described later) in the horizontal direction D2 is handled. This will be described in detail below with reference to the drawings.

(1) Various methods such as a screen printing method, a scraping method, a sand blast method, and an additive method can be applied to form the light-shielding body 1. However, the metal mask printing method most suitable for thick film printing has already been described in FIG.
It is not easy to apply to a stripe structure as shown in FIG. This is because a thin stripe cannot secure the strength of the metal mask. In order to solve this problem, as shown in FIG. 7, a plurality of light-shielding members 1 may be formed by providing cuts 40 in the stripe in the horizontal direction D2. In this case, the pitch SA of the cut 40, and thus the horizontal direction D
Pitch (horizontal pitch) SA of the light-shielding members 1 arranged in 2
However, as a countermeasure against moire that can be caused by interference between the pitch SA and the pixel pitch Q of the display panel (image display element), the method of the first or second embodiment is also applied to the pitch SA. It goes without saying that you can do it.

(2) The arrangement of the light shields 1 does not need to be a stripe structure. For example, as shown in FIG. 8, the light shields 1 may be arranged in a staggered pattern at a horizontal pitch SA1. . Also in this case, it is possible to use the method of the first or second embodiment as a countermeasure against moiré that can be caused by the pitch SA1 and the pixel pitch Q.

When a pattern formed by arranging a large number of light shields 1 having a short longitudinal dimension as described in (1) and (2) above in the horizontal direction D2 is used, the metal mask has a mesh structure. Therefore, there is an advantage that a mask for thick film printing can be easily formed. For printing, a paste-like light shielding material adjusted to be thixotropic by mixing a high boiling point organic solvent or the like may be used. If the light shielding body 1 is formed by using this method, sufficient accuracy can be ensured as the filter plate 20 and the processing cost is reduced because of excellent mass productivity.

(3) In the case of forming a pattern by such thick film printing, blurring of the pattern edge may occur due to dripping of the paste. Therefore, as a method of improving this point, it is effective to paste a transparent ceramic powder such as silica or alumina in advance on the light-shielding body forming region in the surface 6S1 of the filter substrate 6 and form a uniform thick film. is there. By interposing such a thick film layer containing ceramic powder, the solvent in the pattern-printed light-shielding paste can be immediately absorbed into the thick film layer to prevent dripping, and the cross section can be reduced to the surface 6S1. It is possible to easily form the light-shielding body 1 having a shape that is steeply perpendicular to the light-emitting element. Therefore, an image display device with high contrast can be realized by the light-shielding body 1 without bleeding.

Fourth Embodiment This embodiment relates to an improvement of the filter plate 20 according to the first to third embodiments. In particular, the shape (rectangular parallelepiped) of the light shielding body 1 is changed to increase the viewing angle. Things.
That is, in the present embodiment, one side surface 1S1 which is the upper surface in the vertical direction D1 of each light shielding body is opposed to the other lower surface so that it is inclined downward from the connection portion with the surface 6S1 of the substrate 6. The shape of the light shield 1 is set so that the other side surface 1S2 is a plane perpendicular to the surface 6S1. Hereinafter, the specific configuration will be described in detail with reference to the drawings.

(1) FIG. 9 is an enlarged longitudinal sectional view showing a main part of a filter plate 20 according to the present embodiment. As shown in the figure, the vertical cross-sectional shape of each light shielding body 1 has a shape of a right triangle, and as a result, the emission angle of display light differs in the vertical direction. That is, the emission of the display light upward is limited by the second side surface 1S2 on the lower surface side, but the emission of the display light downward is directed to the outside along the first side surface 1S1 as the upper surface inclined downward. The amount of emitted display light is increased as compared with the case of the first embodiment in FIG. This has an opposite effect on the incidence of external light, and the incident light obliquely from above is substantially equal to the first side surface 1S1.
On the other hand, most of the light incident from below having a shallow angle enters the filter substrate 6 without being absorbed by the light shield 1. Accordingly, the effect of improving the contrast with respect to external light from below is reduced, but the visibility from a position lower than the screen is significantly improved. In general, lighting is performed from above, and the intensity of light reflected from the floor or wall is weaker than that of the direct light from the lighting equipment.Therefore, when lighting is performed from below or when the reflectance of the floor or wall is extremely high. In most cases, it can be expected that the viewing angle increasing effect is larger than the contrast lowering effect.

(2) However, the light shielding body 1 shown in FIG. 9 has an extremely thin top, so that there is a tendency that mechanical damage such as chipping or chipping is likely to occur. What improves this point is a modified example shown in FIG. That is, each light shielding body 1 is processed so that its vertical cross-sectional shape becomes a trapezoid including a right angle. By providing a flat region on the top of the light shielding body 1 as described above, a thin tip is eliminated and mechanical damage such as chipping or chipping on the top is less likely to occur. Moreover, similarly to the case of FIG. 9, the first side surface 1S1 inclined downward and the display surface 6S1 of the filter substrate 6 are formed.
Since the light shielding body 1 has the second side surface 1S2 perpendicular to the above, the operation and effect described above in the case of FIG. 9 can be secured.

Embodiment 5 This embodiment is directed to the filter plate 2 according to the first to fourth embodiments.
0 for further improvement, especially for filter plate 20
In addition to the function of realizing high contrast without causing moiré, it also has an EMI filter function. The latter function can be realized by including a conductive material in each of the light shields 1. That is, since the light shielding body 1 itself has conductivity, when electromagnetic waves pass between the light shielding bodies, energy loss occurs due to electromagnetic induction, so that electromagnetic interference is reduced. Hereinafter, a specific configuration of the light shield 1 will be described in detail with reference to the drawings.

(1) The production of a filter plate for improving contrast using an eaves-like light-shielding body involves fine processing of a large area corresponding to the screen of an image display element. ND that has been used for
They generally require a considerable cost compared to filters. In addition, as a major problem of the image display device, it is necessary to reduce electromagnetic radiation, that is, to take measures against EMI. To realize this function, glass with an ITO film has been generally used conventionally. However, since the material of the ITO film is expensive, a vacuum chamber is required for the film formation, and the sputtering device is also expensive, the cost of the image display device is increased by providing a filter plate for EMI countermeasures. There is a disadvantage that it will. However, the contrast improvement filter and the EMI countermeasure filter are both indispensable devices in the image display device. Therefore, in mass production, both filter functions can be realized together without incurring a considerable cost that is not negligible compared to the cost of the image display device, and thus not reducing the industrial value of the image display device itself. It is required that filters can be manufactured at low cost. This request has been made by IT
The EMI filter function realized by the O film or the like can be effectively solved by providing the light-shielding body filter plate 20 itself described in the first to fourth embodiments.

FIG. 11 is an enlarged sectional view of the light shielding body 1 which also has a function of blocking electromagnetic radiation. Although the shape of the light shielding body 1 is drawn as a rectangular parallelepiped for convenience, the shape shown in FIGS. 9 and 10 may be used. In FIG. 11, 2 is a fine powder of a conductive material such as a metal, 3 is black pigment particles, and 4 is a molding material for molding and holding the light shielding body 1. For example, the molding material 4 is made of an adhesive glass containing PbO or B ₂ O ₃ , an acrylic resin, ethyl cellulose, an epoxy resin, or the like. Other configurations as the filter plate 20 are not different from the first to fourth embodiments. By using a light-shielding body having such a material component as the light-shielding body 1 of the filter plate 20, an extremely high electromagnetic shielding property can be obtained by using a material which is much cheaper than a transparent conductive oxide thin film such as an ITO film. Can be obtained. In particular, the light-shielding body 1 has not only a significantly lower material cost than the ITO film but also a method of forming the same, which can be manufactured in a vacuum-free state, such as screen printing, scraping, or sandblasting. Since there is an advantage that there are many options by being able to select, the mass production effect can be easily derived.

As described above, by using the filter plate 20 with the light shielding body shown in FIG. 11, the EMI countermeasures can be reduced while improving the contrast without causing moire and at a lower cost than the filter plate of FIG. This has the advantage that it can be realized at low cost.

(2) The filter plate 2 illustrated in FIG.
Numeral 0 corresponds to a modification of this technique, in which carbon particles 5 are used as a conductive material instead of metal particles and black pigment. By using the inexpensive carbon particles 5 which are originally black and have conductivity, it is possible to obtain the filter plate 20 with a light shielding member which is more inexpensive and has electromagnetic shielding properties than the case of FIG.

(3) Further, for the purpose of pursuing the electromagnetic shielding property, as shown in FIG.
A transparent conductive film 12 of ITO, tin oxide, zinc oxide, etc.
It is also possible to provide. In this case, the light shielding body 1 may be any of those described in the first to fourth embodiments, or may be the one shown in FIG. 11 or FIG. 12 of the present embodiment. Further, the transparent conductive film 12 may be provided on the surface 6S1, or may be provided on both surfaces 6S1 and 6S2.

Embodiment 6 This embodiment relates to Embodiment 1.
Pertaining to the improvement of the filter plate according to
It aims to realize blue enhancement at low cost.

(1) From the viewpoint of realizing the blue enhancement while reducing the cost of the image display device, the intensity of blue light emission is low in characteristic and the color temperature of white display is low, especially in a plasma display element or the like. When the element is used in combination with the light-shielding filter plate 20, it is effective to color the filter substrate 6 in blue.

In the conventional plasma display device, the front glass substrate of the image display device is colored blue in order to increase the relative intensity of blue in the three primary colors of blue, green and red. I was However, despite the fact that the glass plate colored in blue is expensive, the front substrate of the image display element often forms a more complicated structure than the filter plate, and controls patterning and surface physical properties by photolithography. It is difficult to obtain a high yield because such advanced steps are performed a plurality of times. For this reason, it is important to use as low a cost material as possible for the substrate of the image display element. In addition, when an external blue glass plate or the like is mounted in front of the display surface of the image display device, the image display device is colored blue, and the interior is impaired.

On the other hand, for the filter plate 20 with a light shielding member using a blue (glass) substrate as the filter substrate 6, only the yield of the light shielding member 1 needs to be considered at the time of manufacturing. In addition, the use of the black light shielding body 1 reduces the bluish color tone of the entire filter plate 20, and is practically hardly visually recognized as blue.
As a result, by using such a filter plate 20, it is possible to obtain an image display device which is inexpensive, has high interior properties, and has high visibility with blue color emphasized.

(2) As another method for obtaining the blue enhancement function at low cost, the first and second side surfaces 1S
In 1,1S2, there is a method of coloring at least one side surface in blue. When the display light emitted from the pixel 9 (FIG. 1) is incident on the blue-colored side surface of the light shielding plate 1, the light shielding body side surface can selectively reflect only the blue color. Can be emphasized. The same can be said for incident light from the outside.However, blue light is perceived to be lower in luminance than green or red due to human luminosity characteristics. The decrease in contrast caused by a part of the blue light reflected by the side surface and incident on the image display element is slight. At this time, the top of the light shield 1 may be separately colored black so that the color tone of the entire light shield may be close to gray. In this case, the same effect is obtained, and the contrast is improved only in the portion where the top is black. Can be further improved.

Modifications Common to First to Sixth Embodiments (1) In order to further enhance the contrast improving effect,
A substrate containing a dimming material, that is, a gray translucent substrate having no wavelength characteristic may be used as the filter substrate 6. In this case, the external light incident from between the adjacent light shielding bodies 1 is attenuated by transmitting through the same substrate 6, reflected by the display surface 7 </ b> S of the image display element 7, and transmitted through the filter substrate 6 again. Attenuated. Therefore, the same substrate 6 only once
According to this modification, the relative intensity of the external light with respect to the display light radiated to the outside after passing through is reduced, so that the light shielding body 1 is provided as in any one of the first to sixth embodiments. In addition to the improvement of contrast (no moiré), the contrast is further improved.

The present modification (1) is a modification of the filter plate 2 according to all the above-described embodiments except (1) of the sixth embodiment.
0 is applicable.

(2) In an image display device using a phosphor such as a CRT or a plasma display device,
In order to improve the contrast, a filter plate made of glass or transparent resin containing neodymium oxide is sometimes used. The principle is as follows. That is, since neodymium ion has an absorption band in the middle of the green and red phosphor emission spectra, it is necessary to selectively block external light having a wavelength belonging to this absorption band without substantially impairing the phosphor emission. Can be achieved, thereby improving the contrast. In addition, neodymium oxide also has an effect of blocking unnecessary orange light emission from Ne emitted from the plasma display element. Therefore, the substrate 6 of the filter plate 20 according to any of Embodiments 1 to 6
In addition, if neodymium oxide is contained, a function of further improving the contrast without generating moiré and a function of removing Ne light of the plasma display element can be obtained.

(3) In the first to sixth embodiments, the PDP
Has been described as an image display element, but the concepts in Embodiments 1 to 6 can also be applied to other flat panel display elements and CRTs.

[0066]

According to the first, second, fourteenth, and fifteenth aspects of the present invention, a high-contrast image display apparatus free from moire can be realized by using the present filter plate.

Moreover, since all of the plurality of light shields are formed on the substrate surface on the observer side instead of on the image display element side, an image display device with higher contrast can be obtained.

According to the third, fourteenth and fifteenth aspects of the present invention, since a large number of short-sized light shields are arranged in the horizontal direction, a screen printing method using a metal mask is used for forming the light shields. And the effect that the formation of the mask becomes easy can be obtained.

According to each of the inventions described in claims 4, 14 and 15, when the light shield is formed by screen printing, the solvent in the light shield paste on which the pattern is printed bleeds, and the pattern edge bleeds. Can be effectively prevented.

According to each of the inventions described in claims 5, 14 and 15, there is an effect that an image display device having a high contrast (no moire generated) and a wide viewing angle can be realized.

According to each of the sixth, thirteenth and fourteenth aspects of the present invention, since the light-transmitting substrate is a gray color having a reduced transmittance, an image display device having a higher contrast can be obtained.

According to the seventh, fourteenth, and fifteenth aspects of the present invention, since the light-transmitting substrate contains neodymium oxide, the emission spectra of green and red can be obtained without impairing the intensity of light emitted from the pixel. It is possible to selectively block external light having a wavelength belonging to the intermediate range, and to eliminate unnecessary light emission from Ne when the image display element is a PDP. An image display device having a removal function can be obtained.

According to each of the eighth, fourteenth, and fifteenth aspects of the present invention, it is possible to improve the contrast and the EMI while suppressing the occurrence of moire.
A filter plate that can also serve as a countermeasure can be provided at low cost, and an inexpensive and high-contrast image display device can be obtained.

According to the ninth, fourteenth and fifteenth aspects of the present invention,
Since the light shield contains metal powder, the filter plate for improving contrast can also serve as a measure against EMI, and a filter plate having an inexpensive light shield can be obtained.

According to the tenth, fourteenth, and fifteenth aspects of the present invention, the filter plate for improving contrast can also serve as an EMI countermeasure because the light shielding member contains carbon powder, and a filter having an inexpensive light shielding member. You can get a board.

According to the eleventh, fourteenth and fifteenth aspects of the present invention, a filter plate for realizing an image display device having excellent electromagnetic shielding characteristics because the light-transmitting substrate has conductivity is provided. Can be.

According to the twelfth, fourteenth, and fifteenth aspects of the present invention, since the light-transmitting substrate is colored blue, a high-color-temperature image display device having a blue enhancement function can be realized at low cost. be able to.

According to each of the thirteenth to fifteenth aspects,
Since at least one side surface of each light shield is colored blue, an image display device having a high color temperature and also having a blue enhancement function can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view of a characteristic portion of a plasma display device according to a first embodiment of the present invention.

FIG. 2 is a plan view schematically showing an arrangement of light shielding members of the filter plate according to the first embodiment.

FIG. 3 is a longitudinal sectional view schematically showing a mechanism of the plasma display device according to the first embodiment.

FIG. 4 is a diagram showing that it is preferable to reduce the width of the light shielding body.

FIG. 5 is an enlarged longitudinal sectional view showing an advantage of the filter plate according to the first embodiment.

FIG. 6 is an enlarged longitudinal sectional view comparatively showing a problem in the case of the prior art.

FIG. 7 is a plan view schematically showing an arrangement of light shielding members of a filter plate according to a third embodiment.

FIG. 8 is a plan view schematically showing an arrangement of light shielding members of a filter plate according to a third embodiment.

FIG. 9 is an enlarged longitudinal sectional view showing a main part of a filter plate according to a fourth embodiment.

FIG. 10 is an enlarged longitudinal sectional view showing a main part of a filter plate according to a fourth embodiment.

FIG. 11 is an enlarged vertical cross-sectional view of a light shield on a filter plate according to a fifth embodiment.

FIG. 12 is an enlarged longitudinal sectional view of a light shield on a filter plate according to a fifth embodiment.

FIG. 13 is a partial longitudinal sectional view of a filter plate according to a fifth embodiment.

FIG. 14 is an enlarged vertical cross-sectional view of a plasma display device according to the related art.

[Explanation of symbols]

Reference Signs List 1 light shielding body, 6 filter substrate, 6S1 observer side surface, 7 image display element, 7S display surface, 9 pixels, 2
0 filter plate, S vertical pitch, Q pixel pitch,
D1 vertical direction, D2 horizontal direction.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA34X FA41Z FB02 FC13 FC14 GA01 GA03 LA12 LA17 LA19 5C058 AA01 AA06 AA11 BA08 DA03 5C060 HC14 JA00 JA17 5G435 AA00 AA01 AA02 AA17 BB01 BB06 BB11 HGG11 BB11 BB11 BB11 CC09 DD12

Claims (15)

[Claims] 1. A filter plate installed in front of a display surface of an image display device for improving contrast of a viewed image, comprising: a light-transmitting substrate; A plurality of eave-shaped light shields formed and arranged parallel to each other at a vertical pitch S in the vertical direction in the display surface, wherein each of the light shields is orthogonal to the vertical direction. The vertical pitch S and the pixel pitch Q of the image display device
And a positive integer n, wherein the condition Q / S = n + 1/2 is satisfied. 2. A filter plate installed in front of a display surface of an image display device for improving contrast of a viewed image, comprising: a light-transmitting substrate; A plurality of eave-shaped light shields formed and arranged parallel to each other at a vertical pitch S in the vertical direction in the display surface, wherein each of the light shields is orthogonal to the vertical direction. A filter plate, which extends in a horizontal direction in the vertical direction, and wherein the vertical pitches S between the light shielding bodies adjacent to each other in the vertical direction are unequal intervals. 3. The filter plate according to claim 1, wherein a plurality of light shields are arranged also in the horizontal direction. 4. The filter plate according to claim 1, wherein each of the plurality of light shields is formed on a surface on the observation side of the substrate via a thick film layer containing ceramic powder. A filter plate characterized by being made. 5. The filter plate according to claim 1, wherein one side of each light shield, which is an upper surface with respect to a direction perpendicular to the screen, is on the observation side of the substrate. The other side surface, which is inclined downward from the surface and is the lower surface with respect to the vertical direction of the screen, of each light shield, is orthogonal to the surface on the observation side of the substrate. Filter plate. 6. The filter plate according to claim 1, wherein the substrate is made of a gray material having no wavelength characteristics. 7. The filter plate according to claim 1, wherein said substrate contains neodymium oxide. 8. The filter plate according to claim 1, wherein each of the plurality of light shields contains a conductive material. 9. The filter plate according to claim 8, wherein the conductive material is a metal powder. 10. The filter plate according to claim 8, wherein the conductive material is a carbon powder. 11. The filter plate according to claim 1, wherein a transparent conductive film is formed on at least one of the surface on the observation side and the surface on the image display element side of the substrate. A filter plate characterized by having a pattern formed thereon. 12. The method according to claim 1, wherein the first and the fifth methods are the same as the first and the second methods.
The filter plate according to any one of claims 1 to 3, wherein the substrate is colored blue. 13. The filter plate according to claim 1, wherein at least one side surface of both side surfaces of each light shield is colored blue. 14. An image display device, wherein the filter plate according to claim 1 is disposed in front of a front surface of a panel. 15. An image display device comprising the image display element with the filter plate according to claim 14.