JP2001228314A - Reflecting plate, reflection type liquid crystal display device, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflecting plate excellent in contrast characteristics and paper white characteristics, and to provide and a reflection type liquid display device using the reflecting plate and its manufacturing method. SOLUTION: In a manufacturing method of a reflecting plate having a plurality of projected parts 4 obtained by melt-deforming of a columnar body 15 consisting of a photosensitive resin material, the elevation angle when seeing the vertex of the projected part from the peripheral edge of the bottom surface of the projected part 4 is defined as the average tilt angle of the projected part, and the ratio of the height to the width of the columnar body 15 is defined as the aspect ratio. The photosensitive resin material shows such a characteristic of the aspect ratio-average tilt angle that the average tilt angle θ increases and reaches a local maximum, and then is converged to a constant value through a decreasing region when the aspect ratio is gradually increased from around zero value. The set value of the aspect ratio of the columnar body 15 obtained after a development process is set at a larger aspect ratio than that of the start point of convergence into the constant value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used for OA equipment, personal computers, portable telephones, portable information terminals, etc., which does not require a backlight and displays an image by reflecting external light. The present invention relates to a reflection plate used for a reflection type liquid crystal display or the like, a method of manufacturing the same, and a reflection type liquid crystal display element.

[0002]

2. Description of the Related Art In recent years, as AV devices and information devices have become smaller and thinner, the demand for liquid crystal display devices for these devices has increased. In the field of information devices, the advent of the multimedia society has demanded liquid crystal display elements that can be mounted on notebook personal computers with higher portability. In the field of portable information terminals, thinner, lighter, and lower power consumption devices have been required. There is a need for liquid crystal display devices. In particular, the reflective liquid crystal display element is a method of displaying an image by reflecting external light, and does not require a light source such as a backlight unit. Therefore, power consumption is lower than that of a conventional transmissive liquid crystal display element. It is possible to reduce the thickness and weight. The display mode of this reflective liquid crystal display element is T
N (Twisted Nematic), STN (Super Twisted N)
ematic), guest-host (Guest
-Host) method is mainly used.

In this reflective liquid crystal display device, in order to obtain a brighter and better display, it is necessary to increase the intensity of light that reflects and scatters incident light in the normal viewing direction perpendicular to the display screen. Furthermore, for incident light,
In addition to reflecting and scattering external light incident at a fixed angle from a predetermined direction in the normal viewing angle direction, external light incident at an arbitrary angle from various directions is similarly reflected and scattered in the normal viewing angle direction. It is desirable. Therefore, it is necessary to manufacture a reflection plate having optimal reflection characteristics so that external light incident from any direction can be efficiently used as display light. Here, the optimal reflection characteristic means that the reflection plate has a characteristic of reflecting incident light in a wide range and with high reflectance.

In the case of using a conventional reflector, for example, a mirror-like metal film formed on a substrate, incident light is reflected only in the regular reflection direction, and the reflectivity is reflected in directions other than the regular reflection direction. Was low. Therefore, there is a problem that the display screen becomes extremely dark in a viewing direction of the observer such as a normal viewing angle direction, which causes a significant deterioration in display quality.

[0005] In order to solve such a problem, a pixel electrode having a reflection characteristic in which reflection of incident light to a regular reflection region is reduced is provided.
For example, it is disclosed in JP-A-6-27481. According to this publication, as shown in FIG.
10 has a configuration in which a polymer resin film 103 is provided on a substrate 101 on which a plurality of convex portions 102a and 102b are formed, and a pixel electrode 104 is further provided on the polymer resin film 103. . The surface of the pixel electrode 104 has a continuous wave shape.

The following method is used as a method of forming the above-mentioned reflector 110. First, FIG.
As shown in (1), a resist film 112 made of a photosensitive resin is applied on the substrate 101 by a spin coating method, and then prebaked at a predetermined processing temperature. Subsequently, FIG.
As shown in (b), the photomask 105 is used to expose and expose the resist film 112. Next, development is performed using a developer, and as shown in FIG.
On the substrate 101, convex portions 112a and 112b having different heights are formed. Subsequently, as shown in FIG. 15D, heat treatment is performed by heating the protrusions 112a and 112b at a predetermined temperature for one hour. Thereby, the convex portions 102a and 102b in which the corners of the convex portions 112a and 112b are rounded are formed. next,
As shown in FIG. 15E, the heat-treated substrate 101
A polymer resin film 1 by spin-coating a polymer resin
03 is formed. Finally, a picture element electrode 104 is formed on the polymer resin film 103 by a sputtering method (FIG. 15F).

Then, the convex portion 102 is formed by the above-described method.
The inclination angles of a and 102b (the angle between the minute surface on the uneven pixel electrode surface and the substrate surface) are controlled to improve the reflection characteristics.

[0008]

However, according to the above-mentioned conventional manufacturing method, it is theoretically possible to control the tilt angle, but since the manufacturing process margin is small, it is possible to manufacture a desired reflector. Can not. That is, at the time of actual manufacturing, a reflector having a desired inclination angle cannot be manufactured due to, for example, an error in a heating temperature, an error in a heating time, and the like. Therefore, the reflection plate obtained by the conventional manufacturing method has a problem that the brightness in the viewing angle direction is insufficient and good paper whiteness cannot be obtained in a wide range. As described above, it is an important issue in an actual manufacturing process whether a manufacturing process margin can be increased.

In the conventional manufacturing method, the shape is controlled by reflow by heating, and a second resist layer is applied. Therefore, there is a problem that the tact is reduced and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a large manufacturing process margin so that the inclination angle of the uneven reflecting surface can be controlled with high accuracy, and the contrast characteristics and paper white can be improved. It is an object of the present invention to provide a reflector having excellent properties, a reflective liquid crystal display device using the reflector, and a method for manufacturing the same.

Another object of the present invention is to provide a reflector capable of improving the tact time and reducing the production cost by simplifying the production process, and a reflection type liquid crystal using the reflector. It is an object to provide a display element and a manufacturing method thereof.

[0012]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 provides a substrate provided with a plurality of convex portions obtained by melting and deforming a columnar body made of a photosensitive resin material; In the reflection plate having a light-reflective thin film covering the convex portion, the photosensitive resin material is a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and the bottom surface of the convex portion. Is defined as the average inclination angle of the convex portion, and when the aspect ratio indicated by the ratio of the two representative dimensions defining the shape of the columnar body is gradually increased from a value near 0, the average inclination angle increases. It has an aspect ratio-average inclination angle characteristic that reaches a maximum value through a change process and then converges to a constant value through a descending process, and the average inclination angle of the plurality of protrusions is the aspect ratio-average. Characterized in that the convergence value in the inclination angle characteristic is used. To.

With the above configuration, a reflector having excellent reflection characteristics is formed. Here, the cross section of the columnar body may be circular, elliptical, polygonal, or any other irregular shape. Further, the “representative dimension” in the present invention includes not only the height and width of the column, but also the cross-sectional area of the column. Therefore,
The “aspect ratio” is used as a concept including not only the height of the column / the width of the column, but also, for example, the height / cross section perpendicular to the axis.

According to a second aspect of the present invention, in the reflector according to the first aspect, the aspect ratio is a ratio of a height to a width of the columnar body.

Here, the “width of the columnar body” means, for example, the diameter or radius of the cross section when the columnar body is a columnar body,
When the columnar body is an elliptical columnar body, it means the short axis or the long axis of the cross section.

According to a third aspect of the present invention, there is provided a method of manufacturing a reflection plate, comprising the steps of: forming an uneven thermoplastic resin layer comprising a thin film portion and a plurality of columnar portions on a substrate; By performing a heat treatment on the substrate on which the plurality of columnar portions are formed, the columnar portion is melted and deformed, and a heat treatment step of forming a plurality of convex portions having a predetermined average inclination angle, and on the convex portions Forming a light-reflective thin film, wherein the resin material is formed by projecting an angle between a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and an angle between the bottom surface of the convex portion and When the aspect ratio, which is defined by the ratio of two representative dimensions defining the shape of the columnar body, gradually increases from a value near 0, the average tilt angle reaches a local maximum value through an ascending change process. , And then converge to a certain value through the descending process. It has a ratio-average inclination angle characteristic, and the set value of the aspect ratio of the columnar body obtained in the resin layer forming step is set to an aspect ratio larger than a starting point at which the column starts to converge to the constant value. And

As described above, the aspect ratio larger than the starting point at which the average inclination angle starts converging to a constant value in the aspect ratio-average inclination angle characteristic is set as the set value of the columnar body aspect ratio, so that the manufacturing process margin is improved. Can be made much larger than in the conventional example. Therefore, it is possible to form a convex portion having a high-precision average inclination angle without being affected by a processing error or the like. As a result, a reflector having excellent reflection characteristics can be obtained. In forming the columnar body, not only the photolithography method but also a method such as a mold may be used. Further, the term "thin film portion" corresponds to "residual film" in the invention according to claim 4 using a photolithography method.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a reflector having a plurality of convex portions obtained by melting and deforming a column made of a photosensitive resin material, wherein the photosensitive resin material is applied onto a substrate. A coating step, an exposure step of irradiating the photosensitive resin material film obtained in the coating step with a light through a photomask having a light-shielding portion patterned in a predetermined shape, and the light-irradiated photosensitive resin Developing the film to form a residual film and a plurality of columnar bodies; and performing a heat treatment on the substrate on which the plurality of columnar bodies are formed, thereby melting and deforming the columnar bodies, thereby obtaining a predetermined average inclination angle. A heat treatment step of forming a plurality of curved convex portions having: and a step of forming a light-reflective thin film on the convex portions, wherein the photosensitive resin material has a predetermined shape on an outer peripheral edge of a bottom surface of the convex portions. And a straight line connecting the point of When the angle formed with the bottom surface is defined as the average inclination angle of the convex portion, and the aspect ratio indicated by the ratio of the two representative dimensions defining the shape of the columnar body is gradually increased from a value near 0, the average inclination angle becomes It has an aspect ratio-average tilt angle characteristic of reaching a maximum value through an ascending change process and thereafter converging to a constant value through a descending process, and a set value of an aspect ratio of the columnar body obtained in the developing process. Is set to be an aspect ratio larger than the starting point at which convergence to the constant value starts.

With the above configuration, the manufacturing process margin can be made much larger than in the conventional example, as in the third aspect of the present invention. Therefore, it is possible to form a convex portion having a high-precision average inclination angle without being affected by a processing error or the like. As a result, a reflector having excellent reflection characteristics can be obtained.

Further, in the conventional manufacturing method using the photolithography method, a step of forming a resin layer for covering the convex portion before forming the light-reflective thin film was required, but the manufacturing method of the present invention requires such a step. The resin layer forming step is not required.
Therefore, the manufacturing process is simplified as compared with the conventional example, and the tact is improved.

According to a fifth aspect of the present invention, in the method for manufacturing a reflection plate according to the fourth aspect, the photosensitive resin material has a low γ.
It is a resist material.

When a low-γ resist material is used as the photosensitive resin material as described above, it is possible to form a region where no residual film exists, and to control the thickness of the residual film in other regions.

According to a sixth aspect of the present invention, in the method of manufacturing a reflector according to the fourth aspect, the aspect ratio-average tilt angle characteristic is such that the convergence value of the average tilt angle increases when the heating temperature for heating the columnar body is increased. It has the property that the convergence value of the average inclination angle changes to a large value when the heating temperature changes to a small value, and conversely, when the heating temperature is reduced, the heating temperature is set to the predetermined average inclination angle of the convex portion in the heat treatment step. It is characterized by a corresponding heating temperature.

By controlling the heating temperature as described above, a projection having a desired average inclination angle can be formed.

According to a seventh aspect of the present invention, in the method of manufacturing a reflector according to the fourth aspect, the aspect ratio-average tilt angle characteristic is such that the convergence value of the average tilt angle decreases as the thickness of the remaining film increases. Has a property that the convergence value of the average inclination angle changes to a large value when the thickness of the residual film is reduced, and the thickness of the residual film obtained after the development step is the predetermined average inclination angle of the convex portion. So that the thickness of the remaining film corresponds to
The exposure amount to the photosensitive resin in the exposure step is adjusted.

By controlling the thickness of the remaining film as described above, a convex portion having a desired average inclination angle can be formed.

According to an eighth aspect of the present invention, in the method for manufacturing a reflector according to the third aspect, the aspect ratio is 0.05.
As mentioned above, it is characterized by being in the range of 0.7 or less.

According to a ninth aspect of the present invention, in the method of manufacturing a reflector according to the fourth aspect, the film thickness of the photosensitive resin film in the coating step is in a range of 1 μm to 10 μm. .

The thickness of the photosensitive resin film is regulated for the following reasons. That is, if the thickness of the photosensitive resin layer is smaller than 1 μm, the unevenness of the surface of the light-reflective thin film becomes too small, and light reflected in the regular reflection direction increases, which is not preferable. The photosensitive resin layer has a thickness of 10 μm.
If it is larger than m, the difference in unevenness becomes too large. For example, when a reflection plate is applied to a reflection type liquid crystal display device, the nonuniformity of the cell gap becomes too large, and the display quality such as display unevenness is deteriorated. Because it becomes.

According to a tenth aspect of the present invention, in the method of manufacturing a reflection plate according to the fourth aspect, prior to the coating step of coating the photosensitive resin material on the substrate, the photosensitive resin is made of the same material as the photosensitive resin material. The method includes a step of forming a film on a substrate.

According to an eleventh aspect of the present invention, in the method of manufacturing a reflector according to the fourth aspect, prior to the coating step of coating the photosensitive resin material on the substrate, a photosensitive resin different from the photosensitive resin material is used. The method includes a step of forming a film on a substrate.

As described above, the photosensitive resin layer formed on the substrate may be composed of a plurality of layers, and the photosensitive resin serving as the underlayer is made of the same material as the upper layer photosensitive resin. May be different materials.

The twelfth aspect of the present invention is the third aspect of the present invention.
2. The method for manufacturing a reflector according to claim 1, wherein the aspect ratio is a ratio of a height to a width of the columnar body.

According to a thirteenth aspect of the present invention, there is provided a reflection type liquid crystal display element, wherein a substrate is provided on one side and a reflection plate according to the first aspect is provided on the other side with a liquid crystal display layer interposed therebetween. I do.

With the above configuration, a reflection type liquid crystal display device having excellent contrast characteristics and paper whiteness is formed.

According to a fourteenth aspect of the present invention, there is provided a method of manufacturing a reflective liquid crystal display device comprising a reflector, a substrate provided to face the reflector, and a liquid crystal display layer sandwiched between the reflector and the substrate. In the method, the reflector is manufactured by the method according to any one of claims 3 to 12.

With the above configuration, it is possible to manufacture a reflective liquid crystal display device having excellent contrast characteristics and paper whiteness.

According to a fifteenth aspect of the present invention, a plurality of concentrically or juxtaposedly arranged convex portions are formed by melting and deforming concentrically or juxtaposed columnar bodies made of a photosensitive resin material. A diffraction grating type reflection plate having the obtained substrate provided with such a plurality of protrusions, and a light-reflective thin film covering the protrusions, and having a characteristic of separating incident light by reflection diffraction. In the photosensitive resin material, an angle formed between a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and an angle formed between the bottom surface of the convex portion and the average inclination angle of the convex portion, When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the shape, gradually increases from a value near 0, the average inclination angle reaches a local maximum value through a rising change process, and then becomes constant through a falling process. With an aspect ratio-average tilt angle characteristic that converges , The average tilt angle of the plurality of protrusions,
The convergence value in the aspect ratio-average tilt angle characteristic is set as the convergence value.

With the above configuration, a diffraction grating reflector having a wide color reproduction range is formed.

According to a sixteenth aspect of the present invention, in the diffraction grating reflector according to the fifteenth aspect, the aspect ratio is a ratio of a height to a width of the columnar body.

According to a seventeenth aspect of the present invention, in the reflective liquid crystal display device, a substrate is provided on one side with the liquid crystal display layer interposed therebetween, and the diffraction grating type reflector according to the fifteenth or sixteenth aspect is provided on the other side. It is characterized by.

With the above configuration, a reflection type liquid crystal display device having a diffraction grating type reflection plate having a wide color reproduction range is constituted.

According to the present invention, there is provided a diffraction grating type reflection device having a plurality of convex portions obtained by melting and deforming a column made of a photosensitive resin material and having a characteristic of separating incident light by reflection diffraction. In the method for manufacturing a plate, a coating step of coating a photosensitive resin material on a substrate, and a photosensitive resin material film obtained by the coating step, via a photomask having a light shielding portion patterned in a predetermined shape. An exposure step of irradiating light; a developing step of developing the light-irradiated photosensitive resin film to form a residual film and a plurality of concentrically or parallelly arranged columns; and the plurality of columns. Heat-treating the substrate on which is formed a melt-deformation of the columnar body to form a plurality of convex portions having a predetermined average inclination angle arranged concentrically or in parallel, and A light reflective thin film The photosensitive resin material, the angle between the straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and the angle between the bottom surface of the convex portion and the average inclination of the convex portion. Angle, and gradually increasing the aspect ratio indicated by the ratio of the two representative dimensions that define the shape of the column from a value near 0, the average inclination angle reaches a local maximum value through a rising change process, After that, it has an aspect ratio-average inclination angle characteristic that converges to a constant value through a descending process, and the set value of the aspect ratio of the columnar body obtained in the developing step starts to converge to the constant value. The aspect ratio is larger than the point.

With the above configuration, a diffraction grating reflector having a wide color reproduction range can be manufactured.

A nineteenth aspect of the present invention is the method for manufacturing a diffraction grating reflector according to the eighteenth aspect, wherein the aspect ratio is a ratio of a height to a width of the columnar body.

According to a twentieth aspect of the present invention, there is provided a method for manufacturing a reflection type liquid crystal display device comprising a reflection plate, a substrate provided to face the reflection plate, and a liquid crystal display layer sandwiched between the reflection plate and the substrate. 20. The method of claim 18, wherein the reflector comprises:
It is characterized by being manufactured by the method described.

With the above configuration, it is possible to manufacture a reflection type liquid crystal display device provided with a diffraction grating type reflection plate having a wide color reproduction range.

[0048]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited by the embodiment.

(Embodiment 1) FIG. 1 is a sectional view of a main part of a reflector according to Embodiment 1, and FIG. 2 is a plan view thereof. FIG. 2 is a plan view of the reflector in a state before the light reflective thin film is deposited. Reflector 1
Is formed by forming a substrate 2, a residual film 3, a plurality of convex portions 4 formed integrally with the residual film 3, and a plurality of convex portions 4 so that the surface (the upper surface in FIG. 1) is uneven. Light-reflective thin film 5. Here, the remaining film means a portion which is left undeveloped in a developing process in a photolithography process described later. Therefore, according to the definition of the residual film, only the portion of the residual film 3 located between the protrusions 4 corresponds to the residual film,
The portion of the residual film 3 located below the convex portion 4 is not exactly a residual film, but for convenience of description, the portion of the residual film 3 located below the convex portion 4 is also referred to as a residual film. I will. The substrate 2 is an insulating substrate such as glass (trade name: 1737, manufactured by Corning Incorporated), and has a thickness of, for example, 1.1 mm. The light reflective thin film 5 is made of a metal thin film such as aluminum (Al).

The remaining film 3 and the projections 4 are made of a photosensitive resin, and examples of the photosensitive resin include a positive resist and an electron beam resist. In this embodiment, a low γ positive resist as a positive resist (trade name: PC
409, manufactured by JSR Corporation).

The convex portion 4 has a circular cross section parallel to the substrate 2 and has a gentle curved surface. here,
A predetermined point on the outer peripheral edge 4a of the bottom surface of the convex portion 4 (in this embodiment, since the bottom surface of the convex portion 4 is circular, the average inclination angle θ is the same regardless of which point on the outer peripheral edge 4a is selected). Therefore, in the present embodiment, the above-mentioned predetermined point means an arbitrary point on the outer peripheral edge 4a of the bottom surface.) And the vertex 4b of the convex portion 4 and the angle formed by the bottom surface of the convex portion 4 When defined as the average inclination angle θ of the portions (see FIGS. 3 and 4), the average inclination angles θ of all the projections 4 are substantially the same. It should be noted that this average inclination angle θ has almost no error from the set value at the design stage. For this reason, there is a feature that the accuracy of the concave-convex shape of the light reflective thin film 5 is high and the accuracy of the reflection characteristics of the reflector is extremely high. This is because the light-reflective thin film 5 has a structure that covers the convex portion 4, and thus the unevenness of the light-reflective thin film 5 reflects the surface shape of the convex portion 4. The predetermined point of the outer peripheral edge 4a of the bottom surface of the convex portion is, for example, a point at which the outer peripheral edge 4a intersects with the long axis or the outer edge 4a intersects with the short axis if the bottom surface of the convex portion 4 is elliptical. A predetermined point, such as a point to be performed. Therefore, the average inclination angle θ is uniquely determined based on the predetermined point. Further, the reason why the convex portion 4 having the high-precision average inclination angle θ can be manufactured will be described in detail in the description of the manufacturing method described later.

The reflector according to the present invention can be applied to a reflector of a reflection type liquid crystal display device. However, the reflector according to the present invention is not limited to this, and can be widely applied to other technical fields, for example, a reflector of an optical device.

FIG. 5 is a flowchart showing the manufacturing process of the reflector, and FIG. 6 is a sectional view showing the manufacturing process of the reflector. First, with reference to FIGS. 5 and 6, an outline of a method for manufacturing the reflector having the above-described configuration will be described. The manufacturing method and the reason that the convex portion 4 having a constant average inclination angle θ is obtained by the manufacturing method will be described.

The outline of the method of manufacturing the reflection plate is as follows. The reflection plate is basically manufactured by six steps of a coating step, a pre-bake step, an exposure step, a development step, a heat treatment step and a light-reflective thin film formation step. Is done. Each step is outlined below.

First, the photosensitive resin 10 is applied onto the substrate 2 (application step: see FIG. 6A). Next, the substrate 2 coated with the photosensitive resin 10 is pre-baked (pre-bake step). Next, a photomask 11 having a predetermined pattern is arranged above the substrate 2, and the photosensitive resin 10 is irradiated with ultraviolet light through the photomask 11 (exposure step: see FIG. 6B). Next, the photosensitive resin 10 is developed with a developer. Thus, a residual film 3 having a predetermined thickness and a columnar body 15 having a predetermined shape (a cylindrical body in the present embodiment) are formed (development step: see FIG. 6C). Next, the columnar body 15 is melted by a heat treatment. As a result, the average inclination angle θ
Is formed (heat treatment step: FIG. 6D).
reference). Next, the plurality of projections 4 are covered, and a metal thin film such as aluminum (Al) is deposited to form the light-reflective thin film 5 (light-reflective thin film forming step: see FIG. 6E). Thus, the reflection plate 1 shown in FIG. 1 is manufactured.

Here, in the above-described manufacturing method, the protrusion 4
The main feature of the present invention is that the average inclination angle θ can be manufactured with high accuracy. Specifically, it can be realized by setting the aspect ratio γ of the columnar body 15 to a value described below, and controlling the thickness of the remaining film 3 and the heating temperature. The reason will be described below.

In forming the convex portion 4 by melting and deforming the columnar member 15, there is a characteristic shown in FIG. 7 between the average inclination angle θ of the convex portion 4 and the aspect ratio γ of the columnar member 15. Here, the aspect ratio γ of the columnar body 15 means the ratio H / D of the diameter D and the height H of the cross section of the columnar body 15. In addition,
The height H of the columnar body 15 is the height from the remaining film 3. Therefore, the height H of the columnar body 15 can be changed by controlling the thickness of the remaining film 3. Further, as the aspect ratio γ, the ratio H / S of the cross-sectional area S to the height H may be used instead of the diameter D, and the cross-sectional area S and the height H may be used. In the case of other irregular shapes, the aspect ratio γ is preferably set to H / S.

The aspect ratio γ-average tilt angle θ characteristic indicating the change of the average tilt angle θ with respect to the change of the aspect ratio γ was found by the present inventors based on experimental results. 7, the aspect ratio γ-average tilt angle θ characteristic shows that as the aspect ratio γ gradually increases from a value near 0, the average tilt angle θ reaches a local maximum value through a process of increasing and decreasing, and then decreases. It is recognized that the material has a characteristic that converges to a constant value through the process. Note that FIG. 7 shows that the heating temperature and the heating time are the same, the height H of the columnar member 15 is fixed, and the diameter D of the cross section of the columnar member 15 is changed. The average inclination angle θ is measured to determine the relationship between the aspect ratio γ and the average inclination angle θ. In FIG. 7, the change in the aspect ratio γ is such that although the height H is fixed and the diameter D is changed, the same characteristic can be obtained even when the diameter D is fixed and the height H is changed. The inventor has confirmed. In addition, it has been confirmed that there is a similar relationship between the aspect ratio γ and the average inclination angle θ regardless of the type of the photosensitive resin.

It is considered that the characteristic shown in FIG. 7 is obtained for the following reason. That is, the columnar body 15 starts to melt from the front end portion by heating, and is dripped. At this time, the height of the convex portion 4 rises due to the cohesive force of the softened photosensitive resin portion. The degree of the rise increases as the aspect ratio γ increases. Therefore, the average inclination angle θ increases as the aspect ratio γ increases. When the load caused by the raised portion of the convex portion 4 becomes larger than the cohesive force of the softened photosensitive resin portion, the softened portion shifts from the rising phenomenon to the lateral spreading phenomenon. Therefore, at this critical point, the height of the projection 4 becomes a maximum value, and thereafter, the aspect ratio γ
The degree of expansion of the softened portion increases with an increase in. Therefore, the average inclination angle θ of the projection 4 becomes smaller. Then, the convergence value gradually approaches as the aspect ratio γ increases. This is because it is considered that when the volume of the softened portion becomes equal to or more than a certain value, the contact angle mainly approaches asymptotically determined by the wettability inherent to the photosensitive resin constituting the convex portion 4.

Considering the influence of the average inclination angle θ on the variation of the aspect ratio γ in the characteristics shown in FIG. 7, the aspect ratio is sufficiently large as compared with, for example, the condition where the average inclination angle is maximized. Under the conditions, it can be seen that the variation in the average inclination angle is smaller than the variation in the aspect ratio. That is, the area where the average inclination angle changes with respect to the variation of the aspect ratio near the maximum value is B1, the area where the average inclination angle changes with the variation of the aspect ratio near the ascending or descending process is B2, and the average inclination angle is a constant value. Assuming that a change region of the average inclination angle with respect to the change of the aspect ratio in the region where the light beam converges is B3, B1, B2≫B3. This means
If the aspect ratio is set to a value equal to or higher than the convergence start point A of the average inclination angle θ, even if the aspect ratio greatly changes, the finally obtained average inclination angle θ is hardly affected. Means that an average inclination angle substantially equal to the average inclination angle θ is obtained. Therefore, if the aspect ratio γ is set to a value equal to or higher than the convergence start point A, it is possible to increase the margin during the manufacturing process. As a result, a highly accurate average inclination angle can be obtained for an actually manufactured product without being affected by processing errors or the like during manufacturing.

By setting the aspect ratio γ to a value equal to or higher than the convergence start point A as described above, it is possible to increase the margin during the manufacturing process, but it is possible to obtain a reflector having desired reflection characteristics by itself. I can't. This is because it is necessary to control the average inclination angle θ to a desired angle in order to manufacture a reflector having desired reflection characteristics.

In this regard, it has been found that the average inclination angle θ can be controlled by changing various parameters such as the remaining film thickness, the heating temperature, and the shape of the columnar body. Hereinafter, description will be made with reference to FIG.

FIG. 8 is a graph showing an aspect ratio γ-average tilt angle θ characteristic when the remaining film thickness and the heating temperature are changed. In FIG. 8, line L1 shows the case where the heating temperature is 120 ° C. and the remaining film thickness is 0.62 μm, line L2 shows the case where the heating temperature is 160 ° C. and the remaining film thickness is 0.62 μm, and line L3 shows The heating temperature is 120 ° C. and the remaining film thickness is 1.
The line L4 has a heating temperature of 160 μm.
C. and the remaining film thickness is 1.74 μm, and the line L5
Indicates the case where the heating temperature is 120 ° C. and the remaining film thickness is 2.10 μm, and line L6 indicates the case where the heating temperature is 160 ° C. and the remaining film thickness is 2.36 μm. The heating time and other conditions were the same. From lines L1 and L2 in FIG. 8, when the remaining film thickness is the same, if the heating temperature is high, the average inclination angle converges to a small value, and if the heating temperature is low, the average inclination angle converges to a large value. Is allowed to do so. Also, the lines L1, L3, L5 or the line L in FIG.
According to 2, L4 and L6, when the heating temperature is the same,
It is recognized that when the remaining film thickness is large, the average inclination angle converges to a small value, and when the remaining film thickness is small, the average inclination angle converges to a large value.

Therefore, even if the aspect ratio is the same, the convergence value of the average inclination angle θ can be changed by changing the heating temperature and the remaining film thickness. That is, it is understood that the average inclination angle can be controlled by changing the heating temperature and the remaining film thickness. The present inventor has confirmed that the average inclination angle converges to a small value when a photosensitive resin having a large wettability is used, and that the average inclination angle converges to a large value when a photosensitive resin having a small wettability is used. Have been. Therefore,
The average tilt angle can also be controlled by selecting the photosensitive resin material. Further, it is considered that the average inclination angle can be controlled by the shape of the column, the viscosity of the photosensitive resin material, the atmosphere at the time of production, and the like.

Next, a method of manufacturing the reflector according to the present embodiment will be described in detail based on the characteristics of FIGS. 7 and 8 based on the schematic description of the manufacturing method described above.

(1) Setting of the aspect ratio γ First, the aspect ratio γ is specifically set prior to the manufacture of the reflector. In setting the aspect ratio γ, if the photosensitive resin material to be used is determined, the photosensitive resin is used to change the remaining film thickness, the heating temperature, etc., and to change various aspect ratios γ-average inclination angle θ in advance. The characteristics are determined from experiments. Then, when manufacturing a reflector having an average inclination angle θ = θp, an aspect ratio-average inclination angle characteristic in which the average inclination angle θp becomes a convergence value is searched for. Next, the aspect ratio γ is set to any value equal to or higher than the convergence start point A of the aspect ratio-average tilt angle characteristic.

For example, assuming that the average inclination angle θp is 7.5, the aspect ratio-average inclination angle characteristic in which the convergence value of the average inclination angle is 7.5 is searched for. In this case, reference numeral L1 in FIG. 8 is an aspect ratio-average tilt angle characteristic with a convergence value of 7.5. Therefore, a value equal to or higher than the convergence start point A, for example, the aspect ratio γ =
Set to 0.8. The remaining film thickness is 0.62 μm, and the heating temperature is 120 ° C. Under these conditions,
The reflector is manufactured by the method already described with reference to FIGS.

(2) Coating Step First, as shown in FIG. 6A, the substrate 2 (trade name: 17
37, manufactured by Corning Incorporated) by spin coating. As the application condition, for example, spin coating is performed at a rotation speed of 700 rpm for 30 seconds so that the thickness of the application film is 3.6 μm.

(3) Prebaking Step Next, the substrate 2 coated with the photosensitive resin material is heated to 105 ° C.
For 90 seconds to evaporate the solvent in the coating film to form the photosensitive resin layer 10.

(4) Exposure Step Next, as shown in FIG. 6B, a photomask 14 is disposed above the photosensitive resin layer 10 and the photomask 11
And irradiate and expose to ultraviolet light through the process (exposure step). Here, the light-shielding portion pattern (diameter of the circular pattern) of the photomask 11, the exposure amount, the exposure time, and the development time in the subsequent development process are determined by a predetermined remaining film thickness and a predetermined aspect ratio γ (average slope). When the angle θp = 7.5, the remaining film thickness is
0.62 μm and the aspect ratio γ are set to 0.8) in advance.

(5) Developing Step Subsequently, NMD-3 (trade name) manufactured by Tokyo Ohka Co., Ltd.
% Is used as a developing solution, and unnecessary portions are dissolved (developing step). By this step, FIG.
As shown in (c), a residual film 3 and a plurality of pillars 15 are formed on the substrate 2. The width (diameter) of the columnar body manufactured in the present invention is desirably 1 μm or more. If it is smaller than 1 μm, the exposure limit is exceeded, and it becomes difficult to form a columnar body of such a size. When the reflection plate is applied to a reflection type liquid crystal display device, the height of the columnar body is desirably 30 μm or less. If it is larger than 30 μm, the area of the portion where the unevenness occurs becomes large, and as a result, the nonuniformity of the cell gap becomes too large, and the display quality such as display unevenness is deteriorated.

The photosensitive resin layer 10 has a thickness of 1 μm
It is desirable that this is the case. If it is smaller than 1 μm, the unevenness of the surface of the light-reflective thin film 5 becomes too small, and light reflected in the regular reflection direction increases, which is not preferable. When the reflection plate is applied to a reflection type liquid crystal display device, the thickness of the photosensitive resin layer 10 is desirably 10 μm or less. If the thickness is larger than 10 μm, the difference in unevenness becomes too large, the nonuniformity of the cell gap becomes too large, and the display quality such as display unevenness is deteriorated.

(6) Heat Treatment Step Next, as shown in FIG. 6D, a heat treatment is performed by heating the substrate 2 at 120 ° C. for 5 minutes. Thereby, the remaining film 3 and the plurality of convex portions 4 are formed. At this time, since the aspect ratio γ of the columnar body 15 is set to the above value, a large manufacturing margin can be obtained, and as a result, the average inclination angles of almost all the projections 4 are almost the same. In other words, even if there is a processing error or the like in the manufacturing process, it is possible to form the convex portion having the average inclination angle according to the set value almost without being affected by the processing error.

Various methods have been devised in the conventional method of manufacturing a reflection plate in order to form the average inclination angle of the projections with high accuracy. However, this is only theoretical at the design stage, and the manufacturing margin is narrow. On the other hand, when a reflector is actually manufactured, a processing error or the like occurs, and even if a high-precision average tilt angle is theoretically obtained, manufacturing with that method will result in a projection of the actually manufactured protrusion. The average inclination angle varies greatly.

With respect to this point, the conventional example and the present invention will be described with reference to FIG. As shown in FIG. 9A, it is assumed that the columnar bodies P1 and P2 having the same diameter D but different heights due to processing errors are formed. At this time, in the conventional example, the average inclination angle θ1 of the convex portion G1 and the average inclination angle θ2 of the convex portion G2 manufactured as shown in FIG.
Will be different. On the other hand, in the present invention, the convex portion G1 and the convex portion G2 manufactured as shown in FIG. 9B have substantially similar shapes, and the average inclination angle θ1 and the average inclination angle θ2 are substantially equal. Become.

Further, according to the manufacturing method of the present invention, a plurality of rounded convex portions 4 can be formed without further coating a resin layer on the convex portions as in the conventional example. Therefore, compared with the conventional example, the step of coating the resin layer can be omitted, and the manufacturing cost and the manufacturing time can be reduced.

(7) Light-Reflective Thin Film Forming Step Next, a plurality of convex portions 4 are covered to form aluminum (Al).
The light reflective thin film 5 is formed by depositing a metal thin film such as Thus, the reflection plate shown in FIG. 1 is manufactured. This reflector 1
Since the average inclination angle of the convex portions is almost the same as the set value, the unevenness of the light reflective thin film 5 formed on the convex portions 4 is almost as set. Therefore, a reflector having desired reflection characteristics can be obtained.

Next, a case where the above-structured reflector is applied to a reflector of a reflection type liquid crystal display device will be described. FIG.
FIG. 2 is a sectional view of a main part of the reflective liquid crystal display element. The reflection type liquid crystal display element 30 includes a reflection plate 1, a counter substrate 31 (display surface side), and a liquid crystal layer 32 sandwiched between the reflection plate 1 and the counter substrate 31. On the light reflecting thin film 5 of the reflecting plate 1,
An alignment film 33 is formed. In addition, the light reflective thin film 5
Function as pixel electrodes.

The counter substrate 31 is a light-transmitting substrate such as a glass substrate, for example. On the counter substrate 31, indium tin oxide (ITO) is provided.
Is formed. Further, an alignment film 35 is formed on the transparent electrode 34. The liquid crystal layer 32 includes a guest-host liquid crystal in which a black dichroic dye is dissolved in liquid crystal. The alignment films 33 and 35
Are made of, for example, a polyimide resin, and their alignment treatment directions are set to be opposite to each other. At this time, the orientation state of the liquid crystal molecules is twisted about 360 degrees between the substrates.

Examination of the display state of the reflection type liquid crystal display device having the above-mentioned structure revealed that the display quality was very bright over a wide range, excellent in paper whiteness, and excellent in contrast.

Incidentally, for reference, the aspect ratio is, for example, the value used in the above embodiment, for example, 0.43
There are conventional examples using such a device. However, even if the aspect ratio has the same value, the significance of the aspect ratio differs between the conventional example and the present invention. That is, in the conventional example, it is not the aspect ratio in the region where the average inclination angle θ converges. On the other hand, in the present invention, an aspect ratio in a region where the average inclination angle θ converges is used. Therefore, in the conventional example, the average inclination angle of the manufactured protrusions varies, and the reflection characteristics of the reflector are not desired. On the other hand, in the present invention, since the aspect ratio in the region where the average inclination angle θ converges is used as described above, a large manufacturing margin can be obtained. A projection having a desired average inclination angle can be formed.

(Embodiment 2) FIG. 11 is a cross-sectional view showing a manufacturing process of a reflector according to Embodiment 2. The reflection plate according to the present embodiment is a reflection plate used for a reflection type liquid crystal display element driven by an active matrix. The method of manufacturing such a reflector is similar to the method of the first embodiment. However, the reflection plate of the second embodiment is slightly different from the reflection plate used in the reflection type liquid crystal display element driven by the active matrix. Hereinafter, the features of the manufacturing method according to the second embodiment will be mainly described.

On the reflection plate of the second embodiment, a thin film transistor (TFT) 40 is formed as a pixel switching element. Therefore, a contact hole 41 (FIG. 11C) for electrically connecting the TFT 40 and the light-reflective thin film 5 having a function as a pixel electrode is required. You need to avoid it. This is because the presence of a residual film in the contact hole formation portion may cause a conduction failure and may degrade display quality.

Accordingly, a low γ positive resist (trade name: PC409, manufactured by JSR Corporation) was used as the photosensitive resin.
In the first embodiment, it is not necessary to use a low-γ resist as the photosensitive resin, but in the second embodiment, a low-γ resist must be used. Explaining the reason, as shown by the solid line in FIG. 12, the low γ resist has such a characteristic that the residual film thickness decreases linearly as the integrated exposure amount increases. In the case of a normal photosensitive resin material, the remaining film thickness shows a constant value up to a certain integrated exposure amount as shown by a broken line in FIG. 12, but the remaining film thickness rapidly decreases when the integrated exposure amount is exceeded. Is shown. In the present invention, it is necessary to constitute a portion having no residual film and a columnar body formed integrally with the residual film and the residual film,
When a usual photosensitive resin material is used, it is difficult to control the remaining film thickness at the contact hole forming portion without removing the remaining film, so that the above-described structure according to the present invention cannot be manufactured. In this regard, when a low γ resist is used, the characteristics shown in FIG. 6 are obtained. Therefore, if the integrated exposure amount is controlled, the above configuration according to the present invention can be easily manufactured.

In the manufacturing method according to the present embodiment,
FIG. 11B shows a photomask used in the exposure step.
The configuration shown in FIG. That is, the photomask 42
Are ultraviolet transmission regions 40a and ultraviolet shielding regions 40b.
, And regions 40c having a light blocking ratio smaller than the light blocking region. Each area 40a, 40b, area 40c is
It is circular or elliptical. The region 40a is for forming the contact hole 41, the region 40b is for forming the columnar body 15, and the region 40c is for forming the remaining film 3. The region 40 can be realized by forming openings having a size of the exposure limit or a size in the vicinity thereof in a mesh shape.

By using such a photomask 42, the exposure amount is adjusted, and a portion that dissolves during development and a portion that does not dissolve much are formed. As shown in FIG. , The residual film 2 and the projections 4 can be formed. Then, the convex portion 4 is covered and a metal thin film such as aluminum (Al) is deposited to form a light-reflective thin film 5.
Is formed, the light reflective thin film 5 and the TFT 40 are electrically connected via the contact hole 41. (FIG. 10 (e)).

(Embodiment 3) FIG. 13 is a plan view of a principal part of a reflector according to Embodiment 3, and FIG.
It is an X arrow cross section. Embodiment 3 is an example in which the present invention is applied to a diffraction grating reflector. The third embodiment is similar to the first embodiment and corresponding parts are denoted by the same reference numerals. In the third embodiment, instead of the protrusions 4 of the first embodiment, concentric protrusions 51 are used. In addition, the convex portion 51 is obtained by melting and deforming a concentric columnar body made of a photosensitive resin material.

The diffraction grating reflector 50 having such a structure is manufactured by using the manufacturing method of the first embodiment, and a reflection type liquid crystal display device is manufactured. Since these values were almost the same, a reflective liquid crystal display device having a wide color reproduction range could be obtained.

As described above, in the diffraction grating type reflection plate having the characteristic of dispersing by reflection diffraction, high accuracy is required for the inclination angle of the side surface of the projection 51. Therefore, manufacturing by the manufacturing method according to the present invention is extremely effective. The diffraction grating patterns are not limited to concentric shapes, but may be arranged in parallel.

(Other Matters) (1) In the above embodiment, a case is described in which the same photosensitive resin is formed as a residual film below the convex portion, but other photosensitive resins are formed. After filming, the above JSR
Even if a positive resist PC409 manufactured by Co., Ltd. is applied and exposed and developed using a photomask, it is possible to set an arbitrary average inclination angle in a stable region having a large process margin, and the same can be implemented.

(2) Also, after applying a positive resist PC409 similarly manufactured by JSR, a heat treatment is performed, and
It is also possible to form the concavo-convex structure after the application of 409 and the formation of an uneven structure after exposure and development via a photomask.

(3) In the above embodiment, one photosensitive resin layer is formed. For example, after applying a photosensitive resin, the same photosensitive resin is further applied to form a two-layer photosensitive resin layer. It may be formed and exposed and developed through a photomask to form a projection. Also, after applying the first layer of photosensitive resin, after performing a process such as heat treatment, or electron beam irradiation treatment, ultraviolet light irradiation treatment, the same photosensitive resin is applied and exposed through a photomask. Alternatively, the protrusions may be formed by developing. Further, even if the photosensitive resin of the first layer is different from the photosensitive resin of the second layer thereon, a stable region can be arbitrarily set, and the present invention can be similarly implemented. Furthermore, in place of the photosensitive resin in the first layer, a material whose surface energy is almost the same as the photosensitive resin in the second layer is formed, and then a stable region is formed even when the second layer is formed. Can be set, and can be similarly implemented.

(4) In the above embodiment, the photolithography method is used to form the columnar body. However, even if the columnar body is formed by another method, for example, by using a mold or another method, the photosensitive material may be formed. This can be performed as long as a resin is used.

(5) In the above embodiment, the photosensitive resin is formed on the substrate and the projections are formed by using the photolithography method. However, the thermoplastic resin is formed on the substrate.
The protrusion may be formed by heat treatment.

[0095]

As described above, according to the present invention, the process margin can be significantly increased as compared with the conventional example. Therefore, it is not affected by processing errors, etc.
The average inclination angle of the actually manufactured convex portion is substantially equal to the set value. Accordingly, the surface of the light-reflective thin film covering the convex portions has a desired uneven shape, and a reflector and a reflective liquid crystal display device having excellent contrast characteristics and paper whiteness can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a reflector according to a first embodiment.

FIG. 2 is a plan view of the reflector according to the first embodiment.

FIG. 3 is an enlarged cross-sectional view of a protrusion 4;

FIG. 4 is an enlarged perspective view of a convex portion 4;

FIG. 5 is a flowchart showing a manufacturing process of the reflector according to the first embodiment.

FIG. 6 is a cross-sectional view showing a manufacturing process of the reflector according to the first embodiment.

FIG. 7 is a graph showing an aspect ratio γ-average tilt angle θ characteristic.

FIG. 8 is a graph showing an aspect ratio γ-average tilt angle θ characteristic according to changes in remaining film thickness and heating temperature.

FIG. 9 is a diagram for explaining a difference between a conventional example and the present invention due to a processing error.

FIG. 10 is a sectional view of a principal part of a reflection type liquid crystal display device using the reflection plate of the first embodiment.

FIG. 11 is a cross-sectional view showing a manufacturing process of the reflector according to the second embodiment.

FIG. 12 is a characteristic diagram of a low γ resist.

FIG. 13 is a plan view of a main part of the reflector according to the third embodiment.

FIG. 14 is a sectional view taken along the line XX of FIG. 13;

FIG. 15 is a cross-sectional view showing a step of a conventional manufacturing method.

[Explanation of symbols]

 1,50: Reflecting plate 2: Substrate 3: Remaining film 4,51: Convex portion 5: Light reflective thin film 15: Column θ: Average tilt angle

Continued on the front page F term (reference) 2H042 BA04 BA15 BA20 DA02 DA12 DA17 DE04 2H091 FA16Y FA19Y FB02 FB08 FC02 FC10 FC22 FC23 LA12 LA16 LA17 2H092 JB07 JB08 NA01 NA03 PA01 PA12 QA10 5G435 AA01 BB12 BB16 FF08 KK

Claims (20)

[Claims] 1. A reflection plate comprising: a substrate provided with a plurality of projections obtained by melting and deforming a columnar body made of a photosensitive resin material; and a light-reflective thin film covering the projections. The conductive resin material, and a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and the angle between the bottom surface of the convex portion and the average inclination angle of the convex portion,
When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the columnar body, gradually increases from a value near 0, the average inclination angle reaches a maximum value through an ascending and changing process, and then decreases in a descending process. Has an aspect ratio-average inclination angle characteristic that converges to a constant value through the above, and the average inclination angle of the plurality of convex portions is the convergence value in the aspect ratio-average inclination angle characteristic. A reflector. 2. The reflector according to claim 1, wherein the aspect ratio is a ratio of a height to a width of the columnar body. 3. A step of forming an uneven thermoplastic resin layer composed of a thin film portion and a plurality of columnar portions on a substrate, and performing heat treatment on the substrate on which the plurality of columnar portions are formed. A heat treatment step of melting and deforming the columnar body portion to form a plurality of convex portions having a predetermined average inclination angle, and a step of forming a light-reflective thin film on the convex portions; The material is a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and an angle formed between the bottom surface of the convex portion and the average inclination angle of the convex portion,
When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the columnar body, gradually increases from a value near 0, the average inclination angle reaches a maximum value through an ascending and changing process, and then decreases in a descending process. Starting point at which the set value of the aspect ratio of the columnar body obtained in the resin layer forming step starts to converge to the constant value. A method of manufacturing a reflector, wherein the aspect ratio is larger than the above. 4. A method of manufacturing a reflecting plate having a plurality of convex portions obtained by melting and deforming a columnar body made of a photosensitive resin material, comprising: a coating step of coating a photosensitive resin material on a substrate; An exposure step of irradiating the photosensitive resin material film obtained in the step with light through a photomask having a light-shielding portion patterned into a predetermined shape, and developing the light-irradiated photosensitive resin film, A developing step of forming a residual film and a plurality of pillars; and performing a heat treatment on the substrate on which the plurality of pillars are formed, thereby melting and deforming the pillars, and forming a plurality of curved shapes having a predetermined average inclination angle. A heat treatment step of forming a convex portion, and a step of forming a light-reflective thin film on the convex portion, wherein the photosensitive resin material comprises a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and a vertex of the convex portion. And the angle between the straight line connecting The average angle of inclination of the part,
When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the columnar body, is gradually increased from a value near 0,
Aspect ratio-such that the average inclination angle reaches a maximum value through a rising process and then converges to a constant value through a falling process.
A reflector having an average inclination angle characteristic, wherein a set value of an aspect ratio of the columnar body obtained in the developing step is set to an aspect ratio larger than a start point at which the columnar body starts converging to the constant value. Manufacturing method. 5. The reflector according to claim 4, wherein said photosensitive resin material is a low γ resist material. 6. The aspect ratio-average tilt angle characteristic is as follows:
When the heating temperature for heating the columnar body is increased, the convergence value of the average inclination angle changes to a small value, and conversely, when the heating temperature is decreased, the convergence value of the average inclination angle changes to a large value. The method according to claim 4, wherein in the heat treatment step, a heating temperature is set to a heating temperature corresponding to the predetermined average inclination angle of the projection. 7. The aspect ratio-average tilt angle characteristic is as follows:
When the thickness of the residual film is increased, the convergence value of the average inclination angle changes to a small value, and when the thickness of the residual film is decreased, the convergence value of the average inclination angle changes to a large value. The amount of exposure to the photosensitive resin in the exposure step is adjusted so that the thickness of the remaining film obtained later becomes the thickness of the remaining film corresponding to the predetermined average inclination angle of the convex portion. The method for manufacturing a reflector according to claim 4. 8. The method according to claim 1, wherein the aspect ratio is 0.05 or more.
The method for manufacturing a reflector according to claim 4, wherein the thickness is in the range of 7 or less. 9. The method according to claim 4, wherein the thickness of the photosensitive resin film in the coating step is in a range of 1 μm or more and 10 μm or less. 10. The method according to claim 1, further comprising a step of forming a photosensitive resin material of the same material as the photosensitive resin material on the substrate before the applying step of applying the photosensitive resin material on the substrate. 5. The method for producing a reflector according to item 4. 11. The method according to claim 1, further comprising, prior to the step of applying the photosensitive resin material on the substrate, forming a film of a photosensitive resin material different from the photosensitive resin material on the substrate. 5. The method for producing a reflector according to item 4. 12. The method according to claim 3, wherein the aspect ratio is a ratio of a height to a width of the columnar body. 13. A reflective liquid crystal display device comprising a liquid crystal display layer interposed therebetween and a substrate provided on one side and the reflection plate according to claim 1 provided on the other side. 14. A method of manufacturing a reflection type liquid crystal display device comprising: a reflection plate; a substrate provided to face the reflection plate; and a liquid crystal display layer sandwiched between the reflection plate and the substrate. 13. A method of manufacturing a reflective liquid crystal display device, wherein the method is manufactured by the method according to claim 3. 15. A plurality of concentrically or juxtaposedly arranged protrusions, which are obtained by melting and deforming concentrically or juxtaposedly arranged columns made of a photosensitive resin material. A substrate provided with a plurality of convex portions, and a light-reflective thin film covering the convex portions, and a diffraction grating type reflection plate having a characteristic of separating incident light by reflection diffraction. The material is a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and an angle between the bottom surface of the convex portion and an average inclination angle of the convex portion,
When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the columnar body, gradually increases from a value near 0, the average inclination angle reaches a maximum value through an ascending and changing process, and then decreases in a descending process. Has an aspect ratio-average inclination angle characteristic that converges to a constant value through the above, and the average inclination angle of the plurality of convex portions is the convergence value in the aspect ratio-average inclination angle characteristic. Diffraction grating type reflector. 16. The diffraction grating reflector according to claim 15, wherein the aspect ratio is a ratio of a height to a width of the columnar body. 17. A reflection type liquid crystal display device comprising a substrate provided on one side and a diffraction grating type reflection plate according to claim 15 provided on the other side across a liquid crystal display layer. 18. A method of manufacturing a diffraction grating reflector having a plurality of projections obtained by melting and deforming a columnar body made of a photosensitive resin material and having a characteristic of separating incident light by reflection diffraction. An application step of applying a photosensitive resin material on a substrate; and an exposure step of irradiating the photosensitive resin material film obtained by the application step with light through a photomask having a light-shielding portion patterned into a predetermined shape. A developing step of developing the light-irradiated photosensitive resin film to form a residual film and a plurality of concentrically or parallelly arranged columns, and a substrate on which the plurality of columns are formed Heat treatment to melt deform the columnar body, heat treatment step of forming a plurality of convex portions arranged concentrically or side by side and having a predetermined average inclination angle, a light reflective thin film on the convex portions Forming and The photosensitive resin material, and a straight line connecting a predetermined point on the outer peripheral edge of the bottom surface of the convex portion and the vertex of the convex portion, and the angle between the bottom surface of the convex portion and the average inclination angle of the convex portion,
When the aspect ratio, which is indicated by the ratio of two representative dimensions defining the shape of the columnar body, gradually increases from a value near 0, the average inclination angle reaches a maximum value through an ascending and changing process, and then decreases in a descending process. Has an aspect ratio-average inclination angle characteristic that converges to a constant value through the process.The set value of the aspect ratio of the columnar body obtained in the developing step is smaller than the starting point at which the convergent value starts to converge to the constant value. A method for producing a diffraction grating reflector, wherein the reflector has a large aspect ratio. 19. The method according to claim 18, wherein the aspect ratio is a ratio of a height to a width of the columnar body. 20. A method of manufacturing a reflection type liquid crystal display device comprising a reflection plate, a substrate provided so as to face the reflection plate, and a liquid crystal display layer sandwiched between the reflection plate and the substrate. Is manufactured by the method according to claim 18 or 19.