JP2007017735A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device capable of improving the reflectivity. <P>SOLUTION: The device comprises a translucent substrate 101 on which a first electrode 104 is formed, a backside substrate 102 which is disposed as to face the translucent substrate, and on which a second electrode is formed, a partition which is formed between the translucent substrate and the backside substrate, and surrounds a plurality of electrodes of one of the first electrode and the second electrode; a translucent medium 107 filled into a plurality of regions formed by the translucent substrate, the backside substrate and the partition; and electrophoretic particles 106 to which mobile control is implemented in the direction of the electric field which is generated between the first electrode and the second electrode in the translucent medium. Either the first electrode or the second electrode is formed so that its region is smaller than the region, where the other electrode is surrounded by the partition. The partition comprises both a translucent member 108B, which is disposed on the translucent substrate side, and an optical member 108A, which has a boundary surface contacting the translucent member, and of which real part has a complex refractive index that is different from the refractive index of the translucent member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device using electrophoretic particles.

A translucent medium is sealed in a pixel partitioned in a matrix using a partition provided between a transparent substrate and a back substrate, and colored charged particles are dispersed in the translucent medium, and electric field control is performed for each pixel. An image display device that displays an image by moving particles is disclosed (Patent Document 1).
In this image display device, the colored charged particles are moved by modulating the voltage applied to the first electrode disposed on the rear substrate and the second electrode disposed on the partition. By this particle movement, the image is displayed by switching between the particle color and the background color for each pixel. For example, when colored charged particles are attracted to the electrode on the back substrate side, this pixel exhibits the first color of the colored charged particles. Further, when the colored charged particles are moved to the electrode on the partition wall side, the pixel exhibits the second color of the electrode on the back substrate side.
Further, in Patent Document 2, an electrode is provided on a pixel on a transparent substrate and a back substrate, and electrophoretic particles (colored charged particles) are moved to the transparent substrate side so as to see the color of the electrophoretic particles. A display device is disclosed that is moved to view the color of the solvent in which the electrophoretic particles are dispersed. In addition, the partition wall of this apparatus uses a transparent member on the observer side so that the color can be observed from the partition wall, and the reflectance and contrast, which are the ratio between the incident light amount and the reflected light amount, are reduced. It is preventing.
JP 9-2111499 A JP 2003-66494 A

In the technique of Patent Document 1, since the incident light is blocked by the partition wall, the incidence of the light from the oblique direction and the reflection in the oblique direction are limited, and the reflectance and viewing angle characteristics of the display device are deteriorated.
In the technique of Patent Document 2, light incident obliquely from a partition wall to the layer of electrophoretic particles moved to the electrode on the transparent substrate side or the solvent-only layer on the transparent substrate side contributed to the reflectance. In addition, if a transparent member is used not only on the observer side but also on the entire partition wall so that light is also incident obliquely on the layer on the back substrate side, the color on the back substrate side appears, leading to a decrease in contrast. is there.
An object of the present invention is to provide an image display device capable of improving the reflectance, which is the ratio between the incident light amount and the reflected light amount.

  In order to solve the above problems, one means of the present invention includes a light-transmitting substrate on which a single or a plurality of first electrodes are formed, and a single electrode or a plurality of second electrodes that are disposed to face the light-transmitting substrate. And a partition wall formed between the translucent substrate and the back substrate, each surrounding a plurality of any one of the first electrode and the second electrode, A translucent medium enclosed in a plurality of regions formed by the translucent substrate, the back substrate, and the partition; and between the first electrode and the second electrode in the translucent medium An electrophoretic particle that is controlled to move in the direction of an electric field generated in the image display device, wherein one of the first electrode and the second electrode is surrounded by the partition wall. The incident light that is formed narrower than the region to be incident on the partition wall is inclined. It characterized by emitting from the light-transmissive substrate by reflecting by the reflecting member including a second electrode.

  Since one of the first electrode and the second electrode is formed narrower than the region where the other electrode is surrounded by the partition wall, the electrophoretic particles are narrowed in any electric field direction. It moves to the bright state. In this state, incident light that is inclined and incident on the partition wall is reflected by the reflecting member including the second electrode, and this light is emitted from the translucent substrate. Thereby, the reflectance which is a ratio of the incident light quantity and the reflected light quantity is improved.

  According to another aspect of the present invention, there is provided the image display device, wherein one of the first electrode and the second electrode is narrower than a region where the other electrode is surrounded by the partition wall. A translucent member formed on the translucent substrate side and an optical member having a boundary surface in contact with the translucent member and having a real part having a complex refractive index different from the refractive index. A partition wall is provided.

When an optical member having a complex refractive index of n = n ₁ −jk is perpendicularly incident from air, the intensity reflectance R ₀ , which is a ratio of the intensity of incident light and the intensity of reflected light, is
R ₀ = | n−1 | ² / | n + 1 | ² = {(n ₁ −1) ² + k ² } / {(n ₁ +1) ² + k ² }
It is expressed by If the imaginary part k is zero, this optical member is a translucent refractive member that is refracted at a refractive index n _1. Is larger than R ₀ = 1 and represents a reflecting member.

That is, if the imaginary part k of the complex refractive index is zero and the member is a refractive member, the partition wall is in contact with the light transmitting member on the light transmitting substrate side as a refractive member having a different refractive index. Thereby, the incident light that enters the partition and passes through the translucent member is refracted at the boundary between the translucent member and the refractive member. Since this refracted light is reflected by the second electrode, the amount of reflected light increases. In particular, if the refractive index of the refractive member is larger than the refractive index of the translucent member, the refracted light toward the second electrode increases.
On the other hand, if the imaginary part k of the complex refractive index is very large and the reflective member is in contact with the translucent member, incident light passing through the translucent member reflects the reflective member. Furthermore, if the boundary surface between the translucent member and the reflecting member is inclined, the reflected light is reflected by the second electrode, and the amount of reflected light increases.

  ADVANTAGE OF THE INVENTION According to this invention, the image display apparatus which can improve the reflectance which is a ratio of incident light quantity and reflected light quantity can be provided.

(First embodiment)
FIG. 1 shows a structural diagram of the image display apparatus of the present embodiment. 1A is a top view, and FIG. 1B is a cross-sectional view taken along the line AA ′. Pixels composed of a lower electrode 103 and particle moving means 105 to be described later are two-dimensionally arranged on the back substrate 102. Each pixel is partitioned by a partition wall 108. Further, the translucent substrate 101 is provided with the upper electrode 104 in a stripe shape. Here, the width of the stripe-shaped upper electrode 104 is narrower than the width of the lower electrode 103 provided on the translucent substrate 101 in the AA ′ cross-sectional direction in the substrate plane. Then, between the translucent substrate 101 and the back substrate 102, the translucent medium 107 and the colored charged particles 106, which are translucent liquids, are filled, and by the action of the particle moving means 105, the translucent medium is transmitted as shown in FIG. The colored charged particles 106 are moved pixel by pixel in the optical medium 107 to modulate the reflectance and display an image. Here, when the upper electrode 104 is set to a constant potential and the lower electrode 103 is switched to a positive voltage or a negative voltage as compared with the upper electrode 104 by the action of the particle moving means 105, the colored charged particles 106 are transferred to the upper electrode 104 or the lower electrode. Move to electrode 103. As shown in FIG. 2A, when the colored charged particles 106 move to the upper electrode 104, the pixel exhibits the color of the lower electrode 103 or the back substrate 102. Here, when the lower electrode 103 or the back substrate 102 has a high intensity reflectance in the entire visible light, white is displayed. When moving onto the lower electrode 103 as shown in FIG. 2B, the color of the pixel is switched to the particle color. For example, when the colored charged particles 106 have a high absorption rate over the entire visible light range, the light is absorbed and black is displayed. In the following description, “upper and lower” is an expression based on a drawing, and depending on how the drawing is represented, it is upside down or left and right.

  FIG. 3 shows a partition wall 108 in which translucent members having different refractive indexes are connected in parallel to the substrate on the translucent substrate 101 side and the back substrate 102 side. Here, the partition wall on the translucent substrate 101 side is the upper partition wall 108B, and the partition wall on the back substrate 102 side is the lower partition wall 108A.

This image display device displays the image by moving the particles for each pixel to modulate the reflectivity. However, in order to suppress the temporal change of the particle density in the screen and to keep the distance between the two substrates uniform in the plane. It is effective to provide a partition wall for each pixel or for each of a plurality of pixels. Therefore, when a light-transmitting material is used for the partition wall in the display device having the pixel structure as described above, the light shielding effect in the vicinity of the partition wall is greatly reduced, the incident light amount and the reflected light amount are increased, and the reflectance and viewing angle characteristics are improved. Greatly improved. Further, if the light shielding layer 111 is provided on the rear substrate 102 side with respect to the partition wall 108, the reflectance during black display can be kept low, and an image display device with a high contrast ratio can be obtained.
Here, the light shielding layer 111 may be formed of a resin in which black particles such as carbon black are dispersed or a metal such as Cr that is blackened. The light shielding layer 111 may be formed on the back substrate 102 side with respect to the partition wall 108.
As shown in FIGS. 3A and 3B, the light shielding layer 111 may be formed by patterning under or on the lower electrode 103, or under the lower electrode 103 as shown in FIG. It may be formed as a flat or uneven layer. In addition, as shown in FIG. 3D, the same effect can be obtained even if a part or the entire surface of the back substrate 102 is shielded from light.

  The upper surface structure of the partition walls may be provided in a lattice shape for each pixel as shown in FIG. 4, or it is effective to use a stripe shape as shown in FIG. 4 and 5, the partition walls having the same pitch as the pixel pitch are formed. However, it is also effective to form the partition walls by an integer multiple of the pixel pitch.

  FIG. 6 shows a ray trajectory when a ray is incident from an oblique direction during white display of the image display device described in Patent Document 1. The light beam A incident on the side surface of the partition wall 203 or the light beam B incident on the upper surface is shielded by the light shielding layer 208, the colored charged particles 206, or the first electrode 204, and the reflectance decreases. Further, among the light rays C and D incident on the reflective electrode (second electrode) 205, the light ray D is also reflected in the vicinity of the partition wall 203 after being reflected, causing a reduction in viewing angle characteristics. FIG. 7 shows the relationship between the incident angle θ of the light beam and the reflectance according to this technique. It can be seen that the reflectance decreases rapidly as the incident angle θ increases. This reduction in reflectance is particularly noticeable in high-definition image display devices in which the area ratio occupied by the partition walls is large.

  On the other hand, FIG. 8 shows a ray trajectory when a ray is incident from an oblique direction during white display of the image display apparatus of the present embodiment. Since the upper partition wall 108B and the lower partition wall 108A are translucent, the colored charged particles 106 are not collected in the vicinity of the partition wall, and the light shielding layer 111 is disposed on the back substrate 102 side of the lower partition wall 108A. Since the rays A and B are incident on the lower electrode 103 without being blocked, the reflectance is improved. Further, since the light beam D reflected by the lower electrode 103 is also reflected without being blocked by the partition wall 108, the viewing angle characteristic is improved. In the relationship between the incident angle θ and the reflectance of the light beam of the present embodiment shown in FIG. 7, it can be seen that the reflectance does not decrease even when the incident angle θ is large.

  Here, if the partition wall material shown in FIG. 8 is made of a material having higher refraction than that of the translucent medium 107, a light beam incident from the side wall of the partition wall as in the light beam A is refracted so as to avoid the bottom wall of the partition wall. Is incident on the lower electrode 103, and the reflectance can be increased. On the other hand, with respect to the light beam B incident from the upper surface of the upper partition wall 108B, the use of a low refractive material for the upper partition wall 108B refracts so as to avoid the partition wall bottom, so that more light beams enter the lower electrode 103. The reflectance can be increased, which is preferable. For this reason, it is particularly preferable that the upper partition wall 108B is made of a material having a lower refractive index than the lower partition wall 108A. Further, when a material having a lower refractive index than that of the translucent medium 107 is used, a light beam incident from the upper surface of the partition wall is not guided to the bottom of the partition wall due to total internal reflection with the translucent medium, and a particularly preferable structure is obtained.

  The discontinuity point in the reflectance characteristic A of the present invention shown in FIG. 7 is due to the fact that total reflection occurs with the light incident from the upper surface of the partition wall at a lower incident angle θ than this point. By doing so, the discontinuous point A is preferably shifted to the low angle side, and the reflectance can be increased on the low incident angle side. Further, when the refractive index is lower than that of the light-transmitting medium 107, discontinuous points can be eliminated, and the reflectance can be further increased on the low incident angle side, which is particularly preferable. On the other hand, the reflectivity in a region with an incident angle higher than A is due to incidence from the side wall of the partition wall, and higher reflectivity is possible by increasing the refractive index of the lower partition wall 108A.

  The same optical effect as that of the partition wall can be obtained on the upper electrode 104. FIG. 9 shows an image display device in which an upper electrode 104 is provided through a protruding layer 113 protruding from a light-transmitting substrate 101. It is preferable to make the protruding layer 113 translucent. If a refractive material is used higher than the translucent medium 107, loss of light incident from the side surface can be reduced, and an image display device with high reflectance can be obtained. Further, as shown in FIG. 10, when a projection layer 113B made of a material having a low refraction compared to the projection layer 113A is provided between the projection layer 113A made of a high refractive material and the light-transmitting substrate 101, the incident light from the upper surface is prevented. Loss can also be reduced, which is more preferable.

  In the present embodiment, the translucent medium 107 is a colorless liquid such as water, alcohol, oils, or petroleum. In some cases, the gas may be oxygen, nitrogen, inert gas, air, or vacuum. The colored charged particles 106 are charged with pigment particles of a desired color. For example, when black colored charged particles 106 are used, an image display device capable of monochrome display is obtained. In addition, an image display device that exhibits a color corresponding to the absorption color of the colored charged particles 106 can be obtained.

Here, as the partition material, organic materials such as polyvinyl cinnamate, azide / novolak resin, styrene polymer polymer, methacrylate polymer polymer, acrylic resin, cardo polymer polymer, fluorine resin, and translucent material are used. These inorganic materials can be formed by a technique such as photolithography using photosensitivity, etching, or thermal deformation that is pushed into a mold. In particular, the high refractive material portion at the bottom of the partition wall may be made of a material having a high refractive index, and TiO ₂ , Al ₂ O ₃ , ZnO, and a high refractive index translucent material in the resin. The fine particles may be impregnated to about 10 to several 100 nm. In addition, a low refractive material may be used alone for the low refractive material portion on the upper surface of the partition wall, or a low refractive index translucent material is impregnated into the resin as fine particles having a particle size of about 10 to several 100 nm. You may let them. Moreover, the same effect is acquired even if it makes porous.

  Further, in this image display device, when a conductive material that reflects visible light is used for the lower electrode 103, this portion also serves as a reflective layer, and a high-definition display device with little parallax can be obtained. As the conductive material that reflects visible light used here, a metal material such as Al, Ag, Cr, Mo, Au, Ni, or Cu can be used alone or in combination. Moreover, diffusibility can be given to reflected light by giving an appropriate unevenness | corrugation to this reflective surface. The diffuse reflection surface can set the diffused range of reflected light to a desired range due to its uneven shape, and a high brightness image can be obtained in an appropriate range by narrowing the diffuse range.

  Such diffusibility can be obtained by the diffuse reflection effect by forming the lower electrode 103 on the uneven layer 114 as shown in FIG. Here, the uneven layer 114 is preferably formed in a plurality of microlenses. Further, when the uneven layer 114 is translucent and has a refractive index different from that of the translucent medium 107, it is formed on the lower electrode 103 as shown in FIG. 11B or FIG. By providing the concavo-convex layer 114 on the inner surface of the conductive substrate 101, diffusivity is obtained by the lens effect. Further, when the uneven layer 114 is translucent and the refractive index is other than 1, the diffusivity can be adjusted by providing an uneven layer on the outer surface of the translucent substrate 101 as shown in FIG. Thus, an image display device having suitable viewing angle characteristics can be obtained.

  Here, in the configuration of FIG. 11C or FIG. 11D, the concavo-convex layer 114 may be formed on the translucent substrate 101 by a technique such as coating, exposure, or pasting a film. The substrate front and back surfaces may be directly formed using a technique such as thermal deformation or chemical etching. Further, in order to obtain a desired diffusibility, the methods shown in FIGS. 11A to 11D may be used singly or in combination.

  Furthermore, in order to increase the screen brightness and obtain a reflection color close to pure white at the time of white display, a translucent medium in which a fluorescent whitening agent that absorbs ultraviolet light and emits visible light on the reflective surface is coated on the reflective layer. What is necessary is just to make it contain in. As the optical brightener, diaminostilbene, imidazole, imidazolone, triazole, thiazole, oxazole, oxadiazole, coumarin, carbolysyl, thiazole, naphthalimide and the like can be used as a simple substance and a composite material.

As the material of the upper electrode 104, any of conductive metals Al, Ag, Cr, Mo, Au, Ni, Cu and the like can be used. In this case, it is preferable to make the color of the colored charged particles 106 on the upper electrode 104 the same as that by improving the display characteristics in the particle color display state in which the particles cover the lower electrode 103. For example, when the colored charged particles 106 are black, the upper electrode 104 may be formed after a color thin film having substantially the same planar shape is formed in advance on the light-transmitting substrate 101. Furthermore, it is preferable to use a light-transmitting conductive material such as ITO, IZO, or SnO ₂ as an electrode because the contrast can be improved by the same effect without forming a thin film having the same color as such particles.

  As the particle moving means 105, a transistor formed on a silicon substrate or a thin film transistor formed on a substrate such as glass or plastic may be combined in a matrix.

  The upper electrode 104 may be patterned with a conductor as described above, but may be formed by covering a part of the conductor with an insulating layer as shown in FIG. Here, by providing the light-transmitting insulating layer 110 over the light-transmitting partial electrode 104 and opening a part thereof, the opening substantially functions as an electrode. In this case, the substantial electrode portion serving as the opening of the insulating layer 110 may have a stripe shape like the upper electrode 104 shown in FIG. 4, or the substantial portion of each pixel like the upper electrode 104 shown in FIG. 13. You may provide discretely in the center. In the structure as shown in FIG. 13, the portion covered with the particle color in the white display state is further reduced, and the contrast is greatly improved. Here, the upper electrode 104 is not limited to a quadrangular shape as shown in FIG. 13, but may be a round shape or the like. It is a preferable form that it is formed at the approximate center of each pixel in the plane. Further, the upper surface structure of the partition walls may be provided in a grid pattern for each pixel as shown in FIGS. 4 and 13, or it may be effective to form a stripe pattern as shown in FIGS. 4, 5, 13, and 14, the partition walls having the same pitch as the pixel pitch are formed. Further, when the partition wall color is the same as that of the particles, the display performance in the particle color display state is enhanced and the contrast is improved.

Furthermore, as shown in FIG. 12, an insulating layer 110 having a thickness of several hundred nm or more is stacked on the transparent medium 107 side of the upper electrode 104 so that the opening of the insulating layer 110 has a groove shape or a hole shape. In this case, the colored charged particles 106 can be collected in the holes or grooves, and the contrast is further improved.
The effect of making the partition wall 108 translucent is the following form in which the colored charged particles 106 are moved for each pixel, in particular, a pixel structure in which the position where the colored charged particles 106 are assembled in a white display state is other than the vicinity of the partition wall 108. The effect is great.

  15, FIG. 16, and FIG. 17 show the translucent substrate 101 on which the first translucent electrode group is formed, and the first electrode group is arranged in one direction within the substrate surface so as to face the translucent substrate. An image display device in which electrophoretic particles and a light-transmitting medium are sealed between a rear substrate having a second electrode group narrower than the width of each electrode and a light-transmitting partition wall is provided between pixels. In FIG. 15, a part of the lower electrode 103 that also serves as a reflective electrode is covered with a light-transmitting insulating layer 110 and functions as an electrode narrower than the upper electrode 104 provided on the light-transmitting substrate 101 that is effectively opposed.

  The lower electrode 103 is electrically connected to the particle moving means 105, and by modulating the voltage, the particles can be gathered at the opening of the insulating layer 110 or can be spread on the upper electrode 104. Done. Thereby, the white display state shown in FIG. 15A showing the color of the lower electrode 103 and the black display state shown in FIG. 15B are displayed for each pixel. FIG. 16 shows a structure in which the region of the lower electrode 103 is narrowed and a reflective layer 112 is provided around the lower electrode 103. In this case, the lower electrode 103 electrically connected to the particle moving means 105 may be formed by patterning. In this case, the reflective layer 112 that reflects light in the white display state in FIG. 103 and electrically separated. Here, as shown in FIG. 16, the lower electrode 103 and the reflective layer 112 are preferable in manufacturing because the number of photolithography steps formed in the same layer can be reduced.

  However, a gap is necessary for electrical separation between the lower electrode 103 and the reflective layer 112, the reflective area is narrowed and the reflectance is lowered. For this reason, as shown in FIG. 17, it is preferable to form the two layers as different layers and to provide the insulating layer 110 between the lower electrode 103 and the reflective layer 112 because the gap when viewed from above can be reduced. In the structure of FIG. 17, the lower electrode 103 is formed in the opening of the insulating layer 110, but the opening may be protruded. In addition, when the thickness of the insulating layer 110 is several hundred nm or more and the opening is formed in a groove shape or a hole shape, the colored charged particles are collected in the hole or the groove, so that the contrast is further improved.

  Furthermore, between the translucent substrate 101 and the back substrate 102 having the second electrode group wider than the width of each electrode constituting the first electrode group in one direction within the translucent substrate 101 surface. In an image display device in which electrophoretic particles 106 and a translucent medium 107 are enclosed and a partition wall 108 is provided between pixels whose display is switched by a particle moving unit 105 electrically connected to the first electrode group, the partition wall 108 By making the light translucent, the effect of improving the high reflectance and viewing angle can be obtained.

  FIG. 18 shows a configuration in which an upper electrode 104 serving also as a reflective electrode and a lower electrode 103 electrically connected to the particle moving means 105 are formed by patterning. FIG. 18B shows a white display state shown in FIG. 18A in which particles are gathered on the lower electrode 103 by modulating the voltage and the color of the upper electrode 104 is displayed on the image display device, and FIG. ) Is displayed for each pixel. This embodiment is preferable because no electrode is formed on the light-transmitting substrate 101 and the transmittance is not lowered by the electrode.

  In FIG. 19, the upper electrode 104 and the lower electrode 103 are formed in different layers, and an insulating layer 110 is provided between the two electrodes. This is preferable because the gap can be reduced when viewed from above. In the structure of FIG. 19, the lower electrode 103 is formed in the opening of the insulating layer 110, but display is possible even if the opening protrudes. Further, when the thickness of the insulating layer 110 is several hundred nm or more and the opening is formed in a groove shape or a hole shape, the colored charged particles are collected in the hole or the groove, so that the contrast is further improved. FIG. 19A shows a white display state, and FIG. 19B shows a black display state.

  In the structure described so far, it is preferable to provide a plurality of small electrodes that aggregate particles in a white display state in a pixel because the distance that the particles move in the pixel is narrowed, and the display switching time can be shortened. 20, 21, and 22 are examples of structures in which a plurality of electrodes are formed based on the cross-sectional structures of FIGS. 2, 12, and 18, respectively. FIGS. 23 and 24 are examples in which a plurality of electrodes are formed based on the top surface structure of FIGS. Here, twice as many electrodes are provided in one direction in the pixel. However, the number of electrodes is not limited to this number, and it is not always necessary to have the same multiple in the two directions of the plane as shown in FIG. Such a plurality of electrodes makes it easy to obtain an image display even if the alignment accuracy of the upper and lower substrates is low. For this reason, it is effective in a high-definition image display device having a pixel pitch of 200 μm or less. In addition, it is effective in a flexible image display device, and a high-definition image display device can be obtained even when a material such as thin glass, resin, or a metal thin plate is used.

  In the image display apparatus as described so far, the halftone is preferably displayed by area gradation. As shown in FIG. 25A, this can be realized by a structure in which the lower electrodes 103A,..., 103D are divided perpendicularly to the upper electrode 104. In this case, the area gradation display is performed by moving the colored charged particles 106 independently on the divided lower electrodes 103A,..., 103D. The lower electrodes 103A,..., 103D may be divided with the same width as shown in FIG. 25A, but may be divided with different widths as shown in FIG. In this case, since the amount of light reduction is different when the colored charged particles 106 move on the respective reflecting surfaces, more gradation display can be realized. For example, when the reflection surface is divided into four parts, and when the equal width division is performed as shown in FIG. 25A, all the light reduction amounts of the reflection surfaces are ¼, the light reduction amount of the entire pixel is 0,1. / 4, 1/2, 3/4, and 1. On the other hand, in FIG. 25B, when the division width of the four reflecting surfaces is 1: 2: 4 (2 to the second power): 8 (2 to the third power), the light reduction amount on the four reflecting surfaces is 1 / 15,2 / 15, 4/15, 8/15, which is preferable because gradation display in 16 levels of 0, 1/15,..., 14/15, 1 is possible. As described above, when the reflecting surface is divided into N pieces with unequal intervals, gradation display of 2 to the Nth power becomes possible.

  In order to color the image display apparatus, as shown in FIG. 26, color display portions 115A, 115B, and 115C for displaying three colors of red, green, and blue may be provided in one pixel. In this case, the colored charged particles 106 are black, and the reflecting surface formed of the substrate or the lower electrode 103 has a substantially uniform reflectance over the entire visible light, and transmits red, green, and blue according to each color portion. A filter may be arranged. Further, when no color filter is used, the reflecting surface may reflect red, green, and blue according to each color portion. Furthermore, when the reflective surface has substantially uniform reflectivity over the entire visible light without using a color filter, the colored charged particles 106 are black and the translucent medium 107 transmits only red, green, and blue according to each color portion. It can be realized even if it is illuminated. It can also be realized by a three-layer laminated structure as shown in FIG. In this case, only the lowermost layer 103A of the three layers of lower electrodes 103 has a reflective surface, and the upper two layers of lower electrodes 103B and 103C and the substrate use translucent electrodes. Here, if the colored charged particles 106A, 106B, and 106C use liquids that absorb only red, green, and blue, respectively, full-color display can be performed by moving three layers of liquids.

(Specific example 1)
A specific example of an image display apparatus according to an embodiment of the present invention will be described with reference to FIGS.
In the present image display device, as shown in FIG. 4, the lower electrode 103 is two-dimensionally arranged at intervals of 50 μm for each pixel, and the pixels are partitioned by a grid-like partition wall 108, and pass through almost the center of each pixel. The upper electrode 104 is formed in a stripe shape. The cross section is shown in FIG. A translucent upper electrode 104 made of a transparent conductive film such as ITO is formed on the translucent substrate 101 side of the translucent substrate 101 by using photolithography. On the other hand, the lower electrode 103 was made of a highly reflective metal material such as Al on the back substrate 102 on which the particle moving means 105 was formed in a two-dimensional array. Further, a 5 μm-high lower partition wall 108A made of a cardo polymer having a refractive index of 1.59 and a 2 μm high partition wall 108B made of an acrylic polymer having a refractive index of 1.49 were patterned in a lattice shape with a width of 5 μm. An upper partition wall 108B was formed.

  The region surrounded by the partition wall 108, the translucent substrate 101, and the back substrate 102 is filled with a translucent medium 107 having a refractive index of 1.38 in which black colored charged particles 106 are dispersed, and then integrated with the substrate 101. The image display apparatus was obtained by sealing. In the present image display device, the upper electrode 104 is maintained at 0 V, and the lower electrode 103 is modulated by +/− 10 V by the action of the particle moving means 105 to be dispersed in the translucent medium 107 as shown in FIG. The black colored charged particles 106 moved, and black and white display was performed for each pixel. Here, the particle moving means 105 uses, for example, a thin film transistor 117 formed of a material such as amorphous silicon or polycrystalline silicon, and controls the particle movement of the pixel cells 118 by combining them in a matrix as shown in FIG. indicate. Here, the thin film transistor 117 is controlled by the driver circuits 121 and 122 via the drain line 119 and the gate line 120.

As the colored charged particles 106 used here, for example, any of various colored pigments and the like provided with charges by various methods can be used. For example, for black and white display, a black liquid such as a liquid in which carbon black is dispersed may be used. As the translucent medium 107, any liquid that is transparent to water, alcohol, petroleum, or the like can be used. Here, when each pixel is partitioned by the partition wall 108 as in this specific example, disturbance due to movement of particles between pixels is prevented.
For the lower electrode 103, it is more preferable to use a metal material having a high reflectance in visible light such as aluminum, silver, or gold because it also serves as a reflective surface. In this case, if the surface of the electrode is a diffusive reflecting surface that has fine unevenness and imparts diffusibility to the reflected light, the uneven range of the reflected light can be set to a desired range by the uneven shape. It is preferable that a high-luminance image is obtained in an appropriate range by narrowing.

(Specific example 2)
Another specific example of the image display apparatus according to the present embodiment will be described with reference to FIGS.
In the image display device of this specific example, as shown in FIG. 13, the pixels including the lower electrode 103 and the upper electrode 104 are two-dimensionally arranged. Unlike the case of the specific example 1, the upper electrode 104 is formed for each pixel. In this image display device, a light-transmitting electrode layer 104 made of ITO and a light-transmitting insulating layer 110 are formed on a light-transmitting substrate 101, and then a hole penetrating to the electrode layer 104 is formed in the insulating layer 110. Thus, openings that effectively function as electrodes are two-dimensionally discretely formed. Here, the hole shape is not limited to the rectangular shape as shown in FIG. 13, and may be a circle or the like. It is important that the pixel is formed at substantially the center of each pixel in the plane. After this substrate was filled with a translucent medium 107 in which black colored charged particles 106 were dispersed on a substrate 102 in which the particle moving means 105, the partition wall 108, and the lower electrode 103 were formed in a two-dimensional array, as in Example 1. Then, the image display device is obtained by being integrated and sealed with the translucent substrate 101. In the present image display device, since the area of the opening of the insulating layer 110 that effectively functions as an electrode in the upper electrode 104 is small, particles are collected in a small space, and the aperture ratio in the white display state is increased, resulting in a high reflectance. Thus, a high-contrast image display device can be obtained.

(Specific example 3)
Another specific example of the image display apparatus according to this embodiment will be described with reference to FIGS.
In the image display apparatus of this specific example, as shown in FIG. 13, pairs of the lower electrode 103 and the upper electrode 104 are two-dimensionally arranged to constitute a pixel. In this image display apparatus, the thickness of 0.2mm F _e N _i 42 particles moving means 105 in a similar two-dimensional array as in example 1 on a flexible substrate coated with the resin insulating smoothing layer on a metal thin plate made of alloy After the partition wall 108 was formed, an Al layer was deposited and patterned to form the lower electrode 103 and the upper electrode 104 in the same layer. This is filled with a translucent medium 107 in which black colored charged particles 106 are dispersed, and then integrated with a 0.1 mm-thick flexible resin substrate and sealed to obtain an image display device. In this image display device, since a pixel pattern is not formed on the substrate 101, a flexible substrate such as a thin glass, a resin, or a thin plate metal is used without the need to match the translucent substrate 101 and the back substrate 102 with high accuracy. Therefore, an image display apparatus that is flexible and resistant to impact can be obtained. A similar effect is also obtained in the structure shown in FIGS. 15, 16, 17, and 19 in which the surface-side translucent substrate 101 has no pattern. By using the flexible substrate, the image display device is flexible and resistant to impact. Is obtained.

(Specific example 4)
Another specific example of the image display apparatus according to this embodiment will be described with reference to FIGS.
Also in the image display device of this specific example, as shown in FIG. 24, pixels including the lower electrode 103 and the upper electrode 104 are two-dimensionally arranged. Unlike the case of the specific example 2, the upper electrode 104 is formed at four points in each pixel. In this image display device, a light-transmitting upper electrode 104 and a light-transmitting insulating layer 110 made of ITO or the like are formed on a light-transmitting substrate 101, and then a hole penetrating to the upper electrode 104 is formed in the insulating layer 110. Thus, openings that effectively function as electrodes are formed two-dimensionally discretely. After this substrate was filled with a translucent medium 107 in which black colored charged particles 106 were dispersed on a back substrate 102 in which particle moving means, partition walls 108, and lower electrodes 103 were formed in the same two-dimensional arrangement as in Example 1, An image display device is obtained by being integrated with the light-transmitting substrate 101 and sealed. This image display device can reduce the distance between the openings of the insulating layer 110 that effectively functions as an electrode in the upper electrode 104 and shorten the distance of particle movement at the time of image switching. Speed is improved. Further, in such a structure having a plurality of electrodes in a pixel, even if a pattern is formed on the substrate 101, the image display performance with respect to the misalignment of the alignment positions of the translucent substrate 101 and the back substrate 102. Therefore, a flexible substrate such as thin glass, resin, and sheet metal is suitable for use, and an image display device that is flexible and resistant to impact can be obtained.

(Second Embodiment)
Although 1st Embodiment used the translucent member for the whole partition, it can also comprise also using a translucent member and a reflection member. This reflection member is an optical member mainly composed of the imaginary part of the complex refractive index as described above.
An image display apparatus according to the second embodiment will be described with reference to FIGS.
FIG. 30 is a cross-sectional view of a pixel portion of the image display device. The present embodiment is characterized in that an in-partition protrusion 1001 having a protrusion structure having an inclined surface is provided in a transparent partition 108, and a reflective layer 1002 is formed thereon. Here, a pixel structure in which the lower electrode 103 is a collecting electrode is shown. When white display is performed, a voltage is applied to the lower electrode 103 to collect colored charged particles 106. FIG. 30 shows a pixel performing this white display. In the case of white display, a voltage is applied to the lower electrode 103 by a thin film transistor (not shown) connected through a through hole (not shown), and the colored charged particles 106 that are electrophoretic particles are driven.

  First, with reference to FIG. 30, the action of the reflective layer 1002 on the in-partition protrusion 1001 on a light beam incident from the outside will be described. Here, the intra-partition wall protrusion 1001 has an isosceles triangle shape with a cross section having an inclination angle α. A metal thin film was formed on the in-partition protrusion 1001 to form a reflective layer 1002. The reflective layer 1002 has a high reflectance and desirably has a substantially constant reflectance in the visible wavelength range, and a metal film may be formed using Al or Ag. Here, the real part of the complex refractive index of Al is 1.44, the imaginary part is 5.23, and the reflectance is 0.83. The real part of Ag's complex refractive index is 0.20, the imaginary part is 3.44, and the reflectance is 0.94. When the reflective layer 1002 is formed using a metal film in this way, a film formed in the same manner as the lower electrode 103 can be used. Alternatively, a reflective film having a structure in which dielectric films are stacked can be used. As described above, since the in-partition protrusion 1001 has the inclined reflection surface, the light beam 1100a incident on the partition 108 at an incident angle near to the light-transmitting substrate 101 is reflected by the reflection layer 1002 and is adjacent to the pixel cell. It enters into 118b.

  When the adjacent pixel cell 118 performs white display, the light beam that has hit the reflective layer 1002 can contribute to the display in the same manner as the illumination light that has hit the direct diffuse reflection layer 1003. As described above, light that has been incident on the partition wall 108 and has not been used can be applied to the diffuse reflection layer 1003 of the pixel cell 118 and used as illumination light. Therefore, a brighter display than before can be achieved. However, when the light beam reflected by the reflective layer 1002 directly goes out of the light-transmitting substrate 101 without hitting the diffuse reflective layer 1003, the contrast is lowered or the reflection is caused, and the image quality is deteriorated. . Therefore, the condition of the inclination angle α for preventing the incident light beam from directly coming out of the translucent substrate 101 after being reflected by the reflective layer 1002 was obtained.

となることを示すことができる。このように傾斜角度αを定めると、反射層１００２で反射した光線が直接透光性基板１０１の外に出ることはなく、その多くは、隣接する画素セル１１８内の拡散反射層１００３に当たるか透光性基板１０１に当たり全反射することになる。透光性基板１０１で全反射した光線の多くも、隣接する画素セル１１８あるいは他の画素に入射する。この光線が白表示画素に入射すると、外界から直接白表示画素に入射した光線と同じく表示に寄与することができる。また、反射層１００２に当たらず隔壁１０８を透過した光線も、これまで説明した本発明の画像表示装置と同ように画素セルの照明に利用される。したがって、隔壁１０８に入射した光線は、隔壁１０８内でほとんど損失することなく、画素セル１１８の照明に利用されることになる。そのため、隔壁１０８を設けても隔壁１０８がない場合と同程度に明るい表示を行うことができる。また、反射層１００２を設けても隔壁１０８から直接的に透光性基板１０１の外に光線が出ることがないため、コントラストの低下が生じず、さらに、反射層１００２を鏡面としても写り込みが生じない。 In order to prevent the light beam reflected by the reflective layer 1002 from going out of the translucent substrate 101, the light beam reflected by the reflective layer 1002 toward the translucent substrate 101 is totally reflected on the surface of the translucent substrate 101. What should I do? For this purpose, the light beam 1100b (incident angle of 90 °) incident almost parallel to the surface of the light-transmitting substrate 101 is reflected by the reflective layer 1002 and then totally reflected by the surface of the light-transmitting substrate 101. You just have to decide. The inclination angle α for that purpose depends on the magnitude relationship between the refractive index n ₂ of the translucent solvent and the refractive index n ₃ of the partition wall.

Can be shown. When the inclination angle α is determined in this way, the light beam reflected by the reflective layer 1002 does not directly go out of the translucent substrate 101, and most of the light hits the diffuse reflective layer 1003 in the adjacent pixel cell 118. The light hits the optical substrate 101 and is totally reflected. Many of the light rays totally reflected by the translucent substrate 101 also enter the adjacent pixel cell 118 or other pixels. When this light ray enters the white display pixel, it can contribute to display in the same manner as the light ray directly incident on the white display pixel from the outside. Further, the light beam that does not hit the reflective layer 1002 and passes through the partition wall 108 is also used to illuminate the pixel cell as in the image display device of the present invention described so far. Therefore, the light beam incident on the partition wall 108 is used for illumination of the pixel cell 118 with almost no loss in the partition wall 108. Therefore, even when the partition 108 is provided, a bright display can be performed as much as when the partition 108 is not provided. Further, even if the reflective layer 1002 is provided, light does not come out of the light-transmitting substrate 101 directly from the partition wall 108, so that the contrast does not decrease, and the reflection layer 1002 is mirrored. Does not occur.

In general, the refractive index n ₂ of the translucent medium 107, which is a liquid used for electrophoresis, is often lower than that of the transparent medium used for the partition wall. Is often determined. In that case, when the refractive index n ₃ of the partition wall 108 is closer to the refractive index n ₂ of the translucent medium 107, the inclination angle α can be reduced and the height of the protrusion part 1001 in the partition wall can be reduced. The part 1001 is easy to manufacture, which is desirable. That is, it is often desirable to use the partition material 108 having a small refractive index for the normally used translucent medium 107. As the translucent medium 107, it is preferable to use a solvent having a large refractive index n ₃ because the inclination angle α can be reduced.

  Next, the operation of the reflective layer 1002 when light is extracted from the pixel as display light to the viewpoint side will be described with reference to FIG. In the white display pixel 1011, illumination light incident from the outside of the translucent substrate 101 is diffused by the diffuse reflection layer 1003, and this diffused light is extracted from the translucent substrate 101 to the viewpoint side and appears white (light ray 1100 c). When the diffusion angle is large in the diffused light and the protrusions 1001 in the partition walls are not provided, the light is absorbed by the black display pixels, or is totally reflected by the light-transmitting substrate 101 and outside the light-transmitting substrate 101. A part of the light beam 1100 d that does not come out can be extracted from the light-transmitting substrate 101 by being partially reflected by the reflective layer 1002. Therefore, it is possible to improve the light extraction efficiency of diffused light and contribute to the improvement of luminance. Thus, the white display pixel 1011 side slope of the reflective layer 1002 appears white because the light diffused by the diffuse reflective layer 1003 is reflected.

  On the other hand, on the black display pixel 1012 side, most of the light rays 1100e incident from the outside and reflected by the reflective layer 1002 are absorbed by the colored charged particles 106 in the black display pixel 1012. Even if it is not absorbed by the black display pixel 1012, it is totally reflected by the translucent substrate 101, so that it does not go directly to the outside and the contrast is not lowered. Since almost no light rays hit the reflective surface 1002 from the black display pixel 1012 side, the black display pixel 1012 side inclined surface of the reflective layer 1002 looks black even if there is a reflector inside the partition wall 108.

  Thus, since the reflective layer 1002 looks white or black according to the display state of the adjacent pixels, the black and white changes according to the adjacent pixels even though the partition wall 1001 does not have a switching function. Therefore, when the black matrix is simply provided on the upper part of the partition wall and the reflected light is eliminated, the area of one pixel is larger in the black pixel than in the white pixel. The area of one pixel can be made substantially equal. Conventionally, this area difference between white and black pixels has become more prominent as the resolution increases, and even when the resolution is large, a faithful image in which the areas of the white and black pixels are almost equal can be obtained. Will be able to.

  Up to now, the condition that all the light beams reflected by the reflective layer 1002 do not directly go out of the translucent substrate 101 has been described. In this case, since almost all of the light incident on the partition wall 108 can be used for illumination, the light use efficiency can be maximized. On the other hand, from the viewpoint of facilitating the production of the in-partition protrusion 1001, it is desirable to use the in-partition protrusion 1001 having a small inclination angle α. Therefore, this light use efficiency is allowed to be somewhat reduced, and even if the in-partition protrusion 1001 having a smaller inclination angle α is used, the brightness can be improved as compared with the conventional case without causing a reduction in contrast and reflection. The conditions are as follows.

と表され、傾斜角度αは、（１０１）式及び（１０２）式の半分にできることが分かる。 The condition of the inclination angle α obtained from the viewpoint that no background reflection occurs and the contrast does not decrease will be described with reference to FIG. When viewing the display of the image display device, the image display device is often viewed from the front. In order to prevent the reflection of the background when viewed from the front of the image display device, the light beam 1100f incident on the grazing surface of the translucent substrate 101 (incident angle 90 °) and reflected by the reflecting surface 1002 is obtained. However, what is necessary is just to determine inclination-angle (alpha) so that it may radiate | emit to the light-incidence side rather than a front direction (emission angle 0 degree). The condition of the inclination angle α for that is

It can be seen that the inclination angle α can be half that of the equations (101) and (102).

  Therefore, the height of the projections 1001 in the partition walls can be reduced, and the manufacturing becomes easy. When the image display device is actually viewed, since it is viewed at a certain angle with respect to the front, the range of the expected angle is taken into account, and the inclination angle α obtained from the equation (103) or (104) is set to a larger value. desirable.

  Next, the condition of the inclination angle α obtained from the viewpoint that the contrast does not decrease will be described with reference to FIG. As described above, in the case where at least one pixel performs white display, even if the light beam reflected by the reflective layer 1002 is extracted from the translucent substrate 101, it can contribute to white display. Therefore, when at least one pixel of the partition wall 108 displays white, the contrast is not lowered even if the reflected light from the reflective layer 1002 directly goes out of the translucent substrate 101. Therefore, it is only necessary to consider that the contrast does not decrease only for the partition wall 108 sandwiched between the black display pixels on both sides. When both sides display black, the light-shielding colored charged particles 106 are dispersed in the display cell 118, so that the light incident on the partition wall 108 enters from the surface of the partition wall 108 on the translucent substrate 101 side. Only the rays need be considered. In order not to decrease the contrast, in order to prevent this light beam from being reflected by the reflection layer 1002 and then passing through the light-transmitting substrate 101 again, the light beam is incident on the adjacent black display pixel. So that it can be absorbed.

を満たすように定めればよいことが示される。この式から傾斜角度αの満たすべき条件を求めると、ｄ≧ｗとし、

とすればよいことになる。この式より、隔壁の幅ｗと高さｄが等しい場合には、傾斜角度αを４５°以上とすればよいことになる。また、さらに傾斜角度αを小さくするためには、ｄ＞ｗとなるようにアスペクト比の大きな隔壁を用いることが有効であることが分かる。 The light beam 1100h that passes through the partition wall 108 without hitting the reflective layer 1002 is incident on the black display pixel and absorbed, so that the light beam 1010g that passes through the vicinity of the corner of the partition wall 108 and enters the vicinity of the vertex of the projection 1001 in the partition wall. However, the inclination angle α may be determined so as to be reflected in the black pixel cell. For this purpose, if the width of the partition wall is w and the height is d, the inclination angle α is

It is shown that it should be determined to satisfy From this equation, the condition to be satisfied of the inclination angle α is determined as d ≧ w,

It will be enough. From this equation, when the width w and height d of the partition walls are equal, the inclination angle α may be set to 45 ° or more. Further, it can be seen that in order to further reduce the inclination angle α, it is effective to use a partition wall having a large aspect ratio so that d> w.

  In this case, since the light reflected by the reflective layer 1002 is absorbed by the adjacent black display pixels so that the contrast is not lowered, the colored charged particles 106 at the time of black display are within the pixel cell as shown in FIG. It is necessary to disperse them on the display substrate 101 side. Note that in the case where the brightness of display is most important than the contrast, a pixel structure in which the colored charged particles 106 gather on the back substrate 102 side during black display may be employed. In this case, part of the light reflected by the reflective layer 1002 adjacent to the black display pixel reaches the translucent substrate 101, where it can be totally reflected to illuminate other pixels, and the brightness is further increased. Can be improved.

  The intra-partition protrusion 1001 can be formed using, for example, a photoresist. A photoresist is applied and heated by a spin coat method or the like so as to have a desired thickness, thereby forming a photoresist film. The photoresist film can be exposed and developed using a photomask in which only the portion corresponding to the protrusion is exposed, whereby a trapezoidal protrusion can be obtained. Alternatively, the exposure amount may be changed depending on the position using a photomask whose effective transmittance is continuously changed. If a negative photoresist is used, the photoresist melts from the unexposed portion, so that it is easy to obtain a rectangular or trapezoidal cross-sectional shape.

An inorganic material such as silicon oxide or silicon nitride may be used as the protrusion. A protrusion can be formed by forming an inorganic film, forming a photoresist pattern thereon by photolithography, and etching the film. It is also possible to control the shape of the inclined surface of the protrusion after etching by stacking a plurality of silicon nitride films having different film qualities by changing the conditions of the concentration of NH ₃ or SiH ₄ supplied in the film forming process. .

  So far, the shape of the in-partition protrusion 1001 has been described as an ideal triangle with a sharp apex. However, the actual apex of the in-particle protrusion 1001 has a curvature, and a portion with a gentle inclination angle is generated. It is desirable to form the in-partition protrusions 1001 so that such gentle slope portions are minimized. A light absorption layer may be provided at a small inclination angle so that light is not reflected. Alternatively, the height or width of the protrusions 1001 in the partition walls may be randomly modulated in order to suppress reflection (regular reflection) or contrast reduction due to a gentle slope. In this case, it is desirable that the shape modulation is limited to such an extent that scattering from a random structure is not a problem.

  In addition, the inclination angle of the in-partition protrusion 1001 need not be a constant angle over the entire inclined surface, and may vary depending on the location. In that case, it is desirable that the inclination angle α satisfy at least the expression (103) or (104), and in order to obtain a brighter display, as many portions as possible satisfy the expression (101) or (102). It is desirable to form so that it becomes. Therefore, the cross-sectional shape of the in-partition protrusion 1001 is not limited to a triangle, but may be a semicircular shape. A convex structure having such a curvature can be formed, for example, by heating and melting a patterned resist. If the width of the resist pattern is randomly modulated, the width or height of the convex structure after melting can be changed depending on the location. The convex structure can also be formed by using a method such as screen printing or direct drawing by ink jet.

  In this embodiment, since metal films are used for the reflective layer 1002 and the diffuse reflective layer 1003, it is desirable that these potentials have potentials that have a positive effect on the movement of the colored charged particles 106. In this embodiment, the voltage of the lower electrode 103 is controlled by a thin film transistor (not shown), and the colored charged particles 106 are moved by a potential difference between the lower electrode 103 and the transparent electrode 109. In other words, if the colored charged particles 106 are positively charged, the colored charged particles 106 are displayed by setting the transparent electrode to 0 V (common voltage) and the lower electrode 103 to −Vd (Vd> 0 V) during white display. Are collected in the lower electrode 103. When black display is performed, the voltage of the lower electrode 103 is once set to + Vc (Vc> 0 V), and then is set to 0 V, whereby the colored charged particles 106 are dispersed and black display is performed. In the case of driving the voltage in this way, it is desirable that the potentials of the reflective layer 1002 and the diffuse reflective layer 1003 be 0 V or a voltage between 0 V and + Vc.

  Further, the colored charged particles 106 can be driven by applying a voltage between the lower electrode 103 and the diffuse reflection layer 1003 without providing the transparent electrode 109. Alternatively, the colored charged particles 106 can be driven by providing the collective electrode on the light-transmitting substrate 101 side and using the diffuse reflection layer 1003 as the pixel electrode.

  As described above, a light beam that has hitherto been incident on the partition wall 108 and has not been used for display can be used for pixel illumination in the present embodiment, and a bright display can be performed. It was. In particular, when the display resolution increases, the proportion of the partition wall 108 in the display portion increases. Therefore, the improvement in brightness by using the light incident on the partition wall 108 is particularly effective when the resolution is large. Further, even when the width of the partition wall 108 is increased to increase the area ratio occupied by the partition wall 108, bright display can be obtained. Therefore, the aspect ratio of the partition wall 108 can be reduced so that the partition wall 108 can be easily manufactured. Alternatively, since the width of the partition wall 108 can be increased, the partition wall can be increased without increasing the aspect ratio, and the cell gap can be increased. When the colored particles 106 have a large particle size or a low concentration, it is desirable to widen the cell gap. Even in this case, a high resolution and bright display can be obtained. Even if the partition wall is made thick, the viewing angle is not easily blocked by the partition wall when the image is viewed obliquely, and a display with a wide viewing angle can be obtained.

An image display apparatus which is another modified example according to the present embodiment will be described.
FIG. 34 is a cross-sectional view of a pixel of the image display device. In this embodiment, the in-partition protrusion 1001 has a trapezoidal shape. The reflective layer 1002 is the same layer as the diffuse reflective layer 1003 and is driven by a thin film transistor using the diffuse reflective layer 1003 as a pixel electrode. By separating the reflective layer 1002 at the top of the trapezoid, the pixels are electrically separated.

The angle of the trapezoidal inclined surface is determined so as to satisfy the expression (103) or (104), preferably the expression (101) or (102), as in the above-described embodiment. Can be improved.
The top of the trapezoid was the opening 1005. By providing the opening 1005, the light beam 1100 i incident on the top of the trapezoid passes through the opening 1005 and enters the intra-partition protrusion 1001, and is absorbed by the black matrix 1013 provided below the intra-partition protrusion 1001. The Therefore, even if there is a flat portion at the top of the protrusion 1001 in the partition wall, the contrast does not decrease. Even if the black matrix 1013 is not provided, it is not always necessary to provide the black matrix 1013 because the ratio of the light rays that have entered the protrusions 1001 in the partition walls to be reflected internally and go out from the openings 1005 again is small. Alternatively, even when the insulating layer 1009 is transparent and light is allowed to escape to the back substrate 102 side, generation of return light can be suppressed.

In the case where the protruding portion 1001 in the partition wall can be sufficiently high, the partition wall 108 may not be provided. Further, the in-partition protrusion 1001 may be used as a partition part for separating pixels. Since this case corresponds to the case of n ₃ = n ₂ , the inclination angle α of the reflective layer 1002 may satisfy the relationship of the expression (102) or the expression (104).

とする必要がある。さらに、台形底部の幅をｗ_sとすると、台形の高さｈを

とする必要があることを示すことができる。 Further, in the present embodiment, the discrete upper electrode 104 is also provided on the side surface of the trapezoidal discrete electrode protrusion 1006. In the case of white display, the colored charged particles 106 gather along the discrete upper electrodes 104. During the white display, the external light incident on the discrete electrode protrusion 1006 is reflected by the discrete upper electrode 104 and enters the pixel cell, and can be used for illumination of the pixel. Here, as shown in FIG. 34, since the discrete upper electrodes 104 are provided on both sides of the trapezoid, the light rays incident on the discrete electrode protrusions 1006 are reflected multiple times between the discrete upper electrodes 104 to be outside the translucent substrate 101. In order to reduce the contrast when returning, the shape of the discrete electrode protrusion 1006 is determined so that such return light does not occur. In order to prevent the light beam 1100j (incident angle 90 °) incident along the translucent substrate 101 from being reflected by the discrete electrode projection 1006 and then returning to the translucent substrate 101 side, the discrete electrode projection If the refractive index of 1006 is n ₆ , the inclination angle β of the trapezoidal slope is

It is necessary to. Furthermore, if the width of the trapezoid bottom is w _s , the height h of the trapezoid is

You can show that you need to.

  As described above, since the colored charged particles 106 are collected on the discrete upper electrodes 104 formed on the inclined surface, the colored charged particles 106 are shadows of a trapezoidal slope (back substrate) when viewed from the translucent substrate 101 side during white display. 102), the absorption of incident light by the colored charged particles 106 is reduced. As a result, the amount of light incident on the pixel cell can be increased and the display can be brightened. In addition, the light diffused by the diffuse reflection layer 1003 also passes through the discrete electrode protrusions 1006 and comes out of the translucent substrate 101, so that the discrete electrode protrusions 1006 appear white.

On the other hand, in the case of black display, the light beam reflected by the discrete upper electrode 104 does not return directly to the translucent substrate 101 side, and the light beam transmitted through the discrete electrode protrusion 1006 is absorbed by the colored charged particles 106. Therefore, the discrete electrode protrusion 1006 looks black.
As described above, the discrete upper electrode 104 of the present embodiment can also use the light incident on the discrete upper electrode 104 portion as pixel illumination without reducing contrast, and a bright display can be obtained.

とすればよい。 The discrete electrode projections 1006 may be provided in the form of stripes with the discrete upper electrodes 104 on both side surfaces thereof, or may be formed in the shape of islands on the entire side surfaces as the discrete upper electrodes 104. Further, the discrete upper electrode 104 does not need to be provided on both sides of the discrete electrode protrusion 1006 and can be provided on one side. In that case, the condition of the inclination angle β that does not reduce the contrast is the same as the form shown below,

And it is sufficient.

  The trapezoidal in-partition protrusions 1001 and the discrete electrode protrusions 1006 can be formed using, for example, a photoresist. A photoresist is applied and heated by a spin coat method or the like so as to have a desired thickness, thereby forming a photoresist film. The photoresist film is exposed using a photomask in which only a portion corresponding to the protrusion is exposed and developed, whereby a trapezoidal protrusion can be obtained. Alternatively, the exposure amount may be changed depending on the position using a photomask whose effective transmittance is continuously changed. If a negative photoresist is used, the photoresist melts from the unexposed portion, so that it is easy to obtain a rectangular or trapezoidal cross-sectional shape. These positive type and negative type resists may be selected so that projections having a desired shape can be easily obtained.

An inorganic material such as silicon oxide or silicon nitride may be used as the protrusion. A protrusion can be formed by forming an inorganic film, forming a photoresist pattern thereon by photolithography, and etching the film. It is also possible to control the shape of the inclined surface of the protrusion after etching by stacking a plurality of silicon nitride films having different film qualities by changing the conditions of the concentration of NH ₃ or SiH ₄ supplied in the film forming process. .

  Here, a combination of the upper electrode 104 structure using the discrete electrode protrusions 1006 and the partition wall structure provided with the trapezoidal intra-partition protrusions 1001 is shown in combination, but it is not always necessary to use them in combination. The discrete upper electrode 104 using the discrete electrode protrusion 1006 can be widely applied to pixel structures in which discrete electrodes are provided on the light-transmitting substrate 101 side.

と表される。この式より、全反射する光の割合を大きくするためには、隔壁内突起部１００１の屈折率ｎ₄は小さく、隔壁１０８の屈折率ｎ₃は大きいことが望ましく、また、傾斜角度αは大きいことが望ましいことになる。 An image display apparatus which is another modified example according to the present embodiment will be described.
FIG. 35 is a cross-sectional view of a pixel portion of the image display device.
Here, the light projection efficiency of external incident light is improved by making the protrusions 1001 in the partition walls have a low refractive index, the partition walls 108 have a high refractive index, and using total reflection generated at the interface between the protrusions 1001 in the partition walls and the partition walls 108. I planned. The incident angle θ of the light beam 1100k totally reflected at the interface is expressed as follows: n _{3 is} the refractive index of the partition wall 108 and n ₄ is the refractive index of the protrusion 1001 in the partition wall

It is expressed. From this equation, in order to increase the ratio of the totally reflected light, it is desirable that the refractive index n ₄ of the in-partition protrusion 1001 is small, the refractive index n ₃ of the partition 108 is large, and the inclination angle α is large. Would be desirable.

  A light ray having an incident angle larger than the expression (110) is incident on the in-partition protrusion 1001 and hits the bottom 1014 of the in-partition protrusion 1001 (light 1100 m), or is transmitted through the in-partition protrusion 1001 to the adjacent pixel. (Light ray 1100n). In this embodiment, the light diffusion layer 1007 is provided on the bottom 1014 of the in-partition protrusion 1001 with emphasis on brightness. The light 1100 m reaching the bottom portion 1014 can be diffused by the light diffusion layer 1007 and taken out of the translucent substrate 101. In this case, the partition wall looks white. When the pixel is displayed in black, the light beam 1100m is absorbed because it passes through the pixel in black display, and the amount of light reaching the partition 108 is reduced. Therefore, even if a light diffusing member or a reflecting member is provided on the bottom 1014, the reduction in contrast can be reduced. Therefore, even if the light diffusion layer 1007 is provided on the bottom portion 1014, the partition wall 108 sandwiched between the black pixels looks black. In order to suppress the decrease in contrast as much as possible, a light absorption layer may be provided instead of the light diffusion layer 1007, or the insulating layer 1009 may be transparent so that light can escape to the back substrate 102 side.

  As shown by the formula (110), it is desirable that the projections 1001 in the partition walls have a low refractive index, and when the refractive index of the translucent solvent 107 is small, the projections 1001 in the partition walls are used. It can also be used. In this case, for example, a partition wall 108 having a cavity in the partition wall protruding portion 1001 is formed on the translucent substrate 101 side, and a voltage is applied between the electrodes so as to collect the colored charged particles 106 on the discrete upper electrode 104. By sealing the cell, the translucent medium 107 can be filled in the protruding portion 1001 in the partition wall.

  In the present embodiment, since total reflection is used, no light loss occurs at the interface between the protrusions 1001 in the partition walls and the partition walls 108. Therefore, when the refractive index difference between the protrusions 1001 in the partition walls and the partition walls 108 is large and the inclination angle α is also increased, the utilization efficiency of the light incident on the partition walls 108 can be increased.

となるようにすればよい。透光性基板１０１から入射した光線が、離散上部電極１０４で反射した後、直接透光性基板１０１から外に出ないため、離散上部電極１０４を反射面としてもコントラストの低下は起きない。 Further, in the present embodiment, the discrete upper electrodes 104 are provided on the side surfaces of the V-shaped groove portion 1015 formed on the translucent substrate 101. Also here, the inclination angle γ of the groove 1015 is determined so that the light incident from the translucent substrate 101 is not reflected directly from the translucent substrate 101 after being reflected by the discrete upper electrode 104. For that purpose, assuming that the refractive index of the translucent substrate 101 is n ₁ , the inclination angle γ of the groove 1015 is:

What should be done. After the light beam incident from the translucent substrate 101 is reflected by the discrete upper electrode 104 and does not go directly out of the translucent substrate 101, the contrast does not decrease even if the discrete upper electrode 104 is used as a reflective surface.

  As described above, since the colored charged particles 106 are collected on the discrete upper electrode 104 in the groove portion 1015, the colored charged particles 106 come to the back of the discrete upper electrode 104 when viewed from the translucent substrate 101 side. In the white display, absorption of incident light by the colored charged particles 106 can be reduced. A light beam incident from the outside and reflected by the discrete upper electrode 104 does not directly go out of the translucent substrate 101, and can be used as illumination light for illuminating the pixel. Therefore, the amount of light incident on the pixel cell can be increased and a bright display can be obtained. It is desirable that the light beam reflected by the discrete upper electrode 104 directly strikes the diffuse reflection layer 1003 of the same pixel as much as possible because the ratio of the light beam reflected by the discrete upper electrode 104 to the white display pixel can be increased. For this purpose, it is desirable to increase the inclination angle γ.

On the other hand, in the case of black display, since the light beam reflected by the discrete upper electrode 104 does not return directly to the translucent substrate 101 side, the groove portion 1015 looks black.
In the present embodiment, as described above, the light incident on the discrete upper electrode 104, which has not been conventionally used, can be used as pixel illumination without reducing the contrast, so that a bright display can be obtained. Become.

The discrete electrode projections 1006 may be provided in the form of stripes with the discrete upper electrodes 104 on both side surfaces thereof, or may be formed in the shape of islands on the entire side surfaces as the discrete upper electrodes 104. In addition, the groove 1015 may not be provided directly on the light-transmitting substrate 101, but a transparent layer may be separately provided inside the light-transmitting substrate 101, and the groove 1014 may be formed there.
Note that the discrete electrode structure using the groove 1015 does not need to be used in combination with the partition wall structure of the present embodiment, and can be widely applied when a discrete electrode is provided on the translucent substrate 101 side.

Another image display apparatus according to this embodiment will be described.
FIG. 36 is a cross-sectional view of a pixel of the image display device.
In the present embodiment, in addition to the form of the partition wall portion shown in FIG. 35, a lens portion 1008 having a convex shape on the translucent substrate 101 side is provided on the translucent substrate 101. The refractive index n ₅ of the lens unit 1008 is made smaller than the refractive index n ₁ of the translucent substrate 101 so that the lens unit 1008 functions as a concave lens. By making the lens portion 1008 a concave lens, the incident angle of the light beam incident on the in-partition protrusion 1001 from the upper part of the partition is reduced. For this reason, the amount of light totally reflected at the interface between the protrusions 1001 in the partition walls and the partition walls 108 is increased, and the display can be brightened.

As described above, it is desirable that the lens unit 1008 functions as a concave lens, but the convex lens structure also functions as a convex lens when a light beam having a large angle is transmitted to an adjacent pixel unit before hitting the in-partition protrusion 1001. A structure may be provided.
Even if only the lens portion 1008 is provided without the intra-partition protrusion 1001, the amount of light incident on the bottom of the partition (on the back substrate 102 side) can be reduced, and the effect of improving brightness can be obtained. The effect of providing the lens portion 1008 is also effective in the form of the partition wall using the above-described reflective layer.

  As described so far, by providing the reflecting member in the partition wall, it is possible to improve the brightness of the display by reusing light that has not been used after being incident on the partition wall. This light reuse is large in the partition adjacent to the white display pixels. Furthermore, in order for the light totally reflected by the translucent substrate 101 to enter the white display pixel again and be used as illumination light, it is desirable that the ratio of the white display portion to the black display portion is large. Therefore, the more white display portions, the higher the light reuse efficiency, and it is particularly suitable for a display device that displays black characters or the like on a white background such as an electronic book terminal.

The present embodiment is characterized in that light incident on the partition wall 108 is extracted from the partition wall 108 to improve the brightness, and the pixel cell structure collects the colored charged particles 106 at a position different from the partition wall 108. What is necessary is not to limit the structure.
In the above, the protrusions 1001 in the partition walls have been described as having a single protrusion in the partition wall 108, but a plurality of protrusions having such a size that diffraction and scattering do not become a problem can be provided.

(Specific example 5)
A specific example of the image display apparatus according to the second embodiment will be described with reference to FIG.
The resolution of the image display device was 600 ppi (pixel pitch 42 μm). The partition wall 108 was formed using an acrylic resin having a refractive index of 1.49 and had a width of 5 μm. In this case, the area occupied by the partition wall 108 when viewed from the front is 12%. As the translucent medium 107, silicone oil having a refractive index of 1.38 was used. In this case, it is desirable that α ≧ 50.3 ° from the equation (101). In this specific example, the protrusion in the partition wall 1002 is formed with the height of the protrusion part in the partition wall 1002 set to 4.3 μm so that the inclination angle α is 60 °.

(Specific Example 6)
Another specific example of the image display apparatus according to the second embodiment will be described with reference to FIG.
The resolution of the image table device was 600 ppi (pixel pitch 42 μm). The partition wall 108 was formed using an acrylic resin having a refractive index of 1.49 and had a width of 5 μm. As the translucent medium 107, silicone oil having a refractive index of 1.38 was used. In this case, it is desirable that α ≧ 50.3 ° from the equation (101). In this specific example, the height of the projection in the partition 1002 is determined so that the inclination angle α is 60 °, and the projection in the partition 1002 is formed.

  Also, the discrete electrode protrusion 1006 was formed using a polymer having a refractive index of 1.76. As the high refractive index polymer, a polymer having a high refractive index by dispersing fine particles of titanium oxide in a polymer material was used. The expression (107) shows that the inclination angle β of the discrete electrode protrusion 1006 needs to satisfy β ≦ 62.3 °. In this specific example, the inclination angle β is set to 65 °, and the width ws on the surface substrate side of the discrete electrode protrusion 1006 is set to 10 μm and the height h is set to 1.8 μm so as to satisfy the expression (108).

(Specific example 7)
Still another specific example of the image display apparatus according to the second embodiment will be described with reference to FIG.
A polymer having a refractive index of 1.76 was used for the partition wall 108, and a polymer having a refractive index of 1.34 was used for the protrusion 1001 in the partition wall. Since the width and height of the bottom surface of the in-partition protrusion 1001 were equal to 5 μm, the inclination angle α was set to 63.4 °. According to the equation (109), the light incident on the translucent substrate 101 at an incident angle smaller than 24.9 ° is totally reflected by the light incident on the interface between the partition wall 108 and the projection in the partition wall 1001 to illuminate the pixel. be able to.
Further, polycarbonate having a refractive index of 1.59 was used for the light-transmitting substrate 101. Therefore, the inclination angle γ satisfying the expression (110) is 39 ° or more. In this specific example, the inclination angle γ is 45 °. The groove portion 1015 was formed into a stripe shape, and the light-transmitting substrate 101 was processed with a dicer. The discrete upper electrode 104 was formed in the groove portion 1015 using Al.

(Specific example 8)
Still another specific example of the image display apparatus according to the second embodiment will be described with reference to FIG.
The structure of the partition wall was the same as that in Example 7, and a lens portion 1008 was provided in the light-transmitting substrate 101 on the partition wall 108. The lens portion 1008 was formed by embedding a resin having a refractive index of 1.34 in a semicircular groove having a width of 5 μm and a height of 2.5 μm formed on the light-transmitting substrate 101 having a refractive index of 1.59. By providing this lens portion 1008, the light beam incident on the translucent substrate 101 at an incident angle smaller than about 35 ° is totally reflected at the interface between the partition wall 108 and the protrusion portion 1001 in the partition wall.

  As described above, according to the present embodiment, the intended purpose of increasing the reflectance of the image display apparatus can be achieved. Further, the viewing angle characteristics are improved, and a high-quality image display device can be realized.

It is the upper side figure and sectional drawing of the image display apparatus of 1st Embodiment. It is a figure explaining the display principle of the image display apparatus of 1st Embodiment. It is sectional drawing of the image display apparatus which is a modification of 1st Embodiment. It is a top view of the image display apparatus of a 1st embodiment. It is a top view of the image display apparatus which is a modification of 1st Embodiment. It is a figure explaining the display principle of the image display apparatus of a prior art. It is a figure which shows the reflectance with respect to an incident angle. It is a figure explaining the image display apparatus which is another modification of 1st Embodiment. It is a figure explaining the image display apparatus which is another modification of 1st Embodiment. It is a figure explaining the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is a top view of the image display apparatus which is another modification of 1st Embodiment. It is a top view of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is sectional drawing of the image display apparatus which is another modification of 1st Embodiment. It is a top view of the image display apparatus which is another modification of 1st Embodiment. It is a top view of the image display apparatus which is another modification of 1st Embodiment. It is a figure for demonstrating a gradation display. It is a figure for demonstrating multicolor display. It is another figure for demonstrating multicolor display. It is a figure for demonstrating operation | movement of the image display apparatus which is another modification of 1st Embodiment. It is a figure which shows a drive circuit. It is a figure explaining the image display apparatus of 2nd Embodiment. It is a figure explaining the image display apparatus which is a modification of 2nd Embodiment. It is a figure explaining the image display apparatus which is another modification of 2nd Embodiment. It is a figure explaining the image display apparatus which is another modification of 2nd Embodiment. It is a figure explaining the image display apparatus which is another modification of 2nd Embodiment. It is a figure explaining the image display apparatus which is another modification of 2nd Embodiment. It is a figure explaining the image display apparatus which is another modification of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Translucent substrate 102 Back substrate 103 Lower electrode 103A, 103B, 103C, 103D Lower electrode 104 Upper electrode 104A, 104B, 104C, 104D Upper electrode 105 Particle moving means 106 Colored charged particle 107 Translucent medium (translucent liquid )
108 Partition 108A Lower partition 108B Upper partition 109 Transparent electrode 110 Insulating layer 111 Light-shielding layer 112 Reflective layer 113 Projection layer 113A Projection layer (high refractive index portion)
113B Protrusion layer (low refractive index part)
114 Concavity and convexity layers 115A, 115B, and 115C Coloring member 117 Thin film transistor 118 Pixel cell 119 Drain line 120 Gate line 121 and 122 Driver circuit 201 Translucent substrate 202 Back substrate 203 Partition 204 First electrode 205 Second electrode 206 Colored charge Particles 207 Translucent medium 208 Light-shielding layer 1001 In-partition protrusion 1002 Reflective layer 1003 Diffuse reflection layer 1005 Opening 1006 Discrete electrode protrusion 1007 Light diffusion layer 1008 Lens part 1009 Insulating layer 1011 White display pixel 1012 Black display pixel 1013 Black matrix 1014 Bottom 1015 Groove

Claims (18)

A translucent substrate on which one or a plurality of first electrodes are formed, a rear substrate on which the one or more second electrodes are formed opposite to the translucent substrate, and the translucent substrate; A partition formed between the back substrate and surrounding each of the plurality of electrodes of the first electrode and the second electrode, and formed from the translucent substrate, the back substrate, and the partition A translucent medium enclosed in a plurality of regions, and electrophoretic particles whose movement is controlled in a direction of an electric field generated between the first electrode and the second electrode in the translucent medium An image display device comprising:
Either one of the first electrode and the second electrode is formed narrower than a region where the other electrode is surrounded by the partition wall,
An image display device, wherein incident light incident on the partition wall at an angle is emitted from the translucent substrate by being reflected by a reflecting member including the second electrode.   The image according to claim 1, wherein the partition wall includes a plurality of light-transmitting members having different refractive indexes, and a boundary surface of the light-transmitting member is parallel to the light-transmitting substrate. Display device.   2. The image display according to claim 1, wherein the partition wall includes a translucent member and a reflective layer having an inclination with respect to the translucent substrate at a boundary between the translucent member and the translucent substrate. apparatus. A translucent substrate on which one or a plurality of first electrodes are formed, a rear substrate on which the one or more second electrodes are formed opposite to the translucent substrate, and the translucent substrate; A partition formed between the back substrate and surrounding each of the plurality of electrodes of the first electrode and the second electrode, and formed from the translucent substrate, the back substrate, and the partition A translucent medium enclosed in a plurality of regions, and electrophoretic particles whose movement is controlled in a direction of an electric field generated between the first electrode and the second electrode in the translucent medium An image display device comprising:
Either one of the first electrode and the second electrode is formed narrower than a region where the other electrode is surrounded by the partition wall,
The partition includes: a translucent member provided on the translucent substrate side; and an optical member having a boundary surface in contact with the translucent member and having a real part having a complex refractive index different from the refractive index. An image display device comprising both. The optical member is another translucent member in which the real part of the complex refractive index is larger than the refractive index of the translucent member and the imaginary part is zero.
The image display apparatus according to claim 4, wherein the boundary surface is a refracting surface parallel to the translucent substrate. The optical member is a light reflecting member whose complex refractive index is mainly an imaginary part,
The image display device according to claim 4, wherein the boundary surface is a reflective surface having an inclination with respect to the light-transmitting substrate. The back substrate reflects light, and a reflection member including the second electrode is formed,
The refracted light refracting the refracting surface or the reflected light reflecting the reflecting surface is emitted from the translucent substrate by being reflected by the reflecting member. The image display device described.   The narrowly formed electrode is formed by laminating a light-transmitting insulating layer around a metal layer formed in a region surrounded by the partition wall on the surface of either the light-transmitting substrate or the back substrate. The image display device according to claim 1, wherein the image display device is provided. The second electrode is a reflective electrode that is formed narrower than a region surrounded by the partition wall and reflects light;
The image display device according to claim 1, wherein a reflecting member is provided around the reflecting electrode. The second electrode is a reflective electrode that reflects light;
The image display device according to claim 1, wherein the first electrode is a light-transmitting electrode that transmits light.   11. The image display device according to claim 1, wherein any one of the first electrode and the second electrode is formed of a plurality of columns.   The image display device according to claim 1, wherein a translucent uneven layer is formed on one of the surfaces of the translucent substrate and the back substrate.   The image display device according to claim 12, wherein the uneven layer is formed with a plurality of microlenses. The maximum tilt angle that is the maximum value of the angle at which the reflective surface and the translucent substrate are tilted, where the refractive index of the translucent medium is n ₃ , the refractive index of the translucent member is n ₂ , and Is α
If n ₃ > n ₂ then

When n ₃ ≦ n ₂ ,

The image display device according to claim 6, wherein: When the refractive index of the translucent medium is n ₃ and the maximum inclination angle that is the maximum value of the inclination angle of the reflecting surface and the translucent substrate is α,

The image display device according to claim 6, wherein: A concave lens-shaped lens member is provided on the partition wall of the translucent substrate,
9. The image display device according to claim 6, wherein light enters the partition wall through the lens member. The first electrode is a light reflective electrode formed on an inclined surface of a V-shaped groove of the translucent substrate,
When the refractive index of the translucent substrate and the n _1, the inclination angle γ of the groove

The image display device according to claim 6, wherein the image display device is an image display device. The optical member is another translucent member in which the real part of the complex refractive index is smaller than the refractive index of the translucent member and the imaginary part is zero.
The image display device according to claim 4, wherein the boundary surface is a reflective surface having an inclination with respect to the translucent substrate.

Images