JPH1124070A - Reflector and reflection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflector having a reflecting angle in a wide range and capable of improving reflection efficiency by successively providing many grooves extending in one direction on the surface of the reflector and many grooves in a direction crossing with hat direction. SOLUTION: For example, the many stripe first grooves 21a whose curved surface cross sectional shapes are the same R and which extend in the same direction, and also the many second grooves 21b in the direction crossing with that direction are successively provided on the surface of a planar resin base material 21 constituted of a photoreceptive resin layer. When the depth (d1 ) of the grooves 21a is made much larger than the depth (d2 ) of the grooves 21b; the deep grooves 21a are formed on the surface of the reflector as a basic structure, and shallow concave parts are formed on a ridge line part made between the grooves 21a. Consequently, secondary operation that the reflecting direction incident light from a direction orthogonally crossing with a first grooves 21a direction is widened in a direction other than the direction orthogonally crossing with the first grooves 21a by irregular reflection is added to central operation that the reflecting direction of incident light is widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a reflector having a high reflection efficiency on a reflection surface, and a reflection type liquid crystal display device using the reflector.

[0002]

2. Description of the Related Art In recent years, a reflection type liquid crystal display device has been widely used as a display portion of a handy type computer or the like, particularly because of low power consumption. This reflective liquid crystal display device includes a reflector for reflecting light incident from the display surface side to perform display. As a conventional reflector, a reflector having a mirror-finished surface or a reflector having a random uneven surface formed on the surface has been used. As shown in FIG. 10, this conventional reflector 60 having a random uneven surface has a thickness of 300 to 50, for example.
By heating a 0 μm polyester film, an uneven surface 61 a made of unevenness having a height of several μm is formed on the surface thereof, and a reflective film 62 made of aluminum or the like is formed on the uneven surface 61 a by a method such as evaporation. It is formed by forming a film.

FIG. 11 is a cross-sectional view showing a conventional reflection type liquid crystal display device using a reflection plate 60 of this type. This conventional reflective liquid crystal display device 50 includes a pair of glass substrates 51,
52, transparent electrode layers 53, 54 are provided on the respective opposing surfaces, and liquid crystal alignment films 55, 56 are provided on the transparent electrode layers 53, 54, respectively.
A liquid crystal layer 57 is provided between the liquid crystal layers 5 and 56. Then, first and second polarizing plates 58 and 59 are provided outside the glass substrates 51 and 52, respectively,
On the outside of the polarizing plate 59, the above-described reflecting plate 60 is provided with a reflecting film 62.
It is attached with its side facing the second polarizing plate 59 side. In FIG. 11, reference numeral 65 denotes the glass substrate 5.
The sealing body 65 seals the liquid crystal layer 57 between the first and second liquid crystal layers 52.

In the reflection type liquid crystal display device 50 having the above-described structure, the light incident on the first polarizing plate 58 is linearly polarized by the polarizing plate 58, and the polarized light is elliptically polarized by passing through the liquid crystal layer 57. You. The elliptically polarized light passes through the second polarizing plate 59 and is linearly polarized. The linearly polarized light is reflected by the reflecting plate 60, passes through the second polarizing plate 59 and the liquid crystal layer 57 again, and is emitted from the first polarizing plate 58.

The reflection plate 60 and the reflection type liquid crystal display device 5
FIG. 10 shows the reflection characteristics with respect to incident light at 0.
The angle of incidence of the incident light J from the point light source disposed on the reflective film 62 is made constant at an incident angle of 30 degrees with respect to the perpendicular to the reflective film surface as shown in FIG. When the reflectance (a value expressed as a percentage (%) obtained by dividing the output of the reflected light K by the reference output) was plotted and the reflection characteristic curve was examined,
The reflection characteristic curve of the reflection plate 60 itself has a reflection angle of 30 degrees as a peak (reflection rate of about 1100%) and a left and right reflection angle 2.
The reflectance is almost the lowest at 0 degrees or less and 40 degrees or more, and the reflection characteristic curve of the reflection type liquid crystal display device itself has a peak at about 100% of the reflection angle of 30 degrees.
It falls to 0% in the range from a reflection angle of 23 degrees or less to 37 degrees or more. The reference output was measured using a liquid crystal panel evaluation device (LCD 5000 model manufactured by Otsuka Electronics Co., Ltd.), and a white plate (MgO
This is the output of the reflected light at a reflection angle of 30 degrees when the light is irradiated onto a plate having a standard white surface at a light incidence angle of 30 degrees.

In addition, the reflection characteristics of a conventional reflector having a mirror-finished surface are generally very high at a specific reflection angle with respect to the incident angle as compared with a reflector having a random uneven surface. Shows the reflectance. However, it has the characteristic that the range of the reflection angle with high reflectance is extremely narrow, that is, the viewing angle is narrow.

[0007]

As described above, the conventional reflection plate 60 having a random uneven reflection surface has a low reflectance as a whole due to poor reflection efficiency, so that incident light can be reflected over a wider range of reflection angles. It was not possible to sufficiently meet the needs of a reflecting plate for reflecting light. Therefore, this type of reflector 60
Has a viewing angle of about 25 to
There is a problem that the range of 35 degrees is relatively narrow and the brightness of the display surface is not sufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a reflector having a wide range of reflection angles and capable of improving the reflection efficiency, and the use of such a reflector. It is another object of the present invention to provide a reflective liquid crystal display device having a wide viewing angle in any direction and a bright display surface.

[0009]

According to the reflector of the present invention, a large number of first grooves extending in one direction are continuously provided on the surface of the reflector, and a large number of first grooves are provided in a direction intersecting the first grooves. Two grooves are continuously provided, and the depth of the first groove is different from the depth of the second groove. According to such a reflector, the reflection direction of light incident from a direction perpendicular to the direction in which the grooves extend is increased, so that the reflection efficiency is improved, and in addition, a large number of recesses are formed in the ridge portion between the adjacent grooves. As a result, the light incident on the concave portion is irregularly reflected, and the irregular reflection causes the reflection direction to expand in directions other than the direction perpendicular to the groove. For example, when the configuration was sufficiently large depth d ₁ of the first groove with respect to depth d ₂ of the second groove is deeper first groove to the reflecting surface as a basic structure is formed Above, these first
A shallow concave portion is formed in the ridge line portion formed between the grooves, and therefore, the central effect that the reflection direction of incident light from the direction orthogonal to the first groove direction is widened, This has the additional effect that the reflection direction expands in a direction other than the direction orthogonal to the first groove.

In the reflector according to the present invention, a large number of first grooves extending in one direction are continuously provided on the surface of the reflector, and a large number of second grooves are continuously provided in a direction intersecting the first grooves. The depth of the first groove is equal to the depth of the second groove. According to such a reflector,
The reflection efficiency of the light incident from a direction perpendicular to the direction in which the first groove extends is increased, so that the reflection efficiency is improved, and the light incident on the second groove intersecting the first groove is irregularly reflected. Due to the irregular reflection, the reflection direction spreads in directions other than the direction perpendicular to the first groove.

The plurality of grooves may have a linear shape in plan view, or may be curved with a predetermined curvature. When the groove is curved, light impinges on a surface that is curved along the direction in which the groove extends, so that the light reflection direction is wider than when the groove is not curved. In the present invention, the first groove depth refers to a height from the top of the ridge line to the bottom of the first groove. The second groove depth refers to the height from the top of the ridge line to the bottom of the second groove.

The reflector according to the present invention is formed, for example, by transferring a mold surface of a transfer mold having a large number of grooves extending in one direction onto a resin substrate for a reflector by transferring the mold surface to the resin substrate for a reflector. A first transfer step of forming a large number of first grooves extending in one direction, and a transfer die having a large number of grooves extending in one direction, the direction of the grooves extending in the first transfer step. By arranging the mold so as to be in a direction intersecting the direction and transferring the mold surface to the resin base material for the reflector, the ridge line between the first grooves formed in the first transfer step has the above-mentioned first groove. Either a number of concave portions (second grooves) having a depth different from the depth are formed, or a depth that is equal to the depth of the first groove intersects with the first groove formed in the first transfer step. Having a second
Performing a second transfer step of forming the grooves of the first and second steps, and thereafter, forming a reflective film on the surface of the resin base material for the reflector on which the large number of the first grooves and the concave portions or the second grooves are transferred. It can be manufactured by the method performed. That is, this method is to perform the transfer twice with changing the direction of the groove on the surface of the resin substrate for a reflector by using a transfer mold having a large number of grooves extending in one direction, so that a large number of first grooves are formed. And forming a second groove intersecting the first groove. Then, the depth of the first groove formed in the first transfer step and the second groove formed in the second transfer step
The groove depths of the first groove and the second groove may be different or equal, and several methods can be considered as specific means for forming the first groove and the second groove.

For example, for the depth d ₂ of the _second groove,
When manufacturing the reflector arrangement with a larger depth d ₁ of the groove of using the first transfer mold having a plurality of grooves in the first transfer step, use in the first transfer step in the second transfer step When transfer is performed using the second transfer die having a large number of grooves shallower than the depth of the groove of the first transfer die, d _{2 is} replaced by d ₁
The first groove and the second groove satisfying the relationship that the relationship is large can be formed. Alternatively, transfer is performed in each step by using a transfer die having the same groove depth and controlling the press pressure in the second transfer step to be smaller than the press pressure in the transfer in the first transfer step. It may be. When the transfer molds having the same groove depth are used, another transfer mold having a groove having the same depth may be used, or one transfer mold may be used as the first and second transfer molds.
It may be used again in both transfer steps.

When manufacturing a reflector having a structure in which the depth d ₂ of the _second groove is equal to the depth d ₁ of the first groove, a large number of first grooves are provided in the first transfer step. Using the first transfer mold, in the second transfer step, transfer is performed using the second transfer mold having a large number of grooves having the same depth as the grooves of the first transfer mold used in the first transfer step. By doing so, the first groove and the second groove satisfying the relation of d ₂ and d ₁ being equal can be formed. Alternatively, a first transfer mold having a large number of grooves in the first transfer step is used, and a second transfer step having a large number of grooves shallower than the depth of the first transfer mold used in the first transfer step in the second transfer step. The transfer in each step may be performed by using the second transfer mold and controlling the press pressure in the second transfer step to be larger than the press pressure in the transfer in the first transfer step.

In the reflection type liquid crystal display device according to the present invention, a large number of first grooves extending in one direction are continuously provided on the surface of the reflector, and a large number of grooves are provided in a direction intersecting the first grooves. A second groove is continuously provided, and a depth of the first groove is different from a depth of the second groove, or a plurality of first grooves extending in one direction on the surface of the reflector. Grooves are provided continuously, and a number of second grooves are provided in a direction intersecting with the first grooves. The depth of the first groove and the second
And a reflector characterized by having the same groove depth. The reflector provided in the reflection type liquid crystal display device according to the present invention may be either an external type or a built-in type. According to the reflective liquid crystal display device of the present invention, since the reflector itself has high reflection efficiency and a wide range of reflection directions, the viewing angle is increased in any direction as compared with the conventional reflective liquid crystal display device. ,
The display surface can be made bright overall.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a reflector according to the first embodiment. As shown in this figure, the reflector of the present embodiment has, for example, a large number of stripes having a curved cross-sectional shape of the same R and extending in the same direction on the surface of a flat resin substrate 21 made of a photosensitive resin layer. First groove (first groove)
21a, and a large number of second grooves 21b are provided in a direction intersecting with the first grooves 21a. A thin film of, for example, aluminum or silver is formed on the first and second grooves 21a, 21b. The reflection film 22 is formed by vapor deposition or printing. In this reflector, a large number of recesses 20a are formed so as to be continuous along the ridge 20 between the adjacent grooves 21a.

The first grooves 21a are formed such that adjacent first grooves have mutually different groove widths so that interference fringes do not occur due to light reflected from these grooves, and the curved surface R has a zero curvature. 0.4 μm or more and 100 μm or less. When R exceeds 100 μm, the groove is visually recognized, and the display quality of the liquid crystal display element is largely reduced, so that R is preferably 100 μm or less. On the other hand, if R is smaller than the order of visible light, that is, smaller than 0.4 μm, effective reflection characteristics cannot be obtained. Also, the depth d of the first groove 21a
₁ is formed to be larger than the depth d ₂ of the concave portion 20a of the ridge portion 20 is about approximately 1 to 2 [mu] m.

Next, a method of manufacturing the reflector according to the first embodiment will be described with reference to FIG. First, as shown in FIG. 2A, a surface of a flat plate-shaped mold 30 made of, for example, a copper alloy, an iron alloy, or the like is flattened to have a radius R of a cutting edge 31a of 30.
While being cut linearly by a grinding jig 31 such as a cutting tool having a size of about 100 μm and changing the feed pitch in a direction orthogonal to the direction in which the grooves extend, the adjacent stripe grooves 30a shown in FIG. A matrix 30 having mold surfaces with mutually different groove widths is formed. The feed pitch P during grinding of the grinding jig 31 is, for example, P _{1 of} 13 μm, P _{2 of} 16 μm,
There are four types of P _{3 of} 7 μm and P ₄ of 18 μm.
It sends while changing the kind of feed pitch P irregularly. For example, the feed pitch is 18 μm, 13 μm, 13 μm, 16
μm, 17 μm, 13 μm, 13 μm, 17 μm, 13
R30μm at the same depth for each μm unit
Cutting using a cutting tool is performed.

The cutting edge 31a of the grinding jig 31 for grinding is used.
May be not only an arc-shaped surface but also various other curved surfaces, but an arc-shaped surface is desirable because the jig itself is most easily processed. The feed pitch is not limited to the above-described four types of dimensions, and several types of dimensions may be combined in an irregular order. Also, by repeatedly cutting a unit consisting of a certain number of stripe grooves with the same feed pitch and a different cutting depth for each stripe groove, the groove widths of adjacent stripe grooves shown in FIG. A matrix having different mold surfaces may be formed. Furthermore, by repeatedly cutting a unit consisting of an arbitrary number of stripe grooves while changing the feed pitch and changing the cutting depth for each stripe groove, the groove width of the adjacent stripe groove 30a shown in FIG. Alternatively, a matrix 30 having different mold surfaces may be formed. Furthermore, by repeatedly cutting a unit consisting of an arbitrary number of stripe grooves while changing the feed pitch and changing the cutting depth for each stripe groove, the groove width of the adjacent stripe groove 30a shown in FIG. Alternatively, a matrix 30 having different mold surfaces may be formed.

Thereafter, as shown in FIG.
0 is stored in a box-shaped container 32, a resin material 33 such as silicone is poured into the container 32, and left to cure at room temperature. The cured resin product is taken out of the container 32 and unnecessary portions are cut off. Then, as shown in FIG. 2D, a transfer mold 40a having a mold surface having a large number of reverse stripe grooves 40a having a concave and convex shape opposite to the large number of stripe grooves 30a forming the mold surface of the matrix 30 is produced.

Next, as shown in FIG. 2E, a photosensitive resin solution 19 such as an acrylic resist, a polystyrene resist, an azide rubber resist, or an imide resist is spin-coated on the upper surface of the transparent glass substrate 2. After applying by a coating method such as a printing method, a screen printing method, or a spraying method, the photosensitive resin liquid 19 on the substrate 2 is heated in a temperature range of, for example, 80 to 100 ° C. for 1 minute using a heating device such as a heating furnace or a hot plate. By performing the prebaking by heating as described above, the resin base material 21 made of the photosensitive resin layer is formed on the substrate 2. However, since the pre-bake conditions differ depending on the type of the photosensitive resin used, it is needless to say that the treatment may be performed at a temperature and a time outside the above range. The thickness of the resin substrate 21 formed here is preferably in the range of 2 to 5 μm.

Thereafter, as shown in FIG.
After using the transfer mold (first transfer mold) 40 shown in FIG. 3D and pressing the mold surface of the transfer mold 40 against the resin base material 21 on the glass substrate 2 for a certain period of time, as shown in FIG. The transfer mold 40 is removed from the resin substrate 21 as described above. In this manner, the reverse stripe groove 40 of the transfer mold 40 is formed on the surface of the photosensitive resin substrate 21.
The mold surface on which a is formed is transferred to form a large number of striped first grooves 21a (first transfer step). Further, it is preferable to select a value suitable for the type of the photosensitive resin to be used as the pressing pressure at the time of embossing, for example, 30 to 50 kg / cm.
Pressure should be about ² . As for the pressing time, it is preferable to select a value suitable for the type of the photosensitive resin to be used, for example, about 30 seconds to 10 minutes.

Next, as shown in FIG. 3C, the transfer die 40 used in the first transfer step is rotated about the axis G, and the direction in which the groove 40a of the transfer die 40 extends is the first direction. The transfer mold 40 is arranged so as to intersect with the extending direction of the first groove 21a on the resin base 21 formed in the transfer process (arranged at an angle of 90 degrees in the drawing), and the pressing pressure is reduced. The transfer mold 40 is pressed against the resin base material 21 for a certain period of time in the same manner as in the first transfer step except that the pressure is smaller than the press pressure at the time of the stamping in the first transfer step.
After transferring the mold surface of No. 0, when the transfer mold 40 is removed from the resin base material 21, a large number of second grooves 21b shown in FIG. 1 are formed (second transfer step).

Thereafter, light such as ultraviolet rays for curing the resin substrate 21 is irradiated from the back side of the glass substrate 2 to cure the resin substrate 21. When the resin base 21 is made of a photosensitive resin layer of the above-described type, the light rays such as ultraviolet rays are applied to the resin base 2 if the strength is 50 mJ / cm ² or more.
1 is sufficient to cure, but depending on the type of the photosensitive resin layer, it is a matter of course that irradiation may be performed at other intensities. Then, the glass substrate 2 is heated using a heating device such as a heating furnace or a hot plate used in the pre-bake.
The resin base 21 on the glass substrate 2 is post-baked by heating the upper resin base 21 at, for example, about 240 ° C. for 1 minute or more.
1 is fired. By performing the transfer twice by changing the extending direction of the groove in this manner, the resin base material 2 on the glass substrate 2
A large number of stripe-shaped first grooves 21a are continuously provided on the surface of the device 1, and a large number of recesses 20a are continuously formed along a ridge 20 between adjacent first grooves 21a.
The depth d ₂ of the concave portion 20 a of the ridge 20 is the first groove 21.
It is smaller than the depth d ₁ of a. Finally, a film of, for example, aluminum is formed on the surface of the resin substrate 21 by electron beam evaporation or the like to form the first groove 21a and the recess 20.
By forming the reflective film 22 along the surface of a, the reflector of the first embodiment shown in FIG. 1 is obtained.

As described above, using the transfer mold having the same groove depth,
When transfer is performed in each step while controlling the press pressure in the second transfer step to be smaller than the press pressure in the transfer in the first transfer step, d ₁ is sufficiently larger than d ₂ . A first groove that satisfies the relationship can be formed with a concave portion at a ridge portion between the first grooves. When the transfer mold having the same groove depth is used, another transfer mold having a groove having the same depth may be used, or one transfer mold may be used in both the first and second transfer steps. You may turn it. Alternatively, a first transfer mold having a large number of grooves in the first transfer step is used, and a second transfer step having a large number of grooves shallower than the depth of the first transfer mold used in the first transfer step in the second transfer step. The transfer may be performed using the second transfer mold.

According to the reflector of the first embodiment, the reflector
After the deep first groove 21a is formed on the surface,
A shallow concave portion is formed in the ridgeline portion 20 formed between the first grooves 21a.
20a has been formed, and therefore the
Incident light from a direction orthogonal to the direction in which one groove 21a extends
The central effect that the reflection direction of
Other than the direction orthogonal to the direction in which the first groove 21a extends.
Reflection direction spreads. The direction in which the grooves intersect is orthogonal.
Or may intersect at any angle. Others
Other than the stripe-shaped groove of the reflector in the above embodiment
It is possible to form a groove having the form shown in FIG. The fruit of the above reflector
In the embodiment, the depth d of the second groove is_TwoThe depth of the first groove
D ₁Explained the configuration with a sufficiently large configuration
However, in the reflector according to the present invention, the depth d of the first groove is
₁With respect to the depth d of the second groove_TwoThailand with enough size
It may be one of the group.

FIG. 4 is a perspective view showing a second embodiment of the reflector according to the present invention. Reflector of the second embodiment, the first embodiment the reflector differs from the that shown FIG. 1, the depth d ₁ of the first groove 21a is the depth d ₂ of the second groove 21 The point is that they are formed to be equal. The reflector has a large number of substantially quadrangular pyramid-shaped protrusions 2 on its surface.
0b is formed.

In the method of manufacturing a reflector according to the second embodiment, when a transfer die having the same groove depth is used, the press pressure during the transfer in the first transfer step and the press pressure in the second transfer step are equal. except controlled to be performed transcription in each step, by producing in the same manner as the manufacturing method of the reflector of the first embodiment described above, the satisfy a relationship of d ₂ and d ₁ is equal to The first groove 21a and the second groove 21b can be formed. Alternatively, in the first transfer step, a first transfer mold having a large number of stripe-shaped grooves is used, and in the second transfer step, a large number of grooves shallower than the grooves of the first transfer mold used in the first transfer step are formed. The transfer in each step may be performed by using the second transfer mold having the control so that the press pressure in the second transfer step is larger than the press pressure in the transfer in the first transfer step. .

According to the reflector of the second embodiment, not only the reflection efficiency is improved by expanding the reflection direction of the incident light from the direction perpendicular to the direction in which the first groove 21a extends, but also the first Since the _second groove 21b whose depth d2 is equal to the depth d1 of the _first groove 21a is continuously provided in the direction intersecting the groove 21a, the light incident on the second groove 21b is irregularly reflected. ,
Due to the irregular reflection, the reflection direction is expanded in directions other than the direction orthogonal to the first groove 21a.

Hereinafter, the ST using the reflector of the present embodiment will be described.
A reflection type liquid crystal display device of the N (Super Twisted Nematic) type will be described. FIG. 5 is a cross-sectional view showing the configuration of the reflection type liquid crystal display device. In this reflection type liquid crystal display device, for example, a liquid crystal layer 3 is provided between a pair of display side glass substrates 1 and a rear side glass substrate 2 having a thickness of 0.7 mm. One retardation plate 4 made of resin or polyarylate resin is provided,
Further, a first polarizing plate 5 is provided on the upper surface side of the phase difference plate 4.

On the lower surface side of the rear glass substrate 2, a second polarizing plate 6 and the reflector 25 of the embodiment of the present invention shown in FIG. 1 or 4 are sequentially provided. The reflector 25 is laminated on the lower surface side of the second polarizing plate 6 with the reflecting film 22 opposed thereto, and between the second polarizing plate 6 and the reflecting film 22, adversely affects the refractive index of light such as glycerin. An adhesive 7 made of a material that is not given is filled. Transparent electrode layers 8 and 9 made of ITO (indium tin oxide) or the like are formed on the opposing surfaces of the two glass substrates 1 and 2, respectively, and an alignment film 10 made of a polyimide resin or the like is formed on the transparent electrode layers 8 and 9 respectively. 1
1 is provided. The liquid crystal in the liquid crystal layer 3 is twisted by 240 degrees due to the relationship between the alignment films 10 and 11 and the like. In FIG. 5, reference numeral 12 denotes a sealing body for sealing the liquid crystal layer 3 between the glass substrates 1 and 2. Further, a color filter layer (not shown) may be formed between the rear glass substrate 2 and the transparent electrode layer 9 by a printing method or the like, so that the liquid crystal display device can perform color display.

The reflector 25 serves to increase the viewing angle by reflecting and diffusing incident light. As described in detail above, the reflector 25 in this reflection type liquid crystal display device has a large number of stripe-shaped first grooves 21a continuously formed on the surface of the resin base material 21 and ridge portions between the first grooves 21a. The first groove 21 has a depth d ₂ at 20.
a depth d ₁ is smaller than a number of recesses 20a are formed,
The first groove 21 a and the concave portion 20 a on which the reflection film 22 is formed, or a plurality of stripe-shaped first grooves 21 a are continuously provided on the surface of the resin base material 21, and the first groove 2 is formed.
It crosses the 1a, and the depth d ₂ of the first groove 21a depth d ₁
Are formed, and these first grooves 2b are formed.
The reflective film 22 is formed on the first groove 1a and the second groove 21b.

According to the reflection type liquid crystal display device of the embodiment,
Since the reflector 25 itself has a high reflection efficiency and a wide range of reflection directions, the viewing angle can be increased in any direction as compared with the conventional reflection type liquid crystal display device, and the display surface can be made bright overall. it can. In the reflection type liquid crystal display device of the present embodiment, an example is described in which the reflection plate is externally attached, but the reflection type liquid crystal display device may be a built-in type. Also, the depth d of the second groove
A reflective liquid crystal display device provided with a reflector having a sufficiently large _first groove depth d ₁ with respect to ₂ has been described.
A type in which a reflector having a depth d ₂ of the second groove sufficiently larger than the depth d ₁ of the groove may be provided. When such a reflector is provided in the liquid crystal display device, It can be used if the reflector is arranged rotated by 90 ° about the axis. Although the STN type liquid crystal display device has been described as an example of the liquid crystal display device, the reflector of the present invention is also applied to a TN (Twisted Nematic) type liquid crystal display device in which the twist angle of liquid crystal molecules in the liquid crystal layer is set to 90 degrees. Of course, it can be applied.
Further, it is needless to say that the reflector of the present invention can be applied to a color liquid crystal display device instead of a monochrome liquid crystal display device having no color filter.

(Experimental Example) At the time of the transfer in the first transfer step, the transfer was performed under the press conditions shown in Table 1 below to obtain a depth d _1.
The first groove is formed, and a second groove having a depth d ₂ orthogonal to the first groove is formed by performing the transfer under the pressing conditions shown in Table 2 at the time of the transfer in the second transfer step. Then, a reflective film was formed on the first groove and the second groove to produce various reflectors.

[0035]

[Table 1]

[0036]

[Table 2]

Next, the reflector (sample No.
The reflection characteristics with respect to incident light in 1 to 22) were examined. The results are shown in Table 3 and FIGS. In the column of the depth d2 of the _second groove in Table 3, 0 indicates that the second groove is not formed.

[0038]

[Table 3]

Here, the reflection characteristic is such that incident light from a point light source disposed on the reflecting surface of the reflector is incident at an angle of 30 degrees from a direction parallel to the direction perpendicular to the surface of the reflector and extending from the direction in which the first groove extends. From the reflection characteristic curve showing the relationship between the reflectance% (vertical axis) and the reflection angle θ (horizontal axis) when the reflectance is constant, the maximum value of the reflectance (Max reflectance) and the left side of the peak (Max reflectance) Was evaluated by examining the range (viewing angle Δθ) from the reflection angle corresponding to the Ｍ Max reflectance and the reflection angle corresponding to the Ｍ Max reflectance on the right side of the peak. Also, the reflectance when the incident light from the point light source disposed on the reflecting surface of the reflector is fixed at an incident angle of 30 degrees with respect to a direction perpendicular to the surface of the reflector and perpendicular to the direction in which the first groove extends. % (Vertical axis) and the reflection characteristic curve showing the relationship between the reflection angle θ (horizontal axis) and the maximum value of the reflectance (Max reflectance);
Evaluation was made by examining the range (viewing angle Δθ) from the reflection angle corresponding to the １ ／ Max reflectance on the left side of the peak (Max reflectance) and the reflection angle corresponding to the Ｍ Max reflectance on the right side of the peak. The reflectance was measured using a liquid crystal panel evaluation device (LCD 5000 model manufactured by Otsuka Electronics Co., Ltd.).
With reference to the output of the reflected light at a reflection angle of 30 degrees when a white plate (a plate having a MgO standard white surface) is irradiated at an incident angle of 30 degrees, the output of the reflected light of each sample is divided by the reference output to obtain a percentage. It is a value expressed in (%).

FIG. 6 is a graph showing the reflection characteristics of the reflector of Sample No. 1 with d ₁ = 1 μm and d ₂ = 1 μm.
The solid line is a direction (90 °) parallel to the direction in which the first groove extends.
, And the dashed line is a reflection characteristic curve when light is incident from a direction (0 °) orthogonal to the direction in which the first groove extends. FIG. 7 shows that d ₁ =
FIG. 4 is a graph showing the reflection characteristics of the reflector of Sample No. _{2 with} 1 μm and d ₂ = 0.5 μm, and the solid line indicates the case where light is incident from a direction (90 °) parallel to the direction in which the first groove extends. It is a reflection characteristic curve, and a broken line is a reflection characteristic curve when light is incident from a direction (0 °) orthogonal to the direction in which the first groove extends. FIG. 8 is a graph showing the reflection characteristics of the reflector of Sample No. 6 with d ₁ = 1 μm and d ₂ = 0 μm. The solid line indicates the direction parallel to the direction in which the first groove extends (90).
反射) is a reflection characteristic curve when light is incident, and a broken line is a reflection characteristic curve when light is incident from a direction (0 °) orthogonal to the direction in which the first groove extends. FIG.
d ₁ = 1 [mu] m, a graph showing reflection characteristics of the reflector of d ₂ = 2.5 [mu] m sample No.18, the solid line is incident light from a direction parallel to the direction of extension of the first groove (90 °) And a broken line is a reflection characteristic curve when light is incident from a direction (0 °) orthogonal to the direction in which the first groove extends.

As is clear from the results shown in Table 3 and FIGS. 6 to 9, the reflector (d ₂ = 0) in which only the first groove is formed is perpendicular to the direction in which the first groove extends. Although the range of the high reflection angle of the output of the reflected light of the light incident from the wide direction is wide, the range of the high output of the reflected light of the light incident from the direction parallel to the extending direction of the first groove is extremely narrow, that is, the visual field. It can be seen that the corner has become narrower. On the other hand, the reflector in which the first groove and the second groove orthogonal to the first groove are formed has an output of reflected light of light incident from a direction orthogonal to the direction in which the first groove extends. The range of the high reflection angle is wide, and the range of the output of the reflected light of light incident from a direction parallel to the direction in which the first groove extends is wider than that in which the second groove is not formed. It can be seen that the corner has become wider. The depth d ₂ and equally the reflector depth of the first groove d ₁ and the second groove, and when the light is incident from a direction orthogonal to the extending direction of the first groove, the It can be seen that the reflection characteristics when light is incident from a direction parallel to the direction in which the one groove extends are substantially equal.

As is clear from the above data, in the reflector according to the present embodiment, the reflection efficiency of the incident light is increased by expanding the reflection direction of the incident light from the direction perpendicular to the direction in which the first groove extends. In addition, since the second groove orthogonal to the first groove is formed, the light incident on the second groove is irregularly reflected, and the irregular reflection causes the light in a direction other than the direction orthogonal to the extending direction of the groove. The direction of light reflection can be made wider. As a result, according to the liquid crystal display device using such a reflector, even when the user views the display surface from any direction as compared with the conventional liquid crystal display device, the viewing angle is widened and bright display is achieved. Plane.

[0043]

As described above, in the reflector according to the present invention, a large number of first grooves extending in one direction are continuously provided on the surface of the reflector, and the first grooves extend in a direction intersecting the first grooves. A large number of second grooves are provided in series, and the depth of the first grooves is different from the depth of the second grooves, so that the light enters from a direction perpendicular to the direction in which the first grooves extend. The reflection efficiency is improved by expanding the light reflection direction, and in addition, a large number of recesses are formed on the ridge portion between the adjacent first grooves. Are diffusely reflected, and due to the diffuse reflection, the reflection direction is widened in directions other than the direction orthogonal to the groove, and the reflection efficiency is improved. Also, a large number of first grooves extending in one direction are continuously provided on the surface of the reflector, and a large number of second grooves are continuously provided in a direction intersecting with the first grooves. By making the depth of the second groove equal to that of the second groove, the reflection direction of light incident from a direction perpendicular to the direction in which the first groove extends is increased, so that the reflection efficiency is improved. Light incident on the second groove intersecting with the first groove is irregularly reflected, and the irregular reflection causes the reflection direction to expand in a direction other than the direction orthogonal to the first groove, thereby improving the reflection efficiency. Therefore, according to the reflective liquid crystal display device of the present invention provided with such a reflector, the reflector itself has high reflection efficiency and a wide range of reflection directions, so that it is compared with the conventional reflective liquid crystal display device. The viewing angle can be widened in any direction, and the display surface can be made bright overall.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a reflector according to the present invention.

FIG. 2 is a cross-sectional view illustrating a method of manufacturing the reflector according to the first embodiment in the order of steps.

FIG. 3 is a perspective view illustrating a method of manufacturing a reflector according to the first embodiment in the order of steps.

FIG. 4 is a perspective view showing a second embodiment of the reflector according to the present invention.

FIG. 5 is a cross-sectional view showing one embodiment of the reflective liquid crystal display device according to the present invention.

FIG. 6 is a graph showing reflection characteristics of a reflector in which the depth of a first groove is 1 μm and the depth of a second groove is 1 μm.

FIG. 7 is a graph showing reflection characteristics of a reflector in which the depth of a first groove is 1 μm and the depth of a second groove is 0.5 μm.

FIG. 8 is a graph showing reflection characteristics of a reflector in which the depth of a first groove is 1 μm and the depth of a second groove is 0 μm.

FIG. 9 is a graph showing reflection characteristics of a reflector in which the depth of a first groove is 5 μm and the depth of a second groove is 2.5 μm.

FIG. 10 is a perspective view showing an example of a conventional reflector.

FIG. 11 is a cross-sectional view illustrating an example of a conventional reflective liquid crystal display device.

[Explanation of symbols]

21a: first groove, 21b: second groove, 25: reflector.

Claims (3)

[Claims] 1. A plurality of first members extending in one direction on a reflector surface.
And a plurality of second grooves are continuously provided in a direction intersecting with the first grooves, and the depth of the first groove is different from the depth of the second groove. And the reflector. 2. A plurality of first members extending in one direction on the reflector surface.
And a plurality of second grooves are continuously provided in a direction intersecting with the first grooves, and the depth of the first groove is equal to the depth of the second groove. And the reflector. 3. A reflective liquid crystal display device comprising the reflector according to claim 1.