JP2001092389A - Array type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of such phenomenon that the boundaries of adjacent planar display elements looks like joints due to reflected and refracted light beams on a display, in which the planar display elements are arranged in a tile shape, by covering the boundaries with a diffraction grating. SOLUTION: The reflected light beams L1 and L3 and the refracted light beams L2 at the boundary bd are displayed into a direction orthogonal to the direction of the boundary bd by covering each of the planar display elements 11 that are arranged in a tile shape with the diffraction grating 7 in which its direction of grooves is aligned with the boundary bd of the adjacent elements 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which flat display elements are arranged in tiles, and more particularly to a display device in which boundaries between adjacent flat display elements are made inconspicuous.

[0002]

2. Description of the Related Art One type of display is an electroluminescent display (ELD). The ELD is based on electroluminescence, which is a phenomenon that emits light when a voltage is applied to a phosphor.

[0003] EL elements are classified into inorganic EL elements using inorganic compounds and organic EL elements using organic compounds according to the chemical composition of the display material (fluorescent material). From a dispersion type EL element in which the display material is made into a powder, and a thin film EL in which the display material is made into a dense thin film.
They are classified into elements. In recent years, of these, organic thin film EL
The element has attracted special attention because it can provide high luminance at low voltage and because the fluorescent color of the organic compound itself is a luminescent color, so that the luminescent color can be easily selected.

In this organic thin film EL device, a transparent anode is formed in a stripe shape on a glass substrate, and an organic layer comprising an organic hole transport layer, an organic light emitting layer and an organic electron transport layer is formed on the anode. On the organic layer, a cathode is formed in a stripe shape perpendicular to the anode.

As the anode, for example, an electrode made of ITO (indium-tin oxide) is used. As the cathode, a metal electrode such as aluminum or an alloy of aluminum and lithium is used.

[0006] The organic hole transport layer has a role of moving holes injected from the anode to the organic light emitting layer. The organic electron transport layer has a role of transferring electrons injected from the cathode to the organic light emitting layer. A fluorescent material according to the color to be displayed is used for the organic light emitting layer.

When a voltage is applied between the anode and the cathode, the holes injected from the anode move to the organic light emitting layer via the organic hole transport layer, and the electrons injected from the cathode pass through the organic electron transport layer. Move to the organic light emitting layer. The holes and electrons are located at the intersection of the anode and cathode in the organic light emitting layer,
Rejoin. The fluorescent material in the organic light emitting layer is excited by this recombination as an external stimulus. Then, when the fluorescent material returns from the excited state to the ground state again, fluorescence is emitted from the fluorescent material, and the light is observed through the glass substrate.

Therefore, when a display signal and a scanning signal are supplied to the organic thin film EL element using the anode and the cathode as, for example, a signal electrode and a scanning electrode, respectively, a desired image is formed by using each intersection of the anode and the cathode as a pixel. Can be displayed. (Note that, in this specification, when an image is displayed in units of a plurality of pixels such as RGB pixels, the plurality of pixels are called a picture element, and the image is displayed in units of a single pixel. Even when displayed, the single pixel is called a picture element.)

[0009]

In recent years, the need for a large-screen display has been increasing. However, a single display panel (in the case of an organic thin-film EL element, an organic thin-film EL element is formed on a substrate, and a driving circuit is required). The display panel is provided with an extraction electrode for supplying a display signal and a scanning signal to an anode and a cathode. In this specification, such a display panel is called a flat display element.) In this case, there are many difficulties in terms of mechanical strength and the necessity of increasing the drive voltage with an increase in the resistance of the electrode.
Therefore, unitizing the flat display elements and arranging a plurality of flat display elements in a tile shape is an effective method for realizing a large screen. In the case of an organic thin film EL element, it can be said that it is particularly suitable for such unitization because the device structure is relatively simple and vacuum sealing is not required.

However, in such a display in which the flat display elements are arranged in a tile shape (herein, referred to as an array type display device or a tiling display), boundaries between the adjacent flat display elements are inconspicuous. It is important to do so.

The reason why this boundary is conspicuous is that a non-display portion (a portion where no picture element is formed) having a width wider than the picture element pitch of the flat display element is present at this border. However, even if such a non-display portion does not exist, the boundary may be conspicuous due to light reflection or refraction at the boundary.

FIG. 15 shows how light is reflected and refracted at this boundary. In FIG. 15A, a slight air layer (air gap) is present at the boundary bd between the adjacent flat display elements 51, so that light enters the air gap from the picture element PX of the flat display element 51 at a critical angle or more. The reflected light L1 is totally reflected on the display surface side.

[0013] The totally reflected light L1 reaches the eyes of a person viewing the display surface, whereby the boundary bd is seen as a joint. In addition, other than the air gap, light from the picture element PX is also reflected on the display surface side by minute dust existing at the boundary bd or slight distortion of the side surface of the glass substrate on the display surface side of the flat display element 51. Therefore, the boundary bd is seen as a joint.

In FIG. 15B, since the corner 51a of the glass substrate on the display surface side of the flat display element 51 is missing, the light L2 incident on the corner 51a from the picture element PX is refracted to the display surface side. ing. In FIG. 15C, this corner 5
External light L3 incident toward 1a is reflected on the display surface side. The lights L2 and L3 also reach the eyes of the viewer who sees the display surface, whereby the boundary bd also appears as a joint.

In view of the above, the present invention has been made in consideration of the above-described problem, in order to make the boundary between adjacent flat display elements less conspicuous in an array type display device, in which the boundary is seen as joints due to light reflection or refraction. The object of the present invention is to prevent or at least suppress the above.

[0016]

Means for Solving the Problems To solve this problem, the present applicant has proposed that a portion of the display surface other than immediately above a picture element is:
An array-type display device covered with a light-blocking member is proposed.

In this array type display device, a portion other than directly above the picture element on the display surface (ie, a portion other than directly above the picture element on each flat display element and a boundary between the adjacent flat display elements). ,
It is covered with a light blocking member.

As described above, since the boundary between the adjacent flat display elements is covered with the light shielding member, the reflected light or the refracted light at this boundary as shown in FIGS. 15A and 15B is blocked by this member. , It is not reachable to the viewer. FIG.
External light as shown in FIG. 5C is blocked by this member and does not reach this boundary, so that it is not reflected at this boundary. As a result, this boundary is not seen as a joint.

Since portions other than directly above the picture elements on each flat display element are also covered with the same light-blocking member as the boundary, unlike the case where only this boundary is covered with the light-blocking member, This boundary is not noticeable by the existence of.

It is preferable to use, for example, a black mask as the light shielding member.

Further, as an example, the flat display element constituting this array type display device includes a display material and a display material between a first transparent substrate located on the display surface side and a second substrate located on the back surface side. It is preferable that a film for sealing the display material and the electrodes is formed on the side surfaces of the first and second substrates with electrodes interposed therebetween.

In this flat display element, since the film is sealed on the side surface of the substrate by the film, the picture element can be formed immediately near the edge of the substrate surface. The thickness of this film can be made sufficiently smaller than the pixel pitch.

Thus, in the array type display device in which the flat display elements are arranged, the non-display portion of the boundary between the adjacent flat display elements is eliminated, so that the boundary becomes less noticeable.

Next, the present applicant proposes an array type display device in which a display surface is covered with a member for dispersing light in a direction orthogonal to a direction of a boundary between adjacent flat display elements.

In this array type display device, the display surface (ie, the boundary between each flat display element and the adjacent flat display element)
Is covered with a member that disperses light in a direction orthogonal to the direction of the boundary.

As described above, since the boundary between the adjacent flat display elements is covered with the member for dispersing the light in the direction orthogonal to the direction of the boundary, the reflected light at this boundary as shown in FIG. And refracted light are dispersed in a direction orthogonal to the direction of the boundary. As a result, the intensity of the reflected light reaching the eyes of the viewer on the display surface is reduced, so that the boundary is not seen as a joint (or at least is hardly seen as a joint).

Also, since each flat display element is covered with the same member as the boundary, light is dispersed similarly to the boundary. Therefore, unlike the case where light is dispersed only at the boundary, the boundary does not become conspicuous due to the dispersion of the light.

Further, since the entire display surface is covered with a member for dispersing light, not only the portion on the display surface other than immediately above the picture element, the shape of the member on the display surface has a periodic pattern. Absent. Therefore, moire does not appear in the image displayed on the array type display device.

As a member for dispersing the light,
For example, it is preferable to use a diffusion object (diffuser). As a result, the reflected light at this boundary is scattered in all directions, so that the reflected light is also dispersed in a direction orthogonal to the direction of this boundary.

Alternatively, as a member for dispersing the light, it is preferable to use a diffraction grating in which the direction of the groove matches the direction of the boundary. Thereby, the reflected light at this boundary is dispersed into the 0th-order diffracted light and the other-order diffracted lights (mainly ± 1st-order diffracted lights) in a direction orthogonal to the direction of the boundary. Moreover, in the direction orthogonal to the direction of this boundary,
Since the light is only scattered in a particular direction, the picture elements do not look blurry.

When a diffraction grating is used in an array type display device in which flat display elements are vertically and horizontally arranged, as an example, the direction of the groove is made to coincide with the vertical boundary of the adjacent flat display elements. It is preferable that the diffraction grating and a diffraction grating in which the direction of the groove coincides with the lateral boundary of the adjacent flat display element are overlapped in a direction perpendicular to the display surface.

As a result, both the vertical boundary and the horizontal boundary do not appear as joints.

When a diffraction grating is used, as an example, it is preferable to overlap a plurality of diffraction gratings having the same groove direction in a direction perpendicular to the display surface.

As a result, the reflected light at the boundary is dispersed a plurality of times, so that the intensity of the reflected light reaching the eyes of a person viewing the display surface is further reduced. Therefore, this boundary becomes more difficult to see as a joint.

When a plurality of diffraction gratings are stacked, it is preferable to use, as an example, a planar member having a diffraction grating formed on both surfaces.

Further, as an example, the flat display element constituting the array type display device also includes a display material and a display material between a first transparent substrate located on the display surface side and a second substrate located on the back surface side. It is preferable that a film for sealing the display material and the electrodes is formed on the side surfaces of the first and second substrates with electrodes interposed therebetween.

As a result, the non-display portion of the boundary between the adjacent flat display elements is eliminated, so that the boundary becomes less noticeable.

Next, the applicant of the present invention has proposed an array type display device in which unevenness is provided on a side surface of a flat display element, and adjacent flat display elements are bonded to each other by an adhesive filled in a gap between the unevenness. Suggest.

In this array type display device, since the side surfaces of the flat display element are uneven, less of the light totally reflected at the boundary between adjacent flat display elements is reflected on the display surface side. . Therefore, this boundary is not seen as a joint (or at least becomes difficult to see as a joint).

Further, since the side surfaces of the flat display element are uneven, it is easy to evenly fill the gap between the adjacent flat display elements with the adhesive. Therefore,
Since the total gap itself is less likely to occur at the boundary due to the decrease in the air gap, this boundary is also less likely to be seen as a joint at this point.

Further, since the side surfaces of the flat display element are uneven, the bonding area between the flat display elements is larger than in the case where the side surface is flat. Is getting bigger. This makes it possible to realize a large-screen display that is thin and has sufficient strength.

In this arrangement type display device, for example, it is preferable that the refractive index of the adhesive is substantially equal to the refractive index of the transparent substrate on the display surface side of the flat display element.

As a result, the light incident on the adhesive from the transparent substrate is hardly refracted, so that the boundary between the adjacent flat display elements is hardly seen as joints.

Also in this array type display device, it is preferable to provide a member for dispersing light, such as the aforementioned diffusing object or diffraction grating. Thereby, the boundary between the adjacent flat display elements becomes more difficult to see as joints.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a tiling display using an organic thin film EL device will be described below.

FIG. 1 is a perspective view showing an example of an arrangement of flat display elements in a tiling display according to the present invention. Four flat panel display elements 11 are arranged two by two in the horizontal direction and the vertical direction (x and y directions in the drawing).

FIG. 2 is a side sectional view showing an example of the configuration of the tiling display according to the present invention. In the tiling display 1, on the glass substrate 12 on the display surface side of each of the flat display elements 11 arranged as shown in FIG. 1, a portion other than immediately above the picture element PX of each of the flat display elements 11 (ie, The black mask 2 is formed at a position directly above the black mask BM in the gap between the picture elements PX on each flat display element 11 and a position directly above the boundary bd between the adjacent flat display elements 11. FIG. 3 is a plan view of the black mask 2 viewed from the display surface side of the tiling display 1.

As a material of the black mask 2, metal chromium, resin black in which carbon or the like is dispersed in a photoresist, or a metal material such as nickel is used. As a method of forming the black mask 2, for example, a method of forming a film of such a material by sputtering is employed.

FIG. 4 is a side sectional view showing reflected light and refracted light at the boundary bd of the tiling display 1 in correspondence with FIG.

FIG. 4A corresponds to FIG. 15A. Among the light from the picture element PX, the light L1 incident on the boundary bd
Is reflected toward the display surface due to the presence of an air gap or the like. In this tiling display 1, this light L
1 is blocked by a black mask 2 that covers the boundary bd and does not reach the eyes of a person viewing the display surface. Thereby, this light L
The reflection of 1 prevents the boundary bd from being seen as a joint.

FIG. 4B corresponds to FIG. 15B. Since the corner 12a of the glass substrate 12 on the display surface side is missing, the light L incident on the corner 12a from the picture element PX is obtained.
2 is refracted toward the display surface. This light L2 is also at the boundary b
It is blocked by the black mask 2 covering d, and does not reach the eyes of a person viewing the display surface. This prevents the boundary bd from being seen as a joint due to the refraction of the light L2.

FIG. 4C corresponds to FIG. 15C, and the external light L is applied in the direction of the chipped corner 12a of the glass substrate 12.
3 is incident. This external light L3 is blocked by the black mask 2 covering the boundary bd, and does not reach the corner 12a. Thus, the external light L3 does not reflect at the corner 12a, and therefore, the boundary bd does not appear as a joint due to the reflection.

As described above, in the tiling display 1, since the boundary bd is covered with the black mask 2, the boundary bd is caused by the reflection or refraction of light at the boundary bd.
Is prevented from appearing as joints.

Since the black mask BM on each flat display element 11 is also covered with the same black mask 2 as the boundary bd, unlike the case where only the boundary bd is covered with the black mask 2, The boundary bd is not noticeable due to the existence.

As a member for covering a portion other than directly above the picture element PX, an appropriate member other than the black mask that can block light may be used.

The thickness of the glass substrate 12 is made as thin as possible without hindering the strength or the like so that the boundary bd is not seen even when the display surface of the tiling display 1 is viewed obliquely. It is desirable.

FIG. 5 is a side sectional view showing another example of the configuration of the tiling display according to the present invention.
In this figure, parts common to those in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted.

In the tiling display 3, FIG.
A glass plate 4 for securing flatness is bonded with an adhesive or the like (not shown) over the entire surface of the glass substrate 12 on the display surface side of each of the flat display elements 11 arranged as described above.

On the upper surface (surface on the display surface side) of the glass plate 4,
A sheet (diffusion sheet) 5 made of a diffusion object such as, for example, opal plastic is applied as an optical low-pass filter with an adhesive or the like (not shown) over the entire surface.

The degree of light scattering on the diffusion sheet 5 is set as high as possible in a range where the picture element PX is not blurred to a viewer of the display surface (that is, in a range where the resolution is not deteriorated).

FIG. 6 is a side sectional view showing reflected light and refracted light at the boundary bd of the tiling display 3.
In the tiling display 3, since the boundary bd is covered with the diffusion sheet 5, the lights L1, L2, and L3 reflected or refracted at the boundary bd are scattered in four directions by the diffusion sheet 5 as illustrated in FIG. I do. Therefore,
The lights L1, L2, and L3 are also dispersed in a direction orthogonal to the direction of the boundary bd (left and right directions in the drawing).

As a result, the intensity of the light L1, L2, L3 reaching the eyes of the viewer viewing the display surface is reduced, so that the boundary bd is no longer seen as a joint (or at least is hardly seen as a joint). .

Then, immediately above each flat display element 11,
By being covered with the same diffusion sheet 5 as the boundary bd, light is scattered in the same manner as in the boundary bd. Therefore, unlike the case where light is scattered just above the boundary bd, the boundary bd does not become conspicuous due to this light scattering.

Further, since the shape of the diffusion sheet 5 on the display surface does not have a periodic pattern, moire does not appear on the image displayed on the tiling display 3.

Instead of the diffusion sheet 5, a sheet that diffuses light by a hologram pattern formed on the surface may be attached to the upper surface of the glass plate 4. An example of such a sheet is the holographic
Diffuser.

The diffusion sheet 5 may be attached to the lower surface of the glass plate 4 instead of the upper surface of the glass plate 4. Alternatively, glass that diffuses light, such as frosted glass or opal glass, may be used for the glass plate 4 itself.

FIG. 7 is a side sectional view showing still another example of the configuration of the tiling display according to the present invention. In FIG. 7, parts common to those in FIGS. 2 and 5 are denoted by the same reference numerals. And a duplicate description is omitted.

In the tiling display 6, a sheet (diffraction grating sheet) on which a diffraction grating is formed as an optical low-pass filter over the entire upper surface of the glass plate 4.
7 is attached with an adhesive or the like (not shown).

The diffraction grating sheet 7 has diffraction gratings formed on both sides, and the direction of the grooves of the diffraction grating on one surface is the boundary between the adjacent flat display elements 11 in the horizontal direction (x direction in FIG. 1). bd, and the direction of the groove of the diffraction grating on the other surface is in the vertical direction of the adjacent flat display element 11 (y in FIG. 1).
Direction) and the boundary bd.

These diffraction gratings are, for example, diffraction gratings having a symmetrical groove cross section, such as a laminar grating (a rectangular wave-shaped groove diffraction grating) or a sine wave grating (a sine wave shaped groove diffraction grating). Therefore, the diffraction efficiency of the positive order and the diffraction efficiency of the negative order for vertically incident light are equal.

When the display surface is viewed through the diffraction grating, the picture element P
X appears not only at the original position by the 0th-order diffracted light but also shifted to the left and right of the original position by diffracted light of orders other than the 0th order (mainly ± 1st-order diffracted light). However, if this shift amount is approximately の of the pixel pitch or smaller than that, the pixel P is diffracted by an order other than the 0th order.
Since the position where X can be seen overlaps the left and right black masks BM of the picture element PX, the image quality does not deteriorate. The grating pitch of the diffraction grating of the diffraction grating sheet 7 is also determined so that this shift amount is approximately の of the pixel pitch.

Shifting picture elements by means of a diffraction grating in this manner is a technique that is also used, for example, to mosaic the color filters of a liquid crystal color viewfinder.

FIG. 8 is a diagram showing the relationship between the grating pitch and the shift amount. Assuming that the grating pitch is g, the distance from the picture element to the diffraction grating is b, the wavelength of the incident light is λ, and the shift amount is x, the grating pitch g and the shift amount x have a relationship as shown in Equation 1 below. .

(Equation 1)

Therefore, for example, each of the glass substrate 12 and the glass plate 4 of the flat display element 11 has a thickness of 1.1 m.
m, 5 mm, and the thickness of the diffraction grating sheet 7 is negligible with respect to these thicknesses.
nm and the pixel pitch is 0.2 mm,
Grating pitch g for x = 0.2 / 2 = 0.1 mm
Is obtained as in the following Expression 2.

(Equation 2)

FIG. 9 is a side sectional view showing reflected light and refracted light at the boundary bd of the tiling display 6.
In the tiling display 6, the light L1, L2, L reflected or refracted at the boundary bd as illustrated in FIG.
Reference numeral 3 denotes a diffraction grating sheet 7 covering the boundary bd, and mainly the 0th-order diffracted light L10 in a direction orthogonal to the direction of the boundary bd.
And ± 1st-order diffracted light L11.

More specifically, the light beams L1, L2, and L3 at the boundary bd in the horizontal direction (x direction in FIG. 1) are transmitted by the diffraction grating whose groove direction matches the boundary bd in the horizontal direction. 1
On the y direction), the light is dispersed mainly into the 0th-order diffracted light and ± 1st-order diffracted light. Lights L1, L2, and L2 at a vertical boundary bd
L3 is dispersed mainly in the 0th-order diffracted light and ± 1st-order diffracted light in the horizontal direction by a diffraction grating in which the direction of the groove coincides with the vertical boundary bd.

As a result, the intensity of the light L1, L2, L3 reaching the eyes of the viewer on the display surface is reduced, so that the boundary bd is no longer seen as a joint (or at least hardly seen as a joint). .

Then, immediately above each flat display element 11,
By being covered with the same diffraction grating sheet 7 as the boundary bd, light is also dispersed in the same manner as at the boundary bd. Therefore, unlike the case where light is dispersed just above the boundary bd, the boundary bd does not become conspicuous due to this light dispersion.

Further, since the light is dispersed only in a specific direction, the picture element PX does not look blurred.

Although only one diffraction grating sheet 7 is shown in FIG. 7, it is more preferable to laminate two or more diffraction grating sheets 7 on the glass plate 4.

FIGS. 10 and 11 are diagrams showing an example of the relationship between the number of diffraction grating sheets 7 and the intensity of light reflected or refracted at the boundary bd in the straight traveling direction.

The light incident on the diffraction grating sheet 7 is divided into the 0-order diffracted light having an intensity of 50% of the incident light and 25% of the incident light respectively.
15A, when one diffraction grating sheet 7 is attached, as shown in FIG. 10A, the light L reflected or refracted at the boundary bd (L in FIG. 15).
1, L2, L3) are the 0th-order diffracted light L having an intensity of 50% of L
10 and ± 1st-order diffracted light L11 having an intensity of 25% of L.

As a result, the intensity of the light L reflected or refracted at the boundary bd in the straight traveling direction becomes 50% of the intensity of the light L before being reflected or refracted as shown in FIG. 10B.

On the other hand, when two diffraction grating sheets 7 are stuck, as shown in FIG. 11A, the 0th-order diffraction light L10 from the first diffraction grating sheet 7 is In the sheet 7, the 0th-order diffracted light L20 having an intensity of 25% of L (50% of L10) and 12.5% of L (L10
± 25th order) of ± 1st order diffracted light L21. The ± 1st-order diffracted light L11 from the first diffraction grating sheet 7 is also transmitted by the second diffraction grating sheet 7 to L12.
0th-order diffracted light L30 having an intensity of 5% (50% of L11);
± 6 of the intensity of 6.25% of L (25% of L11) respectively
The light is dispersed into the first-order diffracted light L31.

As a result, as shown in FIG. 11B, the intensity of the light L reflected or refracted at the boundary bd in the straight traveling direction is 37.5% of the intensity of the light L before being reflected or refracted.
(Sum of L20 and the central part of L31).

Therefore, the light L reflected or refracted at the boundary bd is better when the two diffraction grating sheets 7 are stuck.
, The light intensity in the straight traveling direction becomes lower, so that the boundary bd is more difficult to be seen as a joint. FIG. 11 shows a case where two diffraction grating sheets 7 are stuck, but as the number of the diffraction grating sheets 7 increases, the intensity of light in this direction decreases.

The diffraction grating sheet affixed to the upper surface of the glass plate 4 has a diffraction grating such as the diffraction grating sheet 7 whose groove direction coincides with the boundary bd in the horizontal and vertical directions on one surface.
It does not have to be formed on the other surface. For example, instead of laminating two diffraction grating sheets 7 on each other, a diffraction grating sheet in which a diffraction grating whose groove direction matches the horizontal boundary bd is formed on both sides, and a groove direction is the vertical boundary bd
Two diffraction grating sheets each having a diffraction grating formed on both sides thereof may be superimposed on each other, or one diffraction grating sheet having a two-dimensional diffraction grating formed on both surfaces may be bonded.

Also, for example, instead of pasting one diffraction grating sheet 7, a diffraction grating sheet in which the direction of the groove coincides with the boundary bd in the horizontal direction on one side, and the boundary in the direction of the groove bd in the vertical direction. Or two diffraction grating sheets each having a two-dimensional diffraction grating formed on one side thereof may be stuck together.

When a diffraction grating sheet having a diffraction grating formed only on one side is adhered, a micro lens for suppressing total reflection on the display surface and increasing the brightness of an image is provided on the other side of the sheet. Alternatively, a prism or the like may be formed.

A diffraction grating sheet such as the diffraction grating sheet 7 may be attached to the lower surface of the glass plate 4 instead of the upper surface of the glass plate 4. Alternatively, on the glass plate 4 itself,
A diffraction grating may be formed.

In the examples shown in FIGS. 5 and 7, a diffusing object and a diffraction grating are used as members for dispersing light. However, a member capable of dispersing light other than these may be used.

In the above-described examples of FIGS. 2, 5, and 7, the refractive index is close to that of glass at the boundary bd (the refractive index is 1.
By applying a liquid (about 5), the air gap at the boundary bd may be eliminated. Thereby, the boundary bd
In this case, the reflection itself of the light is reduced, so that the boundary bd is more difficult to be seen as a joint.

As an example of such a liquid having a refractive index, a liquid immersion method in a microscope (to increase the resolution of the microscope by filling the space between the objective lens and the object with a liquid having a refractive index close to that of glass) is used. And silicone oil which is a low-polymerized silicone having fluidity at room temperature.

Next, the flat display element 1 used in the tiling displays 1, 3, and 6 shown in FIGS.
1 will be described.

FIG. 12 is a side sectional view showing an example of the configuration of the flat display element 11. As shown in FIG. In this flat display element 11, an organic thin-film EL element 13 is formed on the substrate surface of the glass substrate 12 opposite to the display surface side, immediately near an edge of the substrate surface (immediately before a groove 15 described later). As a result, the picture element PX exists right near the edge of the substrate surface. Here, the term “organic thin film EL element” refers to an anode, an organic layer, and a cathode formed on the substrate surface (the anode, the organic layer, and the cathode are stacked in this order when viewed from the glass substrate 12 side). And a black mask BM that fills those gaps.

The organic thin film EL element 13 includes an organic thin film EL
A glass substrate 14 is overlaid so as to be in close contact with the element 13. The size of the glass substrate 14 is equal to that of the glass substrate 12.

Although not shown in FIG. 12, the glass substrate 1
In the substrate surface of No. 4, holes penetrating the substrate are formed at positions facing the respective cathodes of the organic thin film EL element 13 and not facing the anode (that is, positions avoiding the picture elements PX). In addition, holes that penetrate the substrate are formed at positions facing the respective anodes of the organic thin-film EL element 13 but not at the cathodes.

The organic thin-film EL element 13 also has holes that reach the anodes at positions above the anodes and avoiding the cathodes when viewed from the glass substrate 14 side.

Each through-hole of the glass substrate 14 is sealed by gold plating or soldering in a state where extraction electrodes for supplying a display signal and a scanning signal are passed through the cathode and the anode, respectively. These extraction electrodes are respectively connected to a cathode and an anode via bumps.

As described above, in the flat display element 11,
Since a through-hole through which an extraction electrode for supplying a scanning signal and a display signal is supplied to the cathode and the anode, respectively, is provided in the glass substrate 14 on the rear surface side, a driving circuit for supplying the scanning signal and the display signal is provided by a glass. It can be arranged on the substrate surface of the substrate 14 (that is, on the back surface side of the flat display element 11).

The glass substrates 12 and 14 are processed into a shape in which notches 12c and 14c are provided obliquely over the entire edge of one substrate surface. Notches 12c and 14 in substrate surface direction
The length x1 of c is shorter than half the gap pg between the picture elements PX in the flat display element 11.

The organic thin film EL element 13 is
Are formed on the substrate surface having the notch 12c. The glass substrates 14 are also stacked so that the substrate surface having the notch 14c faces the organic thin-film EL element 13 side. Thus, a groove having a depth x1 is formed over the entire periphery at the boundary between the side surface of the glass substrate 12 and the side surface of the glass substrate 14 by the notches 12c and 14c.

The grooves are filled with a photo-setting, thermo-setting or anaerobic adhesive 15 and hardened. On the side surfaces of the glass substrates 12 and 14, a protective film 16 made of a material having low water permeability and oxygen permeability is formed over the entire surface so as to cover the adhesive 15. Protective film 1
6 is a distance x from the pixel PX located at the end of the substrate surface of the glass substrates 12 and 14 to the surface of the protective film 16.
2 is determined to be approximately one half of the gap pg.

The flat display element 11 having such a configuration is described below.
Is disclosed by the present applicant in a patent application filed with Japanese Patent Application No. 11-193277. This patent application also describes more detailed configurations and modifications of the flat display element.

As described above, in the flat display element 11, the organic thin film EL element 13 is sealed by the protective film 16 on the side surfaces of the glass substrates 12 and 14, and the surface of the glass substrates 12 and 14 is sealed. Close to the edge (adhesive 1
The pixel PX is formed up to (before the groove filled with No. 5). Therefore, FIG.
In the tiling displays 1, 3, and 6 shown in FIGS.
The non-display portion no longer exists at the boundary bd between the adjacent flat display elements 11.

In the flat display element 11, the distance x2 from the picture element PX located at the end of the substrate surface of the glass substrates 12 and 14 to the surface of the protective film 16 is approximately two minutes of the gap pg between the picture elements PX. It has become one of. Therefore, in the tiling displays 1, 3, and 6, the picture element P at the boundary bd is displayed.
Since the gap between X is twice the distance x2 (that is, substantially equal to the gap pg in each flat display element 11),
The pixel pitch at the boundary bd is the pixel pitch p (the sum of the gap pg and the width w of the pixel PX) in each flat display element 11.
Is almost equal to

As a result, the tiling display 1,
In 3 and 6, the uniformity of the pixel pitch at the boundary bd between the adjacent flat display elements 11 is ensured, so that the boundary bd is not conspicuous in this regard as well.

Next, as still another tiling display according to the present invention, a tiling display in which flat display elements having side surfaces different from the flat display element 11 are arranged will be described.

FIG. 13 is a side sectional view showing an example of the configuration of the flat display element 31 used in the tiling display. In the flat display element 31, as in the flat display element 11, the glass substrate 3 on the display surface side is used.
The organic thin-film EL element 33 is formed on the substrate surface of No. 2 right up to the edge of the substrate surface, and a glass substrate 34 is superposed so as to be in close contact with the organic thin-film EL element 33. Although not shown in the drawing, a through-hole is provided in the glass substrate 34 in the same manner as in the glass substrate 14 of the flat display element 11 described above, and the extraction electrode passed through the through-hole is used as an organic thin film EL element. 33 are connected to the cathode and anode.

The glass substrates 32, 34 are respectively provided with irregularities 32a, 34 in a direction perpendicular to the substrate surface over the entire periphery of the side surface.
It is processed into the shape provided with a. In the figure, the irregularities 32a,
34a has a saw blade shape, but may have a rectangular wave shape, a sine wave shape or a random shape as another example.

FIG. 14 is a side sectional view showing a configuration example of a tiling display in which the flat display elements 31 are arranged as in the flat display element 11 of FIG. In the tiling display 8, the gap between the unevenness 32a and 34a between the adjacent flat display elements 31 is filled with the adhesive 35, and the adhesive 35 is cured, so that the flat display elements 31 are bonded to each other. .

The adhesive 35 is, for example, an epoxy-based UV-curable adhesive having low moisture permeability and is transparent and has a refractive index substantially equal to that of the glass substrate 32 (1.4 to 1). .7).

Although not shown, in the tiling display 8 as well, the side surface (the side surface facing outward) other than the bonding surface of the flat display element 31 is made of a water-permeable material such as the protective film 16 shown in FIG. Is covered with a material having low permeability and oxygen permeability.

In the tiling display 8, since the side surface of the flat display element 31 is uneven,
As compared with the case where the side surface of the flat display element is flat as shown in A, less light is reflected on the display surface side among the light totally reflected at the boundary bd. Therefore, the boundary bd is no longer seen as a joint (or at least hardly seen as a joint).

Further, when the side surface of the flat display element is flat, it is difficult to evenly fill the gap between the adjacent flat display elements due to the surface tension of the adhesive or the like. As a result, an air gap easily occurs at the boundary bd, so that total reflection easily occurs at the boundary bd.
On the other hand, in the tiling display 8, since the side surfaces of the flat display element 31 are uneven, the adhesive 35 is evenly placed in the gap between the adjacent flat display elements 31.
Is easy to fill. Therefore, the total reflection itself at the boundary bd is less likely to occur due to the decrease in the air gap, and the boundary bd is hardly seen as a joint at this point as well.

In the tiling display 8, since the refractive index of the adhesive 35 is substantially equal to the refractive index of the glass substrate 32 of the flat display element 31, the light incident on the adhesive 35 from the glass substrate 32 is hardly refracted. . Therefore, also at this point, the boundary bd is difficult to see as a joint.

Further, the tiling display 8 has an advantage that not only the boundary bd becomes inconspicuous but also a large-screen display which is thin and has sufficient strength can be realized. The reason will be described below.

In a conventional tiling display, a holding mechanism (for example, a plate having a large screen size to which the flat display elements are mounted) for holding a plurality of flat display elements arranged in a tile shape integrally on the back side thereof is provided. ,
These flat display elements were fixed to each other.

In recent years, there has been a demand for a further reduction in the thickness of a tiling display, and for this purpose, a flat display element has been reduced in thickness. But,
Even if the flat display element is thinned, if the holding mechanism is present on the back surface side, it will hinder the thinning of the tiling display.

If the flat display elements adjacent to each other are fixed to each other by bonding them with an adhesive without providing a holding mechanism, the tiling display can be made thinner. However, for example, when the side surface of the flat display element is flat, the bonding area between the flat display elements is small, so that a very large adhesive strength cannot be obtained. The adhesive strength required to ensure sufficient strength is also related to the screen size, but as the size of the display increases, the total weight of the flat display element increases. become. As a result, when the side surface of the flat display element is flat, it is difficult to realize a large-screen display with sufficient strength by bonding with an adhesive.

On the other hand, in the tiling display 8, since the side surface of the flat display element 31 is uneven, the bonding area between the flat display elements 31 is smaller than that in the case where the side surface is flat. Therefore, the adhesive force by the adhesive 35 is large. This makes it possible to realize a thin and large-screen display having sufficient strength by bonding with the adhesive 35 without providing a holding mechanism.

In this tiling display 8, the black mask 2 is provided as shown in FIG. 2, the diffusion sheet 5 is provided as shown in FIG.
Needless to say, the diffraction grating sheet 7 may be provided as shown in (1), thereby making it more difficult to see the boundary bd as a joint.

In each of the above examples, the flat display element 11
And 31 are arranged two by two vertically and horizontally. However, in the flat display elements 11 and 31, as described above, the driving circuit can be arranged on the back side (that is, the driving circuit can not be located on the side surface side).
It is possible to arrange more than one sheet. Therefore, the flat display elements 11 and 31 are moved in at least one of the vertical and horizontal directions by three.
It may be arranged by more than one. Alternatively, when the two flat display elements 31 are arranged vertically and horizontally, only the two side faces of the glass substrates 32 and 34 of the flat display element 31 that are to be bonded are uneven. 34a may be provided and the remaining two side surfaces may be planar.

Further, the present invention relates to the flat display elements 11 and 31.
The present invention may be applied to a tiling display in which flat display elements having a configuration different from that of the above are arranged. For example, the present applicant has filed a patent application No. 11-197847.
Since a flat display element having a configuration different from that of the flat display elements 11 and 31 and in which a non-display portion does not exist at the boundary when arranged in a tile shape is disclosed, a tiling in which the flat display elements are arranged is disclosed. The present invention may be applied to a display.

Alternatively, the present invention may be applied to a tiling display in which flat display elements in which a non-display portion exists at a boundary when arranged in a tile shape are arranged. Needless to say, it is possible to prevent the boundary of the display element from being seen as a joint due to reflection or refraction of light.

In each of the above examples, the present invention is applied to a tiling display using an organic thin film EL element. However, the present invention may be applied to a tiling display in which a flat display element (for example, a liquid crystal panel or a plasma display panel) using a light-emitting or non-light-emitting element other than the organic thin film EL element is arranged.

Further, the present invention is not limited to the above-described example, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0128]

As described above, according to the array type display device according to the present invention, the reflected light or the refracted light does not reach the viewer's eyes at the boundary between the adjacent flat display elements. The effect is obtained that the boundary is no longer seen as a joint.

In addition, by sealing with a film on the side surface of the substrate, there is no non-display portion at the boundary between the adjacent flat display elements, so that this boundary can be made more inconspicuous.

Next, according to another array type display device of the present invention, reflected light or refracted light at the boundary between adjacent flat display elements is dispersed in a direction orthogonal to the direction of the boundary. Since the intensity of the reflected light or the refracted light reaching the eyes of the viewer of the display surface is reduced, an effect is obtained that the boundary is not seen as a joint (or at least becomes difficult to see as a joint).

In addition, an effect is obtained that moire can be prevented from appearing on the image displayed on the array type display device.

Further, since the light is scattered only in a specific direction, an effect that a picture element can be prevented from being blurred can be obtained.

Further, since the reflected light and the refracted light at the boundary are dispersed a plurality of times, the intensity of the reflected light reaching the eyes of the viewer on the display surface is further reduced, so that the boundary can be seen as a joint. The effect of being able to make it difficult is obtained.

In addition, by sealing with a film on the side surface of the substrate, there is no non-display portion at the boundary between the adjacent flat display elements, so that this boundary can be made more inconspicuous.

Next, according to still another arrangement type display device of the present invention, since the side surfaces of the flat display element are uneven, the light reflected from the boundary between the adjacent flat display elements can be reduced. Since the amount of light reflected on the display surface side is reduced, and the total reflection itself at the boundary is less likely to occur, an effect is obtained that the boundary is not seen as a joint (or at least becomes less visible as a joint).

Further, since the side surface of the flat display element is uneven, the adhesive force by the adhesive is increased, so that a large-screen display which is thin and has sufficient strength can be realized. Is obtained.

Further, by making the refractive index of the adhesive substantially equal to the refractive index of the transparent substrate on the display surface side of the flat display element, light incident on the adhesive from this transparent substrate is hardly refracted. The effect is obtained that the boundary can be made more difficult to be seen as a joint.

Further, by providing a member for dispersing light, such as the above-mentioned diffusing object or diffraction grating, an effect is obtained that this boundary can be further made joints so as to be less visible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an arrangement of flat display elements in a tiling display according to the present invention.

FIG. 2 is a side sectional view showing an example of a configuration of a tiling display according to the present invention.

FIG. 3 is a plan view of the black mask of FIG. 2 as viewed from the display surface side of the tiling display.

FIG. 4 is a side sectional view showing reflected light and the like at a boundary between adjacent flat display elements of the tiling display of FIG. 2;

FIG. 5 is a side sectional view showing another example of the configuration of the tiling display according to the present invention.

6 is a side sectional view showing reflected light and the like at a boundary between adjacent flat display elements of the tiling display of FIG. 5;

FIG. 7 is a side sectional view showing another example of the configuration of the tiling display according to the present invention.

FIG. 8 is a diagram showing a relationship between a grating pitch of a diffraction grating and a shift amount of a picture element.

9 is a side sectional view showing reflected light and the like at a boundary between adjacent flat display elements of the tiling display of FIG. 7;

FIG. 10 is a diagram showing an example of the relationship between the number of diffraction grating sheets and the intensity of reflected light or the like at a boundary.

FIG. 11 is a diagram illustrating an example of a relationship between the number of diffraction grating sheets and the intensity of reflected light or the like at a boundary.

FIG. 12 is a side sectional view showing an example of the configuration of the flat panel display device of FIG. 1;

FIG. 13 is a side sectional view showing another example of the configuration of the flat display element in the tiling display according to the present invention.

FIG. 14 is a side sectional view showing another example of the configuration of the tiling display according to the present invention.

FIG. 15 is a side sectional view showing reflected light and the like at a boundary between adjacent flat display elements of a conventional tiling display.

[Explanation of symbols]

1,3,6,8 Tiling display, 2, B
M black mask, 4 glass plate, 5 diffusion sheet, 7 diffraction grating sheet, 11,31 flat display element, 12,14,32,34 glass substrate, 12a
Corner of glass substrate, 12c, 14c cutout of glass substrate, 13 organic thin film EL element, 15 adhesive,
16 Protective film, 32a, 34a Irregularities on the side of glass substrate, 35 Adhesive, bd Boundary between adjacent flat display elements, PX picture element

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/70 H04N 5/70 Z

Claims (15)

[Claims] 1. A display device in which a plurality of flat display elements are arranged, wherein a portion other than immediately above a picture element on a display surface is covered with a member that blocks light. 2. The array-type display device according to claim 1, wherein said member comprises a black mask. 3. The array type display device according to claim 1, wherein the flat display element is provided between a first transparent substrate located on a display surface side and a second substrate located on a back surface side. A display material and an electrode interposed therebetween, and a film for sealing the display material and the electrode is formed on a side surface of the first transparent substrate and the second substrate. . 4. A display device in which a plurality of flat display elements are arranged, wherein a display surface is covered with a member for dispersing light in a direction orthogonal to a direction of a boundary between adjacent flat display elements. Array type display device. 5. The array-type display device according to claim 4, wherein the member is made of a diffusion object. 6. The array-type display device according to claim 4, wherein the member is formed of a diffraction grating in which the direction of a groove matches the direction of the boundary. 7. The array type display device according to claim 6, wherein the flat display elements are arranged in a vertical direction and a horizontal direction, and a direction of a groove coincides with a vertical boundary of the adjacent flat display elements. An array-type display device, wherein the diffraction grating and the diffraction grating whose grooves are aligned with the horizontal boundaries of the adjacent flat display elements overlap in a direction perpendicular to the display surface. 8. The array type display device according to claim 6, wherein a plurality of diffraction gratings having the same groove direction overlap each other in a direction perpendicular to the display surface. 9. The array type display device according to claim 7, wherein a diffraction grating is formed on each of both surfaces of the planar member. 10. The array type display device according to claim 4, wherein the flat display element includes a first transparent substrate located on a display surface side and a second substrate located on a back surface side. A display material and an electrode are interposed therebetween, and a film for sealing the display material and the electrode is formed on a side surface of the first transparent substrate and the second substrate. Type display device. 11. A display device in which a plurality of flat display elements are arranged, wherein unevenness is provided on a side surface of the flat display element, and the adjacent flat display elements are separated by an adhesive filled in a gap between the unevenness. An array-type display device, which is attached. 12. The array type display device according to claim 11, wherein a refractive index of the adhesive is substantially equal to a refractive index of a transparent substrate on a display surface side of the flat display element. apparatus. 13. The array-type display device according to claim 11, wherein the display surface is covered with a member that disperses light in a direction perpendicular to a boundary between the adjacent flat display elements. Characteristic array type display device. 14. The array-type display device according to claim 13, wherein the member is made of a diffusion object. 15. The array-type display device according to claim 13, wherein the member is formed of a diffraction grating in which the direction of a groove matches the direction of the boundary.