JP2002303866A - Reflective liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an external light and lighting type reflective liquid crystal display device which is thin and lightweight, hardly causes panel cracking, and has superior display quality. SOLUTION: The reflective liquid crystal display panel (100) is equipped with a light reflecting means (12) on the back side of the liquid crystal layer of a liquid crystal cell (90) formed by sandwiching liquid crystal (30) between a back-side cell substrate (10) having at least an electrode (12) on a base substrate (11) and a view-side cell substrate (20) which has at least a transparent electrode (21) provided on a transparent substrate (24) thicker than the base substrate of the cell substrate while both the substrates are arranged having their electrode sides put opposite each other. The liquid crystal display panel has a lighting device (50) at one or more places on its side face and is provided with an optical path control layer (40) having a light projecting means (A) equipped with an optical path conversion oblique surface (A1) on the external surface side of the view-side cell substrate.

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 which is thin and lightweight and has excellent display quality, which is used for both external light and illumination.

[0002]

BACKGROUND OF THE INVENTION Conventionally, a reflection type LCD for both external light and illumination is used.
As a (liquid crystal display device), there has been known a front light type device in which a side light type light guide plate is disposed on a viewing side surface of a liquid crystal display panel, and display light is visually recognized through the light guide plate. JP-A-12-147499). However, the sidelight type light guide plate requires a plate thickness of about 2 mm or more due to the necessity of light transmission, and there is a problem that the thickness and weight of the liquid crystal display device are increased. For this reason, the reduction in thickness and weight has become an important issue, particularly in a reflection type liquid crystal display device for portable use such as a portable personal computer and a portable telephone. In the thin and light weight system in which the cell substrate of the liquid crystal display panel is thinned, there is a problem that the mechanical strength is reduced and the panel is easily broken.

[0003]

An object of the present invention is to develop a reflection type liquid crystal display device for both external light and illumination, which is excellent in thinness and lightness, does not easily cause panel breakage, and has excellent display quality.

[0004]

The present invention provides a rear-side cell substrate provided with at least an electrode on a supporting substrate, and a viewing-side cell substrate provided with at least a transparent electrode on a transparent substrate having a thickness larger than the supporting substrate in the cell substrate. A liquid crystal cell having a liquid crystal sandwiched between its electrode sides facing the liquid crystal layer, provided with light reflecting means on the back side of the liquid crystal layer, and the light incident from the outer surface of the viewing side cell substrate. An illumination device is provided on one or more side surfaces of a reflective liquid crystal display panel in which light is reflected by the light reflecting means and display light transmitted through the liquid crystal layer is emitted from the viewing side cell substrate to be viewed. In addition, an optical path control layer having a thickness of 10 to 300 μm having light emitting means on the outer surface side of the viewing side cell substrate is provided, and the light emitting means emits light incident from the side surface through the lighting device. The back A reflection type liquid crystal display comprising a light path conversion slope on the side of the side cell substrate, the light path conversion slope having an inclination angle of 35 to 48 degrees with respect to a reference plane of the liquid crystal display panel. An apparatus is provided.

[0005]

According to the present invention, the incident light from the illuminating device arranged on the side of the liquid crystal display panel is passed through the light emitting means of the optical path control layer arranged on the viewing side and the light reflecting means arranged on the back side. The light path can be efficiently converted in the viewing direction of the liquid crystal display panel and used for liquid crystal display, and the front light mechanism that can display the liquid crystal even in the external light mode in which external light is incident can be formed. A reflection type liquid crystal display device for both external light and illumination, which is excellent in thinness and lightness, hardly causes panel breakage, and is excellent in display quality, can be obtained by the side arrangement of the control layer and the illumination device.

That is, according to the present invention, it is possible to efficiently transmit incident light from a side-mounted illuminating device through a cell substrate of a liquid crystal display panel, in particular, a transparent substrate on the viewing side, and to supply the light to the optical path control layer. It is possible to achieve good light emission even with an optical path control layer that is much thinner than that of. In addition, by making the transparent substrate on the viewing side thicker than the supporting substrate on the back side, it is possible to increase the side incident light on the transparent substrate on the viewing side as compared with the case where they are the same thickness, thereby increasing the display light. In addition to being able to be bright, the rigidity of the viewing-side cell substrate, which is easily subjected to pressure, can be increased to suppress the display image from being distorted due to its bending due to external force. Even when the total thickness of the substrate is the same as the case of the same thickness, A liquid crystal display device that is difficult to break can be obtained.

Further, since the light emitting means provided in the optical path control layer has an optical path changing slope having a predetermined inclination angle, the incident light from the side surface or the transmitted light can be reflected through the inclined surface to convert the optical path with good directivity. In addition, by controlling the optical path of light in the specular reflection direction showing the peak, directivity advantageous for display, particularly directivity in the front direction, can be easily provided, and a liquid crystal display in a bright illumination mode can be achieved. In addition, even in the external light mode, a bright liquid crystal display can be achieved in the external light mode in addition to the illumination mode because external light can be efficiently incident by using a flat portion other than the optical path conversion slope in the optical path control layer. can do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A reflection type liquid crystal display device according to the present invention comprises a rear cell substrate provided with at least an electrode on a support substrate, and a transparent substrate having a thickness larger than the support substrate in the cell substrate. The viewing-side cell substrate provided is provided with light reflecting means on the back side of the liquid crystal layer of the liquid crystal cell in which the liquid crystal is sandwiched between the electrode sides facing each other. 1 or 2 of a side surface of a reflection type liquid crystal display panel in which external light incident from an outer surface is reflected by the light reflecting means and display light transmitted through the liquid crystal layer is emitted from a viewing side cell substrate to be visually recognized. Having a lighting device as described above and having a light emitting means on the outer surface side of the viewing-side cell substrate, the thickness is 10 to 300 μm.
m light path control layer, the light emitting means of which is provided with an optical path conversion slope for reflecting light incident from the side surface through the lighting device to the side of the back side cell substrate, and the light path conversion slope. Is 35 to 4 with respect to the reference plane of the liquid crystal display panel.
It has an inclination angle of 8 degrees.

FIG. 1 shows an example of the above-mentioned reflection type liquid crystal display device. 100 is a liquid crystal display panel, 90 is a liquid crystal cell, 1
Reference numeral 0 denotes a back-side cell substrate provided with an electrode 12 serving also as a light reflecting means on a support substrate 11, and reference numeral 20 denotes a transparent electrode 21 on a transparent substrate 24.
Is a liquid crystal layer, 40 is an optical path control layer having light emitting means A having an optical path conversion slope A1, and 50 is an illumination device. In the figures, 13 and 22 are alignment films, 23 is a transparent layer having a low refractive index, 25 is a polarizing plate, 26 is a retardation plate, and 31 is a liquid crystal 30 between the cell substrates 10 and 20.
Is a light source, and 52 is a reflector.

[0010] As a liquid crystal display panel, as shown in the figure, a rear-side cell substrate provided with at least an electrode on a support substrate, and a transparent substrate provided with at least a transparent electrode on a transparent substrate having a thickness larger than the support substrate in the cell substrate. A liquid crystal cell in which a liquid crystal is sandwiched between a side cell substrate and their electrode sides facing each other; and a light reflecting means provided on the back side of the liquid crystal layer of the cell, and an optical path control layer. The external light incident from the outer surface of the viewing side cell substrate on which is disposed is reflected by the light reflecting means, and the display light transmitted through the liquid crystal layer is inverted by the light reflection means so that the display light is emitted from the viewing side cell substrate and appropriately viewed. A reflective type can be used, and the type is not particularly limited.

Incidentally, specific examples of the above-mentioned liquid crystal cell include twisted and non-twisted types such as a TN liquid crystal cell, an STN liquid crystal cell, a vertical alignment cell, a HAN cell, and an OCB cell, and a guest host type, based on the orientation of the liquid crystal. And those using ferroelectric liquid crystal, and those utilizing light diffusion.
The driving method of the liquid crystal may be an appropriate method such as an active matrix method or a passive matrix method.
The driving of the liquid crystal is generally performed by a pair of cell substrates 10, 2 as shown in the figure.
This is performed via the electrodes 12 and 21 provided inside 0.

A transparent substrate is used for the viewing-side cell substrate to allow transmission of display light. The transparent substrate can be formed of an appropriate material such as glass or resin, and among others, is preferably formed of an optically isotropic material from the viewpoint of minimizing birefringence and reducing light loss. . Further, a material having excellent colorless transparency such as a non-alkali glass plate with respect to a blue glass plate is preferable in terms of improvement of luminance and display quality, and a resin substrate is more preferable in terms of lightness and the like.

On the other hand, the support substrate in the rear-side cell substrate does not need to be light-transmitting when the electrode 12 serving also as a light reflecting means is provided inside the liquid crystal cell 90 as shown in FIG. The substrate 11 can be used, and may be a colored substrate. In that case, when the liquid crystal cell is of a type that realizes display by scattering or transmission / absorption difference of light, a black substrate can be preferably used from the point of black display. On the other hand, when it is necessary that the rear cell substrate has light transmissivity by providing light reflecting means outside the liquid crystal cell, or when the rear cell substrate, in particular, the light from the lighting device disposed on the side surface of the supporting substrate is used. A transparent substrate is used when the light is incident. The material of the transparent substrate can be in accordance with the above-mentioned viewing-side cell substrate.

The thickness of the transparent substrate of the viewing-side cell substrate and the thickness of the supporting substrate of the back-side cell substrate are not particularly limited except that the transparent substrate is made thicker than the supporting substrate, and depends on the sealing strength of the liquid crystal and the like. Can be determined appropriately. Generally, 10 μm to 5 mm, particularly 50 μm to 3 mm, especially 100 μm
It is 2 mm thick. In the case where the viewing-side cell substrate 20 is used as a transmission substrate for the incident light from the lighting device 50 as shown in the figure, the larger the cross-sectional area of the transparent substrate is, the better and the more preferable, the larger the cross-sectional area is from the viewpoint of the incident efficiency and transmission efficiency.

In the above case, the thickness of the support substrate of the back side cell substrate is 2 / th of the thickness of the transparent substrate of the viewing side cell substrate because the back side cell substrate is more advantageous as it is thinner and thinner and lighter. It is preferably 3 or less, especially 5 to 60%, particularly preferably 10 to 50%. The shape of the transparent substrate may be the same thick plate, or the thickness may be partially different, such as a wedge-shaped cross section, for the purpose of improving the efficiency of transmitting light to the optical path conversion slope by the inclined arrangement of the optical path control layer. May be used. The same applies to the shape of the support substrate.

The viewing-side cell substrate and the back-side cell substrate are
The plane dimensions may be the same or different. When the viewing-side cell substrate is used as a transmission substrate for the incident light from the lighting device, at least the lighting device 5 is used as shown in FIG.
On the side surface on which 0 is arranged, the side surface formed by the viewing-side cell substrate 20 is projected from the side surface formed by the back-side cell substrate 10 when the lighting device is arranged on the projected side surface. It is preferable from the point of efficiency and the like.

The transparent electrode provided on the transparent substrate of the viewing-side cell substrate and, if necessary, the transparent electrode provided on the supporting substrate of the back-side cell substrate can be formed of a suitable material such as ITO, for example. On the other hand, as shown in the figure, the electrode 12 provided on the support substrate 11 of the rear-side cell substrate 10 as a light reflecting means as required can be formed of, for example, an appropriate reflective metal or the like. It is preferably formed as a thin film of an electrically conductive metal. In this case, when the viewing-side cell substrate is used as a transmission substrate for the incident light from the lighting device, it is difficult for the transmission light in the substrate to reach the light reflection means until the transmission light is reflected by the optical path conversion slope of the optical path control layer. The transmission light can be prevented from being disturbed by light scattering, so that the light reflection means can be used as scattering light.

As described above, the light reflecting means provided on the back side of the liquid crystal layer in the liquid crystal cell, that is, the light reflecting means usually provided on the inside or outside of the back side cell substrate is illuminated as shown by a broken line arrow in FIG. The incident light from the device 50 or the transmission light thereof is reflected by the light path changing slope A1 of the light emitting means A in the light path control layer 40 to change the light path to the back cell substrate side, and the light is reflected and inverted to be displayed in the illumination mode. To obtain the light α, and to obtain the display light β in the external light mode by reflecting and reversing the incident external light through a flat portion other than the optical path conversion slope of the optical path control layer or a portion with a gentle inclination angle, As a result, a reflective liquid crystal display device for both external light and illumination is formed.

The light reflecting means, in particular, the light reflecting means provided outside the liquid crystal cell can be formed by a suitable material such as a conventional white sheet. Above all, for example, a coating layer containing a powder of a high reflectivity metal such as aluminum, silver, gold, copper, chromium, or an alloy thereof in a binder resin, the above-mentioned metal, etc. and a dielectric multilayer film are formed by a vacuum deposition method. Layer formed by an appropriate thin film forming method such as sputtering or sputtering, a reflection sheet in which the coating layer or the added layer is supported by a substrate made of a film or the like, and a high-reflectance light reflecting means made of a metal foil or the like Is preferred.

The light reflecting means to be formed may have a light scattering function as described above. It is possible to improve the directivity in the front direction by diffusing the reflected light on the scattering reflection surface, and to improve the visibility by preventing the occurrence of Newton rings due to close contact in the case of roughening. Can be. Therefore, the light reflection means provided outside the cell may be in a state of being simply placed on top of each other, or may be in a state of being closely attached by an adhesion method or a vapor deposition method.

The light scattering type light reflecting means is formed on a film base material having a fine uneven structure on the surface by an appropriate method such as a surface roughening method by sandblasting or matting, or a particle addition method. It can be performed by a method of providing a light reflecting means reflecting the fine uneven structure. The formation of the light reflecting means of the fine uneven structure reflecting the fine uneven structure on the surface is performed, for example, by film-forming a metal by an appropriate method such as an evaporation method such as a vacuum evaporation method, an ion plating method, or a sputtering method, or a plating method. It can be performed by a method of attaching to the surface of a material or the like.

When forming a liquid crystal cell, if necessary, an appropriate functional layer such as an alignment film composed of a rubbing treatment film for aligning liquid crystal, a color filter for color display, a transparent layer having a low refractive index, etc. One or more layers can be provided. In addition, as shown in the figure, the alignment films 12 and 22 are usually
It is formed above the electrodes 12 and 21 so as to be in contact with the liquid crystal 30. In addition, the color filters are usually used for the cell substrates 10 and 2.
0 is provided between the transparent electrode and the support substrate 11 or the transparent substrate 24 on one side. Therefore, when the color filter is arranged on the support substrate side, the electrode is a transparent electrode.

On the other hand, the low refractive index transparent layer is intended to improve the uniformity of brightness over the entire display screen in the illumination mode. Incidentally, in the example of FIG.
A transparent layer 23 having a low refractive index is provided as a layer having a lower refractive index than the transparent substrate 24 forming the same. According to the example of the figure, as indicated by the broken line arrow γ, when the incident light from the lighting device 50 is transmitted inside the viewing-side cell substrate 20, the transmitted light is converted into the refractive index difference between the transparent substrate 24 and the transparent layer 23. Through which the light is efficiently reflected and confined within the viewing-side cell substrate efficiently, whereby the transmission light is efficiently transmitted backward, and the transmission light is evenly supplied to the optical path conversion slope of the optical path control layer at a position far from the lighting device. Then, the uniformity of brightness over the entire display screen can be improved through the optical path conversion by the reflection.

When a transparent layer having a low refractive index is provided on the cell substrate on the viewing side as shown in FIG.
Incident on the screen and undergoes birefringence and scattering, thereby preventing the transmission state from partially changing and causing the transmission light to decrease or become non-uniform. Is also effective in preventing ghosting behind and deteriorating the display quality. Further, when a color filter or the like is arranged, it is effective to prevent a sudden absorption of the transmission light due to the arrangement and avoid a decrease in the transmission light. In the case where the incident light from the illumination device is transmitted through the liquid crystal layer, the transmitted light is scattered by the liquid crystal layer, resulting in a non-uniform transmission state. Cheap. Therefore, a mode in which a transparent layer having a low refractive index is provided on the viewing-side cell substrate and an illuminating device is arranged on the side surface of the viewing-side cell substrate as shown in the figure is preferable from the viewpoint of brightness and display quality.

The low-refractive-index transparent layer is made of 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 cell substrate on the viewing side or the back side. It can be formed by an appropriate method such as a vacuum evaporation method or a spin coating method, and there is no particular limitation on the material and the forming method.

From the viewpoint of the transmission efficiency to the rear due to the total reflection, the larger the difference in the refractive index between the transparent layer and the transparent substrate is, the more advantageous it is, and more preferably 0.05 or more, especially 0.1 to 0.5. Preferably, there is. Such a difference in the refractive index hardly affects the display quality in the external light mode. Incidentally, when the refractive index difference is 0.1, the reflectance of external light at the interface is 0.1.
It is 1% or less, and the decrease in brightness and contrast due to the reflection loss is extremely small.

The arrangement position of the transparent layer having a low refractive index can be determined as appropriate. However, it is preferable that the transparent layer be located between the transparent substrate and the transparent electrode in view of the above-described effect of confining transmitted light and preventing intrusion into the liquid crystal layer. preferable. When a color filter is arranged between the transparent substrate and the transparent electrode, it is preferable that the color filter be located closer to the transparent substrate than the color filter in order to prevent absorption loss of transmission light by the color filter. Therefore, the transparent layer having a low refractive index is usually provided directly on the transparent substrate.
In this case, the smoother the surface on which the transparent layer is provided on the transparent substrate, the smoother the transparent layer is, the more advantageous in preventing scattering of transmission light, and more preferable in terms of preventing influence on display light. The thickness of the low-refractive-index transparent layer is 100 nm or more, particularly 200 nm or more, in view of the above-described confinement effect and thinning.
Particularly, the thickness is preferably 400 nm to 5 μm.

The liquid crystal display panel has a structure in which one or more suitable optical layers such as a polarizing plate 25, a retardation plate 26, and a light diffusing layer are added to a liquid crystal cell as shown in FIG. Good. Polarizing plates aim at achieving display using linearly polarized light, such as liquid crystal display panels of TN type or STN type, and retardation plates improve display quality by compensating for phase differences due to the birefringence of liquid crystal. Aim. In addition, the light diffusion layer expands the display range by diffusing the display light, equalizes the brightness by leveling the bright line emission through the light path conversion slope of the light path control layer, and controls the light path by diffusing the transmission light in the liquid crystal display panel. The purpose is to increase the amount of light incident on the layer. Therefore, the light diffusion layer is usually
It is provided between the optical path control layer and the transparent substrate of the viewing side cell substrate.

The polarizers can be arranged on both sides outside the liquid crystal cell, or only on one side as shown in the figure. An appropriate polarizing plate can be used, and there is no particular limitation. Rather than obtaining a display with a good contrast ratio due to the incidence of highly linearly polarized light, for example, a highly hydrophilic film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film is used. Absorption-type polarizing films consisting of those which are made by adsorbing dichroic substances such as iodine or dichroic dyes on molecular films, and those having a high degree of polarization such as those provided with a transparent protective layer on one or both sides thereof. It can be preferably used.

For the formation of the transparent protective layer, those having excellent transparency, mechanical strength, heat stability and moisture shielding properties are preferably used. Examples thereof include acetate resins, polyester resins, and polyether sulfone. Resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin or acrylic resin, polyether resin or polyvinyl chloride, polymer such as styrene resin or norbornene resin, or acrylic or urethane resin, Examples thereof include thermosetting or ultraviolet-curing resins such as acrylic urethane, epoxy, and silicone. The transparent protective layer can be provided by a bonding method of a film or a coating method of a polymer liquid or the like.

On the other hand, a birefringent film obtained by stretching a film made of a suitable polymer such as those exemplified in the above-mentioned transparent protective layer by a suitable method such as uniaxial or biaxial is also used as a retardation plate. An appropriate film such as an alignment film of a liquid crystal polymer such as a liquid crystal polymer or a discotic one or a film in which the alignment layer is supported by a transparent substrate can be used. The refractive index in the vertical direction may be controlled. The compensating retardation plate is usually arranged as needed between the viewing side and / or back side polarizing plate and the liquid crystal cell, and an appropriate retardation plate may be used according to the wavelength range or the like. Further, the retardation plate may be used by superposing two or more layers for the purpose of controlling optical characteristics such as a retardation.

The illumination device arranged on the side surface of the liquid crystal display panel aims to make light used as illumination light for the reflection type liquid crystal display device 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. From the viewpoint of preventing incident light from the illuminating device from entering the liquid crystal layer, the preferred arrangement of the illuminating device is as described above, in which the visible side projects from the side surface of the viewing side cell substrate, particularly the side surface formed by the back side cell substrate. This is a method of arranging on the side surface of the side cell substrate.

As the illuminating device, an appropriate one can be used, for example, a linear light source such as a (cold or hot) cathode tube, a point light source such as a light emitting diode, or an array body in which the light sources are arranged in a linear or planar manner. Alternatively, an illumination device in which a point light source is combined with a linear light guide plate to convert incident light from the point light source into a linear light source via the linear light guide plate can be preferably used. In the example of FIG. 1, a lighting device 50 including a light source 51 and a reflector 52 surrounding the light source 51 is used. The lighting device can be arranged on one or more side surfaces of the liquid crystal display panel. When the lighting device is arranged on two or more side surfaces, the plurality of side surfaces may be a combination of opposing side surfaces, a combination of side surfaces that intersect vertically and horizontally, or a combination of three or more side surfaces. It may be a combination.

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

The lighting device is provided with a light source 5 as necessary as shown in the figure.
In order to guide the divergent light by 1 to the side surface of the liquid crystal display panel, it may be a combination body in which appropriate auxiliary means such as a reflector 52 surrounding the liquid crystal display panel are arranged. As the reflector, an appropriate reflection sheet that reflects light at least on the lighting device side, such as a resin sheet or a white sheet or a metal foil provided with a high-reflectance metal thin film, can be used. The reflector can also be used as a holding means that also surrounds the light source by, for example, bonding the end to the cell substrate of the liquid crystal display panel, particularly to the upper and lower ends of the cell substrate on the viewing side.

As shown in FIG. 1, the light path control layer converts incident light from the illuminating device 50 disposed on the side surface of the liquid crystal display panel or transmitted light thereof through the light path changing slope A1 of the light emitting means A to the rear side of the panel. The light path is changed in the direction of the cell substrate, and the illumination light (display light) passes through the reflection reversal by the light reflection means 12.
The liquid crystal display panel is disposed on the outer surface side of the viewing side cell substrate 20 of the liquid crystal display panel, generally on the viewing side surface portion as in the example of FIG.

For the above purpose, as shown in FIG.
Is an optical path conversion slope A1 having an inclination angle of 35 to 48 degrees with respect to a reference plane (virtual horizontal plane) of the viewing-side cell substrate in order to reflect incident light from the illumination device and change the optical path in a predetermined direction.
Is provided. Further, the light path control layer is generally formed by distributing a large number of such light emitting means for the purpose of reducing the thickness. When a transparent layer having a low refractive index is provided on the cell substrate, particularly on the viewing side, it is preferable to form the optical path control layer as a layer having a higher refractive index than the transparent layer. If the refractive index of the optical path control layer is lower than that of the transparent layer, the incident light from the lighting device or the transmitted light is easily confined in the cell substrate, and the incidence on the optical path control layer is hindered, making it difficult to use as display light. May be.

The light emitting means in the light path control layer can be formed in any suitable form, except that the light emitting means has a light path changing slope having a predetermined inclination angle. Rather than obtaining display light with excellent directivity in the front direction via optical path conversion or the like, an optical path having light emitting means A having an optical path changing slope A1 facing a side surface (i.e., an incident side surface) on which the illumination device is arranged. A control layer, in particular, an optical path control layer having light emitting means A having an optical path conversion slope A1 composed of prismatic irregularities is preferable.

FIGS. 2 to 4 show examples of light emitting means having the above-described optical path changing slope or prismatic irregularities. FIG. 2 shows a light emitting means A having two light path changing slopes A1 formed by isosceles triangles, and FIG. 3 shows a light emitting means A having an optical path changing slope A1 and a steep slope B having a larger inclination angle with respect to a reference plane than the slope A1. Consists of In FIG. 4, the light emitting means A is formed on the entire surface of one side of the optical path control layer as a repetitive structure in which the light path changing slope A1 and the gentle slope C having a small inclination angle with respect to the reference plane are adjacent to each other.

Therefore, as in the above-described example, the light emitting means
It can also be formed on a prism-shaped convex or concave portion having an equilateral surface or a slope having the same inclination angle, or a prism-shaped convex portion or a concave portion having an optical path conversion slope and a steep slope or a gentle slope or a slope having a different slope angle. Can be formed, and the form of the slope can be appropriately determined by the number and position of the incident side surfaces. As shown in the figure, the shape of the prism-shaped concave portion (groove) that is depressed from the surface 41 of the optical path control layer is protruded from the surface, rather than maintaining the slope function and improving the incident efficiency of transmission light due to the improvement of scratch resistance. It is more preferable than the form of the prism-shaped convex portion (projection).
Further, in the above-described example, the light emitting means A having a substantially triangular shape based on the cross section with respect to the optical path changing slope A1 is shown. Although a substantially triangular cross-section is advantageous in terms of ease of formation, the light emitting means A may have an appropriate cross-sectional shape such as a substantially quadrangular cross-section or a substantially pentagonal cross-section. The “abbreviation” of the cross-sectional shape
Means that a deformation such as a change in the angle of the side or a rounding of the angle formed by the intersection of the sides is permitted.

The optical path control layer, which is more preferable in achieving the above-described characteristics such as the directivity in the front direction, is an optical path conversion slope A having an inclination angle of 35 to 48 degrees with respect to a reference plane as shown in the figure.
1 facing the incident side surface. Therefore, when the illuminating device is disposed on two or more side surfaces of the liquid crystal display panel and has two or more incident side surfaces, a light path control layer having an optical path conversion slope A1 corresponding to the number and position is preferably used. . The arrow in the figure is the transmission direction of light incident from the incident side.

Accordingly, in the case where the illuminating devices are arranged on two opposing side surfaces of the liquid crystal display panel and the two side surfaces are used as the incident side surfaces, the light emitting means A having a substantially isosceles triangular cross section as shown in FIG. An optical path control layer having two optical path converting slopes formed by the light emitting means having a light trapping surface A1 or a substantially trapezoidal cross section in such a state that the ridge line thereof is along the incident side surface is preferably used. In addition, two horizontal and vertical sides of the liquid crystal display panel
When illuminating devices are arranged on the side surfaces, an optical path control layer having an optical path changing slope with ridges corresponding to the side surfaces in both the vertical and horizontal directions is preferably used. Furthermore, when arranging the lighting device on three or more sides including vertical and horizontal,
An optical path control layer having an optical path changing slope composed of the above combination is preferably used.

The optical path changing slope A1 reflects the light incident on the surface A1 out of the incident light from the incident side surface through the illumination device or the transmitted light, and changes the optical path to perform the light path changing on the rear side of the liquid crystal display panel. Play the role of supply. In this case, the inclination angle of the optical path changing slope A1 with respect to the reference plane is set to 35 to 48 degrees, so that the side incident light or its transmission light is subjected to optical path conversion with good perpendicularity to the reference plane as exemplified by the broken line arrow α in FIG. As a result, display light having excellent directivity toward the front can be efficiently obtained. If the inclination angle is less than 35 degrees, the optical path of the reflected light via the light reflecting means is shifted by 30 degrees or more from the front direction, making it difficult to effectively use for display and deteriorating the display quality. on the other hand,
If the angle of inclination exceeds 48 degrees, the condition for totally reflecting the side incident light or its transmitted light is deviated, so that the amount of light leaking from the optical path conversion slope increases and the light utilization efficiency of the side incident light becomes poor.

The preferable angle of inclination of the optical path conversion slope A1 in terms of light path conversion having excellent directivity to the front and suppression of leak light is determined by total reflection based on refraction of light transmitted through the liquid crystal display panel according to Snell's law. 38-45 considering conditions
Degrees, especially 40-44 degrees. Incidentally, the general total reflection condition of the glass plate is 42 degrees, and in that case, the side incident light is incident on the optical path conversion slope while being transmitted in a state of being concentrated in the range of ± 42 degrees.

Light emitting means A having an optical path changing slope A1
Is usually formed as a structure in which a plurality of the light path control layers are arranged for the purpose of reducing the thickness of the optical path control layer as described above.
2 to 4, the incident light from the incident side is reflected backward and efficiently transmitted to the opposite side to emit light as uniformly as possible over the entire liquid crystal display. A structure including a flat surface 41 having an angle of approximately 0 degree or a gentle slope C having an inclination angle of 10 degrees or less, particularly 5 degrees or less, and particularly 3 degrees or less.
Is preferable. Therefore, in the light emitting means A including the steep slope B illustrated in FIG. 3, it is preferable that the angle of the steep slope is 35 degrees or more, particularly 50 degrees or more, and particularly 60 degrees or more to make the structure of the flat surface 41 wide. .

The flat surface 41 and the gentle slope C are not shown in FIG.
As shown in the example, the display light α in the illumination mode, the incident portion of the external light in the external light mode, and the light reflecting means 12 of the incident light
And a portion functioning as a transmission portion of the reflected display light β through the light-emitting device, thereby achieving a reflection type liquid crystal display device for both external light and illumination. In this case, the slope A1 as shown in FIG.
When the light emitting means A has a repeating structure adjacent to the light emitting means C, the angle difference of the gentle slope C with respect to the reference plane is within 5 degrees, preferably within 4 degrees, particularly within 3 degrees, and more particularly within 3 degrees of the entire optical path control layer. It is preferable that the difference in the inclination angle between the nearest gentle slopes is within 1 degree, preferably within 0.3 degree, particularly within 0.1 degree. This is the optimal viewing direction of the reflective liquid crystal display,
In particular, it is an object of the present invention to prevent the optimum viewing direction in the vicinity of the front direction from being largely changed by the transmission of the gentle slope C, and not to make a large change between the nearest gentle slopes. Further, from the viewpoint of obtaining a bright display in the external light mode, it is preferable that the projection area of the gentle slope C with respect to the reference plane be 5 times or more, especially 10 times or more, especially 15 times or more of that of the optical path conversion slope A1. This aims at improving the incident efficiency of external light and the transmission efficiency of reflected display light via the light reflecting means.

The light emitting means A is provided so that its ridge line, that is, the optical path changing slope is parallel or inclined along the incident side surface of the liquid crystal display panel on which the illuminating device is arranged. The emission unit A may be formed continuously from one end to the other end of the optical path control layer, or may be formed discontinuously and discontinuously. In the case of discontinuous formation, the length of the groove or projection along the incident side surface along the incident side, or the length of the long side of the optical path conversion slope is determined by the groove in terms of the transmission efficiency of the transmission light and the optical path conversion efficiency. It is preferable that the depth be 5 times or more the depth or the height of the projection. Further, the length is set to 500 from the viewpoint of uniform light emission of the panel display surface.
μm or less, especially 10 to 480 μm, especially 50 to 450 μm
It is preferable that

There is no particular limitation on the cross-sectional shape of the light emitting means A and the arrangement interval of the optical path changing slope A1 therethrough.
Since the light path conversion slope A1 is a factor in determining the luminance in the illumination mode, the light path conversion slope A1 can be appropriately determined according to the uniformity of light emission of the panel display surface in the illumination mode or the external light mode. Can be controlled. Therefore, the inclination angle of the light path conversion slope may be constant over the entire surface of the light path control layer, or the light emission of the panel display surface may be made uniform by coping with absorption loss and attenuation of transmitted light due to the light path conversion. For the purpose, the light emitting means A may be made larger as the distance from the incident side surface increases.

Also, the light emitting means A can be arranged at a constant arrangement interval, or the distribution density of the light emitting means A can be increased by gradually decreasing the arrangement interval as the distance from the incident side surface increases. In addition, uniform light emission on the panel display surface can be achieved at random arrangement intervals. In addition, when the light emitting means A has irregularities formed of discontinuous grooves or projections, the size and shape of the irregularities, the distribution density, the direction of the ridge line, and the like are made irregular, or the irregular or regular Alternatively, uniform unevenness may be randomly arranged to make light emission uniform on the panel display surface. Therefore, uniform light emission on the panel display surface as in the above-described example can be achieved by applying an appropriate method to the light emitting means A.

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. It is preferable to reduce the size to secure a sufficient light transmittance through the flat surface 41 and the gentle slope C. From this point, the pixel pitch of the liquid crystal cell is generally 100
In consideration of the fact that it is ~ 300 μm,
Is preferably formed to be 40 μm or less, particularly 3 to 20 μm, particularly 5 to 15 μm based on the projection width with respect to the reference plane. Such a projection width is more preferable than the point where the coherent length of the fluorescent tube is generally set to about 20 μm, and the like, from the viewpoint of preventing the deterioration of display quality due to diffraction.

On the other hand, it is preferable that the distance between the optical path changing slopes A1 is larger than the above-mentioned point. On the other hand, the optical path changing slope is a functional part for substantially forming the illumination light by the light path changing of the side incident light as described above. Therefore, if the interval is too large, the lighting at the time of lighting may be sparse, resulting in an unnatural display. In view of them, the arrangement interval of the optical path conversion slope A1 is 5 mm or less, especially 20 μm to 3 mm. , Especially 50 μm to 2 mm
It is preferable that Further, the arrangement structure of the light emitting means may interfere with the pixels of the liquid crystal cell and cause moire. Although moire can be prevented by adjusting the arrangement interval, the arrangement interval has a preferable range as described above. Therefore, a solution for a case where moiré occurs in that range becomes a problem. In the present invention, it is preferable to form a ridge line of the unevenness so as to be inclined with respect to the incident side so that the light emitting means can be arranged in an intersecting state with respect to the pixel to prevent moire.

In the case of the above-mentioned method, if the inclination angle with respect to the incident side surface is too large, the reflection via the optical path changing slope A1 is deflected, and a large deviation occurs in the direction of the optical path changing, which is likely to cause a deterioration in display quality. It is preferable that the inclination angle of the ridge line with respect to the incident side surface is within ± 30 degrees, particularly within ± 25 degrees. The sign of ± means the inclination direction of the ridgeline with respect to the incident side surface. In the case where the resolution of the liquid crystal cell is low and moiré does not occur, or when moiré can be neglected, it is preferable that the ridge line is parallel to the incident side surface. Further, as a measure for preventing moire, a plurality of light emitting means composed of minute grooves such as prism-shaped concave portions or prism-shaped convex portions having the above-mentioned size is discontinuously and irregularly formed on the surface of the optical path control layer. Is also preferable.

The light path control layer can be formed of an appropriate material exhibiting transparency according to the wavelength range of the lighting device. By the way, in the visible light region, the polymer, the curable resin, the glass, and the like exemplified as the transparent protective layer and the like are mentioned. An optical path control layer formed of a material that does not exhibit birefringence or has low birefringence is preferable. In addition, since the incident light from the illuminating device or its transmitted light is efficiently incident on the optical path control layer from the viewing-side cell substrate to achieve a bright display through the optical path conversion slope, the refractive index of the viewing-side cell substrate with respect to the transparent substrate is increased. The difference is within 0.15,
In particular, it is preferable that the optical path control layer has a refractive index of 0.10 or less, particularly 0.05 or less, and particularly has a refractive index higher than that of the transparent substrate.

The optical path control layer can be formed by an appropriate method, and there is no particular limitation on the manufacturing method. As a preferable production method from the viewpoint of mass productivity, for example, a method of transferring a shape by pressing a thermoplastic resin under heating to a mold capable of forming a predetermined light emitting means, a thermoplastic resin melted by heating or heat or solvent A method of filling a resin that has been fluidized through a mold capable of forming a predetermined light emitting means, heat or ultraviolet light,
A method in which a liquid resin or monomer that can be polymerized by an electron beam or radiation is filled or cast into a mold capable of forming a predetermined light emitting means, and a polymerization process is performed. A method in which the film is adhered to polymerize and integrated with the film, after applying the liquid resin or monomer to a transparent film and pressing the applied layer onto a mold capable of forming a predetermined light emitting means, and transferring the shape. Examples of the method include a method of performing a polymerization treatment and integrating the film with the film. Therefore, the light path control layer can be formed by directly giving a predetermined form to the viewing side cell substrate or the like, or can be formed as a transparent sheet or the like having a predetermined form.

The thickness of the optical path control layer is 10 to 300 μm, preferably 15 to 200 μm, particularly 20 to
00 μm. When the light path control layer is independently formed as a transparent sheet or the like, the transparent sheet or the like may be formed as an adhesive layer having a refractive index larger than that of the transparent substrate of the viewing-side cell substrate, particularly the transparent sheet or the like. Adhesion to the outer surface side of the viewing-side cell substrate in the liquid crystal display panel through an adhesive layer having the same refractive index, particularly an adhesive layer having an intermediate refractive index between the transparent sheet or the like and the viewing-side cell substrate can reduce incident light and the like. It is more preferable that a bright display is achieved by efficiently entering the optical path control layer from the viewing side cell substrate. Therefore, the refractive index of such an adhesive layer can conform to the above-described optical path control layer.

The above-mentioned adhesive layer can be formed of an appropriate transparent adhesive, and the kind of the adhesive is not particularly limited.
An adhesion method using an adhesive layer is preferred from the viewpoint of simplicity of the adhesion treatment operation. For forming the adhesive layer, for example, an adhesive using a suitable polymer such as a rubber-based, acrylic-based, vinyl alkyl ether-based, silicone-based, polyester-based or polyurethane-based, polyether-based, polyamide-based, or styrene-based polymer as a base polymer Etc. can be used. Among them, those excellent in transparency, weather resistance, heat resistance and the like, such as an acrylic pressure-sensitive adhesive containing a polymer mainly composed of an alkyl ester of acrylic acid or methacrylic acid as a base polymer, can be preferably used.

The optical path control layer is disposed on the viewing side of the liquid crystal display panel. In this case, the light emitting means A is provided as shown in FIG.
Can be arranged with the surface on which the is formed on the outside (viewing side),
It is more preferable to improve the reflection efficiency of the light emitting means A through the optical path changing slope A1, and furthermore to improve the luminance by effectively utilizing the side incident light.

The outer surface of the optical path control layer may be subjected to a non-glare treatment or an anti-reflection treatment for the purpose of preventing visual disturbance due to surface reflection of external light. Non-glare treatment can be performed by forming a fine uneven structure on the surface by various methods such as a roughening method such as a sand blast method or an embossing method, a method of blending transparent particles such as silica, etc. It can be applied by a method of forming a coherent vapor deposition film. The non-glare treatment and the anti-reflection treatment can also be applied to the above-mentioned method of bonding a film provided with a fine surface unevenness structure or an interference film. The non-glare treatment and the anti-reflection treatment are preferably provided so as not to hinder the function of the light emitting means as much as possible.

The reflection type liquid crystal display device may be provided with the light diffusion layer as described above. The light diffusion layer can be provided by an appropriate method using a coating layer or a diffusion sheet having a fine surface unevenness structure according to the non-glare layer.
The arrangement position of the light diffusion layer can be determined as appropriate, but generally, as described above, the arrangement between the optical path control layer and the viewing side cell substrate is preferable from the viewpoint of stability of display quality and the like. In this case, the light diffusion layer is formed as a light diffusion type adhesive layer formed by blending transparent particles, and is used as a light diffusion layer that also serves as a bonding of a transparent sheet forming an optical path control layer or a bonding between a polarizing plate and a retardation plate. It can also be made thinner. Therefore, one or two or more light diffusion layers can be arranged.

The transparent particles to be incorporated in the adhesive layer include, for example, conductive particles made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, or the like having an average particle size of 0.5 to 20 μm. One or two kinds of appropriate particles such as inorganic particles having a property and organic particles formed of a crosslinked or uncrosslinked polymer or the like may be used.

According to the reflection type liquid crystal display device of the present invention, most of the incident light from the incident side is transmitted backward through the liquid crystal display panel, particularly through the transparent substrate of the cell substrate on the viewing side, through reflection based on the law of refraction. The output path (leakage) from the panel surface is prevented, and the optical path conversion slope A of the optical path control layer is prevented.
The light incident on the light path 1 is efficiently converted in the optical path in the direction of the rear cell substrate with good vertical directivity, and the other transmission light is further transmitted rearward by total internal reflection, and is incident on the optical path conversion slope A1 in the rear and efficiently on the rear side. Optical path conversion is performed with good vertical directivity in the direction of the cell substrate, and display in a bright illumination mode can be achieved. Accordingly, it is possible to form a reflective liquid crystal display device for both external light and illumination, which is bright and easy to see, and has excellent display quality by efficiently using light from the illumination device and external light.

In the present invention, optical elements or components such as an optical path control layer, a liquid crystal cell, a polarizing plate and a retardation plate, which form the above-mentioned reflection type liquid crystal display device, are entirely or partially laminated and integrated and fixed. Or may be arranged in an easily separable state. It is preferable to be in a fixed state rather than to prevent reduction in contrast by suppressing interface reflection. An appropriate transparent adhesive such as a pressure-sensitive adhesive can be used in the adhesion and adhesion treatment, and the transparent adhesive layer can be made to contain the above-mentioned transparent particles and the like to form an adhesive layer having a diffusion function. The optical element or component,
In particular, those on the viewing side can have an ultraviolet absorbing ability by, for example, a method of treating with an ultraviolet absorbing agent such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex salt compound.

[0063]

Reference Example 1 Magnesium fluoride was vacuum-deposited on a transparent plastic plate having a refractive index of 1.505 to form a low refractive index transparent layer having a thickness of 600 nm and a refractive index of 1.38, and an ITO transparent conductive layer was formed thereon. After forming the layer, the transparent electrode was etched and divided, and a polyvinyl alcohol solution was spin-coated thereon, and the dried film was rubbed to obtain a cell substrate on the viewing side. On the other hand, an ultraviolet curable resin layer is formed on a transparent plastic plate having a refractive index of 1.505, and after roughening the layer, aluminum is deposited to form a diffuse reflection electrode, and a rubbing film is provided thereon in accordance with the above. Thus, a back side cell substrate was obtained.

Then, a gap adjusting material is provided with the sighting-side cell substrate and the back-side cell substrate facing each other such that the rubbing surfaces thereof are orthogonal to each other in a rubbing direction, and the periphery thereof is sealed with an epoxy resin. , ZLI-479
2) is injected to form a TN reflective liquid crystal cell, and a polarizing plate (NPF EGW1225DU, manufactured by Nitto Denko Corporation) that has been subjected to anti-reflection treatment and non-glare treatment is adhered to both surfaces thereof, and a normally white reflective liquid crystal cell is adhered. A liquid crystal display panel was obtained. The panel size is 45 mm in width and 34 mm in length, and one side surface of the viewing-side cell substrate in the length direction protrudes 2 mm from the back-side cell substrate. Next, a cold-cathode tube is placed on the protruding side of the viewing-side cell substrate, surrounded by a silver-evaporated polyester film, and the film ends are adhered to the upper and lower surfaces of the viewing-side cell substrate with a double-sided adhesive tape to hold the cold-cathode tube. Fixed.

Reference Example 2 Acrylic UV-curable resin (Aronix UV-3701, manufactured by Toagosei Co., Ltd.) was placed in a mold previously processed into a predetermined shape.
Is dropped and filled with a dropper, and a 70 μm-thick unstretched polycarbonate (PC) film (refractive index 1.5
8) is allowed to stand still and adhered tightly with a rubber roller to remove excess resin and air bubbles, irradiated with ultraviolet light from a metal halide lamp, cured, and then separated from the mold and cut into a predetermined size to have a refractive index of 1.51. A transparent sheet having an optical path control layer was obtained.

The transparent sheet has a width of 40 mm and a length of 30 mm, and the light emitting means composed of prism-shaped concave portions whose ridge lines are inclined at an angle of 21 degrees in the width direction is parallel to the light emitting means.
It has a pitch of 0 μm continuously (FIG. 4), the inclination angle of the optical path changing slope A1 is 42 degrees, and the inclination angle of the gentle slope C is 1.8 to 3.5 degrees, and the inclination angle of the nearest gentle slope is 0.1 change
Degrees, the projected width of the light path changing slope to the reference plane is 10 to 16 μm, and the projected area ratio of the gentle slope / light path changing slope to the reference plane is 12 times or more.

Reference Example 3 A transparent sheet having an optical path control layer was obtained according to Reference Example 2 using different molds. This transparent sheet has an optical path conversion slope A1 having an inclination angle of about 42 degrees and a projection width of 10 μm with respect to a reference plane.
80 μm long light emitting means (FIG. 2) consisting of an isosceles triangle is regularly arranged in a state where the length direction is parallel to the incident side surface, and the area of the flat portion (41) is the optical path conversion slope. Is 10 times or more the total projected area with respect to the reference plane.

Reference Example 4 A transparent sheet having an optical path control layer was obtained according to Reference Example 2 using different molds. This transparent sheet has an optical path conversion slope A1 having an inclination angle of about 42 degrees and a projection width of 10 μm with respect to a reference plane.
And light emitting means (FIG. 3) having a steep slope having an inclination angle of about 65 degrees and having a length of 80 μm and having a length direction parallel to the incident side surface. Is 10 times or more the total projected area of the optical path changing slope and the steep slope with respect to the reference plane.

Reference Example 5 A transparent sheet having an optical path control layer was obtained according to Reference Example 2 using different molds. This transparent sheet has an optical path conversion slope A1 having an inclination angle of about 42 degrees and a projection width of 10 μm with respect to a reference plane.
80 μm long light emitting means (FIG. 2) composed of an isosceles triangle according to the following formula: its length direction is parallel to the incident side face, and the light emitting means becomes gradually denser as the distance from the incident side face increases. Are arranged randomly so that
The area of the flat portion (41) is at least 10 times the total projected area of the optical path conversion slope with respect to the reference plane.

Reference Example 6 A transparent sheet with an optical path control layer was obtained according to Reference Example 2 using different molds. This transparent sheet has an optical path conversion slope A1 having an inclination angle of about 42 degrees and a projection width of 10 μm with respect to a reference plane.
And a light emitting means (FIG. 3) having a steep slope with an inclination angle of about 65 degrees and a length of 80 μm (FIG. 3) in a state where its length direction is parallel to the incident side face, and the light emitting means is further away from the incident side face. The areas are randomly arranged so as to gradually increase in density, and the area of the flat portion (41) is at least 10 times the total projected area of the optical path conversion slope and the steep slope with respect to the reference plane.

Example 1 A viewing-side surface of a reflective liquid crystal display panel of Reference Example 1 in which a viewing-side plastic plate having a thickness of 0.6 mm and a back-side plastic plate having a thickness of 0.2 mm were used. Reference Example 2
Was adhered by attaching an adhesive layer having a refractive index of 1.52 to the surface having no optical path control layer to obtain a reflective liquid crystal display device for both external light and illumination.

Comparative Example 1 The transparent sheet of Reference Example 2 was mounted on the viewing side surface of the reflective liquid crystal display panel of Reference Example 1 in which plastic plates of 0.4 mm in thickness were used for the viewing side and the back side plastic plates. An adhesive layer having a refractive index of 1.465 is attached to a surface having no layer, and adhered;
A reflective liquid crystal display device for both external light and illumination was obtained.

Example 2 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Example 1 except that the transparent sheet of Reference Example 3 was used.

Comparative Example 2 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Comparative Example 1 except that the transparent sheet of Reference Example 3 was used.

Example 3 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Example 1 except that the transparent sheet of Reference Example 4 was used.

Comparative Example 3 A reflective liquid crystal display device for both external light and illumination was obtained according to Comparative Example 1, except that the transparent sheet of Reference Example 4 was used.

Example 4 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Example 1 except that the transparent sheet of Reference Example 5 was used.

Comparative Example 4 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Comparative Example 1 except that the transparent sheet of Reference Example 5 was used.

Example 5 A reflective liquid crystal display device for both external light and illumination was obtained in the same manner as in Example 1 except that the transparent sheet of Reference Example 6 was used.

Comparative Example 5 A reflective liquid crystal display device of both external light and illumination type was obtained in the same manner as in Comparative Example 1 except that the transparent sheet of Reference Example 6 was used.

Evaluation Test 1 With respect to the reflection type liquid crystal display devices obtained in Examples and Comparative Examples, the cold cathode tubes were turned on in a dark room with no voltage applied to the liquid crystal cells, 5 mm from the incident side, the center, and the opposite end. The front luminance at a position of 5 mm was measured with a luminance meter (BM7, manufactured by Topcon Corporation).

The results are shown in the following table.

As can be seen from the above table, in the embodiment, bright display was achieved in the illumination mode. In particular, in the fourth embodiment, the density of the light emitting means was gradually increased from the light source side toward the facing surface. 5 shows that the brightness uniformity over the entire panel is also excellent. On the other hand, it can be seen that the luminance of the comparative example is inferior to that of the example under all conditions.

Evaluation Test 2 After fixing the reflective liquid crystal display devices obtained in Example 1 and Comparative Example 1 on a stainless steel plate, a 10 g iron ball was dropped from a predetermined height, and the presence or absence of panel cracks was visually observed. The sample was evaluated as ○ when it was not cracked, and as X when it was cracked. The results are shown in the following table. From this, it can be seen that in Example 1, the substrate was not damaged until the drop height exceeded 40 cm, but in Comparative Example 1, the substrate was damaged at a drop height of 20 cm. Fall height (cm) 10 20 30 40 50 Example 1 ○ ○ ○ ○ × Comparative example 1 ○ × × × ×

On the other hand, when the display state in the external light mode in which the light source was turned off in the example was observed, it was bright and excellent in display quality. As described above, according to the present invention, it is possible to emit light only by providing a lighting device on the side surface of the liquid crystal display panel while avoiding bulkiness and weight increase by using the conventional sidelight type light guide plate in the present invention. -It turns out that a reflection type liquid crystal display device for both lighting use can be formed.

[Brief description of the drawings]

FIG. 1 is an explanatory side view of an example of a reflection type liquid crystal display device for both external light and illumination.

FIG. 2 is an explanatory side view of an example of a light emitting unit.

FIG. 3 is an explanatory side view of another example of light emitting means.

FIG. 4 is an explanatory side view of still another example of light emitting means.

[Explanation of symbols]

100: liquid crystal display panel 10: back side cell substrate (11: support substrate 12: electrode also serving as light reflection means) 20: viewing side cell substrate (24: transparent substrate 21: transparent electrode) 30: liquid crystal layer 40: optical path control layer (A: light emitting means A1: optical path conversion slope) 50: lighting device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/35 G09F 9/35 (72) Inventor Kiyoji Umemoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Ryoji Kinoshita 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 2H091 FA14Y FA23X FA41Z FB02 FC17 FC29 FC30 FD07 FD12 FD13 FD18 FD23 LA11 LA16 5C094 AA15 AA31 BA43 CA19 ED01 ED11 ED14 JA08 JA09 5G435 AA14 AA18 BB12 BB15 BB16 CC09 EE23 EE27 GG03

Claims (9)

[Claims] A back-side cell substrate provided with at least an electrode on a supporting substrate; and a viewing-side cell substrate provided with at least a transparent electrode on a transparent substrate having a thickness greater than the supporting substrate in the cell substrate. A liquid crystal cell having a liquid crystal sandwiched between electrodes disposed opposite to each other is provided with light reflecting means on the back side of the liquid crystal layer, and reflects external light incident from the outer surface of the viewing side cell substrate on the light reflecting side. The display device further includes an illuminating device on one or more side surfaces of a reflective liquid crystal display panel in which display light reflected by the means and transmitted through the liquid crystal layer is emitted from a viewing side cell substrate to be viewed. The thickness having the light emitting means on the outer surface side of the cell substrate is 10
An optical path control layer having a thickness of about 300 μm, and an optical path changing slope for reflecting light incident from the side surface through the lighting device on the side of the rear-side cell substrate. A reflection type liquid crystal display device, wherein the slope has an inclination angle of 35 to 48 degrees with respect to a reference plane of the liquid crystal display panel. 2. The reflection type liquid crystal display device according to claim 1, wherein the thickness of the supporting substrate on the back side cell substrate is not more than ／ of the thickness of the transparent substrate on the viewing side cell substrate. 3. The transparent substrate of the viewing-side cell substrate according to claim 1, wherein the transparent substrate has a transparent layer having a lower refractive index than the transparent substrate.
A reflection type liquid crystal display device in which an illumination device is arranged on a side surface of a viewing side cell substrate. 4. The reflection type liquid crystal display device according to claim 1, wherein the liquid crystal display panel has a polarizing plate on one side or both sides of the liquid crystal cell. 5. The reflection type light source according to claim 1, wherein the light emitting means of the light path control layer comprises a prism-shaped recess, and the light path changing slope of the light emitting means faces the side surface on which the lighting device is arranged. Liquid crystal display. 6. The reflective liquid crystal display device according to claim 5, wherein the prism-shaped concave portion is substantially triangular based on a cross section with respect to the optical path conversion slope. 7. The prism-shaped recess according to claim 5, wherein the prism-shaped concave portion is formed of a continuous groove extending from one end to the other end of the optical path control layer, and the optical path conversion slope in the groove is parallel or inclined to the side surface on which the lighting device is arranged. Reflective liquid crystal display device in a state. 8. The prism according to claim 5, wherein the prism-shaped concave portion is formed of a minute groove having a substantially triangular cross section, and the substantially triangular shape is based on a cross section with respect to the optical path conversion slope, and the length of the long side of the optical path conversion slope is the minute groove. 5 times or more the depth, and the light emitting means discontinuously forms a plurality of the fine grooves on the surface of the optical path control layer;
And a reflection type liquid crystal display device which is irregularly distributed. 9. The visual path control layer according to claim 1, wherein the optical path control layer is made of a transparent sheet, and is provided on the outer surface side of the visual side cell substrate by an adhesive layer having a refractive index larger than that of the transparent substrate of the visual side cell substrate. Adhesive reflective liquid crystal display.