JP2003195305A - Reflection type liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal display device equipped with a front light is improved in lightness and contrast and low in cost. <P>SOLUTION: The reflection type liquid crystal display device is equipped with the front light comprising a light source and a light guide plate having an incidence surface on which the light from the light source is incident, and a projection surface projecting the incident light and a reflection type liquid crystal display element which controls the light projected front the projection surface of the light guide plate by pixels and reflects the light to the projection surface side of the light guide plate to display an image; and a polarizing plate which includes a polarizing film and a protection film and is characterized by that the angle of the phase delay axis of the projection and the absorption axis of the polarizing plate is 20 to 70° is placed between the front light and reflection type liquid crystal display element. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
Reflective liquid crystal display with an excellent front light
Relates to the device. A liquid crystal display device is a liquid crystal which is a non-light emitting element.
Since it is composed of elements, it has low power consumption.
In addition, the liquid crystal display device is thin and lightweight, and is a flat screen.
Display device. The liquid crystal display device has the above advantages.
Watch, calculator, computer terminal, word processor
As an information display device.
It is used in a wide range of fields. Recently, displays for next-generation portable terminal modules
As a device, monochrome display, high brightness and high contrast
There is a need for a reflective crystal display. In addition, the amount of information increases
Accordingly, there is an increasing demand for colorization of liquid crystal display devices.
However, in color display, the color filter reduces the transmittance.
And the brightness is extremely lower than when displaying in black and white.
The wisdom deteriorates. Therefore, the color liquid crystal display device
Therefore, high brightness and high contrast are essential.
ing. Also, the reflection type liquid crystal display device is weak in outside light.
Then, the display becomes impossible and cannot be used. this
Because of the front light, the reflected light of the front light
Reflective liquid crystal display devices that display using
Yes. A reflective LCD with such a front light
The display device includes an incident surface on which light from the light source is incident and an incident surface.
And a light guide plate having an exit surface for emitting the reflected light.
Lont light and light emitted from the exit surface of the light guide plate
Control each image and reflect it on the exit surface side of the light guide plate to display the image
A reflective liquid crystal display element. In addition, the front
Between the light and the reflective liquid crystal display element or inside,
A λ / 4 plate is placed, and the polarization of light by the polarizing plate and the λ / 4 plate
Utilization of voltage applied to the liquid crystal layer and the alignment state of the liquid crystal layer
Then, the light is modulated to display an image. When light passes through the polarizing plate, it differs from the transmission axis.
The light in the direction of polarization is absorbed, so it is absorbed
If there is too much light, the brightness and contrast of the display device
Will fall. Reflective LCD with front light
In the case of the display device, the light emitted from the front light
Polarized light is transparent because it is polarized light, so-called elliptically polarized light.
Make the absorption axis point in the direction that maximizes the amount of light
Used for high brightness and high contrast
The demand for it is still strong. On the other hand, a polarizing plate is a liquid crystal display (hereinafter referred to as L).
With the widespread use of CDs, demand is increasing rapidly. One polarizing plate
In general, adhere to both sides or one side of polarizing film with polarizing ability.
A protective film is bonded through the agent layer. Polarizing film
As a material, polyvinyl alcohol (hereinafter, PVA)
Is mainly used, PVA film is uniaxially stretched
Or dye with iodine or dichroic dyes or
After dyeing, the film is stretched and cross-linked with a boron compound.
As a result, a polarizing film is formed. As protective film, optical
Is transparent and has low birefringence.
Acetate is used. A polarizing film is usually a continuous film.
Manufactured by uniaxial stretching in the running direction (longitudinal direction) of rumm
Therefore, the absorption axis of the polarizing film is substantially parallel to the longitudinal direction. In a conventional LCD, the screen is vertical.
Is arranged with the transmission axis of the polarizing plate inclined by 45 ° with respect to the horizontal direction.
Punching of polarizing plates manufactured in roll form
In the process, strike at 45 ° to the roll longitudinal direction
I had to pull it out. However, punched in the direction of 45 °
Part that cannot be used near the end of the roll
However, especially with large-size polarizing plates, the yield will be small.
Resulting in increased costs and even abolition
There was a problem of increasing waste. The present invention solves the above problems.
In view of the above, a reflective liquid crystal display device equipped with a front light is
Improved brightness and contrast and low cost
It is a problem to provide as. According to the present invention, the following structure is provided.
The above-mentioned object of the present invention is achieved.
Made. 1. A light source, an incident surface on which light from the light source is incident, and the entrance
And a light guide plate having an exit surface for emitting the emitted light.
Front light and light emitted from the exit surface of the light guide plate
Is controlled for each pixel and reflected on the light exit surface side of the light guide plate.
LCD comprising a reflective liquid crystal display element for displaying
In the apparatus, a front light and a reflective liquid crystal display element
Including a polarizing film and a protective film, and the slow axis of the protective film
And the absorption axis of the polarizing film form an angle of 20 ° or more and less than 70 °.
Reflective liquid crystal surface, characterized in that a polarizing plate is placed
Indicating device. 2. The polarizing film of the polarizing plate is continuously supplied to the polarizing film.
Hold both ends of the remmer film by holding means
Applying tension while moving the means in the longitudinal direction of the film
(I) Polymer for polarizing film
From the actual holding start point on one end of the film,
Trajectory L1 of the holding means up to the holding release point and the polymer fill
The effective retention solution from the effective retention start point at the other end of the system
Trajectory L2 of the holding means up to the removal point and two substantial holdings
The distance W of the release point satisfies the following formula (1), and (ii) poly
Maintains the support of mer film and has a volatile content of 5% or more
Stretched in the presence of a state, and then contracted to reduce the volatile content.
2. The reflective liquid crystal as described in 1 above, wherein
Display device. Formula (1): | L2-L1 |> 0.4W As described above, the light is emitted from the front light.
The polarized light is transmitted through the polarizing plate because it is in the state of elliptically polarized light.
So that the absorption axis is oriented in the direction that maximizes the volume.
Therefore, the minor axis direction of the ellipse is parallel to the absorption axis of the polarizing plate (transmission axis
Is used so that it is vertical. The present invention
Then, the angle between the slow axis of the protective film and the absorption axis of the polarizing film is 20
By setting the angle to be greater than 70 ° and less than 70 °, the protective film can be
The front light is utilized by having a phase difference
The elliptically polarized light emitted from the beam to be close to linearly polarized light
The amount of light that passes through the transmission axis of the polarizing film, that is,
The amount of light transmitted through the polarizing plate can be increased. But
Thus, the light reflectance of the reflective liquid crystal display device of the present invention is improved.
In addition, high brightness and high contrast can be achieved. Preferred between the slow axis of the protective film and the absorption axis of the polarizing film
The correct angle depends on the retardation value of the protective film.
Usually, 30 ° to 60 ° is preferable, and 40 ° to 50 ° is more preferable.
preferable. In addition, a view to increase brightness and contrast
From the point of view, a polarizing plate (consisting of a polarizing film and a protective film) and λ / 4
It is preferable to combine plates, and as its layer structure
Is a protective film / polarizing film / protective film /
(Λ / 4 plate), protective film / polarizing film / (λ / 4 plate), etc.
However, the protective film / polarizing film / (λ / 4 plate)
Particularly preferred. DETAILED DESCRIPTION OF THE INVENTION The base of a reflective liquid crystal display device of the present invention.
The actual configuration is shown as a schematic diagram in FIG. In FIG.
The reflective liquid crystal display device is disposed on the light guide plate 2 and its end face.
A light source 1 and a polarizing plate 3 on the lower side of the light guide plate 2, λ / 4
Plate 4, glass substrate 5, liquid crystal layer 6, reflective electrode 7, glass substrate
A plate 8 is provided in this order. FIG. 2 shows the polarizing plate 3 of FIG.
A polarizing plate 9 with a λ / 4 plate integrated with the λ / 4 plate 4 is provided.
The structure of a reflective liquid crystal display device is shown as a schematic diagram. In addition to these layers, JP-A-4-2298
28, JP-A-6-75115, JP-A-8-5020
For viewing angle compensation of LCD described in each publication of No. 6
Optical anisotropic layer, anti-glare to improve display visibility
Layer, antireflection layer, hard coat to enhance scratch resistance
Layer, gas barrier layer that suppresses diffusion of moisture and oxygen, and polarizing film
Easier to increase the adhesion strength of adhesives or adhesives and adhesives
Arbitrary functional layers such as adhesive layers and layers that provide smoothness are provided.
Can. Placement relationship between functional layer and polarizing plate or λ / 4 plate
The person in charge can be appropriately selected according to the purpose. The reflection type liquid crystal display device displays an image.
The principle to be explained will be explained. Light beam emitted from the light guide plate 2
That is, the linearly polarized light transmitted through the polarizing plate 3 is circularly polarized by the λ / 4 plate 4.
Is incident on the liquid crystal layer 6 through the glass substrate 5.
To do. When the liquid crystal layer 6 does not modulate circularly polarized light,
The direction of rotation of circularly polarized light is reversed when reflected by the pole 7
Then, after passing through the λ / 4 plate 4 again, the transmission axis of the polarizing plate 3 and
Light becomes orthogonal linearly polarized light and does not pass through the polarizing plate 3.
As a result, black display is obtained. On the other hand, the liquid crystal layer 6 is incident.
Reflection of circularly polarized light while preserving its polarization state
In the case of modulation, the reflected light again passes through the λ / 4 plate 4.
When transmitted, it becomes linearly polarized light parallel to the transmission axis of the polarizing plate 3
Since the light passes through the polarizing plate 3, white display is obtained. Further color
It is also possible to perform color display by passing a filter.
is there. FIG. 22 schematically shows the above principle. Next, the light source 1 and the light guide plate used in the present invention.
The front light part combining 2 will be described. Flow
Fluorescent tubes are preferred as the light source of
EL, LED, LED and bar light guide plate combinations, etc.
If it is a light source that uniformly irradiates the light incident surface of the light plate
Deviations can also be used. As a front light,
The thing of the aspect shown by FIGS. 3-6 demonstrated below is mentioned.
However, the present invention is not limited to these. FIG. 3 shows the SID '95 Digest.
p. 37 having the microprism structure described in 37.
It shows a lottolite. Fluorescent lamp for lighting 10
The light emitted from the side surface 11 a of the light guide plate 11 is guided through the light guide plate 1.
1 is a micro prism 1 formed on the display surface side.
Reflection type reflected downward by 1b and installed below
Irradiate the liquid crystal display element. Further, the side surface 11 of the light guide plate 11.
An inclined prism 11c is provided on the a side, and illumination is provided.
Direction of the light guide plate 11 of the light irradiated from the fluorescent lamp 10
The light incident on the light guide plate 11 by narrowing the incident angle to the
Reflected to the bottom of the drawing by the ichro prism 11b
It has become. FIG. 4 is described in JP-A-11-218757.
1 shows a tilted front light mounted. Guidance
The light plate one surface portion 15A (lower side) is a flat surface, and the other surface of the light guide plate
The part 15B (upper side) is predetermined with respect to the light guide plate one surface part 15A.
It consists of an inclined surface portion inclined at an angle α. Such as cold cathode tubes and hot cathode tubes
A light source unit comprising which lamp 17 and lamp holder 18
The light incident on the front light unit 14 from 16 is
Reflection and guidance of the other surface portion 15B of the light guide plate having an inclination angle α of 20 °
The exit angle due to refraction when exiting from the optical plate 15A
Light that is close to the vertical component can be guided. FIG. 5 is described in JP-A-2001-23424.
This is a prism continuous front light.
is there. On the surface of the light guide plate 20, a gentle slope 20a and a steep slope are formed.
A large number of concave and convex portions made of the inclined surfaces 20b are periodically formed in parallel.
ing. Light emitted from the light source 19 and incident on the light guide plate 20
Propagates along the plate surface with total reflection on the gentle slope 20a.
When it hits the steep slope 20c, the entire surface is directed toward the exit surface 20c.
Be shot. When the light reaches the exit surface 20c, the exit surface 20
If the incident angle to c is smaller than the critical angle,
The light is emitted downward as illumination light. Light guide plate material
Polymethylmethacrylate, glass, acrylic tree
I prefer oil, polycarbonate resin, epoxy resin, etc.
Can be used. Preferred period length of irregularities
(P) varies depending on the wavelength of the light source used, but is generally
100 to 600 μm, more preferably 250
˜450 μm. In addition, the periodic formed on the light guide plate
In order to avoid the generation of moire fringes,
The pixel is appropriately selected according to the pixel pattern of the reflective liquid crystal display element.
It is also preferable to give an angle. Reflective liquid crystal
When the pixel pattern of the display element is a delta arrangement,
10-25 ° or 55 ° with the horizontal direction of the pixel pattern
80 °, pixel pattern of reflective liquid crystal display element is striking
In the case of an array, an angle of 15 to 75 ° is given.
It is preferable. FIG. 6 is described in JP-A-11-184387.
A volume hologram type front light is shown.
It is. The light guide plate 22 is disposed between the display surface and the display surface.
The volume hologram layer 23 guides light into the light guide plate 22.
Part of the light from the light source 21 reflected to the display surface side and displayed
Illuminate the surface. The λ / 4 plate is disclosed in JP-A-5-27118 and
Letter days described in Japanese Patent Publication Nos. 5-27119
Large birefringent film and retardation
The birefringence film is small and their optical axes are orthogonal.
Retardation plates laminated in such a manner, Japanese Patent Laid-Open No. 10-68816
Λ / 4 at a specific wavelength
The same polymer and the same material
A polymer film having a wavelength of λ / 2.
Laminate phase difference to obtain λ / 4 over a wide wavelength range
Plate, two sheets described in JP-A-10-90521
By laminating polymer films in a wide wavelength range
Retardation plate capable of achieving λ / 4, WO00 / 26705
Using the modified polycarbonate film described in 1.
Retardation plate capable of achieving λ / 4 in a large wavelength region, WO00 /
Cellulose acetate film described in 65384
Retardation plate that can achieve λ / 4 in a wide wavelength range
Etc. can be used. The slow axis of the λ / 4 plate is liquid crystal
Determined by considering the material, orientation direction, viewing angle characteristics, etc.
Is an angle of 45 ° with the transmission axis (or absorption axis) of the polarizing plate
It is desirable to be arranged at. Also, light wave of λ / 4 plate
To compensate for phase lag tolerance with respect to length,
A λ / 2 plate may be arranged between the λ / 4 plate. In general, these λ / 2 plates and λ / 4 plates are each
Reflective liquid crystal display integrated with polarizing plate through adhesive layer
It is bonded to the element. Furthermore, the polarizing plate of the present invention
To paste various functional films directly on one or both sides
Can do. As an example of the functional film to be bonded, the above λ / 4
Opposite to retardation film such as plate, λ / 2 plate, light diffusion film, polarizing film
Plastic cell with a conductive layer on the surface, reflector, transflective
Examples include a reflector having a function. These functional layers and
Examples of pasting with a light plate are shown in FIGS. It is arranged on the glass substrate 8 on the back side of the liquid crystal layer.
The surface of the reflective electrode has a fine structure and is polarized.
Scattering the light incident through the plate, λ / 2 plate, λ / 4 plate
Reflected so that it can be displayed uniformly over a wide viewing angle range
It is preferable to be devised. Specifically, photo
The litho process forms a microstructure as an underlayer.
The aluminum film is vacuum-deposited on top of it to reflect
A pole is formed. In the liquid crystal display device, the change by the liquid crystal layer is performed.
Characters and images are displayed by controlling the tone for each pixel.
However, when performing color display, it is placed on each pixel.
The three primary colors of red (R), green (G), and blue (B)
Colored light is obtained by transmitting through the ruter layer. This R, G, B arrangement
There are various column patterns, but delta arrangement and stripe arrangement
Etc. are typical. Pixels horizontally and vertically
Repeatedly configured. There are also various pixel numbers and pixel sizes.
For example, in the case of a reflective liquid crystal display element with a delta arrangement
In the 2.0 type, the number of horizontal pixels × vertical pixels is 280 × 2
20, pixel size is horizontal direction 145.5μm, vertical direction
234.5 μm, 2.5 type x horizontal pixels x vertical
The number of pixels is 280 × 220, and the pixel size is 17 in the horizontal direction.
Specifications of 9.5μm and vertical direction of 168.5μm are adopted.
Has been. 3.8-inch QVGA reflective liquid crystal display
In the element, the number of horizontal pixels x the number of vertical pixels in the stripe arrangement
960 × 240, pixel size is 81 μm in horizontal direction, vertical
The specification that the straight direction is 234.5 μm is adopted. Used in the reflection type liquid crystal display device of the present invention.
Polarizing plate (also referred to as “polarizing plate of the present invention” in this specification)
Will be further described. The polarizing plate of the present invention has
It has a polarizing film with optical ability and is maintained on both sides or one side of the polarizing film.
A protective film is provided via an adhesive layer. Also usually
Manufactures long polarizing plates (usually in roll form) and uses them
Practical polarizing plate is obtained by punching to match
It is what The “polarizing plate” in the present invention is particularly
Unless otherwise specified, both the long polarizing plate and the punched polarizing plate
It is used in the meaning including a person. As described above, the polarizing plate of the present invention has a long polarizing plate.
In the optical plate, the absorption axis is neither parallel nor perpendicular to the longitudinal direction.
(This long polarizing plate is simply referred to as “diagonally oriented” below.
Sometimes called a light plate). The longitudinal direction and the absorption axis direction
The angle formed is preferably 10 ° or more and less than 90 °, more preferably
Preferably it is 20 ° or more and 70 ° or less, more preferably 40 °.
50 ° or less, particularly preferably 44 ° or more and 46 ° or less
It is. Thereby, punching process from long polarizing plate
Therefore, a single plate polarizing plate can be obtained with high yield.
In the present invention, the angle formed by the longitudinal direction and the absorption axis direction can be freely set.
Can be set to Therefore, it is combined with other optical members.
The optimum angle can be selected when using together.
The The polarizing plate of the present invention has a single plate transmittance of 5
35% or more at 50 nm and the degree of polarization is 80% at 550 nm
It is the above. Single plate transmittance is preferable
Is 40% or more, and the degree of polarization is preferably 95.0% or less.
Above, more preferably 99% or more, particularly preferably 99.%.
9% or more. In the following description, especially
Unless otherwise indicated, the transmittance is a single plate transmittance. Of the present invention
The polarizing plate has excellent single-plate transmittance and polarization degree.
Therefore, when used as a liquid crystal display device, the contrast
This is advantageous because it can increase the The obliquely oriented polarizing film of the present invention is described below.
It can be easily obtained by a sliding method. That is, oblique
Orientation obtained by stretching the polymer film,
Volatile content during film stretching, when shrinking film
It can be obtained by devising the shrinkage rate of the material. Furthermore,
Adjust the amount of foreign matter adhering to the film before stretching.
Both are preferable. Thereby, even if it extended diagonally, it extended.
The film has no wrinkles or creases and has a small surface roughness.
A smooth polarizing film can be obtained. Below, polarization
Preferred stretching methods for obtaining a film (in this specification, the present
(Sometimes referred to as the stretching method of the invention)
The <Stretching Method> FIG. 11 and FIG.
An example of a method for obliquely stretching a mer film is a schematic plan view and
It is shown as The stretching method of the present invention is indicated by (a).
The process of introducing the original film in the direction of arrow (b),
(B) the width direction stretching step, and (c)
The next step, that is, the step of sending the stretched film in the (B) direction
Including. Hereinafter, when referred to as "stretching step"
(A)-(c) process is included and the extending | stretching method of this invention is performed.
For the entire process. The film is continuously introduced from the direction (a).
For the first time at the B1 point on the left holding means as seen from the upstream side
Retained. At this point, the other film edge is still held
No tension is generated in the width direction. That is, B
One point is a substantial holding start point of the present invention (hereinafter referred to as “substantial holding”).
Does not correspond to “starting point”. In the present invention, the substantial
The holding start point is defined as the point at which both ends of the film are held for the first time
Is done. The real holding start point is the holding start point A on the downstream side.
1 and the center line 111 of the introduction side film from A1 (FIG. 1
1) or 121 (FIG. 12), a straight line drawn substantially perpendicularly
Trajectory 113 (FIG. 11) or 123 of the holding means on the opposite side
This is indicated by two points C1 that intersect (FIG. 12). This point
Starts and transports the holding means at both ends at a substantially constant speed
And every unit time A1 moves to A2, A3 ... An,
C1 similarly moves to C2, C3... Cn. That means simultaneous
Connect points An and Cn through which the reference holding means passes.
The straight line is the drawing direction at that time. In the method of the present invention, as shown in FIGS.
An is gradually delayed with respect to Cn.
Gradually inclines from the vertical in the conveying direction. Reality of the present invention
Qualitative holding release point (hereinafter referred to as “real holding release point”)
Is the Cx point that is disengaged from the holding means more upstream, and Cx
The center line 112 of the film sent to the next process (FIG. 11)
Or a straight line drawn almost perpendicular to 122 (Fig. 12) is opposite
Side holding means trajectory 114 (FIG. 11) or 124 (FIG.
It is defined by two points Ay that intersect with 12). Final
The angle of the film stretching direction is the actual end point of the stretching process.
Left and right holding means stroke difference Ay-A at (substantially holding release point)
x (that is, | L1-L2 |) and the distance between the substantial holding release points
It is determined by the ratio of the separation W (the distance between Cx and Ay). Therefore,
The inclination angle θ formed by the stretching direction with respect to the transport direction to the next step is tan θ = W / (Ay−Ax), that is, an angle satisfying tan θ = W / | L1-L2 |. The upper fill in FIGS. 11 and 12
The end of the head is 118 (FIG. 11) or 128 after the Ay point.
(Figure 12) is held, but the other end is held
Therefore, no new width direction stretching occurs, and 118 and 1
28 is not a substantial holding release point of the present invention. As described above, in the present invention, the film
The substantial holding start points at both ends of the
It is not a simple bite point. Two substance retentions of the present invention
The starting point is a more strict description of what was defined above.
For example, a straight line connecting either the left or right holding point and another holding point
Center line of the film introduced to the film holding process
And these two holding points.
Is defined as the most upstream. Similarly,
In the present invention, the two substantial holding release points are either left or right.
A straight line connecting one holding point and another holding point is sent to the next process.
It is a point that is almost orthogonal to the center line of the film
Moreover, these two holding points are the most downstream
Is defined as Here, substantially orthogonal means the center of the film
Line and left and right real holding start point or real holding release point
It means that the connecting straight line is 90 ± 0.5 °. Left and right strokes using a tenter type stretching machine
When trying to make a difference, it is necessary to meet mechanical constraints such as rail length.
More often, the point of biting into the holding means and the start of substantial holding
If there is a large deviation in the points,
There may be a large shift in the quality retention release point.
The process between the real holding start point and the real holding release point to be defined is an expression.
If the relationship of (1) is satisfied, the object of the present invention is achieved.
The In the above, the obtained stretched film
The angle of inclination of the orientation axis is as follows.
Ratio of stroke difference | L1-L2 | of the two right substantial holding means
It can be controlled and adjusted at a rate. With polarizing plate and retardation film
The film often oriented 45 ° to the longitudinal direction
Desired. In this case, to obtain an orientation angle close to 45 °
In addition, it is preferable to satisfy the following formula (2): Formula (2): 0.9 W <| L1-L2 | <1.1 W More preferably, the following formula (3) is preferably satisfied.
Yes. Formula (3): 0.97W <| L1-L2 | <1.03W The specific structure of the stretching process satisfies Formula (1).
As much as possible, as illustrated in FIGS.
And can be designed arbitrarily in consideration of productivity. The direction of film introduction (b) into the stretching process;
The angle formed by the film transport direction (b) to the next process is arbitrary.
Is possible, but the equipment including the processes before and after stretching
This angle is small from the standpoint of minimizing the total footprint.
Better, preferably within 3 °, more within 0.5 °
preferable. For example, the structure illustrated in FIGS. 11 and 14
This value can be achieved. Fill like this
In a method that does not substantially change the direction of travel, the holding means
Just widening the width is preferable as a polarizing plate and retardation film.
It is difficult to obtain an orientation angle of 45 ° with respect to the longitudinal direction.
The Therefore, as shown in FIG.
To increase | L1-L2 |
You can. The draw ratio is desirably 1.1 to 10.0 times,
More preferably, it is 2 to 10 times, and the shrinkage after that is 1
0% or more is desirable. Also, as shown in FIG.
-Repeating contraction multiple times also increases | L1-L2 |
This is preferable because it can be used. In addition, the equipment cost of the stretching process is minimized.
From the standpoint of
Smaller is better. From this point of view, FIG. 12, FIG. 13, FIG.
At the exit of the process of holding both ends of the film as illustrated in 5
Direction of film travel and the direction of substantial stretching of the film
The film progresses so that the angle between
Bending the direction while holding both ends of the film
Is preferred. In the present invention, tension is applied while holding both ends.
As an apparatus for stretching a given film, so-called FIG.
A tenter device as shown in FIG. 15 is preferred. Also conventional
In addition to the two-dimensional tenter of the mold, a spiral shape as shown in FIG.
It is necessary to use a stretching process that makes a difference in path between the gripping means at both ends.
You can also. In the case of a tenter type stretching machine, the clip is fixed.
There are many structures in which the specified chain advances along the rail,
As a result of taking a non-uniform stretching method like the present invention,
11 and 12, as shown in FIGS.
The end of the rail is shifted, biting at the same time on both sides
It may become. In this case, the substantial process length L1, L2
As described above, with a simple bite-to-release distance
No, as already mentioned, both ends of the film
This is the stroke length of the portion held by the holding means. The speed of travel to the left and right of the film at the exit of the stretching process
If there is a difference, wrinkles and slippage will occur at the exit of the drawing process.
Therefore, the difference in transport speed between the left and right film gripping means is substantially
Must be the same speed. Speed difference is preferable
Is 1% or less, more preferably less than 0.5%
Most preferably, it is less than 0.05%. Mentioned here
The speed at which the left and right holding means advance per minute.
It is the length of the trace. With a general tenter stretching machine
Is the cycle of the sprocket teeth that drive the chain, the drive mode
The speed generated on the order of seconds or less depending on the frequency of the data
There is a degree of unevenness, often causing a few percent unevenness, but these
Does not correspond to the speed difference described in the present invention. <Shrinkage> Shrinkage of the stretched polymer film is
You may perform in any process at the time of extending | stretching and after extending | stretching. Contraction
Is a polymer film that occurs when orienting in an oblique direction
As long as the wrinkles are eliminated, there is a means to shrink the film.
Then, remove the volatiles by applying temperature.
Law, etc., but what if we shrink the film?
It is also possible to use means. Preferred film shrinkage
1 / sin using the orientation angle θ with respect to the longitudinal direction.
By shrinking more than θ times, the value shrinks by 10% or more
[0042] <Volatile content> In the stretching process,
As the difference occurs, wrinkles and shifts occur in the film.
The To solve this problem, support for polymer films
The polymer film has a volatile content of 5% or more.
Stretch in the presence of the condition, then shrink to reduce the volatile content
It is preferable to reduce. Volatile content in the present invention and
Is the body of volatile components contained per unit volume of film
Represents the product, the value obtained by dividing the volume of volatile components by the volume of the film
(%). In the present invention, the polymer film for polarizing plate
At least one step of incorporating a volatile component before stretching the rum
It is preferable to provide a process. Process to contain volatile matter
Cast film and contain solvent, water, etc.
By dipping, applying, spraying, etc. in solvent, water, etc.
Done. <Dyeing prescription and dyeing method>, <Hardener>
(Crosslinking agent), dyeing step described in the section of metal salt addition>
Even if the hardening agent addition process also serves as the process of containing volatile matter
Good. If the dyeing process is combined, the hardener addition process is extended.
It is preferable to provide it before. Where the hardener addition process doubles
In this case, the dyeing process is set before or after stretching.
You may choose. Moreover, if it is before extending | stretching, a dyeing process and an extending process
May be performed simultaneously. The preferred volatile fraction is that of the polymer film.
It depends on the type. The maximum volatile fraction is
This is possible as long as the support of Rum is maintained. Polyvinylarco
In the case of 10% to 100% as a volatile content rate.
For cellulose acylate, 10% to 200% is preferred.
Yes. <Containment distribution of volatile components> Long, especially low
If a polarizing plate is manufactured in an integrated process,
There must be no unevenness or omission. Film before stretching
Non-uniform distribution of volatile components (depending on the location on the film surface)
If there is a difference in the amount of volatile components)
The Therefore, the content of volatile components in the film before stretching
The fabric is preferably small, at least 5% or less
It is preferable. Volatile component distribution is 1m of volatile fraction
² Per variability (maximum or average volatile fraction)
Is the ratio of the larger difference between the minimum value and the average volatile content)))
Represent. As a method of reducing the content distribution of volatile components,
Blow the front and back surfaces of the film with uniform air.
Squeeze evenly with a roller, wipe with a wiper
(Blade, sponge wipe etc.)
However, any method can be used as long as the distribution is uniform.
Yes. 19 to 21 show an air blow device, a nip device, and a block.
An example of a raid apparatus is shown. <Distance from wrinkle occurrence to disappearance> Diagonal direction
The wrinkles of the polymer film that occur when orienting to the
It should have disappeared by the point of substantial retention release in the invention
Yes. However, it takes time from wrinkle generation to disappearance
This may cause variation in the stretching direction.
Or as short a transition distance as possible from the point where the wrinkle occurred
It is better that wrinkles disappear after separation. For this, volatiles
There are methods such as increasing the volatilization rate of the amount. <Foreign matter> In the present invention, the polymer before stretching
-If there is foreign matter on the film, the surface will become rough.
Therefore, it is preferable to remove foreign matter. There is a foreign object
And especially when making a polarizing plate,
Become. In addition, foreign matter does not stay between the protective films.
It is also important not to adhere to it.
It is preferable to manufacture under conditions. The foreign matter in the present invention
The amount is the weight of foreign matter adhering to the film surface.
Express the number of grams per square meter divided by the product.
The Foreign matter is 1 g / m ² The following are preferred, and more preferred
0.5g / m ² The following is preferable. The method for removing foreign matter is not particularly limited,
Without adversely affecting the polymer film before stretching,
Any method can be used as long as it can remove foreign matter.
Yes. For example, scraping off foreign matter by blowing water
Method, scraping foreign matter by gas injection, cloth,
A method of scraping off foreign matter using a blade such as rubber
I can get lost. <Drying> A condition in which the generated wrinkles disappear.
As long as the drying conditions are not limited. However, good
Preferably, as short as possible after the desired orientation angle is obtained.
It is recommended to adjust so that the dry point comes at a long moving distance. Dry
The dry point is the same as the ambient temperature of the film.
It means a place that is the same. Therefore, the drying speed is also
The faster it is, the better. <Drying temperature> Conditions for eliminating generated wrinkles
If so, it doesn't matter what the drying conditions are, but stretching
Depends on the film used. Polyvinyl according to the invention
When creating a polarizing plate using an alcohol film
Is preferably 20 ° C. or higher and 100 ° C. or lower, more preferably
Is 40 ° C. or more and 90 ° C. or less. <Swelling ratio> In the present invention, the polymer film
When Lum is polyvinyl alcohol and a hardener is used
In order to keep the stretched state in an oblique direction without relaxing,
It is preferable that the swelling ratio with respect to water differs before and after stretching.
Specifically, the swelling rate before stretching is high, and swelling after stretching and drying is performed.
It is preferable that the moisture content is low. More preferably, stretching
Swelling ratio after water is 3% or more, and swelling after drying
The rate is preferably 3% or less. <Refractive part> In the present invention, the locus of the holding means is regulated.
Often, a large bending rate is required for the rail to be used.
Interference between film gripping means due to sudden bending, or
Is gripped at the bend to avoid local stress concentration
It is desirable that the means trajectory draws an arc. <Stretching speed> In the present invention, the film is stretched.
The speed to be applied is 1.1, when expressed as the draw ratio per unit time.
2 times / minute or more, preferably 2 times / minute or more, faster is better
Good. Further, the traveling speed in the longitudinal direction is 0.1 m / min or less.
Above, preferably at 1m / min or faster, the faster is the productivity
It is preferable from the point of view. In either case, the upper limit is
Depends on the film and stretching machine. <Tension in the longitudinal direction>
Easy to hold when holding both ends of the rum with holding means
It is preferable to keep the film stretched
Yes. Specifically, the film is stretched by applying tension in the longitudinal direction.
And the like. As the tension,
It depends on the film condition, but it should not be loose
preferable. <Tempering temperature> Environmental temperature during film stretching
Is at least the freezing point of the volatile matter contained in the film
If it is. The film is polyvinyl alcohol
In some cases, 25 ° C. or higher is preferable. Also produced a polarizing film
Polyvinyl alcohol soaked with iodine and boric acid
When stretching the tool, a temperature of 25 ° C. or higher and 90 ° C. or lower is preferred.
More preferably, it is 40 ° C. or higher and 90 ° C. or lower. <Humidity during stretching> Fill with volatile content of water
Such as polyvinyl alcohol, cellulose acylate
Can be stretched in a humidity-controlled atmosphere.
Yes. In the case of polyvinyl alcohol, 50% or more
Preferably, 80% or more, more preferably 90%
% Or more. <Polymer film for polarizing film> In the present invention,
Polymer film to be stretched to form a polarizing film
There is no particular restriction on the volume, and an appropriate thermoplastic
A film made of mer can be used. polymer
Examples of PVA, polycarbonate, cellulose
Examples include acylate and polysulfone.
Preferably, a polyvinyl alcohol-based polymer containing PVA
It is a remer. PVA usually saponifies polyvinyl acetate
For example, unsaturated carboxylic acid, unsaturated
Vinegar like sulfonic acid, olefins, vinyl ethers
It may contain a small amount of a component copolymerizable with vinyl acid.
Yes. Also, acetoacetyl group, sulfonic acid group, carboxy group
Modified PVA containing sil group, oxyalkylene group, etc.
Used preferably in polyvinyl alcohol polymers
Can. Of these, PVA is most preferable. The degree of saponification of PVA is not particularly limited,
80-100 mol% is preferable from the viewpoint of solubility and the like,
90-100 mol% is particularly preferable. The weight of PVA
The degree of integration is not particularly limited, but is preferably 1000 to 10,000.
Particularly preferred is 1500 to 5000. Preferred elasticity of the polymer film before stretching
The rate is expressed in terms of Young's modulus, 0.01 MPa or more and 5000
MPa or less, more preferably 0.1 MPa or more and 500M
Pa or less. If the elastic modulus is too low, after stretching and after stretching
Shrinkage rate is low, wrinkles are hard to disappear, and too high
This increases the tension applied during stretching,
It is necessary to increase the strength of the parts to be held and
Load increases. The thickness of the film before stretching is not particularly limited.
From the viewpoint of film retention stability and stretching uniformity
1 μm to 1 mm is preferable, and 20 to 200 μm is particularly preferable.
Is preferred. <Dyeing prescription and method> The polarizing film is a polarizing film.
Orienting a remer film, for example a PVA film
It is obtained by dyeing. Staining can be by gas phase or liquid phase adsorption.
Done. As an example in the liquid phase, as a polarizer
When iodine is used, iodine-potassium iodide aqueous solution
This is performed by immersing the polymer film for polarizing film in the liquid.
0.1-20 g / l for iodine, 1-2 for potassium iodide
00g / l, the mass ratio of iodine and potassium iodide is 1-2
00 is preferred. The dyeing time is preferably 10 to 5000 seconds
The liquid temperature is preferably 5 to 60 ° C. As a dyeing method
In addition to immersion, apply iodine or dye solution
Any means such as spraying can be used. Dyeing operation is
It may be placed either before or after the bright stretching step. Also moderate
Before the stretching process
It is particularly preferred to dye in the liquid phase. <Hardening agent (crosslinking agent), addition of metal salt> Polarizing film
A polymer film for use, such as a PVA film,
In the process of manufacturing a polarizing film, an additive that crosslinks to PVA
Is preferably used. In particular, the oblique stretching method of the present invention is used.
The PVA is sufficiently hardened at the exit of the stretching process.
Otherwise, the orientation of the PVA will shift due to the process tension.
In the pre-stretching process or the stretching process.
Immerse it in a cross-linking agent solution or apply it to hardener (cross-linking
Agent). Polarizing hardener (crosslinking agent)
Means for applying to the polymer film for the membrane is particularly limited.
It is not a thing, but immersion, coating, spraying etc. of the film in the liquid
Any method can be used, but especially dipping method, coating
The method is preferred. As a coating means, roll coater, Daiko
Data, bar coater, slide coater, curtain coater
Any conventionally known means can be used.
Also, fill the cloth, cotton, porous material, etc. impregnated with the solution.
It is also preferable to make contact with the system. As a hardener (crosslinking agent)
Used in US Reissue Patent No. 232897
Although boric acid and borax are preferred for practical use
It is. Also, zinc, cobalt, zirconium, iron, nickel
Metal salts such as Kel and Manganese can also be used together
The The hardening agent (crosslinking agent) is applied to the drawing machine.
May be done before biting or after biting
11 and 12 in which the stretching in the width direction is substantially finished.
(B) in any process up to the end of the process
Yes. After adding hardener (crosslinking agent), washing and washing process
It may be provided. <Polarizer> Dyeing with dichroic dye in addition to iodine
It is also preferable to do. Specific examples of dichroic dyes include
For example, azo dyes, stilbene dyes, pyrazolone colors
Element, triphenylmethane dye, quinoline dye, oki
Sazine dyes, thiazine dyes, anthraquinone dyes
And other dye-based compounds. Water-soluble
However, it is not limited to this. In addition, these dichroism
Hydrophilic placement of sulfonic acid groups, amino groups, hydroxyl groups, etc. on the molecule
It is preferable that a substituent is introduced. Dichroic molecule ingredient
As an example, for example, C.I. Ai. direct. Yellow
-12, Sea. Eye. direct. Orange 39, shi
-. Eye. direct. Orange 72, sea. Eye. Da
Elect. Red 39, Sea. Eye. direct. Le
79, See. Eye. direct. Red 81, Sea.
Ai. direct. Red 83, Sea. Ai. Directek
G. Red 89, Sea. Ai. direct. Violet
48, See. Eye. direct. Blue 67, Sea.
Eye. direct. Blue 90, Sea. Eye. Directek
G. Green 59, Sea. Ai. Acid. Red 37
In addition, JP-A-62-070802,
Kaihei 1-161202, JP-A-1-172906,
JP-A-1-172907, JP-A-1-183602
No. 1, JP-A-1-248105, JP-A-1-26520
No. 5 and JP-A-7-261024
Etc. These dichroic molecules are free acids or
Is an alkali metal salt, ammonium salt or amine salt
Used. These dichroic molecules combine two or more
Thus, polarizers having various hues can be manufactured.
You can. Polarization axis orthogonal as polarizing element or polarizing plate
A compound (pigment) that exhibits a black color when exposed to black or a black color
The blend of various dichroic molecules is a single plate transmittance,
The polarization rate is excellent and preferable. Also, PVA can be dehydrated or polyvinyl chloride.
By dehydrochlorinating the polyene structure,
So-called polyvinylene systems that obtain polarized light by conjugated double bonds
The stretching method of the present invention is preferably used also for the production of a polarizing film.
You can. <Protective film> The polarizing plate of the present invention comprises both polarizing films.
A protective film is attached to one surface or one surface. protection
The type of membrane is not particularly limited, and cellulose acetate,
Rulose acetate butyrate, cellulose propione
Cellulose esters such as polycarbonate, polycarbonate,
Use reolefin, polystyrene, polyester, etc.
be able to. The protective film is usually supplied in roll form,
For the long polarizing plate, make the longitudinal direction match.
It is preferable that they are bonded continuously. Where protection
The orientation axis (slow axis) of the film may be in any direction and
For convenience, the orientation axis of the protective film is parallel to the longitudinal direction.
It is preferable that Further, the slow axis (orientation axis) of the protective film and the polarizing film
The angle of the absorption axis (stretching axis) is not particularly limited, and the polarizing plate
It can be set appropriately according to the purpose. Long polarizing plate of the present invention
Since the absorption axis is not parallel to the longitudinal direction, the orientation axis is long
A protective film parallel to the direction is continuous with the long polarizing plate of the present invention.
When attaching together, the polarizing film absorption axis and protective film
A polarizing plate whose direction axis is not parallel is obtained. Absorption axis of polarizing film
And the orientation axis of the protective film are bonded at an angle that is not parallel
The polarizing plate has an effect of excellent dimensional stability. This
This performance is particularly favorable when used in liquid crystal display devices.
Devised. In the present invention, the slow axis of the protective film and the absorption of the polarizing film
The angle with the shaft is 20 ° or more and less than 70 °, but dimensional stability
40 ° or more and 50 ° not yet seen from the viewpoint of effective effect
Full is more preferable. The retardation of the protective film is generally low.
However, in the present invention, the exit from the front light is
Since the incident light is elliptically polarized light, the absorption axis of the polarizing film and the protective film
The orientation axis is set to 20 ° or more and less than 70 °, and the protective film is a letter.
To make elliptically polarized light into linearly polarized light
By increasing the distance, the amount of light transmitted through the polarizing plate is increased.
The Therefore, the retardation of the protective film is a certain value.
Preferably at, for example, 632.8 nm
0.5 nm to 10 nm is preferable, and 1 nm to 5 nm.
More preferable is nm or less. From this point of view, protection
The polymer used as the membrane is cellulose triacetate
Is particularly preferred. Also, Zeonex, Zeonore (both
Nippon Zeon Co., Ltd.), ARTON (JSR Co., Ltd.)
Such polyolefins are also preferably used. That
Other, for example, JP-A-8-110402 or JP-A-11-
Non-birefringent optics as described in 293116
Resin material is mentioned. <Adhesive> The adhesive between the polarizing film and the protective layer is special.
Although not limited to PVA resin (acetoacetyl group,
Sulfonic acid group, carboxyl group, oxyalkylene group, etc.
Modified PVA) and boron compound aqueous solution
Of these, PVA-based resins are preferred. Adhesive layer thickness is dry
Preferably 0.01 to 10 μm after drying, 0.05 to
5 μm is particularly preferable. <Integrated process> In the present invention, the film is
After stretching, it has a drying process that shrinks and lowers the volatile content rate.
A protective film on at least one side after drying or during drying
It is preferable to have a post-heating process after bonding.
As a specific pasting method, hold both ends during the drying process
A protective film on the film using an adhesive
Then, listen to both ends or dry and keep both ends
The film was released from the holding part, and both ends of the film were cut off
There is a method of attaching a protective film later. Ears
Methods include cutting with a cutter such as a blade, laser
General techniques such as using
The After bonding, in order to dry the adhesive and
In order to improve the polarization performance, heating is preferred.
Yes. The heating conditions vary depending on the adhesive, but water-based
In this case, the temperature is preferably 30 ° C. or higher, more preferably 4
0 ° C to 100 ° C, more preferably 50 ° C to 8 ° C
0 ° C. or lower. These processes are on a consistent production line
It is more preferable in terms of performance and production efficiency. <Punching> FIG. 17 shows a conventional polarizing plate punching.
Fig. 18 shows an example of punching the polarizing plate of the present invention.
The As shown in FIG.
The absorption axis 171, that is, the stretching axis coincides with the longitudinal direction 172.
In contrast, the polarizing plate of the present invention is shown in FIG.
Thus, the polarization absorption axis 181, that is, the stretching axis is in the longitudinal direction
The angle is 45 ° to 182 and this angle is the LCD
Absorption axis of polarizing plate when bonded to liquid crystal cell
And the angle formed by the vertical or horizontal direction of the liquid crystal cell itself
Therefore, diagonal punching in the punching process
It becomes unnecessary. Moreover, as can be seen from FIG.
The polarizing plate has a straight cut along the longitudinal direction.
Even by slitting along the longitudinal direction without pulling out
Since it can be manufactured, the productivity is remarkably excellent. Less than
On the polarizing plate used in the liquid crystal display device of the present invention
explained. EXAMPLES The present invention will be specifically described below based on examples.
As will be apparent, the invention is not limited to the examples. (Front Lights Used in Examples and Comparative Examples)
1 is a schematic cross-sectional view of the liquid crystal display device provided with
A reflective liquid crystal display device having a configuration shown in FIG. FIG.
As shown in FIG. 4, the liquid crystal display device includes the light guide plate 2 and the light guide plate 2.
The light source 1 disposed on the end face of the light guide plate 2
Polarizing plate 3, λ / 4 plate 4, glass substrate 5, liquid crystal layer 6, reflection
The electrode 7 and the glass substrate 8 are provided in this order. Light guide plate 2
Used the continuous prism system shown in FIG. light source
1 is a fluorescent tube, and the light guide plate 43 is bent
Injection molding of polymethylmethacrylate with a folding ratio of 1.49
What was created in this way was used. The light guide plate 43 is a light source 1
A light incident surface 43a on which light from the light enters, and the light incident surface 43
a light exit surface for emitting incident light in a direction substantially perpendicular to a
43b, an opposing surface 43c facing the light emitting surface 43b
Furthermore, this opposing surface 43c has a propagation part 4
Prism-like periodic concave having 3d and reflecting portion 43e
Convex is formed. Period P is set to 390 μm,
In order to avoid the occurrence of moire fringes, the periodicity of the light guide plate
Direction of streaks with unevenness and pixels of reflective liquid crystal display element
An angle of 23 ° was given between the patterns. The reflective liquid crystal display element is guided by the reflective electrode 7.
While reflecting the illumination light emitted from the plate 2, the liquid crystal layer
6 to adjust the amount of light transmitted through the light guide plate 2 again.
Display an image. In this example and comparative example, such
As a reflective liquid crystal display device, a 3.8-inch QVGA
Type array, that is, the number of pixels is 960 × 240,
The one having a size of 81 μm × 234.5 μm was used. Example 1 Preparation of λ / 4 plate (polycarbonate copolymer) Polycarbonate according to Example 3 of WO 00/26705
Bonate copolymer stretched films were prepared. Wavelength 450
The in-plane retardation (retardation) at nm is 14
The in-plane retardation at 8.5 nm and wavelength 550 nm is 16
The in-plane retardation at 1.1 nm and wavelength of 650 nm is 16
It was 2.9 nm. A polarizing plate integrated with a λ / 4 plate (circularly polarized light
PVA film with an average polymerization degree of 1700 and a film thickness of 75 μm
Wash both sides of the water with ion exchange water at a water flow of 2 L / min.
Air blow with the air blow device shown in 19
After removing surface moisture and removing foreign matter, the PVA film
Iodine 1.0 g / l, potassium iodide 60.0 g / l
Immerse in an aqueous solution at 25 ° C for 90 seconds, and then boric acid 40g
/ L, potassium iodide 30 g / l in an aqueous solution at 25 ° C.
After 120 seconds immersion, air blow on both sides of the film,
Excess water is removed, and the moisture content distribution in the film is 2
% In a tenter stretching machine in the form of FIG.
Introduced. Sending 100m at 5m / min.
And then temporarily extended 5.5 times in an atmosphere of 40 ° C and 95% humidity.
After stretching, it contracts to 4.0 times, and keeps the width constant.
During drying at 60 ° C., λ / 4 produced on one side as described above
The plate, the other side is PVA (Pura-1 manufactured by Kuraray Co., Ltd.)
17H) Fuji saponified with 3% aqueous solution as an adhesive
Fujitac (cellulose triace) manufactured by Photo Film Co., Ltd.
Tate, retardation value 3.0nm, film thickness 40μ
m) and further heated at 60 ° C. for 30 minutes.
After this, it is detached from the tenter and 3 cm from the width direction
The ears, and the effective width is 650mm and the length is 100m.
A roll-shaped polarizing plate was prepared. The drying point is (c)
Moisture content of PVA film that is intermediate
Was 30%, and the water content after drying was 1.5%. Left and right
The difference in transport speed of tenter clips is less than 0.05%
Yes, sent to the center line of the film to be introduced and the next process
The angle formed by the center line of the film was 0 °. Where | L
1-L2 | is 0.7 m, W is 0.7 m, | L1-
L2 | = W. At the tenter exit
No film deformation was observed. Circular polarization obtained
In the plate, the absorption axis direction of the polarizing film is such that the protective film and λ /
It was inclined 45 ° with respect to the slow axis of the four plates. (Measurement of retardation) Oji measurement
Wavelength 632.8n using KOBRA21DH manufactured by
Measured in m. Example 2 The λ / 4 plate was changed to the following cellulose acetate type λ / 4 plate.
The protective film and λ / 4 plate were the same as in Example 1 except that
Polarized light whose absorption axis of the polarizing film is inclined 45 ° with respect to the slow axis of
A plate was made. -Preparation of cellulose acetate type λ / 4 plate Cellulose acetate with an average degree of acetylation of 59.5% at room temperature
Tate 100 parts by weight, triphenyl phosphate 7.8
Parts by mass, 3.9 masses of biphenyl diphenyl phosphate
Part, retardation control agent (41-trans) 1.32
Parts by weight, methylene chloride 587.69 parts by weight, methanol
50.85 parts by mass of a solution is mixed to prepare a solution (dope)
did. The obtained dope was cast on a film-forming band, and the room temperature
And then dried at 45 ° C. for 5 minutes. After drying
The residual solvent amount was 30% by mass. Cellulose acetate
The film is peeled from the band and dried at 120 ° C for 10 minutes.
After drying, at 130 ° C, it is a real magnification in the direction parallel to the casting direction.
The film was stretched 1.34 times. The direction perpendicular to the stretching direction is free
I was able to shrink. After stretching, 30 minutes at 120 ° C
After drying, the stretched film was taken out. Solvent after stretching
The residual amount was 0.1% by mass. Cellulose acetate film after stretching
The thickness of the film is 112.7 μm and the ellipsometer
(M-150, manufactured by JASCO Corporation), wavelength 45
Letterde at 0 nm, 550 nm and 590 nm
The measurement value (Re) was measured to be 12 respectively.
5.2 nm, 137.8 nm and 141.1 nm
It was. Therefore, this cellulose acetate film
Λ / 4 was achieved in a wide wavelength region. In addition, Abbe
Refractive index measurement with a refractometer and angle of retardation
In-plane slow phase at a wavelength of 550 nm
Refractive index nx in the axial direction, refraction in the direction perpendicular to the in-plane slow axis
The refractive index ny and the refractive index nz in the thickness direction are obtained, and (nx−n
z) / (nx−ny) was calculated to be 1.48.
Met. In addition, (nx-nz) / (nx-ny) is
A value called NZ parameter with a large value
The display contrast change due to the viewing angle is less and preferable
Yes. Example 3 A λ / 4 plate was changed to Example 1 of JP-A-2001-4837.
Vertical alignment layer of discotic liquid crystal described (λ / 2 plate
And a stretched polycarbonate film (λ / 4 plate)
Except for the change to the ritsu film, the same as in Example 1.
The absorption axis of the polarizing film with respect to the slow axis of the protective film and λ / 4 plate
A circularly polarizing plate having an inclination of 45 ° was produced. Comparative Example A polarizing plate was prepared by the following procedure and bonded to a λ / 4 plate.
A comparative circularly polarizing plate was prepared in the same manner as in Example 1 outside.
It was. -Comparative example circularly polarizing plate PVA film with iodine 5.0 g / l, potassium iodide
Immerse it in a 10.0 g / l aqueous solution at 25 ° C. for 90 seconds.
Furthermore, it is immersed in an aqueous solution of boric acid 10 g / l at 25 ° C. for 60 seconds.
Then, it extended | stretched 7.0 time using the roll extending | stretching machine. this
Later used in Example 1 prepared on one side of stretched film
Layered polycarbonate copolymer stretched film
Two films stacked on top of each other are made of polyvinyl alcohol
(PVA117, Kuraray Co., Ltd.) 5 wt% aqueous solution as paste
Saponified triacetyl cellulose film
(Fuji Photo Film Co., Ltd. slow axis in the longitudinal direction) 2 sheets
Was laminated. After this, using an adhesive
Bonding with the λ / 4 plate used in Example 1 and further 5 at 70 ° C.
A circularly polarizing plate was produced by drying for minutes. The slow axis of the protective film
The angle with the absorption axis of the polarizing film was almost 0 °. [Evaluation of liquid crystal display device] Examples 1-3
And the circularly polarizing plate produced in Comparative Example 1
Built into the polarizing plate and λ / 4 plate part of the projection type liquid crystal display device
After that, two kinds of evaluation regarding the following display quality were performed. This
Now, as described above, each member is removed from the front light part.
The polarizing plates were arranged in order of λ / 4. In addition, the periodicity of the light guide plate
The direction of the streaks with unevenness and the direction of the absorption axis of the polarizing plate
Made orthogonal. (1) Observe the liquid crystal display device by illumination with ambient light
Without using a display-quality front light.
The white display of the liquid crystal display device using the color meter CM-2002
Measure the reflectance and the reflectance of the black display,
The contrast ratio was calculated. The results are shown in Table 1.
As shown in Table 1, a liquid using the circularly polarizing plate of Comparative Example 1
Compared with crystal display device, liquid crystal display using the circularly polarizing plate of the example
The device has improved white display reflectivity and contrast ratio.
It has improved. (2) Liquid crystal surface by front light illumination
Luminance meter made by TOPCOM Co., Ltd. using a display quality front light when observing the display device
Brightness and black of white display of liquid crystal display device using BM-5A
Measure the brightness of the color display, brightness and contrast of the display
The ratio was calculated. The results are shown in Table 2. Shown in Table 2
The conventional liquid crystal display device (the circularly polarizing plate of Comparative Example 1)
Compared to the liquid crystal display device used)
The liquid crystal display device has a large contrast ratio and brightness.
It can be seen that improvement has been realized. [Table 1] [Table 2] The reflection type provided with the front light of the present invention.
The LCD display value is greatly improved in brightness and contrast
Has been. Moreover, the polarizing plate used has a longitudinal direction and absorption.
The angle of inclination with respect to the direction of the converging axis can be set to 44 ° to 46 °.
Thus, in the punching process from a long polarizing plate
In addition, a single plate polarizing plate can be obtained with good yield, so it is low cost.
The reflective liquid crystal display device of the present invention can be provided at low cost.
You can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a general configuration of a reflective liquid crystal display device including a front light. FIG. 2 is a cross-sectional view showing a basic configuration of a reflective liquid crystal display device according to the present invention. FIG. 3 is a schematic cross-sectional view showing a front light having a microprism structure. FIG. 4 is a schematic sectional view showing an inclined front light. FIG. 5 is a schematic cross-sectional view showing a prism continuous front light. FIG. 6 is a schematic cross-sectional view showing a volume hologram front light. FIG. 7 is a schematic cross-sectional view showing a circularly polarizing plate in which a polarizing plate and a λ / 4 plate are bonded together. FIG. 8 is a schematic cross-sectional view showing a circularly polarizing plate in which a polarizing plate and a λ / 4 plate are integrated. FIG. 9 is a schematic sectional view showing a circularly polarizing plate in which a polarizing plate and a λ / 4 plate are integrated and an antireflection layer is provided. FIG. 10 is a continuous prism type light guide plate of the reflective liquid crystal display device used in Examples. FIG. 11 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 12 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 13 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 14 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 15 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 16 is a schematic plan view showing an example of the method of the present invention for obliquely stretching a polymer film. FIG. 17 is a schematic plan view showing a state of punching a conventional polarizing plate. FIG. 18 is a schematic plan view showing a state of punching out the polarizing plate of the present invention. FIG. 19 is a schematic conceptual diagram of an air blow device. FIG. 20 is a schematic conceptual diagram of a nip device. FIG. 21 is a schematic conceptual diagram of a blade device. FIG. 22 is a diagram schematically showing the display principle of the reflective display device. [Explanation of Symbols] (a) Film introduction direction (b) Film transport direction to the next step (a) Step of introducing the film (b) Step of stretching the film (c) Step of sending the stretched film to the next step A1 Film B1 Film holding position (substantially holding start point: right) B1 Film holding position (left) C1 Film stretching start position (substantially holding start point: left) Cx Film separation position and film stretching end point reference position (substantially holding release point: left) Ay Film stretching end point reference position (substantially holding release point:
Right) | L1-L2 | Stroke difference W between left and right film holding means W Substantially width θ at the end of the film stretching process 1 Angle formed by stretching direction and film traveling direction 1 Light source 2 Light guide plate 2a Incident surface 2b Opposing surface 2c Output surface 3 Polarized light Plate 4 λ / 4 plate 5 Glass substrate 6 Liquid crystal layer 7 Reflector plate 8 Glass substrate 9 Polarizing plate with λ / 4 10 Illuminating fluorescent lamp 11 Light guide plate 11a Side surface (incident surface) of light guide plate 11b Microprism 11c Inclined prism 12 Holder DESCRIPTION OF SYMBOLS 13 Optical compensator 14 Front light 15 Light guide plate 15A Light guide plate one surface part (lower side) 15B Light guide plate other surface part 16 Light source part 17 Lamp 18 Lamp holder 19 Light source 20 Light guide plate 20a Light guide plate gentle slope part 20b Light guide plate steep slope part 20c Output surface 21 Light source 22 Light guide plate 23 Volume hologram layer 1 38 Transparent support 39 λ / 4 plate 40 Polarizing plate 41 Antireflection layer-attached Membrane 42 Adhesive layer 111 Center line 112 of the introduction side film Center line 113 of the film sent to the next process Trajectory of the film holding means (left) 114 Trajectory of the film holding means (right) 115 Introduction side film 116 sent to the next process Film 117, 117 ′ Left and right film holding start (engagement) points 118, 118 ′ Disengagement point from left and right film holding means 121 Introducing film center line 122 Film center line 123 sent to next process 123 Film holding means Trajectory (left) 124 Trajectory of film holding means (right) 125 Introducing film 126 Film 127, 127 ′ sent to next process Left and right film holding start (engagement) points 128, 128 ′ Release from left and right film holding means Points 133, 143, 153, 163 Trajectory of film holding means (left) 134, 14 4, 154, 164 Trajectory of film holding means (right) 135, 145, 155, 165 Introduction side film 136, 146, 156, 166 Film 171 sent to next process Absorption axis (stretching axis) 172 Longitudinal direction 181 Absorption axis ( Stretching axis) 182 Longitudinal direction 191, 192 Iodine-based polarizing film (polarizing layer) 193 Liquid crystal cell 194 Backlight 201 Air blow device 211 Nip device 221 Blade device

Claims (1)

What is claimed is: 1. A front light comprising a light source, a light guide plate having an incident surface on which light from the light source is incident, and an output surface from which the incident light is emitted; In a liquid crystal display device comprising a reflective liquid crystal display element that displays light by controlling light emitted from an output surface for each pixel and reflecting it to the output surface side of the light guide plate, a front light and a reflective liquid crystal display A polarizing plate including a polarizing film and a protective film and having an angle between 20 ° and less than 70 ° between the slow axis of the protective film and the absorption axis of the polarizing film is placed between the element and the element. A reflective liquid crystal display device.