Liquid crystal display device

【0001】

[Technical field to which the invention belongs]

The present invention relates to a liquid crystal display device used as a display device.

【0002】

[Conventional technology]

Conventionally, display devices such as liquid crystal display devices have been used for display screens of mobile information terminals and mobile phones.

【0003】

For example, in the case of an STN type liquid crystal display device, such a liquid crystal display device is made of a rectangular acrylic resin light guide plate 104 and an acrylic resin arranged along one side of the light guide plate 104, as shown in FIG. The liquid crystal layer 108 comprises a light guide rod 105, a planar illumination unit I having a pair of light sources 106 arranged at both ends in the longitudinal direction of the light guide rod 105, and a pair of transparent glass substrates 107 having a rectangular shape. A liquid crystal display panel portion II in which a retardation plate 111 and a polarizing plate 112 are attached to the outer main surface of the transparent substrate 107 with a double-sided tape 113, and a light guide plate of the planar illumination portion I. It is composed of 104 and an adhesive layer 101 for adhering the polarizing plate 112 of the liquid crystal display panel portion II.

【0004】

As described above, such a liquid crystal display device diffuses the light emitted from one main surface of the light guide plate 104 of the planar illumination unit I by the light diffusing particles 103 in the adhesive layer 101, and the diffused light. A voltage is selectively applied to the liquid crystal layer 108 while being incidentally incident on the liquid crystal layer 108 via the polarizing plate 112 and the retardation plate 111, and the molecular arrangement in the liquid crystal layer 108 is changed for each pixel region by the applied voltage. The image is displayed by controlling the ratio of light passing through the liquid crystal layer 108.

【0005】

Then, the adhesive layer 101 causes the light emitted from one main surface of the light guide plate 104 of the planar illumination unit I to enter the liquid crystal display panel II without waste, so that the light guide plate 104 of the planar illumination unit I Light that adheres to the polarizing plate 112 of the liquid crystal display panel II and is composed of an acrylic transparent resin material 102 and a silicone resin, glass, or the like uniformly dispersed in the transparent resin material 102. By making the refractive index different from that of the diffusible particles 103, it functions to diffuse the light incident on the adhesive layer 101.

【0006】

[Patent Document 1]

Japanese Unexamined Patent Publication No. 2000-111908 [0007]

[Problems to be Solved by the Invention]

However, in the conventional liquid crystal display device as described above, the light diffusing particles 103 in the adhesive layer 101 interposed between the polarizing plate 112 and the light guide plate 104 are dispersed in the entire adhesive layer 101. , The presence of the light diffusing particles 103 existing near the interface with the polarizing plate 112 has a great influence, and the interface between the adhesive layer 101 and the polarizing plate 112 is uneven.

【0008】

As a result, the light diffusing particles 103 formed an air layer at the interface of the polarizing plate 112, blocked the diffusion of light from the outside, and caused uneven brightness in the displayed image.

【0009】

Further, since the flatness of the polarizing plate 112 is impaired, a part of the light from the outside does not enter the polarizing plate 112 at a desired angle, and the light utilization efficiency is lowered. Therefore, the brightness and visibility of the liquid crystal display device are reduced. , Induced problems such as deterioration of display definition.

【0010】

The present invention has been devised in view of the above drawbacks, and an object thereof is to effectively prevent the light diffusing particles 103 from protruding from the interface of the adhesive layer 101, and to make the display image of the display device clear. The purpose is to provide a liquid crystal display device.

【0011】

[Means for solving problems]

The liquid crystal display device of the present invention is a liquid crystal display in which a pair of transparent substrates are opposed to each other via a liquid crystal layer, and a polarizing plate and a light guide plate are arranged on the outside of one of the transparent substrates of the pair of transparent substrates. In the device, an adhesive layer containing light-diffusing particles is interposed inside the transparent resin material between the light guide plate and the polarizing plate, and the light-diffusing particles in the adhesive layer are adhered to the light guide plate. It is characterized in that it is set to be small in the region near the interface and the region near the bonding interface of the polarizing plate.

【0012】

Further, in the liquid crystal display device of the present invention, the average distribution density of the light diffusing particles is 0 to 2 × 10 in the region near the adhesive interface.⁵Pieces / cm³It is characterized by being set in the range of.

【0013】

Further, in the liquid crystal display device of the present invention, the adhesive layer is arranged between the first adhesive layer in contact with the light guide plate, the third adhesive layer in contact with the polarizing plate, the first adhesive layer and the third adhesive layer. It is composed of a second adhesive layer to be formed, and is characterized in that the content of light diffusing particles contained in the first adhesive layer and the third adhesive layer is set to be lower than that of the second adhesive layer. Is.

【0014】

Furthermore, the liquid crystal display device of the present invention is characterized in that the average particle size of the light diffusing particles is 0.1 μm to 20 μm.

【0015】

Furthermore, the liquid crystal display device of the present invention has a refractive index (n) of the transparent resin material constituting the adhesive layer.₁) With respect to the refractive index (n) of the light diffusing particles.₂) Percentage (n)₂/ n₁) Is set to be in the range of 0.6 to 0.99 or 1.01 to 1.60.

【0016】

Furthermore, in the liquid crystal display device of the present invention, the light diffusing particles of the adhesive layer have a linear expansion coefficient of 1.0 × 10.^-4It is characterized by having a viscosity of / ° C (in the range of 20 ° C to 150 ° C) or more and a viscosity of the transparent resin material of 6760 CP (centipoise) (20 ° C) or less.

【0017】

According to the liquid crystal display device of the present invention, an adhesive layer containing light-diffusing particles is interposed inside the transparent resin material between the light guide plate and the polarizing plate, and the light-diffusing particles in the adhesive layer are interposed. Since it was set to be small in the region near the adhesive interface of the light guide plate and the region near the adhesive interface of the polarizing plate, the light diffusing particles in the adhesive layer interposed between the light guide plate and the polarizing plate are the interface of the adhesive layer. Since the unevenness of the light can be effectively prevented, the interface between the polarizing plate and the adhesive layer is in close contact with each other, so that light can be diffused well and light of uniform brightness can be supplied to the liquid crystal display panel.

【0018】

Further, since the flatness of the polarizing plate is improved, the light from the outside (the planar illumination unit I and the light from the outside) is incident on the polarizing plate at a desired angle, and the liquid crystal display is performed without deteriorating the light utilization efficiency. The brightness, visibility, and display definition of the device can be improved.

【0019】

Therefore, a liquid crystal display device capable of making the display screen of the display device clear can be obtained.

【0020】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.

【0021】

FIG. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention. Roughly speaking, a planar illumination unit I having a light guide plate 4 and a retardation plate 11 on the outer main surface of the transparent substrate 7 It is composed of a liquid crystal display panel portion II having a structure in which polarizing plates 12 are arranged respectively, and both of these are an adhesive layer 1 between the light guide plate 4 of the planar illumination unit I and the polarizing plate 12 of the liquid crystal display panel portion II. Is bonded by.

【0022】

Then, as shown in FIG. 2, the liquid crystal display panel portion I has a rectangular light guide plate 4, a light guide rod 5 arranged along one side of the light guide plate 4, and a longitudinal direction of the light guide rod 5. It is composed of a pair of light sources 6 arranged at both ends of the.

【0023】

The light guide plate 4 of the planar illumination unit I is formed in a rectangular shape by a thermoplastic transparent resin material such as acrylic resin, polycarbonate resin, norbornene resin, vinyl chloride resin, or transparent glass, and is formed in a rectangular shape on the lower surface of the light guide plate 4. A large number of grooves 4a are provided on (the other main surface).

【0024】

The light guide plate 4 has a function of reflecting the light incident from the light guide rod 5 to the one main surface side by a large number of grooves 4a provided on the other main surface, and emitting the reflected light from the one main surface.

【0025】

Further, a large number of grooves 4a provided on the other main surface of the light guide plate 4 are arranged so as to be substantially parallel to the one side of the light guide plate 4 on which the light guide rod 5 is arranged, and each of them has a triangular cross section. However, the depth is set to 1 μm to 70 μm, and the opening width is set to 1 μm to 70 μm, respectively.

【0026】

The formation density of the large number of grooves 4a gradually increases as the distance from the one side of the light guide plate 4 increases (near the one side: 1 line / mm to 2 lines / mm, near the opposite side of the one side: 9 lines). / mm ~ 10 lines / mm) is formed, so that a large amount of light is reflected in the vicinity of the opposite side of the light guide plate 4 in which the amount of light passing through is small, and the amount of light emitted from the light guide plate 4 is spread over the entire light guide plate 4. It is made to be substantially uniform over the entire surface.

【0027】

Further, the light guide rods 5 arranged along one side of the light guide plate 4 are formed in a rectangular parallelepiped shape, and the end faces thereof and the end faces of the light guide plate 4 are arranged in close proximity to each other. Then, the light incident from the light source 6 is reflected by a large number of grooves 5a provided on the end face opposite to the end face facing the light guide plate 4, and the reflected light is emitted from the end face facing the light guide plate 4. For example, when an acrylic resin is used, it is produced by injecting a liquid acrylic resin into a mold having a predetermined shape and molding the resin.

【0028】

Further, each of the numerous grooves 5a provided on the end face of the light guide rod 5 has a triangular cross section, and the depth thereof is set to 1 μm to 70 μm and the opening width is set to 1 μm to 70 μm, respectively.

【0029】

The formation density of the large number of grooves 4a is gradually increased from the vicinity of the light source 6 arranged at both ends of the light guide rod 5 to the vicinity of the center in the longitudinal direction (near the light source: 1 line / mm to 2 lines / mm, said. Near the center of the longitudinal direction: 9 lines / mm to 10 lines / mm), which reflects a large amount of light near the center of the longitudinal direction of the light guide rod 5 with a small amount of light passing through, and emits light from the light guide rod 5. The amount of light to be made is made to be substantially uniform over the entire area of the light guide rod 5.

【0030】

As the light source 6 arranged at both ends of the light guide rod 5, for example, an LED having a structure in which an n-type semiconductor layer and a p-type semiconductor layer are laminated is preferably used, and a voltage is applied through an electrode (not shown). Then, light is emitted from the vicinity of the pn junction, and the light is emitted into the light guide rod 5.

【0031】

On the other hand, the liquid crystal display panel unit II, which is arranged so as to face each other via the planar illumination unit I and the adhesive layer 1, has a pair of transparent substrates 7 arranged so as to face each other with a predetermined gap between them, and both substrates 7. It has a structure in which a liquid crystal layer 8 is filled in a gap, and a retardation plate 11 and a polarizing plate 12 are arranged on the outer main surfaces of both substrates, respectively. That is, the adhesive layer 1 is interposed between the light guide plate 4 of the planar illumination unit I and the light guide plate 12 of the liquid crystal display panel unit II.

【0032】

The pair of transparent substrates 7 are formed with a transparent electrical insulating material such as alkaline glass such as soda-lime glass and non-alkali glass such as borosilicate glass to a thickness of 300 μm to 1200 μm, and stripes are formed on one main surface thereof. A transparent electrode 10 and an alignment film 9 are provided.

【0033】

Such a pair of transparent substrates 7 are arranged so that their main surfaces face each other so that the transparent electrodes 10 are substantially orthogonal to each other in a plan view, and a matrix-like pixel region is formed in the facing regions of the transparent electrodes 10. Consists of.

【0034】

These pair of transparent substrates 7 support the transparent electrode 10, the alignment film 9, the retardation plate 11 on the other main surface, the polarizing plate 12, and the like, and fill the gap between the two substrates with the liquid crystal layer 8. A predetermined gap is secured.

【0035】

The transparent substrate 7 is produced by, for example, surface-polishing a base glass produced by a conventionally known float method, redraw method, or the like to bring the arithmetic average roughness Ra to 50 nm or less, and then cleaning the substrate glass. Will be done.

【0036】

Further, the transparent electrode 10 is formed of a transparent conductive material such as ITO (Indium Tin Oxide), and by supplying electric power from an external power source, the transparent electrodes 10 of both substrates are individually opposed to each other. It functions to selectively apply voltage to the pixel area.

【0037】

In such a transparent electrode 10, the above-mentioned conductive material is adhered to one main surface of the transparent substrate 7 by a conventionally known sputtering method, a vapor deposition method, or a CVD (Chemical Vapor Deposition) method, and this is conventionally known as a photo. It is formed by patterning in a stripe shape by adopting a lithography technique and an etching technique.

【0038】

Further, a pair of alignment films 9 are provided on one main surface of the pair of transparent substrates 7 so as to cover the transparent electrodes 10, and a liquid crystal layer 8 is interposed between the pair of alignment films 9.

【0039】

Each of the pair of alignment films 9 is made of a polyimide resin having a thickness of 0.03 μm to 0.1 μm, and grooves are formed on the surface thereof along a certain direction, and the directions of the grooves are appropriate angles between the pair of alignment films 9. (For example, 90 degrees to 270 degrees) are set differently.

【0040】

The alignment film 9 is produced by, for example, rubbing the surface of a film made of polyimide resin with a cloth or the like along a certain direction to form a groove.

【0041】

The liquid crystal layer 8 interposed between the pair of transparent substrates 7 can be used as a base material such as phenylcyclohexane (PCH) -based, ester-based, biphenyl-based, or dioxane-based, for example, P-ester-based or P-biphenyl-based (. A nematic liquid crystal material in which an ester system (for viscosity adjustment), a tricyclic system, a tetracyclic system (for temperature characteristic adjustment), etc. are appropriately blended is used. Since such a liquid crystal material has a property of arranging along the grooves on the surface of the alignment film 9, the liquid crystal layer 8 interposed between the alignment films 9 has a structure in which liquid crystal molecules are spirally twisted.

【0042】

On the other hand, the retardation plate 11 attached to the other main surface side of each transparent substrate 7 by a double-sided tape 13 or the like converts the light incident as linearly polarized light into circularly polarized light and transmits it to the liquid crystal layer 8. At the same time, the circularly polarized light is converted into linearly polarized light again and the linearly polarized light is transmitted through the polarizing plate 12, thereby fulfilling the function of increasing the brightness of the liquid crystal display panel portion II.

【0043】

As the retardation plate 11, a film having a thickness of 40 μm to 100 μm made of a material such as polycarbonate or amorphous poreolefin is preferably used.

【0044】

Further, the polarizing plate 12 provided on the outer side of the above-mentioned retardation plate 11 is, for example, a triacetyl cellulose (TAC) film (thickness 70 μm to 90 μm), an iodine alignment film, a polyvinyl alcohol (PVA) film (thickness 15 μm to 25 μm), and the like. A TAC film (thickness 70 μm to 90 μm) and a polycarbonate (PC) film (thickness 80 μm to 100 μm) are sequentially laminated, and only the polarization component (linearly polarized light) in a certain direction is used from the light incident from the outside. It has a function to make it transparent.

【0045】

An adhesive layer 1 is interposed between the light guide plate 4 of the planar illumination unit I and the polarizing plate 12 of the liquid crystal display panel II, and these are fixed and transmitted by the adhesive layer 1. The light is diffused moderately.

【0046】

The adhesive layer 1 is composed of transparent resin material 2 containing light diffusing particles 3, and the light diffusing particles 3 are used as a region near the adhesive interface of the light guide plate 4 or a region near the adhesive interface of the polarizing plate 12. The light diffusing particles 3 are set to be less in the region near the two-adhesion interface than in the region sandwiched between the two-adhesion interface.

【0047】

With such a configuration, the light diffusing particles 3 in the adhesive layer 1 interposed between the light guide plate 4 and the polarizing plate 12 are the interface between the adhesive layer 1 and the light guide plate 4 or the polarizing plate 12. Will not be uneven. Therefore, the adhesion of the interface between the light guide plate 4 and the polarizing plate 12 is improved, and therefore, it is possible to prevent a large amount of bubbles that block the diffusion of light from being mixed in, and it is possible to display an image with substantially uniform brightness. , Adhesive strength is improved.

【0048】

Further, since the adhesive interface in the adhesive layer 1 interposed between the light guide plate 4 and the polarizing plate 12 is flattened, the surface of the polarizing plate 12 also becomes flat, and the polarizing plate 12 is omitted from the transparent substrate 7. It can be formed in parallel, and the light passing through the polarizing plate 12 is emitted at a desired angle to prevent a decrease in light utilization efficiency, and as a result, the brightness, visibility, and display definition of the liquid crystal display device are improved. It becomes possible to do it.

【0049】

In order to form such an adhesive layer 1, first, a transparent resin material 2 containing no light diffusing particles 3 is applied to one main surface of the light guide plate 4 and semi-cured between the light guide plate 4 and the polarizing plate 12. After forming the coating film 1y, the transparent resin material 2 containing the light diffusing particles 3 is applied and semi-cured in the same manner to form the coating film 1x, which further contains the light diffusing particles 3. A coating film 1y is formed by applying a transparent resin material 2 which is not present, and after the polarizing plate 12 is adhered, the coating films 1x and 1y are cured.

【0050】

By making the structure of the adhesive layer 1 multi-layered in this way, the light diffusible particles 3 such as titania and zirconia having a higher specific gravity than the transparent resin material 2 are used in the transparent resin material 2. Even when the particles 3 settle, it is possible to prevent the light diffusing particles 3 from protruding from the adhesive layer 1.

【0051】

As the transparent resin material 2 constituting the adhesive layer 1, for example, an acrylic resin, a polyester resin, an epoxy resin, a polyurethane resin, a polyolefin resin or the like containing a monomer or an oligomer that is cured by ultraviolet rays is preferable. Used.

【0052】

Further, the light diffusing particles 3 contained in the transparent resin material 2 are made of a material having a refractive index different from that of the transparent resin material 2, and specifically, an inorganic type such as silica, alumina, titania, zirconia, or calcium carbonate. Particles or organic particles such as acrylic resin and polycarbonate resin are preferably used.

【0053】

The average distribution density of the light diffusing particles 3 is 0 to 2 × 10 in the region near the adhesive interface.⁵Pieces / cm³, 3x10 in other areas⁶Pieces / cm³~8×10¹⁴Pieces / cm³It is set in the range of.

【0054】

The light diffusing particles 3 contained in the region near the adhesive interface are 2 × 10.⁵Pieces / cm³If it is more than that, the flatness of the adhesive interface of the adhesive layer 1 is impaired, air bubbles are mixed in the adhesive interface, sufficient diffusion of light from the outside cannot be obtained, and there is a possibility that brightness unevenness may occur in the displayed image.

【0055】

In addition, the light diffusing particles 3 contained in other regions are 3 × 10.⁶Pieces / cm³If it is less than that, sufficient light diffusion cannot be obtained, and 8 × 10¹⁴Pieces / cm³If it is more than this, the amount of light diffused by the light diffusing particles 3 is too large, which may cause a problem that the brightness of the light incident on the polarizing plate 12 is lowered.

【0056】

The average particle size of the light diffusing particles 3 is preferably 0.1 μm to 20 μm, optimally 1 μm to 10 μm, and when the average particle size is smaller than 0.1 μm, it is diffused by the light diffusing particles 3. If the amount of light tends to be insufficient and the average particle size is larger than 20 μm, the amount of light diffused by the light diffusing particles 3 is too large, and the brightness of the light incident on the polarizing plate 12 is lowered. May occur.

【0057】

Further, the refractive index (n) of the transparent resin material 2 constituting the adhesive layer 1₁) With respect to the refractive index (n) of the light diffusing particles 3.₂) Percentage (n)₂/ n₁) Is preferably set in the range of 0.6 to 0.99 or 1.01 to 1.6, and when the refractive index ratio is larger than 0.99 or smaller than 1.01, the amount of diffused light tends to be insufficient. When the refractive index ratio is 0.6 or less or 1.60 or more, the amount of light diffused by the light diffusing particles 3 is too large, and the brightness of the light incident on the polarizing plate 12 is lowered.

【0058】

For example, the refractive index of the acrylic resin used as the material of the transparent resin 2 is 1.49, the refractive index of the silica used for the photodiffusive particles 3 is 1.46, and the refractive index ratio is about 1.02. If there is, there is no problem.

【0059】

Furthermore, the adhesive layer 1 has a coefficient of linear expansion of 1.0 × 10.^-4When light diffusing particles 3 exceeding / ° C (20 ° C to 150 ° C) are used, the viscosity of the transparent resin material 2 constituting the adhesive layer 1 is 6760 CP (centipoise) (25 ° C) or less. It is preferable to set it.

【0060】

[Experimental example]

The following experiment was performed to confirm the above results. In this experiment, the adhesive layer 1 has a three-layer structure, and the viscosity of the transparent resin material 2 constituting each of these layers is changed little by little to prepare a plurality of liquid crystal display device samples, and each sample is exposed to a temperature of 80 ° C. The image quality of the liquid crystal display panel II is measured in this state.

【0061】

The materials of each component and the content of light diffusing particles are shown below.

【0062】

Transparent resin material (same material for all three layers): Bisphenol-based epoxy resin Photodiffusive particles: Acrylic resin Polarizing plate: Triacetyl cellulose Light guide plate: Acrylic resin Content of photodiffusible particles The upper and lower layers of the three-layer structure: 0 × 10⁵Pieces / cm³Photodiffusive particles in the center: 2 × 10⁵Pieces / cm³The above results are shown in Table 1.

【0063】

[table 1]<img file="JP2005024924A_D0001.tif" /> 【0064】

According to the results of this experiment, it can be seen that when the viscosity of the transparent resin material is 7020 CP (centipoise) or more, the brightness unevenness occurs in the liquid crystal display panel.

【0065】

On the other hand, when the viscosity of the transparent resin material is 6760 CP (centipoise) or less, the brightness unevenness does not occur in the liquid crystal display panel, and better image quality of the liquid crystal display panel is obtained.

【0066】

As described above, it is preferable to set the viscosity of the transparent resin material 2 to 6760 CP (centipoise) (25 ° C) or less, which means that even if the light diffusing particles 3 expand due to heat, the vicinity of the light diffusing particles 3 The transparent resin material 2 constituting the adhesive layer 1 of the above can escape to the surroundings by the body integral increased by the thermal expansion of the light diffusing particles 3 and absorb the expansion, and can be combined with the light guide plate 4 and the polarizing plate 12. This is considered to be because the light guide plate 4 and the polarizing plate 12 are not concavely deformed at the bonding interface.

【0067】

As a result, the flatness of the interface between the adhesive layer 1 and the light guide plate 4 and the polarizing plate 12 is improved, and the light guide plate 4 and the polarizing plate 12 can be formed substantially parallel to the transparent substrate 7, and the light guide plate can be formed substantially parallel to the transparent substrate 7. 4. By emitting light that passes through the polarizing plate 12 at a desired angle, it is possible to prevent a decrease in light utilization efficiency, and as a result, it is possible to improve the brightness, visibility, and display definition of the liquid crystal display device. Become.

【0068】

For such a transparent resin material 2, for example, when 70% by weight of a bisphenol-based epoxy resin is used, 25% by weight of a functional epoxy resin and 5% by weight of a silane coupling agent are added and mixed thereto, and 2, A transparent resin material having a desired viscosity is prepared by appropriately adding and mixing a curing agent containing 4,6-trioxo-I, 3,5-triyltriethyl-tris as a main component.

【0069】

Thus, in the liquid crystal display device described above, the light emitted from one main surface of the light guide plate 4 of the planar illumination unit I is diffused by the light diffusing particles 3 in the adhesive layer 1, and the diffused light is diffused by the polarizing plate 2. A voltage is selectively applied to the liquid crystal layer 8 while being incident on the liquid crystal layer 8 through the retardation plate 1, and the molecular arrangement in the liquid crystal layer 8 is changed for each pixel region by the applied voltage. Image display is performed by controlling the ratio of light passing through the liquid crystal layer 8.

【0070】

The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

【0071】

For example, in the embodiment shown in FIG. 1 described above, the case where the light guide plate 4 and the polarizing plate 12 used in the transflective liquid crystal display device are bonded by the adhesive layer 1 containing the light diffusing particles 3 has been described. The same applies to the case where a light guide plate, a polarizing plate, a reflecting plate and the like used in a transmissive type and a reflective type liquid crystal display device are adhered.

【0072】

Further, in the above-described embodiment, the transparent resin material 2 constituting the adhesive layer 1 is an ultraviolet curable type, but instead of this, a heat-sensitive curable type, a pressure-sensitive curable type, and a solvent-volatile type resin are also used. Can be used.

【0073】

[Effect of the invention]

According to the liquid crystal display device of the present invention, a pair of transparent substrates are opposed to each other via a liquid crystal layer, and a polarizing plate and a light guide plate are arranged outside one of the transparent substrates. In a liquid crystal display device, an adhesive layer containing light diffusing particles is interposed between the light guide plate and the polarizing plate, and the light diffusing particles in the adhesive layer are placed in the light guide plate. Since the light diffusing particles in the bonding layer interposed between the light guide plate and the polarizing plate are set to be small in the region near the bonding interface and the region near the bonding interface of the polarizing plate, the light diffusing particles in the bonding layer are prevented from protruding from the bonding layer. It can be reduced, and by bringing the interface with the polarizing plate into close contact, the light from the outside can be well diffused, and the light of uniform brightness can be supplied to the display image.

【0074】

In addition, since the flatness of the polarizing plate is improved, light from the outside is incident on the polarizing plate at a desired angle, and the brightness, visibility, and display definition of the liquid crystal display device are improved without reducing the light utilization efficiency. Can be done.

【0075】

Therefore, a liquid crystal display device capable of making the display screen of the display device clear can be obtained.

[Simple explanation of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a plan view of the planar illumination unit I of the present invention.

FIG. 3 is a cross-sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

I Planar illumination part II Liquid crystal display panel part 1 Adhesive layer 1x Coating film containing light diffusing particles 1y Coating film not containing light diffusing particles 2 Transparent resin material 3 Light diffusive particles 4 Light guide plate 4a Light guide plate groove 5 Light guide rod 5a Light guide rod groove 6 Light source 7 Transparent substrate 8 Liquid crystal layer 9 Alignment film 10 Transparent electrode 11 Phase difference plate 12 Polarizing plate 13 Double-sided tape