JP2003307733A - Reflection type liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a reflection type liquid crystal display device used in both of external light and lighting modes which has superior display quality of lightness and its uniformity, etc., while made thin and lightweight. <P>SOLUTION: The reflection type liquid crystal display device has a lighting device (2) on one or more flanks of a reflection type liquid crystal display panel characterized in: having a polarizing layer (15) outside a view-side substrate of a liquid crystal cell, constituted by sandwiching liquid crystal (13) between view-side and rear-side substrates (11, 12) made of transparent substrates having transparent electrodes and having their electrodes opposite each other, across an optical path control layer (13) having a plurality of optical path converting oblique surfaces (A1) having tilt angles 35 to 48° to the reference plane of the substrate; having a polarizing layer (17) outside the back-side substrate across a transparent layer (16) having a lower refractive index than the substrate; and having at least a reflecting layer (18) outside the polarizing layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device for both external light and illumination which is easy to be thin and lightweight and has excellent display quality.

[0002]

BACKGROUND OF THE INVENTION In order to reduce the size and weight of portable personal computers, mobile phones, etc., there is a demand for a thinner and lighter reflective liquid crystal display device. A reflective liquid crystal display device has been proposed in which a lighting device is provided on the side surface of a liquid crystal display panel having a light control layer formed of prismatic irregularities having an inclined surface with a dip angle of 20 degrees between the substrate and the polarizing layer. 2001-33766). In this technique, the viewing side substrate plays a role of optical transmission, and it is possible to omit the side light type light guide plate having a thickness of about 2 mm or more, and to improve the thinness and lightening (Japanese Patent Laid-Open No. 11-1999). -250715).

However, in the illumination mode, there is a problem in that the display becomes darker as it is farther from the illumination device, resulting in a large variation in brightness on the screen.

[0004]

SUMMARY OF THE INVENTION The present invention provides an external light / illumination type reflective liquid crystal display device which is excellent in display quality such as brightness and uniformity in both external light and illumination modes while achieving thinning and weight reduction. Is the development of.

[0005]

According to the present invention, there is provided a liquid crystal cell in which a liquid crystal is sandwiched between a viewing side made of a transparent substrate having a transparent electrode and a rear side substrate with their electrode sides facing each other. A polarizing layer is provided on the outer side of the substrate via an optical path control layer having a plurality of optical path changing slopes having an inclination angle of 35 to 48 degrees with respect to the reference plane of the substrate, and the polarizing layer is provided on the outer side of the rear side substrate rather than the substrate. A reflective liquid crystal display panel having a polarizing layer via a transparent layer having a low refractive index, and at least one reflective layer outside the polarizing layer, and having an illuminating device on one or more side surfaces. A reflective liquid crystal display device is provided.

[0006]

According to the present invention, the incident light from the illuminating device arranged on the side surface of the panel using the liquid crystal cell substrate is efficiently transmitted in the opposite side surface direction while preventing the light from entering the polarizing layer. The transmitted light can be efficiently used for liquid crystal display by changing the optical path in the viewing direction of the liquid crystal display panel through the optical path control layer on the viewing side and the reflective layer on the back side. It is possible to form a front light mechanism with an excellent optical path control layer, and it is possible to display even in the external light mode, has excellent thinness and lightness, and is a bright and excellent display quality. Obtainable.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflective liquid crystal display device according to the present invention comprises a transparent substrate having transparent electrodes and a substrate on the back side and a substrate on the rear side which are arranged so that their electrode sides face each other, and a liquid crystal is sandwiched therebetween. A liquid crystal cell has a polarizing layer on the outside of the viewing side substrate via an optical path control layer having a plurality of optical path conversion slopes having an inclination angle of 35 to 48 degrees with respect to a reference plane of the substrate, and at the same time, the back side substrate has a polarizing layer. An illuminating device is provided on one or more side surfaces of a reflective liquid crystal display panel having a polarizing layer on the outside through a transparent layer having a lower refractive index than the substrate, and having at least a reflecting layer on the outside of the polarizing layer. Is to have.

An example of the above-mentioned reflective liquid crystal display device is shown in FIG. 100 is a liquid crystal display panel, 11 is a viewing side substrate,
12 is a back side substrate, 13 is a liquid crystal layer, 14 is an optical path control layer, A1 is an optical path conversion slope, 15, 17 are polarizing layers, 16 is a low refractive index transparent layer, 18 is a reflective layer, and 2 is an illumination. It is a device.

As the liquid crystal display panel, as shown in the figure, the substrate 1 on the viewing side and the back side is formed of a transparent substrate having transparent electrodes.
On the outside of the viewing side substrate 11 in a liquid crystal cell in which liquid crystal 13 is sandwiched between 1 and 12 with their electrode sides facing each other, an inclination angle of the substrate with respect to a reference plane is 3
A polarizing layer 15 is provided via an optical path control layer 14 having a plurality of optical path changing slopes A1 of 5 to 48 degrees, and a transparent layer 1 having a lower refractive index than the substrate is provided outside the rear substrate 12.
6 is provided with a polarizing layer 17, and at least a reflecting layer 18 is provided outside the polarizing layer, so that incident light from the viewing side where the optical path control layer 14 is arranged is reflected and inverted by the reflecting layer 18, Appropriate reflection type light emitted from the viewing side as display light via control by 13, etc. can be used, and the type thereof is not particularly limited.

By the way, specific examples of the above-mentioned liquid crystal cell include twisted and non-twisted systems such as TN liquid crystal cell, STN liquid crystal cell, vertically aligned cell, HAN cell, OCB cell, and guest host system based on the alignment form of liquid crystal. And ferroelectric liquid crystals, and those that utilize light diffusion.
The liquid crystal drive system may be an appropriate system such as an active matrix system or a passive matrix system.
The liquid crystal is usually driven through a transparent electrode (not shown) provided inside the substrates 11 and 12.

Transparent substrates are used for the viewing-side substrate and the back-side substrate to allow display light to pass therethrough. The transparent substrate can be formed of an appropriate material such as glass or resin, and in particular, it suppresses birefringence as much as possible to reduce optical loss.
Those made of an optically isotropic material are preferable. Further, from the viewpoint of improving the brightness and the display quality, it is preferable to use one having excellent colorless transparency such as a non-alkali glass plate with respect to a blue glass plate, and a resin substrate is more preferable from the viewpoint of lightness and the like.

The thickness of the transparent substrate on the viewing side and the thickness of the transparent substrate on the back side are not particularly limited, and can be appropriately determined depending on the liquid crystal encapsulation strength. Generally, 10 μm to 5 mm, especially 50 μm to 2 m in terms of balance between optical transmission efficiency and thinness and lightness.
It has a thickness of m, particularly 100 μm to 1 mm. When one of the visible-side transparent substrate and the rear-side transparent substrate is used as a transmission substrate for incident light from the lighting device, it is advantageous that the cross-sectional area is large in terms of incidence efficiency, transmission efficiency, and the like.

On the other hand, the thinner the substrate that is not used as the transmission substrate, the more advantageous it is in terms of thinness and lightness. Therefore, the viewing side and the back side of the substrate may have the same thickness,
It may be different. Note that the substrate may be the same thickness plate, and in particular, the substrate on the viewing side has a thickness such as a wedge shape in cross section for the purpose of improving the incident efficiency of transmitted light on the optical path conversion slope by the inclined arrangement of the optical path control layer. May be partially different.

Further, the viewing side substrate and the back side substrate may have the same plane size or may have different plane sizes. When one of the viewing side and the back side of the substrate is used as a transmission substrate for incident light from the lighting device, at least the side face of the substrate on which the lighting device 2 is arranged is more than the side face formed by the other substrate. It is preferable that the side surface of the transmission substrate is in a protruding state from the viewpoint of incidence efficiency when the illumination device is arranged on the protruding side surface.

When forming a liquid crystal cell, if necessary, an alignment film composed of a rubbing film for aligning the liquid crystal, or one or more appropriate functional layers such as a color filter for color display may be provided. Can be provided. The alignment film is usually formed as a surface in contact with the liquid crystal 13.
The color filter is usually provided between the substrate and the transparent electrode on one of the substrates 11 and 12. In that case, it is preferable to provide a color filter on the rear substrate 12 between the low refractive index transparent layer 16 and the transparent electrode in order to prevent incident of transmitted light. The transparent electrodes provided on the substrates 11 and 12 can be formed of an appropriate material such as ITO according to the related art.

The optical path control layer 14 disposed on the outside of the viewing-side substrate 11 receives incident light from the illumination device 2 disposed on the side surface of the liquid crystal display panel or transmitted light thereof, as indicated by the broken line arrow α illustrated in FIG. The purpose is to change the optical path in the direction of the back side substrate of the panel via the optical path conversion slope A1 and use it as illumination light (display light) through reflection inversion by the reflection layer 18.

For the above-mentioned purpose, the optical path control layer 14 is inclined with respect to the reference plane (virtual horizontal plane) of the viewing side substrate in order to reflect the incident light from the illuminating device 2 and change the optical path in a predetermined direction as shown in the figure. Optical path conversion slope A1 with an angle of 35 to 48 degrees
It is assumed to have. Further, the optical path control layer has a plurality of the optical path conversion slopes for the purpose of thinning.

As described above, by reflecting the incident light from the side surface or the transmitted light through the optical path changing slope, the optical path can be changed with good directivity. That is, in the slope reflection type optical path control layer, the main use is the light in the regular reflection direction showing a peak,
Since the optical path of the reflected light is controlled, it is possible to easily provide a directivity advantageous for display, especially a directivity in the front direction, and it is possible to achieve a bright illumination mode. Further, even in the external light mode, since the flat portion of the optical path control layer other than the inclined surface can be utilized, it is possible to easily balance in a state advantageous to both the illumination and the external light modes.

The optical path control layer can be formed in an appropriate form except that it has a plurality of predetermined optical path conversion slopes. From the point of obtaining display light having excellent directivity in the front direction through optical path conversion or the like, a plurality of optical path conversion means A having an optical path conversion slope A1 facing the side surface on which the lighting device is arranged, that is, the incident side surface are provided. An optical path control layer, particularly an optical path control layer having a plurality of optical path conversion means A having an optical path conversion slope A1 composed of prismatic irregularities is preferable.

An example of the optical path changing means having the above-mentioned optical path changing slope or prism-like unevenness is shown in FIGS. 2 (a) to 2 (e). In (a) to (c), the optical path changing means A has a triangular cross section, and in (d) and (e), it has a quadrangular cross section. Further, (a) has two optical path conversion slopes A1 of an isosceles triangle, and (b) has optical path conversion means A having an optical path conversion slope A1 and a steep slope A2 whose inclination angle with respect to the reference plane is larger than the slope A1. It consists of things.

On the other hand, in FIG. 2C, the optical path conversion slope A1
And a plurality of optical path changing means A each having a gentle slope A3 having a small inclination angle with respect to the reference plane are formed on the entire surface on one side of the optical path control layer in the adjacent continuous state. Further, in (d), the optical path changing means A composed of a convex portion (protrusion) is
In the case of (e), the optical path changing means A having a concave portion (groove) is provided.

Therefore, as in the above-mentioned example, the optical path changing means can be formed in a convex portion or a concave portion which are equilateral surfaces or slopes having the same inclination angle, and the optical path changing slope A1 and the steep slope A2.
Or, a gentle slope A3 or slopes A4 and A5 having different inclination angles
It can also be formed in a convex portion or a concave portion made of, and the shape of the inclined surface can be appropriately determined by the number and position of the incident side surfaces.
From the viewpoint of maintaining the slope function by improving the scratch resistance, it is advantageous that the slope is less likely to be scratched because it is formed as an optical path changing means composed of concave portions rather than convex portions.

From the standpoint of achieving the above-mentioned characteristics such as directivity in the front direction, a preferable optical path control layer is an optical path conversion slope A1 having an inclination angle of 35 to 48 degrees with respect to the reference plane as the incident side surface as shown in the figure. The cross sections facing each other are triangular to pentagonal. Therefore, when the illuminating device is arranged on two or more side surfaces of the liquid crystal display panel and has two or more incident side surfaces, an optical path control layer having the optical path conversion slopes A1 corresponding to the number and position thereof is preferably used. .

By the way, in the case of arranging the illuminating device on the two opposite side surfaces of the liquid crystal display panel, the two optical path changing slopes A1 by the optical path changing means A having an isosceles triangular cross section as shown in FIG. Two optical path conversion slopes A by the optical path conversion means A having a trapezoidal transverse cross section as shown in FIGS.
The optical path control layer 14 having the ridge line 1 in the direction along the incident side surface is preferably used.

Further, when the illuminating device is arranged on the two laterally adjacent side surfaces of the liquid crystal display panel, an optical path control layer having an optical path conversion slope A1 with the ridge lines along both the vertical and horizontal directions corresponding to the side surfaces is preferable. Used. Furthermore, when arranging the lighting device on three or more side surfaces including facing and vertical and horizontal directions, an optical path control layer having an optical path conversion slope A1 composed of the above combination is preferably used.

The above-mentioned optical path changing slope A1 reflects the light incident on the surface A1 among the incident light from the incident side surface through the illuminating device or the transmitted light to change the optical path, and the rear side of the liquid crystal display panel. To supply to. In that case, by setting the inclination angle of the optical path conversion slope A1 with respect to the reference plane to be 35 to 48 degrees, as illustrated by the broken line arrow α in FIG.
It is possible to efficiently obtain the display light excellent in the directivity to the front by converting the side incident light or the transmitted light thereof so that the light path is changed with good perpendicularity to the reference plane.

If the inclination angle is less than 35 degrees, the optical path of the reflected light through the reflective layer is largely deviated from the front direction, so that it is difficult to effectively use for display and the front direction brightness becomes poor.
If the degree exceeds, the condition deviates from the condition of totally reflecting the side incident light or the transmitted light, and the amount of leaked light from the optical path conversion slope increases, resulting in poor light utilization efficiency of the side incident light.

From the viewpoints of optical path conversion excellent in directivity to the front and suppression of leaked light, the preferable inclination angle of the optical path conversion slope A1 is based on the refraction of the light transmitted in the liquid crystal display panel according to Snell's law. 38 to 45 in consideration of reflection conditions
Mostly 40 to 44 degrees. By the way, the general condition for total internal reflection of a glass plate is 42 degrees. Therefore, in this case, the side incident light is incident on the optical path conversion slope while being transmitted within the substrate in a state of being gathered within a range of ± 42 degrees. Become.

The optical path changing means A having the optical path changing slope A1 is formed by distributing a plurality of the optical path changing layers for the purpose of thinning the optical path control layer as described above. In that case, as indicated by the broken line arrow γ in FIG. 1, the incident light from the incident side surface is reflected backward and efficiently transmitted to the opposite side surface side, and the light is emitted as uniformly as possible over the entire surface of the liquid crystal display. As illustrated in FIG. 2, the slopes A3, A4, or the optical path control layer 14 having an inclination angle with respect to the reference plane of 10 degrees or less, preferably 5 degrees or less, particularly 3 degrees or less.
It is preferable to have a structure including a flat surface B having an inclination angle of approximately 0 degrees based on the above.

Therefore, in the optical path changing means A including the steep slope A2 illustrated in FIG. 2B, the angle of the steep slope is set to 50 degrees or more, particularly 60 degrees or more, and particularly 70 to 90 degrees, and the width of the flat surface B is set. It is preferable that the structure be wide. The gentle slopes A3 and A4 or the flat surface B are reflected by the display light α in the illumination mode and the external light incident portion in the external light mode and the incident light through the reflection layer 18 as in the example of FIG. This is a portion that functions as a transmission portion of display light, and thereby a reflection type liquid crystal display device for both external light and illumination is achieved.

In the above-mentioned case, especially when the optical path changing means A is constructed by the slopes A1 and A3 as shown in FIG. 2C, the angle difference of the inclination angle of the gentle slope A3 with respect to the reference plane is calculated. Within 5 degrees, especially within 4 degrees,
In particular, it is preferable that the difference is 3 degrees or less, and the difference in inclination angle between the nearest gentle slopes is 1 degree or less, preferably 0.3 degree or less, particularly 0.1 degree or less. This means that the optimum viewing direction of the reflective liquid crystal display device, especially the optimum viewing direction in the vicinity of the front direction, is not significantly changed by the transmission of the gentle slope A3, and in particular, is not significantly changed between the nearest gentle slopes. To aim.

From the point of obtaining a bright display in the external light mode, the projected area of the gentle slope A3 with respect to the reference plane is set to 5 times or more, especially 10 times or more, especially 15 times or more of that of the optical path conversion slope A1. It is preferable. This aims at improving the incident efficiency of external light and the transmission efficiency of reflected display light through the reflective layer. The same applies to the case of the optical path changing means A having the slopes A1 and A4 as shown in FIG.

The ridgeline of the optical path changing means A has the illuminating device 2
It is preferable to provide the liquid crystal display panel in which is arranged so as to be parallel or inclined along the incident side surface of the liquid crystal display panel, from the viewpoint of improving the incidence efficiency of the side surface incident light or its transmitted light, and thus improving the brightness. In that case, the optical path changing means A may be continuously formed from one end to the other end of the optical path control layer, or may be intermittently and discontinuously formed.

In the case of forming discontinuously, the length in the direction along the incident side surface of the unevenness formed by the groove or the protrusion is 5 in terms of depth or height in view of the incident efficiency of transmitted light and the optical path conversion efficiency.
It is preferably double or more, more preferably 10 or more, and particularly preferably 15 to 100 times. Also, from the viewpoint of uniform light emission on the panel display surface,
The length is preferably 500 μm or less, especially 10 to 300 μm, and particularly preferably 20 to 150 μm. The above length is based on the long side direction of the optical path conversion slope.

The cross-sectional shape of the light path changing means A and the pitch of the light path changing slope A1 through the light path changing means A are not particularly limited. Since the light path changing slope A1 is a factor that determines the brightness in the illumination mode, the illumination mode is changed. It can be appropriately determined according to the uniformity of light emission of the panel display surface in the external light mode, etc., and the light amount for changing the optical path can be controlled by the distribution density.

Therefore, the inclination angles of the slopes A1 to 5 may be constant over the entire surface of the optical path control layer, or the panel display surface can be dealt with by absorption loss and attenuation of transmitted light due to the previous optical path conversion. For the purpose of achieving uniform emission of light, the optical path changing means A may be made larger as the distance from the incident side surface increases. Further, the optical path changing means A may have a constant pitch, or the pitch may be gradually narrowed as the distance from the incident side surface increases to increase the distribution density of the optical path changing means A. It is also possible to achieve uniform light emission on the panel display surface.

In addition, in the case where the optical path changing means A is a concavo-convex formed by discontinuous grooves or protrusions, the size and shape of the concavo-convex
It is also possible to make the distribution density, the direction of the ridges, etc. irregular, or to arrange the irregular or regular or uniform irregularities randomly so as to make the light emission on the panel display surface uniform. Further, it is also possible to arrange the illuminating device composed of a point light source in a pitch form (concentric circle form) with respect to the virtual center with the virtual position as the virtual center. Therefore, as in the above-described example, the uniforming of the light emission on the panel display surface is performed by the optical path changing means A.
Can be achieved by applying an appropriate method.

If the optical-path changing slope A1 overlaps the pixels of the liquid crystal cell, the display light may be insufficiently transmitted, resulting in an unnatural display. Small, gently slope A
It is preferable to secure a sufficient light transmittance through 3 or the like and the flat surface B.

From the above point, considering that the pixel pitch of the liquid crystal cell is generally 100 to 300 μm, the optical path conversion slope A1 is 40 μm or less, especially 1 to 20 μm, based on the projection width to the reference plane. In particular, it is preferable that the thickness is 2 to 15 μm. Such a projection width is preferable in that the coherent length of the fluorescent tube is generally set to about 20 μm and the like, and thus the display quality is prevented from being degraded by diffraction.

On the other hand, it is preferable that the distance between the optical path conversion slopes A1 is larger than the above point, but on the other hand, the optical path conversion slopes are, as described above, substantially functional parts for forming illumination light by optical path conversion of side incident light. Therefore, if the interval is too wide, the lighting at the time of lighting may be sparse and unnatural display may occur, and in view of these, the pitch of the optical path conversion slope A1 is 5 mm or less, especially 5 μm to 3 mm. It is particularly preferable that the thickness is 10 μm to 2 mm.

Further, in the case of the optical path changing means composed of prismatic irregularities, particularly when it is composed of stripe-shaped continuous grooves, it may interfere with the pixels of the liquid crystal cell to cause moire. The moire can be prevented by adjusting the pitch, but as described above, the pitch has a preferable range. Therefore, a solution when moire occurs in the pitch range becomes a problem.

In the present invention, it is preferable to prevent moire by forming the ridges of the irregularities in a state of being inclined with respect to the incident side surface so that the irregularities can be arranged in a crossing state with respect to the pixels. In that case, if the inclination angle with respect to the incident side surface is too large, the reflection through the optical path conversion slope A1 is deflected, and a large deviation occurs in the direction of the optical path conversion, which is likely to cause deterioration in display quality.

Therefore, it is preferable that the inclination angle of the ridgeline with respect to the incident side surface is within ± 30 degrees, especially within ± 25 degrees. The sign ± means the inclination direction of the ridgeline with respect to the incident side surface. When the resolution of the liquid crystal cell is low and moiré does not occur, or when moiré can be ignored, it is preferable that the ridge line be parallel to the incident side surface. Further, a method of dispersively distributing discontinuous optical path changing means, particularly a method of irregularly distributing dispersion is also preferable for preventing moire.

The optical path control layer may be formed of an appropriate material which has transparency depending on the wavelength range of the illuminating device and which has a higher refractive index than the transparent layer having a low refractive index. By the way, in the visible light range, for example, acetate resins and polyester resins,
Polymers such as polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin, polyether resin, polyvinyl chloride, styrene resin, norbornene resin, acrylic resin, etc. Examples thereof include urethane-based, acrylic urethane-based, epoxy-based, and silicone-based thermosetting or UV-curing resins and glass. An optical path control layer formed of a material that does not exhibit birefringence or has low birefringence is preferable.

Further, the amount of loss of light that cannot be emitted due to being confined inside the panel due to interface reflection is suppressed, and the side incident light or its transmitted light is efficiently supplied to the optical path control layer, especially the optical path conversion slope A1. The refractive index of the transparent layer is 0.05 or more, especially 0.08 or more, especially 0.1 to 0.1%.
An optical path control layer having a height of 0.5 is preferable.

Further, the incident light from the illuminating device or its transmitted light is efficiently incident on the optical path control layer from the viewing side substrate and / or the rear side substrate to achieve a bright display through the optical path conversion slope, and thus the substrate In particular, an optical path control layer having a refractive index difference of 0.15 or less, particularly 0.10 or less, particularly 0.05 or less with respect to the viewing side substrate, and particularly with an optical path control layer having a higher refractive index than the substrate. Preferably there is.

The optical path control layer can be formed by a cutting method and can be formed by an appropriate method. As a preferable manufacturing method from the viewpoint of mass productivity and the like, for example, a method of transferring a shape by pressing a thermoplastic resin under heat to a mold capable of forming a predetermined shape, a heat-melted thermoplastic resin or heat or a solvent is used. A method of filling a resin that has been fluidized through a mold that can be molded into a predetermined shape, a monomer or oligomer that can be polymerized by heat, ultraviolet rays or radiation, or a liquid resin is filled into a mold that can form a predetermined shape. Or a method of polymerizing by casting.

Further, there is also a method in which the support film is previously coated with the above-mentioned liquid resin or the like which can be polymerized with ultraviolet rays or radiation, and the coating layer is molded with a mold capable of forming a predetermined shape and polymerized. can give. In that case, a transparent support film can be used to form an optical path control layer integrated with the film, or an optical path control layer consisting of only a molding layer based on the coating layer can be peeled off from the support film after formation. It can also be formed. In that case, it need not be a transparent film.

Therefore, the optical path control layer can be formed by directly imparting the predetermined shape to the viewing side substrate so as to be integrated with the substrate, or as a transparent sheet or the like having the predetermined shape as shown in the figure. It can also be formed.

The thickness of the optical path control layer can be appropriately determined, but is generally 300 μm or less, especially 5 to 5 from the viewpoint of thinning.
The thickness is 200 μm, particularly 10 to 100 μm. The shape such as a trigonal to pentagonal shape based on the cross section of the light emitting means does not mean a strict polygonal shape, but roundness of corners and surface distortion based on manufacturing technology and the like are allowed.

When the optical path control layer is independently formed as a transparent sheet or the like, the transparent sheet 14 or the like can be used as an adhesive layer having a refractive index higher than that of the transparent layer 16 having a low refractive index, or the transparent sheet or the like. To the liquid crystal display panel through an adhesive layer having a substantially equal refractive index, particularly an adhesive layer having an intermediate refractive index between the transparent sheet or the like and the viewing side substrate. It is more preferable that the light is efficiently incident on the light source to achieve a bright display. Therefore, the refractive index of the adhesive layer can be similar to that of the above-mentioned optical path control layer.

The adhesive layer can be formed of an appropriate transparent adhesive, and the type of the adhesive is not particularly limited.
The adhesive method using an adhesive layer is preferable from the viewpoint of the ease of the adhesive treatment work. The pressure-sensitive adhesive layer may be formed as a layer in which different kinds of pressure-sensitive adhesive layers are superposed for the purpose of improving the adhesive property.

For the formation of the above-mentioned pressure-sensitive adhesive layer, an appropriate one of various pressure-sensitive adhesives such as acrylic type and rubber type can be used. Among them, the pressure-sensitive adhesive that can be preferably used from the viewpoint of attaining the above-mentioned refractive index is an aromatic ring-containing monomer component of 40% of all monomer components.
The base polymer is an acrylic copolymer containing 90 to 90% by weight. With such an adhesive, it is possible to form an adhesive layer having a refractive index of 1.50 to 1.55.

The above-mentioned pressure-sensitive adhesive contains, for example, an acrylic acid-based alkyl ester not containing an aromatic ring and an aromatic ring-containing monomer as at least a copolymerization component, and the aromatic ring-containing monomer component has a copolymerization ratio of all monomer components. 40 to 9
It can be prepared as an acrylic pressure-sensitive adhesive containing at least 0% by weight of an acrylic copolymer.

As the above-mentioned acrylic acid-based alkyl ester not containing an aromatic ring, an ester such as acrylic acid or methacrylic acid having an appropriate alkyl group which does not contain an aromatic ring and is suitable for conventional acrylic adhesives is used. There is no particular limitation. Generally, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, heptyl group, cyclohexyl group, 2-ethylhexyl group, isooctyl group,
Acrylic acid having a non-aromatic ring-containing alkyl group having 1 to 18 carbon atoms, such as nonyl group, decyl group, isodecyl group, dodecyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group or octadecyl group And esters such as methacrylic acid are used.
Such acrylic acid-based alkyl ester may be used alone or in combination of two or more.

As the aromatic ring-containing monomer, an appropriate one can be used alone or in combination of two or more. Among them, from the viewpoint of controllability of refractive index and adhesive properties, esters such as acrylic acid and methacrylic acid having an alkyl group having an aromatic ring and having 1 to 10 carbon atoms, particularly phenoxyethyl acrylate are preferably used. .

The acrylic copolymer as the base polymer is a copolymer obtained by copolymerizing the above-mentioned acrylic acid alkyl ester not containing an aromatic ring with an aromatic ring-containing monomer. In preparing the copolymer, one or more modifying monomers may be copolymerized, if necessary, for the purpose of adjusting cohesive force, heat resistance, adhesive property, crosslinking property, and the like.

As the above-mentioned modifying monomer, an appropriate one in accordance with a conventional acrylic pressure-sensitive adhesive can be used and is not particularly limited. Incidentally, examples thereof include vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine and N-vinyl. Examples thereof include vinyl monomers such as carboxylic acid amides.

Cyanoacrylate monomers such as (meth) acrylonitrile, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (N-Substituted) amide-based monomers such as (meth) acrylamide are also mentioned as examples of the above-mentioned modified monomer. Note that the above (meta)
Means that, for example, in the case of (meth) acrylonitrile, it also includes a methacrylic acid-based compound such as acrylonitrile and methacrylonitrile (the same applies hereinafter).

Further, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth)
Hydroxyl such as hydroxybutyl acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate The group-containing monomer is also mentioned as an example of the above-mentioned modifying monomer.

Furthermore, an epoxy group-containing acrylic monomer such as glycidyl (meth) acrylate, polyethylene glycol (meth) acrylate or polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate or (meth) acrylic acid Glycol-based acrylic ester monomers such as methoxy polypropylene glycol, tetramethofurfuryl (meth) acrylic acid, fluorine (meth) acrylate, acrylic acid ester-based monomers such as silicone (meth) acrylate and 2-methoxyethyl acrylate are also modified monomers described above. Can be given as an example.

In addition, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) ) Acrylate and trimethylolpropane tri (meth) acrylate,
Pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, polyfunctional monomers such as urethane acrylate, isoprene, butadiene, polyisobutylene, vinyl ether, etc. are also mentioned as examples of the above-mentioned modifying monomers. To be

In addition, alkylaminoalkyl (meth) acrylate monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate. Containing (meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, carboxyl groups such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid Monomers and the like are also mentioned as examples of the above-mentioned modified monomer.

In the above, a monomer containing a functional group or a polar group such as a hydroxyl group-containing monomer or a carboxyl group-containing monomer is preferably used because it can be used for the crosslinking treatment of the acrylic copolymer. Among them, acrylic acid is preferably used as the carboxyl group-containing monomer.

The acrylic copolymer can be obtained by copolymerizing an acrylic acid-based alkyl ester not containing an aromatic ring and an aromatic ring-containing monomer with a modifying monomer, if necessary. The polymerization method is not particularly limited, and a suitable vinyl monomer-based polymerization method can be adopted. By the way, examples thereof include solution polymerization method using polymerization initiators such as azo compounds and peroxides, emulsion polymerization method and bulk polymerization method, and polymerization method of irradiating light or radiation with photoinitiator. .

Examples of the above-mentioned polymerization initiator include 2, 2 '
-Azobisisobutyronitrile (AIBN) or 2,2'-
Examples thereof include azobis-2-methylbutyronitrile, 2,2′-azobis (2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, and dibenzoyl peroxide. The amount of the polymerization initiator used is 0.01 to 2 mol% with respect to the total amount of the monomers, and preferably 0.
It is generally from 02-1 mol%, but is not limited thereto.

The acrylic copolymer contains an aromatic ring-containing monomer component in a copolymerization ratio of 40 to 90% by weight, and the refractive index can be changed by changing the copolymerization ratio of the aromatic ring-containing monomer component. Can be changed.
From the viewpoint of balancing the refractive index and the adhesive property, the preferable copolymerization ratio of the aromatic ring-containing monomer component is 42 to 85% by weight, and particularly 45 to 80% by weight. The copolymerization ratio of the modifying monomer component, if necessary, is 0 to 20% by weight,
It is generally 10% by weight or less, particularly 5% by weight or less, but not limited to this.

The pressure-sensitive adhesive can be obtained in the form of a conventional acrylic pressure-sensitive adhesive such as a solution or dispersion containing one or more acrylic copolymers as a base polymer. Therefore, when the above-mentioned type of polymerizing by irradiation with light or radiation is used, it can also be used as a pressure-sensitive adhesive in the form of the monomer mixture liquid.

The pressure-sensitive adhesive is preferably prepared so that the acrylic copolymer can be crosslinked. By such a cross-linking treatment, releasability from a separator (release liner), adhesive properties, durability such as heat resistance, etc. can be improved. For the cross-linking treatment, an appropriate method according to the conventional acrylic pressure-sensitive adhesive can be adopted. Generally, a method of incorporating a crosslinking agent into the pressure-sensitive adhesive is adopted. The cross-linking agent, for example, polyisocyanate compounds and epoxy compounds,
One or two or more suitable compounds based on conventional acrylic pressure-sensitive adhesives such as aziridine compounds, metal chelate compounds and melamine compounds may be used.

By the way, specific examples of the polyisocyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate and dimers thereof, and reaction of trimethylolpropane with tolylene diisocyanate or hexamethylene diisocyanate. Examples include products, polyether polyisocyanates, polyester polyisocyanates, and the like. Further, specific examples of the melamine-based compound include methylated trimethylolmelamine and butylated hexamethylolmelamine.

In the preparation of the pressure-sensitive adhesive, an appropriate compounding agent according to the conventional acrylic pressure-sensitive adhesive can be added, if necessary, in addition to the above-mentioned crosslinking agent. By the way, examples thereof include tackifiers such as rosin-based resins and terpene-based resins, petroleum-based resins and styrene-based resins, fillers and plasticizers such as powdered silica, colorants and ultraviolet absorbers, and antiaging agents. .

The optical path control layer is arranged on the viewing side of the liquid crystal display panel as shown in the figure. In that case, it is necessary to dispose the slope forming surface, that is, the surface on which the optical path changing means A is formed, on the outside (viewing side).
It is more preferable from the viewpoint of the reflection efficiency via 1, and the improvement of the brightness by effectively utilizing the side incident light. Further, the outer surface of the optical path control layer may be subjected to antiglare treatment or antireflection treatment for the purpose of preventing visual inhibition due to surface reflection of outside light.

The transparent layer having a low refractive index provided on the outer side of the rear substrate is provided as a layer having a lower refractive index than that of the transparent substrate forming the substrate, so that the illuminating device as shown by the broken line arrow β in FIG. When the incident light from 2 is transmitted inside the panel, especially the inside of the cell mainly on the transparent substrate on the viewing side or / on the back side, the transmitted light is reflected by the refractive index difference between the back side substrate 12 and the transparent layer 16. The light is efficiently reflected backward by total reflection through the inside of the cell, thereby efficiently transmitting the transmitted light backward, and at the same time, prevents the light from entering the polarizing layer on the back side to be absorbed and attenuated, and the optical path at a position far from the lighting device. The purpose of the present invention is to improve the uniformity of brightness in the entire display screen by supplying the transmitted light with good uniformity to the optical path conversion slope A1 of the control layer and performing the optical path conversion by the reflection.

That is, the transparent layer 16 having a low refractive index has a confinement effect due to the total reflection based on it, and prevents the transmitted light from being attenuated by being incident on the polarizing layer, and at the same time, makes the incident light from the side surface of the panel efficient in the opposite side surface direction. The purpose is to transmit well and improve the uniformity of brightness on the entire screen to achieve a bright and good display quality. Without the transparent layer having a low refractive index, the transmission efficiency to the rear is poor as in the prior art, and the screen becomes darker as the distance from the illumination device increases, and the display becomes difficult to see.

The low-refractive-index transparent layer is vacuum-deposited by using an appropriate material such as an inorganic or organic low-refractive-index dielectric material having a lower refractive index than the transparent substrate forming the rear substrate. It can be formed by an appropriate method such as a spin coating method or the like, and the material and the forming method thereof are not particularly limited. Therefore, for example, a transparent layer having a low refractive index can also be formed by a method of adhering the polarizing layer to the rear substrate with an adhesive layer or an adhesive layer having a refractive index lower than that of the transparent substrate.

The larger the difference in refractive index between the transparent layer and the transparent substrate is, the more advantageous it is in terms of the rearward transmission efficiency due to the total reflection described above. Preferably there is. Such a difference in refractive index has almost no effect on the display quality in the external light mode. By the way, when the refractive index difference is 0.1, the reflectance of external light at the interface is 0.
It is 1% or less, and the decrease in brightness and contrast due to the reflection loss is extremely small.

The transparent layer having a low refractive index is arranged between the transparent substrate 12 and the polarizing layer 17 on the back side as shown in the figure in view of the effect of confining the transmitted light and the prevention of invasion into the polarizing layer. In particular, it is provided adjacent to the transparent substrate 12. In that case, it is preferable that the surface of the substrate on which the transparent layer is attached is smooth, and thus the transparent layer is smooth, which is advantageous in preventing scattering of transmitted light, and more preferable in terms of preventing influence on display light.

If the thickness of the transparent layer having a low refractive index is too thin, the confinement effect described above may be diminished due to the phenomenon of wave bleeding. Therefore, it is more advantageous in terms of maintaining the total reflection effect. The thickness can be appropriately determined from the viewpoint of the total reflection effect and the like, but in general, from the viewpoint of the total reflection effect and the like for visible light having a wavelength of 380 to 780 nm, particularly for light having a wavelength of 380 nm on the short wavelength side, the refractive index × It is preferable that the thickness is ¼ wavelength (95 nm) or more, especially ½ wavelength (190 nm) or more, and particularly 1 wavelength (380 nm) or more based on the optical path length calculated by the layer thickness. The thickness is preferably 600 nm to 10 μm.

As shown in the figure, the polarizing layer 15 is provided outside the viewing side substrate 11 via the optical path control layer 14 and also outside the rear side substrate 12 via the transparent layer 16 having a low refractive index.
17. Therefore, the polarizing layers arranged on both sides of the liquid crystal cell are
It aims at achieving a liquid crystal display by controlling light through polarized light.

Any appropriate material can be used for forming the above-mentioned polarizing layer, and there is no particular limitation. Therefore, for example, it can be formed as a polarizing layer having a thickness of about 0.1 to 20 μm, which is composed of a coating film of a lyotropic liquid crystalline dichroic dye or a lyotropic substance containing a dichroic dye (see Table 8). -511109, WO 97/39
380 publication).

From the viewpoint of obtaining a good contrast ratio display by the incidence of highly linearly polarized light, for example, a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, an ethylene / vinyl acetate copolymer partially saponified film, etc. Polarization such as absorption type polarizing film consisting of a hydrophilic polymer film stretched by adsorbing dichroic substance such as iodine or dichroic dye, or a transparent protective layer provided on one side or both sides A polarizing layer made of a highly flexible material is preferable.

In forming the transparent protective layer, those having excellent transparency, mechanical strength, thermal stability and moisture shielding property are preferably used. Examples thereof include the polymers exemplified in the above optical path control layer. The transparent protective layer can be provided by an adhesive method of a film or a coating method of a polymer liquid or the like.

The polarizing layer, particularly the polarizing layer on the viewing side, may be subjected to antiglare treatment or antireflection treatment for the purpose of preventing visual inhibition due to surface reflection of external light. The anti-glare treatment is a method of roughening the surface by various methods such as a surface roughening method such as a sand blast method or an embossing method, a method of mixing transparent particles such as silica, or a method of coating a resin containing transparent particles. The antireflection treatment can be performed by a method of forming an interfering vapor deposition film or the like. In addition, the anti-glare treatment and the antireflection treatment can be performed by the above-described method of adhering a film having a surface fine uneven structure or an interference film.

The liquid crystal display panel is of a reflection type having a reflection layer 18 on the outside of the polarizing layer 17 on the back side as shown in the figure. As shown by the polygonal line arrow α in FIG. 1, the reflective layer reflects the incident transmission light from the lighting device 2 on the optical path conversion slope A1 of the optical path control layer 14 to convert the optical path to the rear surface side and reflects the light. The purpose is to obtain the display light α in the illumination mode by reversing it, and to reflect and invert the incident external light via the polarizing layer 15 on the viewing side to obtain the display light in the external light mode. A dual-use reflective liquid crystal display device is formed.

The reflective layer can be formed of an appropriate material such as a white sheet according to the related art. Above all, for example, a coating layer in which a powder of a metal or an alloy thereof having a high reflectance such as aluminum, silver, gold, copper, chromium, etc. is contained in a binder resin, the above metal, etc. and a dielectric multilayer film are vacuum deposited. A layer formed by an appropriate thin film forming method such as a sputtering method or the like, a reflection sheet in which the coating layer or the attachment layer is supported by a base material such as a film, or a reflection layer having a high reflectance such as a metal foil. preferable.

The reflective layer to be formed may have a light scattering function. By diffusing the reflected light on the scattering / reflecting surface, the viewing angle can be improved. Further, in the case of roughening, it is possible to prevent the generation of Newton's rings due to the close contact and improve the visibility. Therefore, the reflective layer provided outside the polarizing layer on the back surface side may be simply stacked or may be closely attached by an adhesive method or a vapor deposition method.

The light-scattering type reflection layer is formed, for example, on a film substrate having a finely roughened surface by a suitable method such as a surface roughening method by sandblasting or matting, or a particle addition method. This can be performed by a method of providing a reflective layer that reflects the fine concavo-convex structure. The reflection layer having a fine concavo-convex structure reflecting the fine concavo-convex structure on the surface can be formed by using an appropriate method such as a vacuum evaporation method, an ion plating method, a vapor deposition method such as a sputtering method, a plating method, or the like. It can be carried out by a method of attaching to the surface of the material or the like.

The liquid crystal display panel may be one in which one or more suitable optical layers such as a retardation layer and a light diffusion layer are added to the liquid crystal cell as needed. The retardation layer is intended to improve the display quality by compensating for the retardation due to the birefringence of the liquid crystal. In addition, the light diffusion layer expands the display range by diffusing the display light, uniformizes the brightness by leveling the bright line emission through the optical path conversion slope of the optical path control layer, and the optical path by diffusing the transmitted light in the liquid crystal display panel. The purpose is to increase the amount of light incident on the control layer.

As the retardation layer, for example, a birefringent film obtained by subjecting a film made of a suitable polymer such as those exemplified in the above-mentioned optical path control layer to a stretching treatment, a nematic type or a discotic type, etc., is used. Appropriate ones such as an alignment layer of a liquid crystal polymer and one in which the alignment layer is supported by a transparent substrate can be used, and the refractive index in the thickness direction is controlled under the action of the heat shrinkage force of the heat shrinkable film. It may be one or the like. An alignment layer of a liquid crystal polymer is preferable from the viewpoint of thinning.

The retardation layer for compensation is usually arranged between the polarizing layers 15 and 17 on the viewing side and / or the back side and the liquid crystal cell, if necessary. As the retardation layer, an appropriate one can be used depending on the wavelength range and the like. Further, the retardation layer may be used by superimposing two or more layers for the purpose of controlling optical characteristics such as retardation.

On the other hand, as for the light diffusing layer, a coating layer having a surface fine concavo-convex structure conforming to the above antiglare layer,
It can be provided by an appropriate method using a diffusion sheet or the like. The light diffusing layer can be formed as an adhesive layer containing transparent particles and can also be formed as a layer that also serves as an adhesive layer such as a polarizing layer, and can be made thin. Therefore, the light diffusing layer can be arranged in one layer or two or more layers at an appropriate position between the liquid crystal cell and the polarizing layer.

In order to form the above-mentioned pressure-sensitive adhesive layer, for example, a rubber type, an acrylic type, a vinyl alkyl ether type, a silicone type, a polyester type, a polyurethane type, a polyether type, a polyamide type, a styrene type or the like is applied in accordance with the above-mentioned case. A pressure-sensitive adhesive containing a suitable polymer as a base polymer may be used. Among them, those having excellent transparency, weather resistance, heat resistance and the like are preferably used, such as an acrylic pressure-sensitive adhesive having a base polymer of a polymer mainly containing an alkyl ester of acrylic acid or methacrylic acid.

Examples of the transparent particles which may be mixed in the adhesive layer include silica and alumina having an average particle size of 0.5 to 20 μm, titania and zirconia, tin oxide and indium oxide, cadmium oxide and antimony oxide. One kind or two kinds of appropriate particles such as inorganic particles which may be conductive and organic particles which are crosslinked or uncrosslinked polymer can be used. Such transparent particles can also be used for the above-mentioned anti-glare treatment and the like.

The illumination device arranged on the side surface of the liquid crystal display panel uses the light used as the illumination light of the reflection type liquid crystal display device,
The purpose is to allow light to enter from the side surface of the liquid crystal display panel. This makes it possible to reduce the thickness and weight of the reflective liquid crystal display device in combination with the optical path control layer disposed on the viewing side of the panel.

The illumination device may be arranged on both the side surfaces of the substrates 11 and 12 on the viewing side and the back side as shown in the figure, that is, on the entire side surface of the liquid crystal cell. It may be arranged on one or both sides of the rear substrate and thus on the transparent substrate.

As the illuminating device, an appropriate one can be used. For example, a linear light source such as a (cold or heat) cathode tube, a point light source such as a light emitting diode, or an array in which the light source is arranged in a linear or planar shape. A body or an illuminating device in which a point light source and a linear light guide plate are combined to convert incident light from the point light source into a linear light source via the linear light guide plate can be preferably used.

The lighting device can be arranged on one or more side surfaces of the liquid crystal display panel. 2 lighting devices
When arranged on the above side surfaces, the plurality of side surfaces may be a combination of side surfaces facing each other, a combination of side surfaces intersecting in the vertical and horizontal directions, or a combination of three or more side surfaces in combination. May be. It is preferable that the illuminating device is arranged on the side surface of the optical path control layer that faces the optical path conversion slope, from the viewpoint of improving the brightness.

The illumination device enables visual recognition in the illumination mode by turning on the lighting, and does not need to be turned on when visually recognizing in the external light mode, so that the lighting device can be switched on and off. As the switching method, any method can be adopted, and any conventional method can be adopted. The illuminating device may be of a different color emission type capable of switching emission colors, or may be of a type capable of emitting different color light through different types of illuminating devices.

As shown in the figure, the lighting device 2 is provided with a combination body in which appropriate auxiliary means such as a light source holder 21 surrounding the liquid crystal display panel are arranged to guide the divergent light to the side surface of the liquid crystal display panel, if necessary. You can also do it. As the light source holder, for example, a suitable reflection sheet that reflects light at least on the illuminating device side can be used, such as a resin sheet provided with a metal thin film having high reflectance, a white sheet, or a metal foil. The light source holder can also be used as a holding means that also doubles as an enclosure of the lighting device by, for example, a method of adhering the end portion to the cell substrate of the liquid crystal display panel, particularly the end portions of the upper and lower surfaces of the viewing side substrate.

According to the reflection type liquid crystal display device of the present invention, most of the incident light from the incident side surface is transmitted through the liquid crystal display panel, especially the substrate on the viewing side and / or the rear side thereof, and is reflected by the law of refraction. The light that is transmitted to the rear side and is prevented from being emitted (leakage) from the panel surface, is efficiently incident on the optical path conversion slope A1 of the optical path control layer, and is efficiently converted to the rear direction with good vertical directivity.

Further, the other transmitted light is further transmitted rearward by total reflection and is incident on the rear optical path conversion slope A1 and is efficiently subjected to optical path conversion in the rear direction with good vertical directivity, and the entire surface of the panel display surface. In, it is possible to achieve a display having excellent brightness uniformity. Therefore, it is possible to form a reflection type liquid crystal display device for both external light and illumination which is bright and easy to see and is excellent in display quality by efficiently utilizing light from the lighting device or external light.

In the present invention, the optical elements or parts such as the optical path control layer, the liquid crystal cell, the polarizing layer and the reflective layer forming the above-mentioned reflective liquid crystal display device are wholly or partially laminated and fixed integrally. It may be arranged, or may be arranged in a state of being easily separated. The fixed state is preferable from the standpoint of preventing the reduction of the contrast by suppressing the interface reflection.

An appropriate transparent adhesive such as a pressure-sensitive adhesive can be used in the above-mentioned adhesion and adhesion treatment, and the transparent adhesive layer contains the above-mentioned transparent particles to form an adhesive layer having a diffusion function. You can also Further, the optical element or parts, particularly those on the visible side, are exposed to ultraviolet rays by a method of treating with an ultraviolet absorber such as salicylic acid ester compound, benzophenone compound, benzotriazole compound, cyanoacrylate compound, nickel complex salt compound, or the like. It can also be made absorbent.

[0104]

EXAMPLES Reference Example Acrylic UV curable resin (Aronix UV-3701, manufactured by Toagosei Co., Ltd.) is applied to a mold that has been processed into a predetermined shape in advance.
With a dropper filled in, a non-stretched polycarbonate film with a refractive index of 1.58 and a thickness of 70 μm was allowed to stand on it, and was adhered with a rubber roller to remove excess resin and bubbles, and a metal halide lamp. After irradiating with ultraviolet rays at the curing treatment with, and peeling from the mold and cutting into a predetermined size, a transparent sheet integrally provided with an optical path control layer having a refractive index of 1.51 is obtained, which does not have the optical path control layer. A phenoxyethyl acrylate-based acrylic pressure-sensitive adhesive layer having a refractive index of 1.52 was pressure-bonded to the side, and heated and defoamed in an autoclave for close contact.

The transparent sheet has a width of 40 mm and a length of 30.
The optical path control layer is composed of a continuous optical path conversion means having a cross-sectional triangular shape consisting of an optical path conversion slope having an inclination angle of 42 degrees and a gentle slope having an inclination angle of 1.8 to 3.5 degrees. Then 21
They are parallel to each other with a pitch of 0 μm and are inclined by 21 ° with respect to the incident side surface (FIG. 2c). The projection width of the optical path conversion slope changed in the range of 10 to 16 μm, and the angle change of the inclination angle of the nearest gentle slope was within 0.1 degree. Furthermore, the area of the gentle slope is about 1 of that of the optical path conversion slope.
It was 2.

Example 1 An ITO transparent electrode was formed on one side of a plastic plate having a thickness of 1 mm and a refractive index of 1.505, a polyvinyl alcohol solution was spin-coated on the ITO transparent electrode, and the dried film was rubbed to obtain a visible side and a back side. The side substrate was obtained. The transparent electrode on the viewing side was divided by etching. Also, magnesium fluoride is vacuum-deposited on the other surface of the back substrate to a thickness of 600 nm,
A low refractive index transparent layer having a refractive index of 1.38 was formed.

Then, the viewing side substrate and the back side substrate are opposed to each other so that the rubbing surfaces thereof are orthogonal to each other, a gap adjusting material is arranged, and the periphery is sealed with an epoxy resin, and then liquid crystal (ZLI manufactured by Merck & Co., Inc.) is used. -4792) is injected to form a TN liquid crystal cell, the transparent sheet obtained in the reference example is adhered to the outside of the viewing side substrate through the adhesive layer, and the refractive index of 1.52 is applied to the outside. A polarizing plate (manufactured by Nitto Denko Corporation, NPF EGW122 through an acrylic adhesive layer)
5DU) was adhered. On the other hand, a reflective liquid crystal display panel was obtained by sequentially adhering the same polarizing plate and an aluminum-based reflection plate to the outside of the rear substrate via a low refractive index transparent layer via an acrylic adhesive layer.

Next, a cold-cathode tube is arranged on the side surface of the panel, surrounded by a silver-deposited polyester film, and the ends of the film are adhered to the upper and lower surfaces of the panel with a double-sided adhesive tape to prevent light from leaking. The cathode tube was held and fixed to obtain an external light / illumination type reflective liquid crystal display device.

Example 2 In place of the magnesium fluoride layer as the low refractive index transparent layer, an acrylic adhesive layer having a refractive index of 1.468 and a thickness of 30 μm was used, and a polarizing plate was bonded through the adhesive layer. In accordance with Example 1, an external light / illumination type reflective liquid crystal display device was obtained.

Comparative Example A reflective liquid crystal display device for both external light and illumination type was obtained in the same manner as in Example 2 except that the adhesive layer as the low refractive index transparent layer was replaced with a refractive index of 1.52.

Evaluation Test With respect to the reflection type liquid crystal display devices obtained in Examples and Comparative Examples, the cold cathode tube was turned on in a dark room without applying voltage to the liquid crystal cell, and at a position 5 mm from the incident side surface and the opposite end thereof. The front luminance of the is examined with a luminance meter (BM-7, manufactured by Topcon),
The luminance ratio of the facing end side / incident side surface side was determined. In addition, the display quality when the display in the illumination mode was observed was evaluated. The evaluation was evaluated as ⊚ when there was almost no attenuation of brightness with increasing distance from the light source, ◯ when the attenuation of brightness was small, and × when the attenuation of brightness was large.

The above results are shown in the following table.

From the table, it can be seen that in the embodiment, the display is excellent in the maintainability of the brightness at the position distant from the light source in the illumination mode and the brightness is excellent in the uniformity. It can be seen that is significantly inferior in the uniformity of brightness. Note that when an electric field was applied to the liquid crystal display device and the display was performed, there was no particular problem in both the illumination mode and the external light mode in the example, and the display was good, but in the comparative example, the external light was used. Although the mode was good,
The display was difficult to see in the lighting mode.

As described above, according to the present invention, while avoiding the bulkiness and weight increase due to the use of the light guide plate, a thin and lightweight optical path control layer system capable of emitting light only by providing an illuminating device on the side surface of the liquid crystal display panel. It is understood that it is possible to form a reflection type liquid crystal display device for both external light and illumination, which has good display quality and is capable of achieving high display quality.

[Brief description of drawings]

FIG. 1 is a cross sectional view for explaining an embodiment.

FIG. 2 is an explanatory transverse cross-sectional view of an optical path changing means in an optical path control layer.

[Explanation of symbols]

100: Liquid crystal display panel 11: Viewing side substrate 12: Rear side substrate 13: Liquid crystal layer 14: Optical path control layer (A: Optical path changing means A1: Optical path changing slope) 15, 17: Polarizing layer 18: Reflecting layer 2: Illuminating device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Seiji Umemoto             Nittoden 1-2, Shimohozumi, Ibaraki City, Osaka Prefecture             Within Kou Co., Ltd. F-term (reference) 2H091 FA14Z FA21X FA41X FA41Z                       HA07 HA08 HA10 HA12 LA30

Claims (2)

[Claims] 1. A liquid crystal cell in which a liquid crystal cell is sandwiched between a viewing-side substrate and a back-side substrate made of a transparent substrate having a transparent electrode so that their electrode sides face each other. The tilt angle of the substrate with respect to the reference plane is 3
A polarizing layer is provided via an optical path control layer having a plurality of 5- to 48-degree optical path changing slopes, and a polarizing layer is provided outside the rear substrate via a transparent layer having a lower refractive index than the substrate. A reflection type liquid crystal display device comprising a reflection type liquid crystal display panel having at least a reflection layer outside the polarizing layer, and an illuminating device provided on one or more side surfaces of the reflection type liquid crystal display panel. 2. The reflective liquid crystal display device according to claim 1, wherein the difference in refractive index between the transparent substrate on the back side and the transparent layer having a low refractive index is 0.05 or more.