JPH09160024A - Back light and liquid crystal display device using the back light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device having high front luminance and a wide visual angle and capable of reducing a change in contrast by an observing angle and a change in a color tone due to the inversion of luminance in an intermediate color, enlarging picture size and being used for various purposes such as observation by plural persons. SOLUTION: The device is constituted of a light source 4, a light guide plate 2 having at least one incident face and one outgoing face opposed to the light source 4, a prism sheet 5 arranged on the light guide plate 2, and a liquid crystal display element 6 arranged on the light guide plate 2. In this case, many lens strings 3 having 45 to 90 deg. from the incident face are formed in parallel on at least one of the outgoing face of the light guide plate 2 and its rear face and the average inclination angle of the lens strings 3 is set up to >=30 deg..

Description

Detailed Description of the Invention

[0001]

The present invention relates to a notebook computer,
The present invention relates to a liquid crystal display device used in a portable liquid crystal TV or the like, and more specifically, a backlight having a narrow distribution angle of emitted light rays and having excellent directivity for emitting light in a normal direction of an emission surface of peak light, Further, the present invention relates to a liquid crystal display device having excellent directivity, a wide viewing angle, a good contrast and no luminance inversion of intermediate colors.

[0002]

2. Description of the Related Art In recent years, color liquid crystal display devices have been widely used in various fields as a portable notebook personal computer, a portable liquid crystal TV using a color liquid crystal panel, a video integrated liquid crystal TV, and the like. In addition, with the increase in information processing volume, diversification of needs, multimedia support, etc.,
Larger screens and higher definition of liquid crystal display devices are being actively pursued. The liquid crystal display device basically includes a backlight unit and a liquid crystal display element unit. As the backlight part, there are a direct type in which a light source is provided directly below the liquid crystal display element and an edge light type in which a light source is provided on the side surface of the light guide body.The edge light type has been widely used due to the compactness of the liquid crystal display device. There is. The edge light system is a backlight system in which a light source is arranged on the side surface of a plate-shaped light guide so that the entire surface of the light guide is illuminated.

The liquid crystal display element portion is roughly classified into a thin film transistor driven thin film transistor type (TFT) and a spar twisted nematic type (STN) according to its driving method. In the TFT type liquid crystal display element, a liquid crystal is twisted by 90 ° and sealed between a TFT substrate on which a thin film transistor is formed and which functions as an electrical switch and a color filter substrate which is provided with a color filter and plays a role of coloring. It has a different structure. Further, a polarizing plate is placed in front of and behind the substrate, and when the light polarized by the polarizing plate enters the liquid crystal layer, the light is reflected along the liquid crystal molecules by 9
It is rotated by 0 ° and the axis of the polarizing plate on the output side is rotated by 90 ° so that light is transmitted and emitted. On the other hand, when the switch of the TFT substrate is turned on, the liquid crystal molecules rise, the light incident on the liquid crystal layer cannot rotate, and cannot pass through the polarizing plate on the emission side. In this way, image information corresponding to the switch state of the TFT substrate is displayed. It is said that such a TFT type liquid crystal display device is capable of high-speed switching and is suitable for displaying halftone colors corresponding to full color.

[0004]

However, in such a liquid crystal display device, the image quality greatly changes depending on the viewing angle, and, for example, the contrast and brightness change depending on the viewing angle of the screen, or the halftone color. However, there is a problem that a normal image cannot be obtained due to the inversion of the luminous intensity and the change in color tone. This is because in the TFT type liquid crystal display element, the liquid crystal molecules are not completely raised in the display of a halftone color, and the light seen in the tilted direction of the liquid crystal molecules passes through the liquid crystal molecules at an angle close to vertical. This is because the probability that the light will be rotated increases, and the amount of light that passes through the polarizing plate will increase, resulting in a whitish display. Further, when viewed from the direction in which the liquid crystal molecules are not tilted, the light passing through the liquid crystal layer is less affected by the liquid crystal molecules, and the light does not rotate, resulting in a dark display. Such a problem has become more serious due to the demand for a larger screen size of the liquid crystal display device and the observation by a plurality of people due to the expansion of applications.

Therefore, according to the present invention, the distribution angle of the emitted light is narrow and the emission surface of the peak light (the light having the highest luminous intensity in the luminous intensity distribution of the emitted light) is used without using a component such as a prism sheet. It provides a backlight with excellent directivity that emits in the direction of the normal line, and with excellent directivity that can maximize the luminous intensity in the front, as well as a wide viewing angle, good contrast, and brightness in intermediate colors. It is an object of the present invention to provide a liquid crystal display device with little inversion.

[0006]

SUMMARY OF THE INVENTION The inventors of the present invention have realized that a light guide having a specific structure is used.
The distribution angle of the emitted light of the backlight is narrow, and it has excellent directivity to emit in the normal direction of the emission surface of the peak light, and it is found that it has excellent directivity that can maximize the luminous intensity in the front, The contrast and color tone of the screen change depending on the viewing direction in the conventional liquid crystal display device, and the angle distribution of the light emitted from the backlight part is wide, and the tilt direction of the liquid crystal molecules due to the light entering the liquid crystal display element from various directions. Focusing on the effect of the above, the light incident on the liquid crystal display element is made into a pseudo-parallel light with a narrow angle distribution, and the light is diffused after passing through the liquid crystal display element, so that the contrast or the intermediate color depending on the viewing angle can be obtained. The inventors of the present invention have found that a liquid crystal display device having a wide viewing angle with little change in color tone due to luminance reversal can be obtained, and the present invention has been completed.

That is, the backlight of the present invention comprises a light source, a light guide having at least one incident surface and an emission surface facing the light source, and a prism sheet disposed on the light guide. At least one of the exit surface and the back surface of the light guide member is at an angle of 45 ° to 90 ° with respect to the entrance surface.
A large number of lens rows having an angle of ° are formed in parallel, and the average inclination angle of the lens rows is 30 ° or more. Further, the liquid crystal display device of the present invention includes a light source, a light guide having at least one incident surface and an emission surface facing the light source, a prism sheet disposed on the light guide, and the light guide. A plurality of lens rows each having an angle of 45 ° to 90 ° with respect to the incident surface are formed in parallel with each other on at least one of the exit surface and the back surface of the light guide body. The average tilt angle of the lens array is 30 ° or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The backlight of the present invention comprises a light source 4, a light guide 2 and a prism sheet 5, as shown in FIG. The light guide 2 has at least one side surface as an incident surface and one surface substantially orthogonal thereto as an emission surface 4, and at least one of the emission surface 4 and a back surface facing the emission surface 4 is, for example, as shown in FIG. A large number of lens rows 3 having different cross-sectional shapes are formed in parallel. The lens array 3 formed on the light guide 2 needs to have shape characteristics such that the average inclination angle thereof is 30 ° or more. As long as it has such shape characteristics, There is no particular limitation, and for example, a lens array such as a prism, a lenticular lens having a semicircular or semielliptical cross section, or a corrugated lens can be formed. By setting the average inclination angle (θa) of the lens array 3 to 30 ° or more, the distribution of the light emitted from the light guide 2 in the horizontal direction can be narrowed, and preferably 45 ° or more.

In the present invention, the average inclination angle (θa) which is an index of the shape characteristic of the lens array 3 is ISO4287 / 1.
It is the average inclination angle (θa) defined in −1987. Specifically, it was determined according to ISO4287 / 1-1984. A stylus type surface roughness meter (Surfcom 570A manufactured by Tokyo Seiki Co., Ltd.) using 010-2528 (1 μmR, 55 ° cone, diamond) as a stylus was used to determine the surface roughness of the rough surface at a driving speed of 0.03 mm / Measured in seconds. The average line is subtracted from the measured average line to correct the inclination, and the average line is calculated by the following equations (1) and (2).

[0010]

[Formula 1] Δa = (1 / L) ∫ ₀ ^L f | (d / dx) f (x) | dx (1)

[0011]

## EQU00002 ## .theta.a = tan.sup.- ¹ .DELTA.a (2) In the present invention, the lens array 3 formed on the light guide 2 is at an angle of 45.degree. It must be formed with an angle of °. This is because the angle of the lens array is 45 ° or more, that is, 45 ° to 90 °.
By setting the angle to be 0 °, the distribution of the light emitted from the light guide 2 in the horizontal direction can be narrowed, and preferably in the range of 60 ° to 90 °.

The pitch of the formed lens rows 3 can be appropriately selected within a processable range, but is 10 to 500.
It is preferably in the range of μm, and more preferably 3
It is in the range of 0 to 300 μm. When the light intensity distribution on the light emitting surface is uneven due to the shape of the light guide 2,
By changing the pitch of the lens array 3 partially or continuously, it is possible to make the light intensity distribution uniform on the light exit surface. The lens array 3 formed on the light guide 2 may be formed by processing the back surface of the light guide 2 by a hot pressing method or the like, or when the light guide 2 is manufactured by extrusion molding, injection molding or the like. It may be processed and formed at the same time. Alternatively, they may be integrally formed by using heat or a photocurable resin or the like.
In the method of integrally forming the lens array 3 on the surface of the light guide 2 using heat or a photo-curable resin, it is possible to manufacture the light guide 2 and the lens array 3 having different refractive indexes. Furthermore, the lens array 3 is made of an active energy ray curable resin on a transparent substrate such as a transparent film or sheet made of polyester resin, acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, or the like. Adhere the formed lens sheet to the light guide 2,
They may be integrated by a method such as fusion.

When the lens array 3 is formed by using the active energy ray-curable resin, the active energy ray-curable resin liquid is injected into a mold having a predetermined lens pattern to form the light guide 2 or the transparent film. Overlap. Then
It can be manufactured by irradiating an active energy ray such as an ultraviolet ray or an electron beam through the light guide 2, polymerizing and curing the active energy ray curable resin liquid, and peeling it from the mold. Examples of the active energy ray curable resin forming the lens array 3 include polyfunctional (meth) acrylic compounds, vinyl compounds, (meth) acrylic acid esters, allyl compounds,
A metal salt of (meth) acrylic acid or the like can be used.

The light guide 2 may have various shapes such as a plate shape, a wedge shape, and a boat shape, and is made of a synthetic resin having a high light transmittance. In order to effectively introduce light from the light source 4 to the light guide body 2, it is preferable that the light incident surfaces of the light source 4 and the light guide body 2 are covered with a case or film coated with a reflecting agent inside. A reflective layer 8 may be formed on the back surface of the light guide body 2 by metal deposition or the like to form a reflective surface. As the synthetic resin forming the light guide 2,
It can be manufactured by a general molding method such as extrusion molding or injection molding using various highly transparent synthetic resins such as methacrylic resin, acrylic resin, polycarbonate resin, vinyl chloride resin and the like. In particular, methacrylic resin is excellent in light transmittance, heat resistance, mechanical properties, and moldability, and is most suitable as a light guide material. Such a methacrylic resin is a resin containing methyl methacrylate as a main component, and methyl methacrylate is preferably 80% by weight or more.

In the backlight of the present invention, the prism sheet 5 is arranged on the emission surface of the light guide 2 as described above. The prism sheet 5 has a lens surface in which a large number of prism rows are formed in parallel on one surface of a transparent base material. The pitch of the prism rows of the prism sheet 5 is 30 μm to 0.
The prism apex angle is preferably about 5 mm, and is appropriately selected depending on the emission angle of the emitted light from the light guide 2, but it is preferably in the range of 50 to 120 °. Further, the orientation of the prism sheet 5 is also appropriately selected depending on the emission angle of the emitted light from the light guide 2, and the prism sheet 5 may be mounted so that the prism surface is on the emission surface side of the light guide 2, or vice versa. You may mount it in the direction.

The prism sheet 5 is arranged so that the prism rows form an angle of 20 ° or less with respect to the incident surface of the light guide 2, and narrows the vertical distribution of the light emitted from the light guide 2. At the same time, the angle is changed in a direction substantially perpendicular to the emission surface. The light emitted from the light guide 2 is a light having a directivity that is inclined by about 70 to 40 ° with respect to the direction perpendicular to the emission surface, and changes this in a direction substantially perpendicular to the emission surface. Therefore, the liquid crystal display element 6 needs to be made incident. The degree of this angle change can be designed using Snell's law according to the prism apex angle and the refractive index of the prism sheet 5. For example, a refractive index of 1.4 composed of acrylic resin
In the prism sheet 5 of about 9 to 1.53, the prism apex angle is set to 55 ° to 65 °, and the prism surface is placed so that the prism surface is on the emission surface side of the light guide 2, so that the inclination of about 60 ° is obtained. It is possible to change the angle of the held light in a direction substantially perpendicular to the emission surface.

In the present invention, the prism sheet 5 is preferably manufactured by using a material having a high visible light transmittance and a relatively high refractive index, such as an acrylic resin, a polycarbonate resin, a vinyl chloride resin. , Active energy ray curable resins and the like. Among them, the active energy ray curable resin is preferable from the viewpoints of scratch resistance, handleability, productivity, etc. of the lens sheet. Further, additives such as an antioxidant, an ultraviolet absorber, an anti-yellowing agent, a bluing agent, a pigment and a diffusing agent may be added to the prism sheet 5 as required. As a method for manufacturing the prism sheet 5, a usual molding method such as extrusion molding or injection molding can be used. In the case of manufacturing the prism sheet 5 using the active energy ray-curable resin, transparent resin such as polyester resin, acrylic resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, and polyolefin resin is used. On the transparent base material such as the transparent film or sheet, the prism portion is formed by the active energy ray curable resin. First, an active energy ray-curable resin liquid is injected into a lens mold having a predetermined prism pattern, and transparent base materials are superposed on each other. Then, active energy rays such as ultraviolet rays and electron rays are irradiated through the transparent base material to polymerize and cure the active energy ray-curable resin solution, and the prism sheet 5 is obtained by peeling from the lens mold.

As shown in FIG. 1, the liquid crystal display device 1 of the present invention comprises a liquid crystal display element 6 and a backlight portion composed of a light source 4 and a light guide 2 having the above-mentioned structure. The light guide 2 including the specific emission surface as described above
By using, the light rays emitted from the light guide 2 become pseudo-parallel light having a small angle distribution when passing through the liquid crystal display element 6, and the influence of the tilt direction of the liquid crystal molecules can be minimized. It is possible to obtain the liquid crystal display device 1 in which the color tone changes little due to the contrast and the brightness inversion of the intermediate color. The liquid crystal display element 6 is not particularly limited, and either an active matrix driving TFT type liquid crystal display element or a simple matrix driving STN type liquid crystal display element can be used. Further, in the TFT type liquid crystal display element, the element and various active elements such as polysilicon, amorphous silicon and metal insulator metal can be used.

Further, as shown in FIG. 1, a microlens sheet or a diffusion sheet 7 having a large number of fine lenticular lenses formed in parallel on at least one surface thereof may be placed on the liquid crystal display element 6. Good. By mounting the microlens sheet 7 or the diffusion sheet on the liquid crystal display element 6 in this way, the pseudo-parallel light transmitted through the liquid crystal display element 6 enters the microlens sheet or the diffusion sheet 7, and the incident light diffuses and exits. Therefore, the viewing angle of the liquid crystal display device 1 can be widened. That is, the light guide 2 formed of a specific exit surface can minimize the influence of the tilt direction of the liquid crystal molecules by the pseudo-parallel light having a small angle distribution when passing through the liquid crystal display element 6. Since the light is diffused by the microlens sheet and the diffusion sheet 7 after passing through 6, it is possible to provide the liquid crystal display device 1 having a wide viewing angle with little change in the color tone due to the contrast or the brightness inversion of the intermediate color depending on the viewing angle.

The microlens sheet and the diffusing sheet 7 placed on the liquid crystal display element 6 are members having a function of widening the viewing angle by diffusing the light transmitted through the liquid crystal display element 6. As the micro lens sheet 7,
A large number of lenses such as a lenticular lens having a semi-cylindrical shape, a semi-elliptic shape, or a shape similar to these are formed in parallel on at least one surface and have a thickness of 0.
It is preferable that the lens pitch is about 1 to 10 mm and the lens pitch is about 10 to 800 μm. The microlens sheet and the diffusion sheet 7 are preferably manufactured by using a material having a high visible light transmittance, and examples thereof include acrylic resin, polycarbonate resin, vinyl chloride resin, active energy ray curable resin, and the like. For example, an ordinary molding method such as extrusion molding, injection molding or a method using an active energy ray-curable resin can be used. In the present invention, the microlens sheet or the diffusion sheet 7 may include an antioxidant, an ultraviolet absorber, an anti-yellowing agent, a bluing agent, if necessary.
Additives such as pigments and diffusing agents can also be added.

[0021]

The present invention will be described below in detail with reference to examples. Measurement of luminous intensity distribution Inverter (TDK CXA-
M10L) to connect to a DC power supply, and apply DC 12 V to light up. The liquid crystal display device was placed on a measuring table, and the center of the liquid crystal display device was adjusted to rotate on a rotation axis parallel to the cold cathode tube axis. Then, a black paper having a 3 mmφ pinhole was fixed on the light guide so that the pinhole was located at the center of the light guide, and a measurement circle was measured using a luminance meter (Minolta nt-1 °). Was adjusted to be 8 to 9 mm.
After aging time of the cold cathode fluorescent lamp for 30 minutes or more, while rotating the rotating shaft from 80 ° to -80 ° at 5 ° intervals,
The angular distribution of the luminous intensity of the emitted light was measured.

As an average inclination angle (θa) stylus, 010-2528 (1 μmR, 55 ° cone,
The surface roughness of the rough surface was measured at a driving speed of 0.03 mm / sec with a stylus type surface roughness meter (Surfcom 570A manufactured by Tokyo Seiki Co., Ltd.) using a diamond. The slope is corrected by subtracting the average line from the measured average line, and
~ Calculated by the formula (2).

Example 1 A pitch 100 having an inclined surface having an average inclination angle (θa) of 60 ° on one surface by injection molding of acrylic resin.
A lenticular lens of μm is formed in a direction of 90 ° with respect to the long side, the size is 100 mm × 90 mm, and the thickness is 4
A mm light guide was prepared. A silver-deposited PET film is adhered to and pasted on the two 90 mm end surfaces of the obtained light guide, and a silver-deposited PET film is taped to the surface opposite to the surface on which the lenticular lens is formed, and a reflection surface is formed. Was formed. A cold cathode tube (KC130T4E72, 4 mmφ × 130 mm, manufactured by Matsushita Electric Industrial Co., Ltd.) was wrapped around a 100 mm two end surface of an acrylic plate with a PET film having silver vapor deposited thereon, and installed as a light source lamp. On the other hand, an acrylic ultraviolet curable resin liquid is injected into a mold having a prism pattern with a prism apex angle of 63 ° and a pitch of 50 μm,
A polyethylene terephthalate film having a thickness of 150 μm is superposed using a roll, and then 570 mJ of ultraviolet rays is irradiated through the polyethylene terephthalate film to polymerize and cure the acrylic ultraviolet curable resin solution, and then peeled off from the mold and refracted. A prism sheet having a ratio of 1.59 and an apex angle of 63 ° was obtained.

The prism sheet is placed on the exit surface (the surface on which the lenticular lens is formed) of the obtained light guide so that the prism surface is located on the exit surface side of the light guide,
Configured the backlight. The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Further, a TFT type liquid crystal display element is placed on a prism sheet, and a microlens sheet in which a lenticular lens having a pitch of 0.22 mm is formed on an acrylic resin plate having a thickness of 5 mm is placed on the TFT type liquid crystal display element. Assembled. The obtained liquid crystal display device was used to measure the angular distribution of the luminous intensity of the emitted light, and the half-value width in the horizontal direction and the half-value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also, observe the liquid crystal display device from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source), and visually check the state of the image (contrast, color tone, brightness). The results are shown in Table 1.

Example 2 Except that a lenticular lens with a pitch of 100 μm having an inclined surface with an average inclination angle (θa) of 60 ° was formed on the surface of the light guide in a direction of 85 ° with respect to the long side. A backlight and a liquid crystal display device were assembled in the same manner as in 1. The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also, the liquid crystal display device was observed from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source),
The state of the image (contrast, color tone, brightness) was visually evaluated, and the results are shown in Table 1.

Example 3 A backlight and a liquid crystal were prepared in the same manner as in Example 1 except that a rough surface having an average inclination angle (θa) of 5 ° was formed on the surface of the light guide opposite to the surface on which the lenticular lens was formed. The display device was assembled. The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also, observe the liquid crystal display device from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source), and visually check the state of the image (contrast, color tone, brightness). The results are shown in Table 1.

Comparative Example 1 A backlight and a liquid crystal display device were assembled in the same manner as in Example 1 except that a lenticular lens was formed on the surface of the light guide to form a matte surface having an average inclination angle (θa) of 15 °. It was The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also,
Observe the liquid crystal display device from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source),
The state of the image (contrast, color tone, brightness) was visually evaluated, and the results are shown in Table 1.

Comparative Example 2 Except that a lenticular lens with a pitch of 100 μm having an inclined surface with an average inclination angle (θa) of 15 ° was formed on the surface of a light guide in a direction of 90 ° with respect to the long side. A backlight and a liquid crystal display device were assembled in the same manner as in 1. The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also, the liquid crystal display device was observed from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source),
The state of the image (contrast, color tone, brightness) was visually evaluated, and the results are shown in Table 1.

Comparative Example 3 Except that a lenticular lens with a pitch of 100 μm having an inclined surface with an average inclination angle (θa) of 60 ° was formed on the surface of the light guide in the direction of 5 ° with respect to the long side. A backlight and a liquid crystal display device were assembled in the same manner as in 1. The obtained backlight was used to measure the angular distribution of the luminous intensity of the emitted light, and the half value width in the horizontal direction and the half value width in the vertical direction with respect to the light source were determined from the results and are shown in Table 1. Also, the liquid crystal display device was observed from an angle of 30 ° with respect to the normal direction (from two directions, horizontal and vertical to the light source),
The state of the image (contrast, color tone, brightness) was visually evaluated, and the results are shown in Table 1.

[0030]

[Table 1]

[0031]

According to the present invention, a large number of lenticular lenses having a specific shape are formed in parallel in a certain direction on the exit surface of the light guide, so that the angular distribution of the exit light beam is narrow and the peak light is in the direction normal to the exit surface. It is possible to provide a backlight having an excellent directivity that emits to the back. Further, it is possible to provide a liquid crystal display device which has a high brightness on the front side, a wide viewing angle, and has no change in contrast depending on the viewing angle and no change in color tone due to brightness inversion in an intermediate color.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of a liquid crystal display device of the present invention.

FIG. 2 is a partial cross-sectional view showing a lenticular lens formed on the light guide according to the present invention.

[Explanation of symbols]

 1 ・ ・ ・ Liquid crystal display device 2 ・ ・ ・ Light guide 3 ・ ・ ・ Lens row 4 ・ ・ ・ Light source 5 ・ ・ ・ Prism sheet 6 ・ ・ ・ Liquid crystal display element 7 ・ ・ ・ Microlens sheet, diffusion sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G02B 6/00 331 G02B 6/00 331

Claims (3)

[Claims] 1. A light source, a light guide having at least one entrance surface and an exit surface facing the light source, and a prism sheet disposed on the light guide, and the exit surface of the light guide. And a large number of lens rows having an angle of 45 ° to 90 ° with respect to the incident surface are formed parallel to each other on at least one of the rear surface and the average inclination angle of the lens rows is 30 ° or more. Backlight. 2. A light source, a light guide body having at least one incident surface and an emission surface facing the light source, a prism sheet arranged on the light guide body, and a light guide body arranged on the light guide body. A large number of lens rows each composed of a liquid crystal display element and having an angle of 45 ° to 90 ° with respect to the incident surface are formed in parallel on at least one of the exit surface and the back surface of the light guide. A liquid crystal display device having an average tilt angle of 30 ° or more. 3. The liquid crystal display device according to claim 2, wherein a lens sheet or a diffusion sheet having a large number of microlenses formed on at least one surface thereof is arranged on the liquid crystal display element.