JP2000321410A - Production of reflection plate and reflection plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a reflection plate which is capable of manufacturing ruggedness with high accuracy with respect to a design and stably manufacturing the reflection plate having the decreased variations between substrates or between batches. SOLUTION: This process for producing the reflection plate consists in forming rugged parts having inclinations or curved surfaces on a substrate 1 and forming a thin film 3 having a light reflection function on these rugged parts. At this time, a photosensitive resin layer 2 is formed on the substrate 1 by using a photosensitive resin as the material for forming the rugged parts and, thereafter, the rugged parts are formed by a photolithography stage on the photosensitive resin layer 2 and the exposure of the photosensitive resin is transiently changed in the inclination direction of the rugged parts, by which the inclinations or curved surfaces are formed in the rugged parts and, therefore, the ruggedness may be manufactured with the high accuracy with respect to the design.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection plate applied to a reflection type liquid crystal display device for monochrome or color display, and more particularly to a method for producing a reflection plate having a concave-convex reflection surface and a method for producing the same. The present invention relates to a reflector manufactured using the same.

[0002]

2. Description of the Related Art A reflection type liquid crystal display device displays an image by reflecting ambient light incident from outside without using a backlight. The liquid crystal display device has features such as cost reduction and is most suitable as a sub-notebook personal computer or a portable information terminal. Because it is not necessary to use a backlight in a reflective liquid crystal display device, it is important to efficiently use the ambient light to brighten the display surface. It plays a large role, and it has been indispensable to design a reflector having optimal reflection characteristics by efficiently using ambient light incident from all angles, and to provide a technique for accurately manufacturing the reflector.

[0003] As an example of the prior art relating to the manufacturing method of the reflector, in the prior art described in Japanese Patent Application Laid-Open No. Hei 8-271884, a cutting tool having a tip with an inclination of 10 ° is manufactured and used to cut a brass plate. And mold. And
The acrylic resin is heated to a temperature higher than the glass transition point, and the mold is pressed against the acrylic resin to perform embossing. Then, aluminum is vapor-deposited thereon to a thickness of 1000 mm to form a saw-tooth-shaped reflector. . Further, in the prior art described in the publication, in order to provide a light diffusing property to the reflection plate,
The surface of the press die is finely uneven by corrosion, sand blasting, or polishing by uneven surface. Furthermore,
In the prior art described in the publication, as a method of reflecting light from a plurality of light sources in the direction of the line of sight, a method of bending a cutting tool for forming a reflecting surface or a method of mixing two types of reflecting surface angles is adopted. .

[0004] As another example of the prior art relating to the method of manufacturing a reflection plate, in the prior art described in JP-A-9-197399, a photosensitive acrylic resin is applied on a substrate such as glass, and the diameter is reduced by exposure and development. A large number of 10 μm convex patterns are formed in a random arrangement, and then the substrate is baked at 200 ° C. to produce a reflector. Also, by baking the substrate at 200 ° C. in this manner, the convex acrylic resin exhibits fluidity, the convex pattern portion has a substantially spherical shape, and a reflective surface such as aluminum or the like that produces a mirror reflection is formed on the surface. The embossed reflection plate is produced by having it. Further, as still another example of the prior art relating to the manufacturing method of the reflection plate, in the prior art described in Japanese Patent Application Laid-Open No. 9-80426, irregularities are formed by brushing the surface of a metal film. By adding the mark, a reflection plate in which the vertices of the horizontally long elliptical convex portion are unevenly distributed downward is manufactured.

[0005]

However, the conventional manufacturing method described above has a problem that the manufacturing accuracy of the reflector cannot be increased. In a reflection type liquid crystal display device, matching between the liquid crystal display mode and the characteristics of the reflection plate is an important factor, and if these are not sufficiently considered, the display is bright and the contrast is low, or the contrast is high and dark. Problem occurs. Even if they are sufficiently considered and an ideal reflector is designed in an optical simulation or the like, if the manufacturing accuracy is low,
From the simulation results, only optical characteristics far apart can be obtained.

In the manufacturing method shown in the prior art, it is necessary to re-polish the cutting tool, for example, every 300 cuts in order to secure the manufacturing accuracy, but the angular accuracy before and after polishing affects the characteristics. There is a problem. Further, even if a convex shape is formed by photolithography and a spherical shape is formed by applying heat, the fluidity changes due to the viscosity of the resin and the like, so that it is difficult to obtain a curvature as designed, and a free shape ( For example, a convex shape cannot be formed on the upper and lower asymmetric type. In addition, the manufacturing method by brushing requires processing for each sheet, and the processing method is basically very similar to cutting. In other words, there is a possibility that the reflection plate may vary depending on the control of the shape of the polishing cloth, the amount of the alumina abrasive powder attached, and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and a method of manufacturing a reflector capable of manufacturing a design shape with high accuracy and a method of manufacturing the same using the manufacturing method. It is an object to provide a reflector.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a reflector in which an uneven portion having an inclined or curved surface is formed on a substrate, and a thin film having a light reflecting function is formed on the uneven portion. . In the method for manufacturing a reflection plate according to claim 1, a photosensitive resin is used as a material for forming the concave and convex portions, a photosensitive resin layer is formed on a substrate, and the photosensitive resin layer is formed with a photolithographic process. By forming a portion and transiently changing the exposure amount of the photosensitive resin with respect to the inclination direction of the uneven portion, a slope or a curved surface is formed in the uneven portion. Further, in the method of manufacturing a reflection plate according to claim 2, a photosensitive resin layer is formed on a substrate such as glass.
After forming an uneven portion by a photolithography process on the photosensitive resin layer and forming a slope or a curved surface on the uneven portion by transiently changing the exposure amount of the photosensitive resin with respect to the tilt direction of the uneven portion. The concave and convex shape formed of the photosensitive resin is transferred to a substrate by dry etching technology to form a reflector plate mold, and a photocurable resin is applied to the mold and cured to form a resin having irregularities. Form a substrate,
After peeling the resin substrate from the mold, a thin film having a light reflecting function is formed on the concave and convex portions of the resin substrate to produce a reflector.

According to a third aspect of the present invention, there is provided a method of manufacturing a reflector according to the first or second aspect, wherein the step of transiently changing an exposure amount of the photosensitive resin is performed by exposing the photosensitive resin. In some cases, a photomask is used, and the line width of the photomask is transiently changed with respect to the inclination direction of the uneven portion. According to a fourth aspect of the present invention, there is provided a method of manufacturing a reflective plate according to the first or second aspect, wherein the step of transiently changing the exposure amount of the photosensitive resin includes the step of: Using a mask, the opening of the photomask is formed as a square dot, and the opening area of the dot is transiently changed with respect to the inclination direction of the uneven portion. Note that, in order to make the slope and the curved surface of the uneven portion gentle, the exposure may be performed with a diffusion plate placed between the exposure lamp and the photomask.
According to a fifth aspect of the present invention, in the method of manufacturing a reflective plate according to the first or second aspect, the means for transiently changing the exposure amount of the photosensitive resin includes: An opening of the photomask is a dot of 1 μm ² or less using a photomask, and the number of dots per unit area is transiently changed with respect to the inclination direction of the uneven portion. Claims 3, 4 or 5
In the method for manufacturing a reflector described above, a stepper (reduction exposure apparatus) can be used as a means for increasing the resolution. The stepper is reduced in size to one fifth of the mask size and projected, and thus is five times as large as the contact exposure mask. In other words, the mask of the stepper can improve the dimensional accuracy (resolution) of the mask five times as compared with the mask of the contact exposure apparatus.

[0010] The reflector according to claim 7 is a reflector having an uneven portion having an inclined or curved surface on a substrate and a thin film having a light reflecting function formed on the uneven portion. It is characterized by being produced by the production method according to any one of 1 to 6.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing a reflector according to the present invention and a reflector manufactured by the method will be described below in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a view showing a first embodiment of the present invention, and is an explanatory view of a process showing a manufacturing process of a reflection plate. As shown in FIG. 1A, a photosensitive resin 2 is applied to the surface of the substrate 1 by spin coating to a thickness of 16 μm and subjected to a baking treatment at a temperature of 90 ° C. for 1 hour.
As a material of the substrate 1, for example, a polyester film,
Plastic films such as polyacrylic films,
Metal plates such as aluminum and copper plates, glass plates and the like can be mentioned. The photosensitive resin 2 is, for example, a photosensitive acrylic resin or a photoresist. Here, for explanation, a positive photoresist OFPR800-800c is used.
This will be described by taking p (manufactured by Tokyo Ohka (product name)) as an example.

Next, as shown in FIG. 1B, the photoresist 2 which is a photosensitive resin layer is exposed and patterned (the arrow in the figure indicates the integrated exposure amount). At this time, a slope or a curved surface can be formed in the projection by transiently changing the exposure amount with respect to the inclination direction of the projection. After this exposure, the photoresist 2 is developed to obtain an uneven resist shape as shown in FIG. Next, as shown in FIG. 1D, a metal thin film 3 such as aluminum or silver having a light reflecting function is formed on the surface of the uneven portion formed on the photoresist 2 by a sputtering method or a vapor deposition method.
A reflector having a plurality of fine irregularities on the reflection surface is completed. Note that, in the process explanatory diagram of FIG. 1, a cross section of a part of the reflector is shown in an enlarged manner for easy understanding of the shape of the concave / convex portion, and the cross section of the entire reflector is not shown.

FIG. 2 is a graph showing the resist film thickness after development when the exposure amount is changed. For example, when the film thickness is 16 μm, the just exposure amount (the exposure amount at which the resist film thickness becomes 0) is 0.9 J / cm ² , and when the film thickness remains half (8 μm), it is 0.23 J / cm ² . . Table 1 below shows the exposure amount for each remaining film thickness from FIG. Considering the case of producing a 45 ° tilt by this method, for example, 0.06 J / c at a distance of 0
m ^2, 0.1J / cm ² at a distance 1 [mu] m, distance 0.14J / cm ² at 2 [mu] m, .. middle omitted .., distance 11
What is necessary is just to select an exposure amount such that it becomes 0.9 J / cm ² at the place of μm. Also, the slope is not limited to a straight line, and a curved surface can be formed by combining an appropriate exposure amount from the graph of FIG.

[0015]

[Table 1]

(Embodiment 2) FIG. 3 is a view showing a second embodiment of the present invention, and is an explanatory view showing a process of manufacturing a reflector. As shown in FIG. 3A, the glass substrate 1 ′
A positive resist is applied as a photosensitive resin 2 to the surface of the substrate by spin coating to a thickness of 16 μm.
Perform a time baking process. Next, as shown in FIG. 3B, the photoresist 2, which is a photosensitive resin layer, is exposed and patterned (arrows in the figure indicate integrated exposure amounts). At this time, similarly to the first embodiment, by changing the exposure amount transiently with respect to the inclination direction of the convex portion, it is possible to form a slope or a curved surface on the convex portion. After this exposure, the photoresist 2 is developed to obtain an uneven resist shape as shown in FIG.

Next, as shown in FIG. 3D, dry etching is performed using the uneven photoresist 2 as an etching mask to change the resist shape to the glass substrate 1 '.
Transfer to At this time, etching is performed under such conditions that the etching rate between the photoresist 2 and the glass substrate 1 ′ is 1: 1. The etching gas is C
A mixed gas such as F ₄ , CHF ₃ , Ar, O ₂ is used,
The etching rate of the glass substrate 1 'and the photoresist 2 is set to 1: 1 depending on the conditions such as the gas partial pressure, the etching pressure, and the applied power.

Next, as shown in FIG. 3 (e), using a glass substrate 1 'on which an uneven portion is formed as a mold, a photocurable resin 4 is applied to the surface of the uneven portion and cured to form a light having an uneven portion. A curable resin substrate 4 is formed, and the resin substrate 4 is separated from the mold. Next, as shown in FIG. 3 (f), a metal thin film 3 such as aluminum or silver having a light reflecting function is formed on the uneven surface of the resin substrate 4 by a sputtering method or a vapor deposition method, so that a fine surface is formed on the reflecting surface. A reflector having a plurality of uneven portions is completed. Note that, in the process explanatory diagram of FIG. 3, a cross section of a part of the reflector is shown in an enlarged manner for easy understanding of the shape of the concave / convex portion, and the cross section of the entire reflector is not shown.

(Embodiment 3) Next, a third embodiment of the present invention will be described. In this embodiment, as a means for changing the exposure amount of the photosensitive resin 2 transiently during the step of exposing the photosensitive resin (photoresist) 2 shown in the first embodiment or the second embodiment, Sometimes using a photomask,
The line width of the photomask is changed transiently with respect to the inclination direction of the uneven portion. FIG. 4 is a schematic plan view schematically showing an example of a photomask pattern used in the exposure step. The dark line portion 5a in FIG. 4 is dark (a light-shielding portion that does not transmit light), and the white line portion 5b is dark.
Is a clear (light transmitting portion through which light passes). The minimum line width of the clear line portion 5b is 0.25 μm, the width is increased by 0.25 μm in the X direction (inclination direction of the uneven portion), and the maximum width is 2.5 μm. A total of ten line portions 5b are arranged in the X direction. The pitch at this time was 4 μm. The linear pattern 5 having the ten clear line portions 5b becomes a pattern forming one peak of the sawtooth-shaped convex portion, and the linear pattern 5 is repeatedly arranged in the X direction. A plurality of similar patterns are arranged in the Y direction. The number of juxtaposed patterns in the X direction and the Y direction is set according to the size of the reflector, and the linear pattern 5 shown in FIG. Photomasks arranged in an array are manufactured.

When an exposure amount of, for example, 1 J / cm ^{2 is applied} to this photomask, light transmission characteristics as shown in FIG. 5 can be obtained. The concavo-convex shape obtained by developing the photoresist exposed by this photomask has a saw blade-like structure as shown in FIG. 1C and FIG. ) Has a gentle concave surface. Also,
By changing the design of the photomask pattern, it is possible to make the reflective surface shape flat or convex,
It is also possible to freely change the pitch and height of the peak of the saw blade.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described. In this embodiment, as a means for transiently changing the exposure amount of the photosensitive resin 2 during the exposure step of the photosensitive resin (photoresist) 2 shown in the first embodiment or the second embodiment, Using a photomask, the opening of the photomask is formed as a square dot, and the opening area of the dot is transiently changed with respect to the inclination direction of the uneven portion. FIG. 6 is a schematic plan view schematically showing an example of a photomask pattern used in the exposure step. The dark portion 6a in FIG. 6 is dark (light-shielding portion that does not transmit light), and the white square dot portion 6b is clear (light-transmitting portion that transmits light). Note that grids (black vertical and horizontal lines) are provided so as to divide each dot portion 6b, but this is for explanation and is not provided on an actual photomask. The minimum dot size of the clear dot portion 6b is 0.5 μm × 0.5 μm, and the dots are increased by 0.25 μm in the X direction (the inclination direction of the uneven portion), and the maximum dot size is 2.75 μm.
A total of 10 rows of m × 2.75 μm are arranged. Also, dots of the same size are arranged in the Y direction, and the pitch at this time is 4 μm in both the X and Y directions. The ten rows of dot patterns 6 in FIG. 6 are patterns forming one peak of the sawtooth-shaped protrusions, and the dot patterns 6 are repeatedly arranged in the X direction. A plurality of similar patterns are also arranged in the Y direction. The number of juxtaposed patterns in the X direction and the Y direction is set according to the size of the reflector, and the dot pattern 6 shown in FIG. Photomasks arranged in an array are manufactured.

When an exposure amount of, for example, 1 J / cm ^{2 is applied} to this photomask, light transmission characteristics as shown in FIG. 7 can be obtained. The concavo-convex shape obtained by developing the photoresist exposed by this photomask has a saw blade-like structure as shown in FIG. 1C and FIG. In), a gentle concave surface reflecting dots is continuously provided at a pitch of 4 μm. In order to make the concave surface smooth, there is a method of exposing the photomask and the photoresist in a state of being separated by 30 to 100 μm. In this method, since the curvature of the concave surface changes depending on the distance, the light can be freely diffused. As another method, contact exposure may be performed with a light diffusion plate placed between an exposure lamp and a photomask.
Since the light diffusion plate can freely select the diffusion angle,
Any suitable one may be used. The shape of the sawtooth-shaped reflecting surface is flat in the case of the light transmission characteristic shown in FIG. 7, becomes convex when the light transmission characteristic curve is laid down, and becomes concave when the light transmission characteristic curve is linear. . It is also possible to freely change the pitch and height of the peak of the saw blade.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described. In this embodiment, as a means for transiently changing the exposure amount of the photosensitive resin 2 during the exposure step of the photosensitive resin (photoresist) 2 shown in the first embodiment or the second embodiment, An opening of the photomask is a dot of 1 μm ² or less using a photomask, and the number of dots per unit area is transiently changed with respect to the inclination direction of the uneven portion. Here, an example will be described in which a reflector having the same structure as the reflector having the saw-toothed structure described in Embodiment 4 is manufactured. FIG. 8 is a schematic plan view schematically showing an example of a photomask pattern used in the exposure step. In FIG. 8, a portion 7a having a high density is dark (a light-shielding portion that does not allow light to pass), and a small square dot portion 7b having white voids is a clear (a light transmitting portion that allows light to pass). still,
A grid (black vertical and horizontal lines) is provided to separate the mask surface, but this is for explanation only and is not attached to the actual photomask. Here, the size of one dot is set to 0.25 μm × 0.25 μm,
However, it is not limited to this.

In the fourth embodiment, the X direction (the inclination direction of the uneven portion)
Although the opening area of the dot 6b is transiently changed in the direction of, the amount of exposure to the photosensitive resin is transiently changed, but in this embodiment, the number of dots per unit area is transiently changed in the X direction. The amount of exposure to the photosensitive resin is changed transiently. More specifically, in the dot pattern 6 of the fourth embodiment (FIG. 6), the opening area of the smallest dot in the first column on the left end is 0.5 μm × 0.5 μm = 0.25 μm ^2. The opening area of the example dot 7b is 0.25μ.
m × 0.25 μm = 0.0625 μm ² , which is four times, so if a portion surrounded by the grid (black vertical and horizontal lines) in FIG. 8 has a unit area of 4 μm × 4 μm, four dots are arranged in this area. In this case, the transmitted light amounts are the same. In the next row of the fourth embodiment, the opening area of the dots is 0.75 μm × 0.
75 μm = 0.5625 μm ² , and the opening area of the dot 7 b of this embodiment is 0.25 μm × 0.25 μm = 0.0
Since this is nine times 625 μm ^2, the same amount of transmitted light can be obtained by arranging nine dots in an area of 4 μm × 4 μm. Similarly, by arranging the dots 7b in a number corresponding to the opening area in the same manner as the increase in the opening area in the fourth embodiment, the same light transmission characteristics as in the fourth embodiment can be obtained. An uneven shape in which the blade-shaped reflecting surface is inclined can be formed. In addition, when this method is used, the gradation is changed by adjusting the number of dots per unit area, and the number of gradations is larger than that described in the fourth embodiment. Surfaces can be made.
As in the case of the fourth embodiment, the dot pattern 7 shown in FIG.
Is one peak of the sawtooth-shaped convex portion, and the dot patterns 7 are repeatedly arranged in the X direction. Also, a plurality of similar patterns are arranged in the Y direction. The number of juxtaposed patterns in the X direction and the Y direction is set according to the size of the reflector, and the dot pattern 7 shown in FIG. Photomasks arranged in an array are manufactured.

(Embodiment 6) Embodiment 1 (Claim 1)
Alternatively, since the reflection plate manufactured by the method for manufacturing a reflection plate according to the second embodiment (claim 2) uses a photolithography method, it can be manufactured with high accuracy for design, and the distance between substrates can be improved. In addition, it is possible to provide a reflector having less variation in characteristics between batches and excellent mass productivity. Further, in the reflector manufactured by the manufacturing method described in the third embodiment (claim 3), a reflector having a sawtooth-shaped reflecting surface can be easily manufactured only by manufacturing a relatively simple photomask having a stripe shape. Not only can the inclination angle of the concave and convex portions of the reflecting surface be freely formed by simply changing the design, but also the inclined surface of the concave and convex portions can be formed in a concave or convex shape. further,
The reflecting plate manufactured by the manufacturing method according to the fourth embodiment (claim 4) or the fifth embodiment (claim 5) can also be formed to have a convex shape other than the saw blade shape. ,
The production of a reflector having a large number of projections 8 as shown in FIG. 9 can also be produced by appropriately designing the dot pattern of the photomask. FIG. 9A is a plan view of one projection of the reflection plate as viewed from above, FIG. 9B is a left side view of the projection, and FIG. 9C is a front view of the projection.

Here, Table 2 below shows the projections when the reflector having the projections 8 having the shape shown in FIG. 9 is manufactured by the manufacturing method using the photomask described in the fifth embodiment (Claim 5). 1
8 shows the design of the dot pattern of each photomask. The opening area of one dot 7b of the dot pattern 7 similar to FIG. 8 is set to 0.25 μm × 0.25 μm = 0.0.
625 μm ² represents the number of dots in a unit area of 4 μm × 4 μm. Then, a photomask in which the dot-shaped patterns are two-dimensionally arranged in an array is prepared, and is patterned by using the photomask in the exposure step of the manufacturing process described in Example 1 or Example 2 to obtain FIG. Is formed.

The reflecting plate having the reflecting surface in which the projections having the shape shown in FIG. 9 are arranged in an array not only efficiently reflects light from an obliquely upward direction but also efficiently reflects light from the right and left and lateral directions. It is designed to reflect well. Further, the present invention is not limited to this. In the manufacturing method of the present invention, several types of convex portions can be mixed, so that the reflector can be manufactured with high precision for the optical design of the reflector.

[0028]

[Table 2]

(Embodiment 7) Next, a seventh embodiment of the present invention will be described. In the present embodiment, in the method of manufacturing a reflection plate according to the third embodiment (Claim 3), the fourth embodiment (Claim 4), or the fifth embodiment (Claim 5), a stepper type is used as an exposure unit in an exposure step. (Claim 6). In the normal contact exposure method, since the photomask and the photoresist are exposed in close contact,
The mask size and the exposure surface are one-to-one and 1: 1 exposure, and the minimum size of the photomask is the minimum size of the photoresist.
On the other hand, in a stepper method using a stepper as an exposure means, a photomask is formed with a size five times as large as the actual size, and the photoresist is exposed by reducing the size to 1/5. Therefore, the dimensional accuracy of the photomask has a resolution five times that of the contact exposure method.

For example, in the contact exposure method in the manufacturing method described in the third embodiment, since the resolution at the time of manufacturing a photomask is at least 0.25 μm, the line width can be increased only by 0.25 μm. However, in the stepper method, since the pattern is formed with a size five times larger, the resolution of the exposed surface is apparently 1/5 of 0.25 μm.
It becomes 0.05 μm. In the contact exposure method in the manufacturing method described in Example 3, the minimum line width is 0.25 μm, the next line width is 0.5 μm, and the line width is sequentially increased by 0.25 μm. In this case, the mask dimensions are 1.25 μm, 2.5 μm, and 1.25 μm
You just have to make them thicker. In addition, since the resolution at the time of manufacturing the photomask is 0.25 μm, it is possible to manufacture a photomask having a line width of 1.5 μm next to 1.25 μm.

In the manufacturing method of the reflector in this embodiment, since the stepper method is used as the exposure means, the resolution is increased as described above. It becomes possible to manufacture a reflection plate. For example, by making the line width of each pitch non-uniform, the reflecting surface can be processed into a concave shape, a convex shape, or the like, and the surface property can be smoothly formed. Also, in the method of manufacturing the reflector described in Example 4 or Example 5, the use of the stepper method as the exposure means at the time of the exposure step makes it possible to form finer irregularities, thereby improving the reflection efficiency. It is possible to manufacture a reflector having good quality as designed.

[0032]

As described above, in the method for manufacturing a reflection plate according to the first aspect, a photosensitive resin is used as a material for forming the concave and convex portions, and a photosensitive resin layer is formed on a substrate. Since an uneven portion is formed in the photosensitive resin layer by a photolithography process and the amount of exposure of the photosensitive resin is transiently changed with respect to the tilt direction of the uneven portion, a slope or a curved surface is formed in the uneven portion, Asperities can be manufactured with high precision for design, and a reflector with less variation between substrates or between batches can be manufactured stably.

According to a second aspect of the present invention, a photosensitive resin layer is formed on a substrate, and an uneven portion is formed on the photosensitive resin layer by a photolithography process. On the other hand, by changing the exposure amount of the photosensitive resin transiently to form a slope or a curved surface in the uneven portion, the uneven shape formed by the photosensitive resin is transferred to the substrate by dry etching technology. Create a reflector plate mold, apply a photo-curing type resin to the mold and cure it to form a resin substrate with irregularities. After peeling the resin substrate from the mold, place it on the irregularities of the resin substrate. Since the reflection plate is made by forming a thin film having a light reflection function, it is possible to make the unevenness with high precision for the design, and also to make the mold and then transfer the uneven shape to the resin. More mass production Suitable are, can be produced less variation reflector between the substrate or between batches stably.

According to a third aspect of the present invention, there is provided a method of manufacturing a reflector according to the first or second aspect, wherein the step of transiently changing the exposure amount of the photosensitive resin is performed by exposing the photosensitive resin. Since a photomask is sometimes used and the line width of the photomask is changed transiently with respect to the inclination direction of the uneven portion, it is possible to form the saw-tooth-shaped uneven portion on the reflector with high precision for the design. it can. Further, depending on the design, the inclined surface (reflection surface) of the uneven portion can be processed into a straight line, a concave surface, a convex surface, or the like.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a reflector according to the first or second aspect, wherein the step of transiently changing an exposure amount of the photosensitive resin is performed by exposing the photosensitive resin. Sometimes a photomask is used, and the opening of the photomask is formed as a square dot, and the opening area of the dot is changed transiently with respect to the inclination direction of the uneven portion. Since other free-form irregularities can be formed on the reflector, a more efficient reflector can be manufactured.

According to a fifth aspect of the present invention, in the method for manufacturing a reflector according to the first or second aspect, the means for transiently changing the exposure amount of the photosensitive resin includes exposing the photosensitive resin to light. Occasionally, a photomask is used, the openings of the photomask are dots of 1 μm ² or less, and the number of dots per unit area is transiently changed with respect to the inclination direction of the uneven portion. Since an uneven portion having a blade shape or other free shape can be formed on the reflector, a reflector having a higher efficiency can be manufactured.
Also, by adjusting the number of dots per unit area, it is possible to form an uneven surface with even higher gradation, so that the reflector can be manufactured with high definition even with a complicated optical design.

In the method of manufacturing a reflector according to the sixth aspect, in the method of manufacturing a reflector according to the third, fourth or fifth aspect, the exposure means is performed by a stepper.
Alternatively, since it is possible to form a shape having higher gradation than the manufacturing method described in 5, the reflective plate can be manufactured with high definition even with a complicated optical design.

Further, the reflector according to claim 7 is a reflector having an uneven portion having an inclined or curved surface on a substrate, and a thin film having a light reflecting function formed on the uneven portion. Since it is manufactured by the manufacturing method according to any one of 1 to 6, it is possible to have a highly efficient reflecting surface having a saw-toothed or other free-shaped uneven portion, and to be upward, obliquely upward, laterally, etc. Incident light can be efficiently reflected to the front. Therefore, a bright reflective display panel can be obtained by applying the reflective plate of the present invention as a reflective plate of a liquid crystal display panel.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of the present invention and is an explanatory view showing a process of manufacturing a reflector.

FIG. 2 is a view showing a remaining resist film thickness after development when an exposure amount is changed in an exposure / development step of the manufacturing process shown in FIG. 1;

FIG. 3 is a view illustrating a second embodiment of the present invention, and is an explanatory view illustrating a process of manufacturing a reflection plate.

FIG. 4 is a schematic plan view showing a third embodiment of the present invention and schematically showing an example of a photomask pattern used in an exposure step.

FIG. 5 is a diagram showing light transmission characteristics of a photomask having the pattern shape shown in FIG.

FIG. 6 is a schematic plan view showing a fourth embodiment of the present invention and schematically showing an example of a photomask pattern used in an exposure step.

FIG. 7 is a diagram showing light transmission characteristics of a photomask having the pattern shape shown in FIG.

FIG. 8 is a view showing a fifth embodiment of the present invention, and is a schematic plan view schematically showing an example of a photomask pattern used in an exposure step.

FIG. 9 is a view showing a sixth embodiment of the present invention, and is a view showing an example of a shape of a convex portion of a reflection plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 1 'Glass substrate 2 Photosensitive resin (photoresist) 3 Metal thin film which has light reflection function 4 Photocurable resin 5 Line pattern 6 Dot pattern 7 Dot pattern

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuhiro Sato 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H042 BA04 BA15 BA20 DA02 DA04 DA10 DA11 DA12 DC08 DC12 DE00 2H091 FA14Z FA16Z FB04 FB08 FC01 FC02 FC10 FC29 LA12 2H095 BB06 BB14 BB25 BB32 BB33 BB36 BC01 BC04

Claims (7)

[Claims] 1. A method of manufacturing a reflector in which an uneven portion having a slope or a curved surface is formed on a substrate, and a thin film having a light reflecting function is formed on the uneven portion. After forming a photosensitive resin layer on the substrate by using a resin, an uneven portion is formed on the photosensitive resin layer by a photolithography process, and the exposure amount of the photosensitive resin is changed with respect to the inclination direction of the uneven portion. Forming a slope or a curved surface in the uneven portion by changing the shape of the reflector. 2. A method for manufacturing a reflector, comprising forming an uneven portion having a slope or a curved surface on a substrate and forming a thin film having a light reflecting function on the uneven portion, wherein a photosensitive resin layer is formed on the substrate. Then, an uneven portion is formed on the photosensitive resin layer by a photolithography process, and a slope or a curved surface is formed on the uneven portion by transiently changing the exposure amount of the photosensitive resin with respect to the inclination direction of the uneven portion. After that, the uneven shape formed by the photosensitive resin is transferred to the substrate by dry etching technology to create a reflector plate mold, and a photocurable resin is applied to the mold and cured to form the uneven portion. Forming a resin substrate having a light-reflecting function on an uneven portion of the resin substrate to form a reflection plate; . 3. A method for manufacturing a reflection plate according to claim 1, wherein a photomask is used at the time of exposure of the photosensitive resin as means for transiently changing an exposure amount of the photosensitive resin.
A method of manufacturing a reflector, wherein the line width of the photomask is changed transiently with respect to the direction of inclination of the concave and convex portions. 4. A method of manufacturing a reflection plate according to claim 1, wherein a means for transiently changing an exposure amount of the photosensitive resin includes using a photomask at the time of exposure of the photosensitive resin.
A method of manufacturing a reflector, wherein the opening of the photomask is a square dot, and the opening area of the dot is transiently changed with respect to the inclination direction of the uneven portion. 5. The method for manufacturing a reflection plate according to claim 1, wherein a means for transiently changing an exposure amount of the photosensitive resin includes using a photomask during exposure of the photosensitive resin.
The opening of the photomask is a dot of 1 μm ² or less,
A method of manufacturing a reflector, wherein the number of dots per unit area is changed transiently with respect to the direction of inclination of the concave and convex portions. 6. The method for manufacturing a reflector according to claim 3, wherein the exposure means is performed by a stepper. 7. A reflector comprising an uneven portion having a slope or a curved surface on a substrate, and a thin film having a light reflecting function formed on the uneven portion, wherein the reflector is provided. A reflection plate produced by the method of (1).