JPH11295713A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device greatly improved in an utilization factor of light, having a bright display screen and a backlight of a low power consumption. SOLUTION: A backlight 2 to be arranged under a liquid crystal display element has a light guide body 37, a fluorescent tube 36 arranged on the side face of the light guide body 37, a diffusion sheet 39 arranged between the liquid crystal display element and the light guide body 37, and a reflection sheet 38 arranged under the light guide body 37, and a hologram sheet 1 is arranged between the light guide body 37 and the diffusion sheet 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal display device,
A backlight that is disposed under the backlight and supplies light to the liquid crystal display element.
Alternatively, the present invention relates to a liquid crystal display device used for a display unit of a wall-mounted television or the like.

[0002]

2. Description of the Related Art For example, a liquid crystal display device (that is, a liquid crystal display module) is formed of two glasses or the like with a predetermined gap therebetween so that the surfaces on which a transparent electrode for display and an alignment film are laminated face each other. The transparent insulating substrates are overlapped with each other, and both substrates are bonded together by a sealing material provided in a frame shape (a square shape) on a peripheral portion between the two substrates, and a liquid crystal sealing opening provided in a part of the sealing material is attached. A liquid crystal display element (ie, a liquid crystal display panel, an LCD) comprising a liquid crystal sealed inside a sealing material between the two substrates and a polarizing plate provided outside the two substrates.
Liquid Crystal Display
splay)), a backlight disposed below the liquid crystal display element and emitting light to the liquid crystal display element by emitting surface light, a driving circuit board disposed outside the outer periphery of the liquid crystal display element, and a backlight. And a metal shield case or the like that stores the above members and has a display window opened.

[0003] The backlight is, for example, a light guide made of a synthetic resin plate such as a transparent acrylic plate for guiding light emitted from a light source to a direction away from the light source and uniformly irradiating the entire liquid crystal display element with light. A cold cathode fluorescent discharge tube as a linear light source disposed along at least one side surface of the light guide near the side surface, and covering the fluorescent discharge tube over substantially the entire length thereof;
A lamp reflection sheet having a substantially U-shaped cross section and an inner surface serving as a reflection surface, a diffusion sheet disposed on the light guide, and diffusing light from the light guide, and disposed on the diffusion sheet And a reflection sheet disposed below the light guide and reflecting light from the light guide toward the liquid crystal display element. The backlight in which the linear light source is arranged on the side surface of the light guide is called a so-called edge light system.

A so-called direct-type backlight in which a plurality of fluorescent discharge tubes are arranged in parallel below a liquid crystal display element via a diffusion plate or the like and a reflector is arranged below the fluorescent discharge tubes as a backlight. There is also.

[0005] Such a conventional liquid crystal display device is disclosed in, for example, Japanese Patent Publication No. 60-19474 and Japanese Utility Model Laid-Open Publication No. 4-22780.
No., published in Japanese Patent Application Publication No.

[0006]

A prism sheet for improving brightness, which is a component of a conventional edge light type backlight of a liquid crystal display device, is disposed between a diffusion sheet on a light guide and a liquid crystal display element. A large number of prisms having a smooth lower surface and a triangular prism on the upper surface are arranged in parallel, and light from the light guide is directed in the front direction (that is, in the direction perpendicular to the display surface of the liquid crystal display element) by the triangular prisms. As close as possible, the brightness in the front direction is secured. Incidentally, two prism sheets are usually arranged, and the prism sheets of each sheet are arranged so that the arrangement directions of the prisms are orthogonal to each other.

However, when the incident angle of the light incident on the prism sheet is large, the incident light does not go to the front direction,
Unnecessary light having a large angle with respect to the front direction is generated, and there is a problem that light use efficiency is reduced.

An object of the present invention is to provide a liquid crystal display device having a backlight with a bright display screen and low power consumption by greatly suppressing the generation of unnecessary light as described above, thereby greatly improving the light use efficiency. To provide.

[0009]

According to another aspect of the present invention, there is provided a liquid crystal display device comprising a liquid crystal display element and a backlight disposed thereunder. And between the backlight,
A hologram sheet is provided.

[0010] Further, a liquid crystal display element, a light guide disposed thereunder, a linear light source disposed on a side surface of the light guide, and a light disposed between the liquid crystal display element and the light guide. In a liquid crystal display device including a diffusion unit and a light reflection unit disposed below the light guide, a hologram sheet is disposed between the light guide and the light diffusion unit.

Further, an air layer is interposed between the light guide and the hologram sheet over the entire surface.

Further, a plurality of minute projections or particles are provided on the lower surface of the hologram sheet, and the air layer is interposed.

Further, on the upper surface of the hologram sheet,
The light diffusion means is provided integrally.

In the present invention, using a hologram sheet,
Since it refracts light and improves the brightness of the backlight,
Compared to the case where a conventional prism sheet is used, light having a deep angle can be bent in the front direction, and the light use efficiency can be improved.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, those having the same functions are denoted by the same reference numerals, and the repeated description thereof will be omitted.

Embodiment 1 FIG. 1 is a cross-sectional view of a backlight of a liquid crystal display device according to Embodiment 1 of the present invention (hatching indicating a cross section is omitted, and FIGS. 3 to 6 are the same).

2 is a backlight, 36 is a cold cathode fluorescent tube,
24 is a lamp reflection sheet, 39 is a diffusion sheet, 1 is a hologram sheet, 37 is a light guide plate, 3 is a light emission surface of the light guide plate 37, 4 is a bottom surface of the light guide plate 37, 5 is an air layer, 17 is a dot pattern, 38 Is a reflection sheet.

The backlight 2 includes a fluorescent tube 36, a lamp reflection sheet 24, a light guide plate 37, a diffusion sheet 39, a hologram sheet 1, a reflection sheet 38, and the like. The light guide plate 37 guides light emitted from the fluorescent tube 36, which is a linear light source, to a direction away from the fluorescent tube 36, and uniformly distributes the light over the entire liquid crystal display element (not shown here; see FIG. 7). Irradiate. The light guide plate 37 is a wedge-shaped plate made of a synthetic resin having high transparency, such as an acrylic resin, a polycarbonate resin, a styrene resin, a vinyl chloride resin, and a silicon resin. The fluorescent tube 36 is arranged near one side surface of the light guide plate 37 along the side surface. The lamp reflection sheet 24 covers the fluorescent tube 36 over substantially the entire length thereof,
The cross-sectional shape is substantially U-shaped, and the inner surface thereof is a reflection surface. The light emitted from the fluorescent tube 36 is reflected and made incident on the light guide plate 37. As the lamp reflection sheet 24, for example, a white foamed PET (polyethylene terephthalate) film, a mirror surface film formed by depositing or sputtering a highly reflective metal film of silver or aluminum on a transparent PET film, or the like is used. Also, a thin aluminum metal plate,
A brass plate formed with a metal film can also be used. The diffusion sheet 39 is disposed on the hologram sheet 1 and diffuses light from the hologram sheet 1. The diffusion sheet 39 is a coating material such as a film embossed so that the surface shape becomes uneven, a film in which fine beads are dispersed and fixed on a substrate, or a silicon gel or the like in which fine unevenness is formed after curing. Is used. The reflection sheet 38 is disposed below the light guide plate 37, and reflects light emitted from the lower surface of the light guide plate 37 toward the liquid crystal display element. Like the lamp reflection sheet 24, the reflection sheet 38 is a white foamed PET film, a mirror-finished film on which a metal film is formed, or the like. The light that has entered the light guide plate 37 from the fluorescent tube 36 guides the light while totally reflecting the inside of the light guide plate 37. However, the dot pattern 17 is required to emit light from the upper surface of the light guide plate 37. 37
Provided on the bottom surface of the light guide plate 37, for example, printed with white ink, or integrally formed on the bottom surface of the light guide plate 37 (may be a concave portion).
Are arranged regularly.

The hologram sheet 1 is arranged on the light exit surface 3 of the light guide plate 37 and is arranged below the diffusion sheet 39. The hologram sheet 1 has a transparent film such as PET as a base layer, on which a hologram layer is formed. As is generally known, the hologram layer forms a diffraction grating composed of irregularities at a fine constant period (several tens to several thousand lines / mm), and refracts and deflects light without depending on a shape effect. . The method for producing the hologram layer is as follows:
For example, a hologram recording material is placed at predetermined points, hologram recording is performed by emitting coherent laser light from two predetermined points, and development processing is performed. The hologram layer is
3 corresponding to several layers, for example RGB (red, green, blue)
Layers are formed. The thickness of one hologram layer is, for example, several μm to several hundred μm. The hologram sheet 1 has a function of bending the light emitted from the light emission surface 3 of the light guide plate 37 in the front direction to improve the brightness. The diffusion sheet 39 diffuses the light bent by the hologram sheet 1.

The light generated from the fluorescent tube 36 enters the light guide plate 37 directly or through reflection of the lamp reflection sheet 24. The light travels while repeating reflection in the light guide plate 37. At this time, when light strikes the dot pattern 17 provided on the bottom surface (lower surface) 4 of the light guide plate 37, a part of the light is scattered and reflected as shown by the arrow L, and from the upper surface 3 of the light guide plate 37. Is emitted. Light guide plate 37 without being emitted
The light remaining inside travels through the light guide plate 37 while being repeatedly reflected. The shape of the light guide plate 37 is
As described above, the side close to the fluorescent tube 36 is thick and the opposite side is thin wedge-shaped. For this reason, each time light is reflected in the light guide plate 37, the incident angle becomes gradually smaller, and finally the incident angle becomes smaller so as not to satisfy the condition of total reflection. At this time, part of the light is emitted from the light guide plate 37.
Therefore, the light emitted from the light guide plate 37 has its traveling direction changed by the dot pattern 17, and the light guide plate 3
7 can be said to be a combination of light emitted outside the light guide plate 37 and light emitted outside the light guide plate 37 by repeating reflection and deviating from the total reflection condition. The light emitted from the light guide plate 37 enters the hologram sheet 1 and the diffusion sheet 39,
Finally, an image is displayed through the liquid crystal display element.

FIG. 2 is a view for explaining the function of the hologram sheet 1 and is an enlarged view of the vicinity of the light exit surface 3 of the light guide plate 37.

The light indicated by the arrow L is light that has traveled in the light guide plate 37, and the incident angle θ ₁ when the light is next incident on the light exit surface 3 is an angle that does not satisfy the condition of total reflection. . For example, when the light guide plate 37 is formed of an acrylic resin, the refractive index n ₁ of the light guide plate 37 is about 1.49, and when the refractive index of air is 1.00, the total reflection angle θ ₀ is , About 4
2.155 degrees. Therefore, θ ₁ <θ ₀ (42.1
(55 degrees), the light is emitted outside the light guide plate 37.
Emission angle theta ₂ at this time is shown in the following formula.

Θ ₂ = sin ⁻¹ (n ₁ / n ₂ sin θ ₁ ) Therefore, when light is incident on the exit surface 3 at an incident angle θ ₁ = 30 degrees, the exit angle θ ₂ is about 48 degrees, Exit angle θ ₂
It is larger than the incident angle θ ₁ of. That is, the light guide plate 3
The light exiting 7 is bent in a direction along the exit surface 3. In particular, light emitted out of the total reflection condition has an emission angle of 80 degrees or more and is very close to the emission surface 3.
In order to irradiate the liquid crystal display element with this light sufficiently efficiently, the direction of the light must be bent in the front direction. In the present invention, the direction of light is bent by the hologram sheet 1. In the present embodiment, the hologram sheet 1 has a transmission hologram formed thereon. Considering light from the light guide plate 37 as reference light in the hologram, the hologram is a hologram that transmits through the hologram and forms an image on the liquid crystal display element side. Generally, a hologram has a characteristic of refracting light at a specific incident angle. By making the angle of incidence θ _in on the hologram sheet 1 coincide with the angle that is efficiently refracted by the hologram, light emitted obliquely from the exit surface 3 is bent in the front direction as shown in FIG. At this time, as another basic characteristic of the hologram, the refraction angle may vary depending on the wavelength of light. Due to this effect, the light transmitted through the hologram sheet 1 may exhibit a rainbow color whose color changes depending on the viewing angle of the viewer of the liquid crystal display device. This has a very bad effect on color display by the liquid crystal display element, and the display quality is degraded. This rainbow change is eliminated by the diffusion sheet 39 shown in FIG. That is, the light incident on the diffusion sheet 39 is scattered by the unevenness and beads on the diffusion sheet 39, and the angular distribution slightly different depending on the wavelength is mixed again to become white light. According to the present embodiment, light having a small angle emitted from the light exit surface 3 of the light guide plate 37 can be effectively made incident on the liquid crystal display element, and the light use efficiency is reduced as compared with the case where a conventional prism sheet is used. A liquid crystal display device having a high and bright screen can be realized.

FIG. 3 is an enlarged sectional view of a main part of the hologram sheet 1 shown in FIG.

The hologram sheet 1 disposed on the light guide plate 37 requires that the air layer 5 be interposed between the hologram sheet 1 and the light guide plate 37 (the reason will be described later in detail). If the light guide plate 37 and the hologram sheet 1 are partially or entirely adhered to each other, the light emission condition on the light emission surface 3 of the light guide plate 37 changes, resulting in partial non-uniformity. In the present embodiment, the hologram sheet 1 and the light guide plate 3
In order to prevent adhesion with the hologram sheet 7, the minute projections 6 are partially provided on the surface of the hologram sheet 1 on the light guide plate 37 side. The hologram sheet 1 is lifted up from the emission surface 3 of the light guide plate 37 by the convex portions 6, and the air layer 5 can be interposed between the light guide plate 37 and the hologram sheet 1. The height of the projection 6 is preferably about 1 μm to 30 μm. The density is determined by the thickness and the material of the hologram sheet 1, but is desirably about 10 to 10,000 / cm ² .

The reason why the hologram sheet is not adhered to the light exit surface of the light guide plate will be described below with reference to FIG.

Light incident on the light guide plate 37 is incident on the light incident portion at various angles. The light having the largest incident angle is light that is reflected by the lamp reflection sheet (reference numeral 24 in FIG. 1) and is incident on the light incident portion almost from the side. The incident angle at this time is a value close to 90 degrees. However, the light once entering the light guide plate 37 has a shape narrowed to a certain angle. For example, if there is light incident at an incident angle of 90 degrees, the refractive index is about 1.49 when the light guide plate 37 is made of, for example, an acrylic resin. The refraction angle is about 42.1 degrees. That is, even the light having the widest angle travels inside the light guide plate 37 as a bundle of light of at most 42.1 degrees. The incident light travels while being reflected by a surface of the light guide plate 37 other than the light incident portion. At this time, the incident angle with respect to a plane substantially orthogonal to the light incident portion is 47.9 degrees at minimum.
Since the total reflection angle of the acrylic resin (refractive index: 1.49) with respect to air is 42.1 degrees, light at this angle is
Unless there are other conditions, all will be reflected.

Snell's law: n ₁ × sin θ ₁ = n ₂ × sin θ ₂ n ₁ : Refractive index of medium 1 θ ₁ : Incident angle from medium 1 to interface n ₂ : Refractive index of medium 2 θ ₂ : Refraction angle when light incident on the interface from the medium 1 enters the medium 2 Above conditions: n ₁ = 1.49, θ ₁ = 47.9 degrees θ ₂ is obtained under the following conditions: n ₂ = 1.00. However, sin θ ₂ = 1.49 / 1.00 × sin 47.9 degrees =
1.105 is inconsistent. That is, the light is transmitted to the air side (the light guide plate 3).
No. 7).

The hologram layer is formed on the base film. Various resin films are used as the base film. For example, a case where the hologram layer adheres to a base film made of polycarbonate will be described. The refractive index of polycarbonate is 1.58.

When each condition is applied in the same manner as described above, θ ₂ is obtained under the following conditions: n ₁ = 1.49, θ ₁ = 47.9 degrees, and n ₂ = 1.58.

Sin θ ₂ = 1.49 / 1.58 × sin
47.9 degrees = 0.700, and light is emitted out of the light guide plate 37 at an angle of θ ₂ = 44.4 degrees.

That is, when the hologram sheet comes into close contact with the light guide plate, light leaks from that portion.
Therefore, it is necessary that the hologram sheet does not adhere to the light guide plate.

Second Embodiment FIG. 4 is an enlarged sectional view of a main part of a hologram sheet 10 according to a second embodiment of the present invention.

In the present embodiment, the hologram sheet 10
The minute particles 7 are dispersed and fixed to the surface of the hologram sheet 10 on the light guide plate 37 side in order to prevent the light guide plate 37 from adhering to the hologram sheet 10. Examples of the fine particles 7 include beads made of a synthetic resin such as a polyethylene resin, a polystyrene resin, a polycarbonate resin, a fluororesin, an acrylic resin, and the like, glass beads, and hollow particles such as hollow beads. Can be used. Particle 7
Is preferably a material having a refractive index close to the refractive index of the hologram sheet 10 on the light guide plate 37 side. The particles 7 are adhered to the surface of the hologram sheet 10 by an adhesive resin. The diameter of the particles 7 is about 1 μm to 30 μm, and the dispersion density thereof is about 10 to 10,000 / cm ² .

Third Embodiment FIG. 5 shows a hologram sheet 100 according to a third embodiment of the present invention.
3 is an enlarged sectional view of a main part of FIG.

In this embodiment, a hologram sheet has a function of a diffusion sheet. As described above, the hologram sheet 100 bends light in the front direction, but the angle of refraction slightly varies depending on the wavelength of the light. Therefore, under certain conditions, a so-called rainbow color may be generated. Iridescent colors have a particularly bad effect on color displays and must be eliminated. Therefore, the minute uneven surface 8 is formed on the surface of the hologram sheet 100 on the light emitting surface side. On the surface of the hologram sheet 100 on the side of the light guide plate 37, similarly to the first embodiment shown in FIG. 3, a minute convex portion 6 for preventing adhesion to the light guide plate 37 is formed. Note that, instead of the minute projections 6, minute particles 7 may be provided as in Embodiment 2 shown in FIG.

The light incident on the hologram sheet 100 is
The light is refracted by the hologram layer and is directed in the front direction. When the light is emitted, the light is slightly diffused by the uneven surface 8 to prevent the generation of iridescence due to the difference in the refraction angle depending on the wavelength.

Fourth Embodiment FIG. 6 shows a hologram sheet 100 according to a fourth embodiment of the present invention.
0 is an enlarged sectional view of a main part of FIG.

This embodiment is another embodiment different from the third embodiment in which the hologram sheet has the function of the diffusion sheet. In the present embodiment, instead of forming the fine uneven surface 8 of the third embodiment on the light emitting surface side of the hologram sheet 1000, fine particles 9 are formed.
The dispersing action is given by dispersing and bonding at high density so as to be in contact with each other. Examples of the fine particles 9 include beads made of a synthetic resin such as a polyethylene resin, a polystyrene resin, a polycarbonate resin, a fluorine resin, and an acrylic resin, glass beads, and highly transparent particles such as hollow beads. Can be used. The particles 9 are adhered to the surface of the hologram sheet 1000 by an adhesive resin.

As in the second embodiment shown in FIG. 4, fine particles 7 for preventing adhesion are dispersed and adhered to the surface of the hologram sheet 1000 on the light guide plate 37 side. The fine particles 7 for preventing adhesion are much lower in density than the fine particles 9 for diffusing light, and are independently dispersed.
Light diffusion is hardly produced.

The diameter of the particles 9 and 7 is preferably about 1 μm to 30 μm. Further, the material of the particles 7 for preventing adhesion is preferably a material having a refractive index close to the refractive index of the hologram sheet 1000 on the light guide plate 37 side, and the material of the particles 9 for light diffusion is preferably Light guide plate 3 of hologram sheet 1000
It is preferable that the refractive index is different from the refractive index on the 7 side.

Fifth Embodiment FIG. 7 is an exploded perspective view of a simple matrix type color liquid crystal display module 63 according to a fifth embodiment of the present invention.

63 is a liquid crystal display module (that is, a liquid crystal display device), 41 is a metal upper shield case, 18 is a display window, 19 is an insulating sheet, 20 is a silicon spacer,
35a and 35b are segment drive circuit boards, 35c is a common drive circuit board, 55a and 55b are drive ICs (segment drivers), 55c is a drive IC (common driver), and 34a, 34b and 34c are drive ICs 5 respectively.
TCP mounted with 5a, 55b, 55c, 62 is a liquid crystal display element, 2 is a backlight, 42 is a liquid crystal display element 62 with a drive circuit and a molded frame holding the backlight 2, 24 is a lamp reflection sheet, 36 Is a cold cathode fluorescent tube, 39 is a diffusion sheet, 1 is a hologram sheet similar to that shown in FIGS. 1, 3 or 4, 37 is a wedge-shaped light guide plate, and 380 is also a reflector of the backlight 2. Metal lower shield case.

The liquid crystal display module 63 is a TC mounted on a metal upper shield case 41, a liquid crystal display element 62, and the driving ICs 55a, 55b, and 55c.
P34a, 34b, 34c and drive circuit boards 35a, 35b, 35c on which a power supply circuit is mounted, mold frame 4
2, a backlight 2, a metal lower shield case 380, and the like.

FIG. 8 shows a simple matrix type liquid crystal display element 6.
2 is a perspective view of a main part of FIG.

In FIG. 8, in order to align the liquid crystal molecules in a twisted helical structure between the two upper and lower electrode substrates 11 and 12 sandwiching the liquid crystal layer 50, for example, a transparent upper glass substrate is used. A method of rubbing the surfaces of the alignment films 21 and 22 made of, for example, an organic polymer resin made of polyimide on the lower electrode substrates 11 and 12 in contact with the liquid crystal in one direction with a cloth, for example, is called a rubbing method. ing. The rubbing direction at this time, that is, the rubbing direction, the rubbing direction 66 in the upper electrode substrate 11, and the rubbing direction 67 in the lower electrode substrate 12 are the alignment directions of the liquid crystal molecules. A gap d is formed between the two upper and lower electrode substrates 11 and 12 thus oriented so that the rubbing directions 66 and 67 cross each other at substantially 180 to 360 degrees.
A notch (that is, a liquid crystal filling port) for injecting liquid crystal between the two electrode substrates 11 and 12 with ₁ facing each other.
When a nematic liquid crystal having a positive dielectric anisotropy and a predetermined amount of a rotatory substance is sealed in the gap between the electrode substrates, the liquid crystal molecules are bonded between the electrode substrates. A molecular arrangement of a helical structure with a twist angle θ inside. 31 and 32 are, for example, indium oxide (ITO: indium tin oxide).
Oxide)). A member that provides a birefringence effect above the upper electrode substrate 11 of the liquid crystal cell 60 thus configured (hereinafter, referred to as a birefringent member).
The upper and lower polarizing plates 15 and 16 are provided with the member 40 and the liquid crystal cell 60 interposed therebetween.

The twist angle θ of the liquid crystal molecules in the liquid crystal 50 can have a value in the range of 180 ° to 360 °, and is preferably 200 ° to 300 °. From the practical viewpoint of avoiding a phenomenon in which the lighting state becomes an orientation that scatters light and maintaining excellent time division characteristics, the range of 230 degrees to 270 degrees is more preferable. This condition basically acts to make the response of the liquid crystal molecules to the voltage more sensitive and to realize excellent time division characteristics. In order to obtain excellent display quality, the product Δn of the refractive index anisotropy Δn ₁ of the liquid crystal layer 50 and its thickness d ₁ is used.
₁ · d ₁ is preferably set in the range of 0.5 μm to 1.0 μm, more preferably in the range of 0.6 μm to 0.9 μm.

The birefringent member 40 functions to modulate the polarization state of the light transmitted through the liquid crystal cell 60, and converts the liquid crystal cell 60, which could only display in a colored state, into a monochrome display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To a range of 0.7 μm.

Further, since the liquid crystal display element 62 uses elliptically polarized light due to birefringence, the axes of the polarizing plates 15 and 16 and the optical axis thereof when a uniaxial transparent birefringent plate is used as the birefringent member 40. And the electrode substrate 11 of the liquid crystal cell 60,
The relationship between the twelve liquid crystal alignment directions 66 and 67 is extremely important.

However, as shown in FIG.
Red, green, blue color filters 33R, 33G, 33 on top
B. By providing the light shielding film 33D between the filters, multi-color display is possible.

In FIG. 9, each filter 33
On the R, 33G, 33B and the light shielding film 33D, a smooth layer 23 made of an insulator is formed to reduce the influence of these irregularities, and then an upper electrode 31 and an alignment film 21 are formed.

FIGS. 10 and 11 show a case where the liquid crystal display module 63 shown in FIG. 7 is used for a display section of a laptop personal computer.

FIG. 10 is a block diagram of the system, and FIG.
The result calculated by the microprocessor 49 is to drive the liquid crystal display module 63 by the driving semiconductor IC 34 via the control LSI 48.

Sixth Embodiment FIG. 12 is an exploded perspective view of an active matrix FCA (flip chip attachment) type color liquid crystal display module MDL according to a sixth embodiment of the present invention.

MDL is a liquid crystal display module, SHD is a shield case (also called a metal frame) made of a metal plate, WD is a display window, SPCs 1-4 are insulating spacers,
PC1 and PC2 are folded multilayer flexible circuit boards (FPC1 is a gate side circuit board, FPC2 is a drain side circuit board), PCB is an interface circuit board, AS
B is an assembled liquid crystal display device with a drive circuit board,
PNL is a liquid crystal display element (also referred to as a liquid crystal display panel) in which a driving IC is mounted on one of two superposed transparent insulating substrates; GC1 and GC2 are rubber cushions;
PS is a diffusion sheet, HGS is a hologram sheet similar to that shown in FIGS. 1, 3 or 4, GLB is a light guide plate, RFS is a reflection sheet, and MCA is a lower case (mold case) formed by integral molding. ), LP is a fluorescent tube, LPC is a lamp cable, LCT is a connector for an inverter, GB is a rubber bush that supports the fluorescent tube LP, and each member is stacked in a vertical arrangement as shown in the figure to display a liquid crystal. The display module MDL is assembled.

FIG. 13A shows a liquid crystal display module MDL at a portion corresponding to the section line AA 'in FIG.
(B) is a cross-sectional view of a main part of the liquid crystal display module MDL at a portion corresponding to a section line BB ′.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention. It is. For example, various materials can be applied to the hologram sheets 1, 10, 100, and 1000 as materials, layer configurations, manufacturing methods, and means for preventing adhesion to the light exit surface 3 of the light guide plate 37. Further, as shown in the third and fourth embodiments of FIGS. 5 and 6, a light diffusing means may be integrally provided on the upper surface of the hologram sheet. Further, the present invention provides a liquid crystal having a so-called direct-type backlight in which a plurality of fluorescent discharge tubes are arranged in parallel under a liquid crystal display element via a diffusion means and the like, and a reflection means is arranged below the fluorescent discharge tubes. In a display device, it is applicable by disposing a hologram sheet under the diffusion means, and the same effect can be obtained.
Further, as partially shown in the above embodiment, the present invention is applicable to a simple matrix type liquid crystal display device, a vertical electric field type or a horizontal electric field type active matrix type liquid crystal display device, or a driving device. It goes without saying that the present invention is also applicable to a liquid crystal display device of an FCA type in which an IC is directly mounted on a substrate of a liquid crystal display element, that is, a COG (chip-on-glass) type.

[0058]

As described above, according to the present invention,
Provided is a liquid crystal display device having a backlight that can be bent in a front direction to a light having a large angle, can improve light use efficiency, has a bright display screen, and has low power consumption in order to improve backlight luminance. Can be.

[Brief description of the drawings]

FIG. 1 is a configuration sectional view of a backlight 2 of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a function of a hologram sheet.

FIG. 3 is an enlarged sectional view of a main part of the hologram sheet 1 shown in FIG.

FIG. 4 is a hologram sheet 10 according to a second embodiment of the present invention.
3 is an enlarged sectional view of a main part of FIG.

FIG. 5 is a hologram sheet 10 according to a third embodiment of the present invention.
0 is an enlarged sectional view of a main part of FIG.

FIG. 6 is a hologram sheet 10 according to a fourth embodiment of the present invention.
It is a principal part expanded sectional view of 00.

FIG. 7 is an exploded schematic perspective view of a simple matrix type liquid crystal display module 63 according to Embodiment 5 of the present invention.

FIG. 8 is an exploded schematic perspective view of a simple matrix type liquid crystal display element 62.

FIG. 9 is a partially cutaway perspective view of an upper electrode substrate 11 of another simple matrix type color liquid crystal display element.

FIG. 10 is a block diagram of an example of a laptop personal computer incorporating the liquid crystal display module of FIG. 7;

11 is an external perspective view of an example of a laptop personal computer incorporating the liquid crystal display module of FIG. 7;

FIG. 12 is an exploded perspective view of an active matrix color liquid crystal display module MDL according to Embodiment 6 of the present invention.

13A is a cross-sectional view of a main part of the liquid crystal display module at a portion corresponding to a section line AA ′ in FIG. 12, FIG.
FIG. 3 is a cross-sectional view of a main part of the liquid crystal display module at a portion corresponding to a section line BB ′.

[Explanation of symbols]

1, 10, 100, 1000 ... hologram sheet, 2 ...
Backlight, 3 ... Light emitting surface of light guide plate, 4 ... Bottom surface of light guide plate, 17 ... Dot pattern, 24 ... Lamp reflection sheet,
36: Cold cathode fluorescent tube, 37: Light guide plate, 38: Reflection sheet, 39: Diffusion sheet, 5: Air layer, 6: Small protrusion for preventing adhesion, 7: Fine particles for preventing adhesion, 8: Fine for light diffusion Concavo-convex surface, 9: fine particles for light diffusion.

Claims (5)

[Claims] 1. A liquid crystal display device comprising a liquid crystal display element and a backlight disposed therebelow, wherein a hologram sheet is disposed between the liquid crystal display element and the backlight. Display device. 2. A liquid crystal display element, a light guide disposed thereunder, a linear light source disposed on a side surface of the light guide, and light disposed between the liquid crystal display element and the light guide. Spreading means;
A liquid crystal display device comprising: a light reflecting means disposed below the light guide; and a hologram sheet disposed between the light guide and the light diffusing means. 3. An air layer is provided on the entire surface between the light guide and the hologram sheet.
The liquid crystal display device as described in the above. 4. A liquid crystal display device according to claim 3, wherein a plurality of minute projections or particles are provided on the lower surface of said hologram sheet, and said air layer is interposed. 5. The liquid crystal display device according to claim 2, wherein said light diffusing means is provided integrally on an upper surface of said hologram sheet.