JP2004354599A - Reflector and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an ideal display without causing uneven reflection by reducing coloring due to interference. <P>SOLUTION: In the reflector, a plurality of different unit ruggedness arrays are arranged in a matrix state, and also, as for each unit ruggedness array, the ruggedness array is constituted so that at least a part of the ruggedness resembles or become similar to fibonacci series. Besides, in an area where the ruggedness is arranged resembling or becoming similar to the fibonacci series, the arrangement of the order of ≤ 500 in the fibonacci series accounts for ≥70%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

表１を見ると明らかなように、次数５００以下の領域が７０％以上である領域において、凹凸傾斜角分布（視角）が略円形になっており、反射率や反射の視角異方性が解消されることがわかった。
【００５０】
実施例１
１×８のマトリクスに、図１（ｂ）に示すように、フィボナッチ配列から８つのパターン（単位凹凸配列）を抽出してランダムに配置した。各単位凹凸配列のサイズは５０μｍ×１５０μｍである。また、単位凹凸配列は次数５００以下の領域が７割以上とした。８つの単位凹凸配列は、フィボナッチ数列の一領域とそれぞれ相似であり、且つそれぞれ異なる。
【００５１】
各単位凹凸配列は、フィボナッチ数列という非周期性から、任意の互いに平行な直線状断面における凹凸形状が互いに独立である。また、それぞれの単位凹凸配列は互いに異なる配列であることから、１×８マトリクス内で任意の互いに平行な直線状断面における凹凸形状が互いに独立である。
【００５２】
このような凹凸を持つ反射体では干渉は生じなかった。また、前述の図３に示す液晶表示装置の反射画素電極１９として用いた場合にも同様の効果を得ることができた。
【００５３】
なお、１×８のマトリクスの単位凹凸配列以上の任意領域の凹凸傾斜角分布を評価したところ、図７（ａ）に示すように、ほぼ円形、乃至は軽微な楕円形であった。例えば、この１×８の単位凹凸配列をフィボナッチ数列のｎ＞５００とした場合、図７（ｂ）に示すような長方形となる。
【００５４】
また、１×８の単位凹凸配列を凹凸傾斜角分布が類似のものを隣り合わせて配置することで、単位配列間のむらが抑制できた。
【００５５】
実施例２
実施例１における１×８マトリクスを１ブロックとし、このブロックをマトリクス状に配置した。１×１の単位凹凸配列のみをマトリクス配置したものと比べると、１×８マトリクスのブロック配置では干渉が低減された。また、前述の図３に示す液晶表示装置の反射画素電極１９として用いた場合にも同様の効果を得ることができた。
【００５６】
実施例３
実施例２における１×８マトリクスを１ブロックとし、このブロックを図８に示すように、市松状に配置した。なお、図８において、＊印が各ブロックの先頭を表している。１×１の単位凹凸配列のみをマトリクス配置したものと比べると、１×８マトリクスからなるブロックを市松配置したものでは、干渉が低減された。また、前述の図３に示す液晶表示装置の反射画素電極１９として用いた場合にも同様の効果を得ることができた。
【００５７】
実施例４
実施例２における１×８マトリクスを１ブロックとし、このブロックを図９に示すように、斜めズラシランダム配置した。なお、図９において、＊印が各ブロックの先頭を表している。１×１の単位凹凸配列のみをマトリクス配置したものと比べると、１×８マトリクスからなるブロックを斜めズラシランダム配置したものでは、干渉が低減された。また、前述の図３に示す液晶表示装置の反射画素電極１９として用いた場合にも同様の効果を得ることができた。
【００５８】
実施例５
実施例２における１×８マトリクスを１ブロックとし、このブロックを図１０に示すように、斜めズラシ配置した。なお、図１０において、＊印が各ブロックの先頭を表している。１×１の単位凹凸配列のみをマトリクス配置したものと比べると、１×８マトリクスからなるブロックを斜めズラシ配置したものでは、干渉が低減された。また、前述の図３に示す液晶表示装置の反射画素電極１９として用いた場合にも同様の効果を得ることができた。
【００５９】
実施例６
実施例２における１×８マトリクスから１×３マトリクスを抽出して１ブロックとし、このブロックをさらにマトリクス状に配置した。また、同様に１×８マトリクスから１×２マトリクスを抽出して１ブロックとし、このブロックをさらにマトリクス状に配置した。単位凹凸配列のみをマトリクス状に配置したものに比べて、１×２マトリクスのブロックをマトリクス状に配置したもの、さらには１×３マトリクスのブロックをマトリクス状に配置したものの方が、反射体のみでは干渉低減が確認された。
【００６０】
前述の図３に示す液晶表示装置では、反射画素電極１９と対向して配設されるカラーフィルタ２４は赤、緑、青のストライプ状パターンの繰り返し周期となっている。したがって、１×３マトリクスのブロックをマトリクス状に配置した反射電極を有する液晶表示装置は、カラーフィルタ２４の色周期と同期するため、１×１の単位凹凸配列のみをマトリクス状に配置したものを反射画素電極１９とした場合と比べて干渉の差はなかった。一方、１×２マトリクスのブロックをマトリクス状に配置した反射画素電極１９を有する液晶表示装置では、干渉低減の効果を得ることができた。同様に、１×８マトリクスをブロックとし、このブロックをマトリクス状に配置した反射画素電極１９を有する液晶表示装置でも、十分な干渉低減の効果を得ることができた。これは、カラーフィルタ２４の色周期に対して、反射体の単位凹凸配列の配置周期が「素」であることによる。
【００６１】
実施例７
実施例２における１×８マトリクスをブロックとし、このブロックをマトリクス状に配置した凹凸反射電極を有する液晶表示装置では、対向するカラーフィルターに透明領域を有する場合にも、充分な干渉低減の効果を得た。
【００６２】
【発明の効果】
以上の説明からも明らかなように、本発明によれば、干渉による色付きを低減し、反射むらのない理想的な表示を実現することが可能な反射体を提供することが可能である。さらに、本発明によれば、かかる反射体を適用することで表示品位に優れた液晶表示装置を提供することが可能である。
【図面の簡単な説明】
【図１】フィボナッチ数列による配列を示す平面図であり、（ａ）は次数５００以下の領域を示し、（ｂ）は８つのパターンの抽出を示す。
【図２】凹凸傾斜角分布を説明する図であり、（ａ）は凸部の平面形状を示す平面図、（ｂ）は凸部のＸ−Ｘ′線での断面図、（ｃ）は凸部のＹ−Ｙ′線での断面図である。
【図３】反射型液晶表示装置の構成例を示す要部概略断面図である。
【図４】反射画素電極における凹凸パターンの形成プロセスを示す概略断面図であり、（ａ）は有機樹脂絶縁膜形成工程、（ｂ）はフォトマスクを用いた露光工程、（ｃ）は有機樹脂絶縁膜現像工程、（ｄ）は加熱処理工程、（ｅ）は反射画素電極形成工程を示す。
【図５】フィボナッチ数列にしたがって凸部を形成した領域をａ１〜ｄ６まで３６分割した様子を示す図である。
【図６】ａ１〜ｄ６まで３６分割した各領域における凹凸傾斜角分布を示す図である。
【図７】（ａ）は１×８の単位凹凸配列をフィボナッチ数列の次数ｎ≦５００としたときの凹凸傾斜角分布を示す図であり、（ｂ）は１×８の単位凹凸配列をフィボナッチ数列の次数ｎ＞５００としたときの凹凸傾斜角分布を示す図である。
【図８】市松配置を示す図である。
【図９】斜めズラシランダム配置を示す図である。
【図１０】斜めズラシ配置を示す図である。
【符号の説明】
１１ マトリクスアレイ基板、１９ 反射画素電極、 ２０ 凹凸パターン、２２ 対向基板、２４ カラーフィルタ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflector having fine irregularities formed thereon as scattered light forming means, and further relates to a liquid crystal display device having such a reflector and performing display using external light.
[0002]
[Prior art]
2. Description of the Related Art In recent years, applications of liquid crystal display devices to personal computers, televisions, word processors, mobile phones, and the like have been further developed, and demands for higher functions such as miniaturization, power saving, and cost reduction have been issued. . In order to satisfy these demands, for example, a reflective liquid crystal display device that reflects and displays ambient light incident from outside without using a backlight, or a transflective type device that has both a transmissive function and a reflective function. Liquid crystal display devices are being developed.
[0003]
In these reflective liquid crystal display devices and transflective liquid crystal display devices, it is important how efficiently ambient light can be used to brighten the display surface. For this reason, the reflector mounted on this type of liquid crystal display device is made to have optimal reflection characteristics by efficiently utilizing ambient light incident from all angles.
[0004]
Specifically, for example, convex patterns protruding in a curved shape having a diameter of about 3 μm to 20 μm and a height of about 0.3 μm to 1.2 μm are regularly arranged on the surface of the reflector as scattered light forming means for forming scattered light. . At this time, according to a translation vector forming an angle of 60 ° so that the center becomes a hexagonal lattice, the convex patterns are regularly arranged so that the distance is constant. By employing such an array pattern, scattered light is generated in addition to regular reflection, so that the reflection characteristics are optimized.
[0005]
However, with the regular arrangement as described above, although the reflection characteristics are improved, there is a disadvantage that coloring due to interference occurs. Coloring due to interference significantly impairs the display quality of images and the like. Therefore, it has been proposed to use a Fibonacci sequence as a concavo-convex array for suppressing coloring due to interference (for example, see Patent Document 1).
[0006]
In the Fibonacci sequence, points on any straight line can be aperiodicly spaced according to a certain regularity. Therefore, by applying the Fibonacci sequence to the arrangement of the unevenness of the reflector, it is possible to make the unevenness in any linear cross section parallel to each other different, thereby suppressing interference caused by the unevenness arrangement. It is thought that it is possible.
[0007]
[Patent Document 1]
JP-A-2002-14211
[0008]
[Problems to be solved by the invention]
By the way, particularly in mobile applications such as a mobile phone to which a transflective or reflective liquid crystal display device is applied, the viewing distance of the display device is assumed to be about 40 cm, and interference caused by a period of several mm or more in the display device is caused. If so, this is difficult to see, and it is thought that if the Fibonacci sequence is applied to the arrangement of the unevenness of the reflector to suppress the interference due to the unevenness arrangement, the interference of the entire display device can be suppressed to a level that does not cause a problem. Can be
[0009]
On the other hand, the unit arrangement such as the dot cycle and the pixel cycle in the liquid crystal display device is several tens to several hundreds μm, and since these cycles can be visually recognized, even if the Fibonacci sequence is applied to the unit arrangement, interference due to uneven arrangement is suppressed. Even so, it is not enough to simply repeat it in dot units.
[0010]
Further, the Fibonacci sequence has a feature that the arrangement near the origin is almost equally spaced, but the distance from the origin increases the difference in density. This difference in density, that is, the deviation of the distance between the irregularities, appears in the characteristics as the reflectance and the viewing angle anisotropy of the reflection. For example, if the reflectance and the viewing angle in adjacent adjacent regions are different, there is a problem that the unevenness is visually recognized as uneven reflection. These problems can occur not only in the uneven arrangement using the Fibonacci sequence but also in the case of random arrangement.
[0011]
The present invention has been proposed in view of such a conventional situation, and has as its object to provide a reflector capable of reducing coloration due to interference and realizing an ideal display without reflection unevenness. Further, it is another object of the present invention to provide a liquid crystal display device having excellent display quality by applying such a reflector.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the reflector of the present invention is a reflector in which a plurality of different unit concavo-convex arrangements are arranged in a matrix, and in each of the unit concavo-convex arrangements, at least a part of each of the concavities and convexities Are arranged in a similar or similar manner to the Fibonacci sequence, and in a region where the irregularities are arranged in a similar or similar manner to the Fibonacci sequence, the arrangement of the order 500 or less in the Fibonacci sequence occupies 70% or more. Features.
[0013]
Further, the liquid crystal display device of the present invention has a pixel electrode formed by a reflector and a liquid crystal layer driven by the pixel electrode, and the reflector has a plurality of different unit uneven arrangements arranged in a matrix. A reflector that is formed, and in each of the unit concavo-convex arrangements, at least a part of each concavo-convex is similar or similar to the Fibonacci sequence, and the concavities and convexities are similar or similar to the Fibonacci sequence. In the arranged regions, an arrangement having an order of 500 or less in the Fibonacci sequence occupies 70% or more.
[0014]
The present invention macroscopically reduces the periodicity of the two-dimensional arrangement of the scattered light forming means by using a plurality of different non-periodic arrays in the arrangement of the unevenness as the scattered light forming means, and reduces coloring due to interference. The basic idea is to suppress it. In the present invention, first, as the non-periodic array, an array similar to or similar to the Fibonacci sequence is adopted. Secondly, in an array in which the order in the Fibonacci sequence exceeds 500, the difference in density is large, and its adverse effect appears in the characteristics. Therefore, in an area in which irregularities are arranged similar or similar to the Fibonacci sequence, The arrangement of the order 500 or less in the Fibonacci sequence occupies 70% or more. With these configurations, in the present invention, the periodicity of the two-dimensional arrangement is reduced and coloring due to interference is suppressed, and at the same time, the difference in reflectance and viewing angle characteristics due to the unevenness of the uneven density created by the array is also reduced. .
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the reflector and the liquid crystal display device of the present invention will be described with reference to the drawings.
[0016]
First, the reflector of the present invention is a reflector in which a plurality of different unit concavo-convex arrangements are arranged in a matrix. When the same unit concave-convex array is repeatedly arranged, interference due to its periodicity becomes a problem. Therefore, in the present invention, by arranging a plurality of unit concavo-convex arrays having different arrangements in a matrix, the periodicity caused by repeatedly arranging the same unit concavo-convex array is eliminated.
[0017]
Each unit concavo-convex array includes an array of convex portions (or concave portions) similar or similar to the Fibonacci sequence which is a non-periodic array. An arrangement similar or similar to the Fibonacci sequence is, for example, an arrangement of sunflower seeds, and is an arrangement having a substantially spiral shape as shown in FIG. Here, the array similar to or similar to the Fibonacci sequence is an array based on the Fibonacci sequence, and includes an array in which some dots are omitted therefrom.
[0018]
The Fibonacci sequence is:
(X, y) = (√n × cos (137.5 / 180 × nπ), √n × sin (137.5 / 180 × nπ)
Is a sequence of numbers. This integer n is hereinafter referred to as the order of the Fibonacci sequence.
[0019]
What is important in the present invention is that, in an arrangement similar or similar to the Fibonacci sequence applied to each of the unit concavo-convex arrangements, an arrangement having an order of 500 or less in the Fibonacci sequence occupies 70% or more. In an array in which the order in the Fibonacci sequence exceeds 500, the difference in density becomes large, and the adverse effect appears in the characteristics. Specifically, the difference in the density, that is, the deviation in the distance between the unevenness, appears in the characteristics as the reflectance and the viewing angle anisotropy of the reflection. Therefore, in the present invention, in each unit concavo-convex array, an array pattern is extracted mainly from an array having an order of 500 or less in the Fibonacci sequence.
[0020]
The fact that it is effective to eliminate the visual anisotropy that the arrangement of the order 500 or less occupies 70% or more in the Fibonacci sequence can be explained using an index called the uneven inclination angle (θx, θy) distribution. it can.
[0021]
As shown in FIGS. 2 (a) to 2 (c), assuming that the coordinates of an arbitrary uneven surface are Z (x, y), the uneven inclination angle θx is obtained by differentiating the cross section of the uneven surface shape in the x direction. The value is dZ (x, y) / dx. Similarly, the uneven inclination angle θy is a value dZ (x, y) / dy obtained by differentiating the cross section of the uneven surface shape in the y direction.
[0022]
The inclination angle in an arbitrary direction is θ = tan-1√ (tan²θx + tan²θy). When the frequency distribution of the concavo-convex inclination angle (θx, θy) is evaluated in an arbitrary area, and the histogram is represented by an equal frequency curve of (θx, θy), the concavo-convex inclination angle distribution is circular, elliptical, or rectangular. Is shown.
[0023]
From this shape, the viewing angle characteristics can be estimated. For example, if the shape is circular, the viewing angle is isotropic, while if the axis appears as a rectangle, the viewing angle is anisotropic. As a result of investigations by the present inventors, it has been found that the arrangement of irregularities at an inclination angle becomes substantially circular by arranging 70% or more of arrays having an order of 500 or less in the Fibonacci sequence.
[0024]
In FIG. 1A, a region surrounded by a circle A is a region of an array having an order of 500 or less in the Fibonacci sequence, and as shown as a rectangular region in FIG. B is extracted to make each unit concave-convex array. In this example, eight patterns are extracted from the area surrounded by the circle A, and these patterns are adopted as the plurality of different unit concave-convex arrays.
[0025]
Each of the eight patterns is formed into a unitary concavo-convex array. For example, those arranged randomly and arranged in a matrix form one block, and the blocks are further arranged in a matrix to constitute a reflector. Examples of the arrangement of the blocks include an oblique shift random arrangement, a checkered arrangement, and an oblique shift arrangement, and any arrangement can be employed as long as the arrangement can eliminate the periodicity.
[0026]
In the reflector as described above, it is preferable that the concavo-convex inclination angle (θx, θy) distribution is substantially circular even in an arbitrary region having a width equal to or greater than the unit concavo-convex arrangement. In addition, it is preferable that the unevenness inclination angles (θx, θy) be substantially equal in two arbitrary regions adjacent to each other having a width equal to or larger than the unit unevenness arrangement.
[0027]
The reflector as described above is applied to a reflector (for example, a pixel electrode) of a liquid crystal display device such as a reflective liquid crystal display device or a transflective liquid crystal display device having both a transmission function and a reflection function. Can be. Hereinafter, a liquid crystal display device to which the reflector of the present invention is applied will be described using a reflection type liquid crystal display device as an example.
[0028]
As shown in FIG. 3, the reflection type liquid crystal display device has a matrix array substrate 11 and a counter substrate 22, and a liquid crystal material is filled between the matrix array substrate 11 and the counter substrate 22 to form a liquid crystal layer 27. It is formed.
[0029]
Here, the matrix array substrate 11 has a glass substrate 12 which is an insulating substrate such as a high strain point glass substrate or a quartz substrate, and an insulating film 14 is formed on the glass substrate 12 via a glass coat layer 13. Have been. A plurality of signal lines 15 are disposed in parallel on the insulating film 14, and a plurality of scanning lines (not shown) are provided in a direction orthogonal to the signal lines 15 in a state of being insulated from the signal lines 15. A thin film transistor which is disposed in parallel and which serves as a switching element is disposed at a portion where the signal line 15 and the scanning line intersect.
[0030]
Further, a transparent protective insulating film 16 is provided on the insulating film 14 including the signal lines 15. An organic resin insulating film 17 is disposed on the transparent protective insulating film 16, and the surface of each of the matrix portions surrounded by the signal lines 15 and the scanning lines of the organic resin insulating film 17 has An uneven pattern 18 in which the convex portions 18a and the concave portions 18b are formed is formed.
[0031]
A reflection pixel electrode which is a reflector made of a metal film such as aluminum (Al), nickel (Ni), chromium (Cr), or silver (Ag) is provided on a portion of the organic resin insulating film 17 where the uneven pattern 18 is located. Reference numerals 19 are formed in a matrix corresponding to the thin film transistors (not shown), and projections 20a and depressions 20b are formed on the reflection pixel electrodes 19 in correspondence with the projections and depressions pattern 18 of the organic resin insulating film 17, so as to form scattered light. Is formed. Note that an alignment film 21 is further provided on the organic resin insulating film 17.
[0032]
On the other hand, a counter substrate 22 disposed opposite to the matrix array substrate 11 similarly has a glass substrate 23 which is an insulating substrate such as a high strain point glass substrate or a quartz substrate. A color filter 24 composed of a plurality of colors in a matrix or a stripe is formed, a counter electrode 25 is provided on the color filter 24, and an alignment film 26 is formed on the counter electrode 25.
[0033]
Then, the alignment film 21 of the matrix array substrate 11 and the alignment film 26 of the counter substrate 22 are arranged to face each other, and a liquid crystal material is sandwiched between the matrix array substrate 11 and the counter substrate 22 to form a liquid crystal layer 27. Then, a liquid crystal display device is formed. In this liquid crystal display device, by applying a voltage between the reflective pixel electrode 19 and the counter electrode 25, the liquid crystal layer 27 is driven to perform display.
[0034]
In the liquid crystal display device having the above configuration, the above-described reflector is applied to the reflective pixel electrode 19. That is, in the concavo-convex pattern 20 as the scattered light forming means, a plurality of different unit concavo-convex arrays are arranged in a matrix, and in each unit concavo-convex array, the concavities and convexities are arranged similar or similar to the Fibonacci sequence. , Are arranged so that an array having an order of 500 or less in the Fibonacci sequence occupies 70% or more.
[0035]
The arrangement of the projections 20a in the concavo-convex pattern 20 is the same as the arrangement of the projections in the reflector described above, but in the case of a liquid crystal display device, it is preferable to consider the color cycle in the color filter 24, and It is preferable that the arrangement cycle of the different unit concavo-convex array is made relatively prime to the color cycle.
[0036]
Further, in an arbitrary region having a width equal to or larger than the unit concavo-convex arrangement of the reflectors (reflection pixel electrodes 19) opposed to each color of the color filter 24, the concavo-convex inclination angle (θx, θy) distribution may be substantially circular. Preferably, the distribution of the concavo-convex inclination angles (θx, θy) for each color is preferably substantially equal.
[0037]
Note that the above is an example of a reflective liquid crystal display device. For example, a reflective liquid crystal display device called TAF, a reflective transmissive liquid crystal display device having both a transmission function and a reflection function, and the like are described. Can also be applied. In the TAF, a matrix or a stripe-shaped color filter having a plurality of colors is provided at a position opposed to the liquid crystal layer of the reflector, and the color filter has one or more transparent regions. Reflector is formed. The reflector of the present invention can be applied to this reflector.
[0038]
Next, a method for forming a reflector according to the present invention will be described with reference to an example of a method for forming the reflective pixel electrode 19 having the above-described uneven pattern 20. FIG. 4 shows a process of forming the reflective pixel electrode 19 in the order of steps.
[0039]
In order to form the reflective pixel electrode 19 having the above-mentioned concave and convex pattern 20, first, as shown in FIG. 4A, a transparent photosensitive insulating film 16 of the matrix array substrate 11 is made of a positive photosensitive resin or the like. The organic resin insulating film 17 is applied on the entire surface by spin coating or the like to a thickness of about 1 μm to 4 μm.
[0040]
Next, as shown in FIG. 4B, after the matrix array substrate 11 is pre-baked, exposure is performed using a photomask 32. Here, the shape and density of the unevenness of the uneven pattern 18 of the organic resin insulating film 17 for forming the convex pattern 20 of the reflective pixel electrode 19 are controlled by the shape, density, exposure amount, and the like of the opening of the photomask 32. For example, the light-shielding portions 31 of the photomask 32 are arranged in accordance with the Fibonacci sequence such that the diameter of the circle of the light-shielding portion 31 is about 5 μm, and the average distance between the centers of the adjacent circles is in the range of 8.5 μm to 11 μm. Note that the exposure amount was 10 mJ to 200 mJ.
[0041]
Then, by developing the exposed organic resin insulating film 17, fine convex portions 18c and concave portions 18d are formed on the surface of the organic resin insulating film 17, as shown in FIG. Since the exposure amount is set to 10 mJ to 200 mJ, the bottom of the concave portion 18 d does not reach the surface of the transparent protective insulating film 16.
[0042]
Thereafter, as shown in FIG. 4D, by heating this matrix array substrate 11, corners of the concave portions 18d and the convex portions 18c are removed, thereby forming a concave / convex pattern 18 having smooth concave portions 18b and convex portions 18a. .
[0043]
Next, a metal film such as aluminum (Al), nickel (Ni), chromium (Cr), or silver (Ag) is formed to a thickness of about 100 nm by a sputtering method, and as shown in FIG. The reflective pixel electrode 19 is formed by patterning into a predetermined shape by a photo etching method. As described above, by forming the reflective pixel electrode 19 on the organic resin insulating film 17 on which the uneven pattern 18 is formed, the reflective pixel electrode 19 corresponds to the uneven pattern 18 formed on the organic resin insulating film 17. An uneven pattern 20 is formed.
[0044]
In the above process, the shape and density of the irregularities on the surface of the reflective pixel electrode 19 can be arbitrarily controlled by the shape, density, exposure amount, and the like of the opening of the photomask 32. Here, for example, FIG. The unevenness that forms one lattice unit of the matrix array should be a unitary unevenness array. This unitary unevenness array should be extracted from the regularity similar to the Fibonacci sequence, and a plurality of mutually different unitary unevenness arrays should be extracted as one block. The opening of the photomask 32 is designed based on the above.
[0045]
The reflector and the liquid crystal display device to which the invention is applied have been described above, but the invention is not limited to these embodiments. For example, although the case where the arrangement based on the Fibonacci sequence is 100% as an example of the arrangement of the concavo-convex pattern is described as an example, the same effect can be obtained even if the region other than the arrangement based on the Fibonacci sequence is a non-periodic arrangement such as a random arrangement. it can. However, in this case, it is preferable that the non-periodic arrangement such as the random arrangement is less than 50% of the unit uneven arrangement. Further, although the arrangement based on the Fibonacci sequence has been described using a convex pattern as an example, a similar effect can be obtained when a concave pattern is formed in the same arrangement.
[0046]
【Example】
Hereinafter, specific examples of the present invention will be described based on experimental results.
[0047]
A study on the order of Fibonacci sequence
In this experiment, the unevenness inclination angle distribution when the convex portions were arranged according to the Fibonacci sequence was verified. As shown in FIG. 5, the area in which the convex portions were formed in accordance with the Fibonacci sequence was divided into 24 areas a1 to d6, and the uneven inclination angle distribution in each calculation area was obtained. In the Fibonacci sequence, when the closest concavo-convex interval is 9 μm, a region having an order of 500 or less is a region having a diameter of about 200 μm or less (a circular region in the drawing).
[0048]
FIG. 6 shows the uneven angle distribution in the areas a1 to d6. As is clear from FIG. 6, in a region deviating from the circular region, for example, a1, a6, d1, d6, etc., the concavo-convex inclination angle distribution is substantially rectangular, whereas a region in the circular region, for example, In b3, b4, c, 3, c4, etc., the unevenness inclination angle distribution is substantially circular. Table 1 summarizes the ratios of the regions of order 500 or less (regions having a diameter within about 200 μm) and the uneven inclination angle distribution (viewing angle) in each region.
[0049]
[Table 1]

As is clear from Table 1, in the region where the region of order 500 or less is 70% or more, the unevenness inclination angle distribution (viewing angle) is substantially circular, and the reflectance and the viewing angle anisotropy of reflection are eliminated. I knew it would be done.
[0050]
Example 1
As shown in FIG. 1B, eight patterns (unit concave-convex array) were extracted from the Fibonacci array and randomly arranged in a 1 × 8 matrix. The size of each unit concave-convex array is 50 μm × 150 μm. Further, in the unit concavo-convex array, 70% or more of the regions having the order of 500 or less were used. The eight unit concavo-convex arrangements are similar to and different from one region of the Fibonacci sequence.
[0051]
In each of the unit concavo-convex arrays, the concavo-convex shapes in arbitrary linear cross sections parallel to each other are independent of each other due to the non-periodicity of the Fibonacci sequence. In addition, since the respective unit concavo-convex arrangements are different from each other, the concavo-convex shapes in arbitrary parallel linear cross sections in the 1 × 8 matrix are independent of each other.
[0052]
No interference occurred in the reflector having such irregularities. Further, similar effects could be obtained when used as the reflective pixel electrode 19 of the liquid crystal display device shown in FIG.
[0053]
When the distribution of the concavo-convex inclination angle in an arbitrary region of a unit concavo-convex array of a 1 × 8 matrix or more was evaluated, as shown in FIG. 7A, it was almost circular or slightly elliptical. For example, when the 1 × 8 unit concavo-convex array has n> 500 in the Fibonacci sequence, a rectangular shape as shown in FIG. 7B is obtained.
[0054]
Further, by arranging the 1 × 8 unit concavo-convex arrays adjacent to each other with similar concavo-convex inclination angle distribution, it was possible to suppress unevenness between the unit arrays.
[0055]
Example 2
The 1 × 8 matrix in the first embodiment is defined as one block, and the blocks are arranged in a matrix. Compared with the case where only the 1 × 1 unit uneven arrangement is arranged in a matrix, the interference is reduced in the block arrangement of the 1 × 8 matrix. Further, similar effects could be obtained when used as the reflective pixel electrode 19 of the liquid crystal display device shown in FIG.
[0056]
Example 3
The 1 × 8 matrix in the second embodiment is defined as one block, and the blocks are arranged in a checkered pattern as shown in FIG. In FIG. 8, the * mark indicates the head of each block. Compared with the case where only the 1 × 1 unit concavo-convex array is arranged in a matrix, the interference is reduced in the case where the blocks composed of the 1 × 8 matrix are arranged in a checkered pattern. Further, similar effects could be obtained when used as the reflective pixel electrode 19 of the liquid crystal display device shown in FIG.
[0057]
Example 4
The 1 × 8 matrix in the second embodiment is defined as one block, and the blocks are arranged obliquely and randomly as shown in FIG. Note that, in FIG. 9, an asterisk (*) indicates the head of each block. Compared with the case where only the 1 × 1 unit concavo-convex array is arranged in a matrix, the interference is reduced in the case where the blocks composed of the 1 × 8 matrix are arranged obliquely and randomly. Further, similar effects could be obtained when used as the reflective pixel electrode 19 of the liquid crystal display device shown in FIG.
[0058]
Example 5
The 1 × 8 matrix in the second embodiment is defined as one block, and the blocks are obliquely shifted as shown in FIG. Note that, in FIG. 10, an asterisk (*) indicates the head of each block. As compared with the case where only the 1 × 1 unit concave-convex array is arranged in a matrix, the interference is reduced in the case where the block composed of the 1 × 8 matrix is arranged obliquely. Further, similar effects could be obtained when used as the reflective pixel electrode 19 of the liquid crystal display device shown in FIG.
[0059]
Example 6
A 1 × 3 matrix was extracted from a 1 × 8 matrix in Example 2 to form one block, and this block was further arranged in a matrix. Similarly, a 1 × 2 matrix was extracted from a 1 × 8 matrix to form one block, and this block was further arranged in a matrix. Compared to the case where only the unit concavo-convex array is arranged in the form of a matrix, those in which 1 × 2 matrix blocks are arranged in a matrix form, and those in which 1 × 3 matrix blocks are arranged in a matrix form, have only a reflector. Then, interference reduction was confirmed.
[0060]
In the above-described liquid crystal display device shown in FIG. 3, the color filter 24 disposed to face the reflective pixel electrode 19 has a repetition cycle of a red, green, and blue stripe pattern. Therefore, a liquid crystal display device having a reflection electrode in which 1 × 3 matrix blocks are arranged in a matrix has a structure in which only a 1 × 1 unit concavo-convex array is arranged in a matrix to synchronize with the color cycle of the color filter 24. There was no difference in interference as compared with the case where the reflective pixel electrode 19 was used. On the other hand, in the liquid crystal display device having the reflection pixel electrodes 19 in which the blocks of the 1 × 2 matrix are arranged in a matrix, the effect of reducing the interference could be obtained. Similarly, a liquid crystal display device having a 1 × 8 matrix as a block and having the reflective pixel electrodes 19 in which the blocks are arranged in a matrix form could obtain a sufficient effect of reducing interference. This is because the arrangement period of the unit uneven arrangement of the reflector is "primary" with respect to the color period of the color filter 24.
[0061]
Example 7
In the liquid crystal display device having a 1 × 8 matrix as a block in the second embodiment and the uneven reflection electrodes in which the blocks are arranged in a matrix, a sufficient interference reduction effect can be obtained even when the opposed color filter has a transparent region. Obtained.
[0062]
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to provide a reflector capable of reducing coloring due to interference and realizing an ideal display without reflection unevenness. Further, according to the present invention, it is possible to provide a liquid crystal display device having excellent display quality by applying such a reflector.
[Brief description of the drawings]
FIG. 1 is a plan view showing an arrangement based on a Fibonacci sequence, in which (a) shows an area having an order of 500 or less, and (b) shows extraction of eight patterns.
FIGS. 2A and 2B are diagrams for explaining a concavo-convex inclination angle distribution, wherein FIG. 2A is a plan view showing a planar shape of a convex portion, FIG. 2B is a cross-sectional view of the convex portion taken along line XX ′, and FIG. It is sectional drawing in the YY 'line of a convex part.
FIG. 3 is a schematic cross-sectional view of a main part showing a configuration example of a reflection type liquid crystal display device.
4A and 4B are schematic cross-sectional views illustrating a process of forming a concavo-convex pattern on a reflective pixel electrode, wherein FIG. 4A is an organic resin insulating film forming process, FIG. 4B is an exposure process using a photomask, and FIG. (D) shows a heat treatment step, and (e) shows a reflective pixel electrode forming step.
FIG. 5 is a diagram showing a state in which a region in which a convex portion is formed in accordance with the Fibonacci sequence is divided into 36 areas a1 to d6.
FIG. 6 is a diagram showing a distribution of uneven inclination angles in each of 36 divided areas a1 to d6.
FIG. 7 (a) is a diagram showing a concavo-convex inclination angle distribution when a 1 × 8 unit concavo-convex array is set to the order n ≦ 500 of the Fibonacci sequence, and FIG. 7B is a diagram showing a 1 × 8 unit concavo-convex array in Fibonacci. It is a figure which shows the uneven inclination-angle distribution at the time of order n> 500 of a sequence.
FIG. 8 is a diagram showing a checkered arrangement.
FIG. 9 is a diagram showing an oblique shift random arrangement.
FIG. 10 is a diagram showing an oblique shift arrangement.
[Explanation of symbols]
11 matrix array substrate, 19 reflective pixel electrode, 20 uneven pattern, 22 opposing substrate, 24 color filter

Claims (16)

A reflector in which a plurality of different unit uneven arrangements are arranged in a matrix,
In each of the unit concavo-convex array, at least a part of each concavo-convex is similar or similar to Fibonacci sequence,
A reflector characterized in that, in a region in which concavities and convexities are arranged in a similar or similar manner to the Fibonacci sequence, 70% or more of the arrangements with an order of 500 or less in the Fibonacci sequence. The reflector according to claim 1, wherein in an arbitrary region having a size equal to or larger than the unit concavo-convex arrangement, a concavo-convex inclination angle (θx, θy) distribution is substantially circular. A reflector characterized in that, in two adjacent regions having a size equal to or greater than the unit concavo-convex arrangement, distributions of concavo-convex inclination angles (θx, θy) are substantially equal. A block in which the plurality of different unit concavo-convex arrays are arranged in a matrix is defined as one block,
The reflector according to claim 1, wherein the blocks are arranged in a matrix. The reflector according to claim 4, wherein the blocks are arranged obliquely at random. The reflector according to claim 4, wherein the blocks are arranged in a checkered pattern. 5. The reflector according to claim 4, wherein the blocks are arranged obliquely. A pixel electrode formed by a reflector, and a liquid crystal layer driven by the pixel electrode;
The reflector is a reflector in which a plurality of different unit concave-convex arrays are arranged in a matrix,
In each of the unit concavo-convex array, at least a part of each concavo-convex is similar or similar to Fibonacci sequence,
A liquid crystal display device characterized in that, in a region in which concavities and convexities are arranged in a similar or similar manner to the Fibonacci sequence, 70% or more of the arrangements with an order of 500 or less in the Fibonacci sequence. Matrix or stripe-shaped color filters comprising a plurality of colors are provided at positions facing each other across the liquid crystal layer of the reflector,
9. The liquid crystal display device according to claim 8, wherein a color cycle of the plurality of color filters and an arrangement cycle of the plurality of different unit concavo-convex arrays are relatively prime. Matrix or stripe-shaped color filters comprising a plurality of colors are provided at positions facing each other across the liquid crystal layer of the reflector,
9. The irregularity inclination angle (.theta.x, .theta.y) distribution is substantially circular in an arbitrary region having a width equal to or greater than a unit concavo-convex array of a reflector facing each color of the color filter. Liquid crystal display. Matrix or stripe-shaped color filters comprising a plurality of colors are provided at positions facing each other across the liquid crystal layer of the reflector,
9. The unevenness inclination angle (.theta.x, .theta.y) distribution for each color is substantially equal in an arbitrary area having a width equal to or larger than the unit uneven arrangement of the reflectors facing each color of the color filter. Liquid crystal display. Matrix or stripe-shaped color filters comprising a plurality of colors are provided at positions facing each other across the liquid crystal layer of the reflector,
9. The liquid crystal display device according to claim 8, wherein the color filter has at least one transparent region, and the reflector is formed to face the transparent region. 9. The reflector according to claim 8, wherein the reflector has a plurality of different unit concavo-convex arrangements arranged in a matrix form as one block, and the blocks are arranged in a matrix. 10. 14. The liquid crystal display device according to claim 13, wherein the blocks are arranged obliquely at random. 14. The liquid crystal display device according to claim 13, wherein the blocks are arranged in a checkered pattern. 14. The liquid crystal display device according to claim 13, wherein the blocks are arranged obliquely.

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