JP3853871B2 - Method and apparatus for creating computer generated hologram data - Google Patents

Description

ここで、Ｏi ：サンプル点ｉの物体光（点光源）の振幅
ｒi （ｘ，ｙ）：サンプル点ｉからの距離
ｋ：波数（２π／λ）
φi ：サンプル点ｉの物体光（点光源）の初期位相
【００３３】
更に、この実施の形態では、参照光として平行光を用いているため、これを（３）式のように表わすことができる。
【００３４】
Ｒ（ｘ，ｙ）＝Ｒo ｅｘｐ（ｊｋｘｓｉｎ（θ）＋ｊφr ）…（３）
ここで、Ｒo ：振幅
θ：参照光の入射角
φr ：初期位相
【００３５】
この実施の形態では、前記図５で説明したように、上記図７に示した物体光は、同図のｘ−ｚ平面においてのみ進行し、ｙ方向には進行しない波として扱っている。従って、ｙ方向の他の断面（ｘ−ｚ平面）との相関はなく、前述した如く、干渉縞はこの各断面毎に独立に、即ちｙを固定して計算される。従って、干渉縞計算領域１０Ａは複数のストライプ状の領域である前記データ上の要素領域１２Ａに分割される。
【００３６】
図８には、干渉縞データを計算する基本単位である、対象物データの水平方向１ラインと、これに対応するデータ上の要素領域１２Ａとの関係を模式的に示す。図中、手前に位置する小さい正方形は対象物データの単位を示ており、該データ単位は、便宜上ここでは平面的に配列されているが、実際には前記図７に示された対象物データの場合と同様に、ｚ方向に変化している３次元データである。
【００３７】
そして、物体光は上記データ単位の中心に○印で示した点光源からの光と仮定して計算する。即ち、水平方向に並ぶ対象物データの単位の各中心に位置する点光源からの光の干渉により、後方に位置する計算機ホログラム１０上の１つの要素領域１２の中心ライン（代表ライン）上に干渉縞が生成するとして、そのデータが計算される。この計算で得られる１ライン分の干渉縞データを模式的に示したのが図９（Ａ）である。
【００３８】
次に、ステップ５において、光学素子選定部２８を用いて、干渉縞データを複写する幅と間隔を設定する。即ち、回折格子を選択する場合は、同一幅で等間隔に、フレネルゾーンプレートの場合は、中心ほど幅を広く、又、場合によっては、中心ほど幅を狭くするように寸法を設定する。ここでは回折格子を選定したものとして以下の説明を行う。
【００３９】
次のステップ６では、２値化部３０を用いて、前記干渉縞計算部２６で計算して得られた、上記図９（Ａ）に示したような１ライン分の干渉縞データを、所定の閾値を設定して２値化し、同図（Ｂ）に示したようなバイナリデータとする。
【００４０】
次に、ステップ７において、データ複写部３２を用いて、図１０に前記図８と同一の大きさのデータ上の要素領域１２Ａを後方に、それを拡大した状態を手前にそれぞれ概念的に示したように、要素領域１２Ａ毎に２値化された中心１ライン分の干渉縞データを、ホログラムにすると回折機能を発揮するように間欠的に複写する。この図１０では、中心１ライン分の干渉縞データを、該中心より上の領域に４本複写した状態が模式的に示してある。その後、同様に下の領域にも４本複写する。この図の場合は、中心部にも同一幅で複写したとすると、合計９本の干渉縞データ列が１つの要素領域１２Ａに作成される場合が示してある。上記データ複写部３２による複写処理により、この実施の形態による計算機ホログラムデータの作成が完了する。
【００４１】
次に、ステップ８において、データ変換部３４を用いて、上記データ複写部３２より作成された計算機ホログラムデータが、計算機上のバイナリデータであるため、これを荷電粒子ビーム描画装置３６を制御駆動するための描画装置用フォーマットのデータに変換し、それを描画データとする。図９（Ｃ）は、この描画データを模式的に示したものである。
【００４２】
次に、ステップ９において、描画装置３６を用いて、上記描画データを用いて装置を駆動し、荷電粒子ビームにより物理的媒体を描画し、計算機ホログラムを作成する。その結果、干渉縞列の本数は、前記図１０に示した干渉縞データ列の本数とは異なるが、前記図１に示した計算機ホログラムが得られる。
【００４３】
この描画装置３６としては、例えば日本電子株式会社製の電子ビーム描画装置を用いることができる。この描画装置３６を、フォーマット変換した上記描画データで制御しながら駆動し、ガラス基板上に塗布されたレジスト膜（物理的媒体）に電子線ビームで描画して、レジスト膜を所定のパターンに硬化した後、未硬化部分を除去する現像を行うことにより、計算機ホログラムは完成する。このようにして作成された計算機ホログラムには、前述した如く、要素領域１２毎に同一パターンの干渉縞列１４が間欠的に形成されることになるが、そのパターンの断面は前記図９（Ｃ）の描画データに相当する。
【００４４】
次に、ステップ１０において、後加工装置３８を用いて、以上のようにして作成された計算機ホログラムを原版として大量生産する場合の処理が行われる。具体的には、図１１（Ａ）に示す、上記描画装置３６により描画した後、現像して作成されたレジストからなる計算機ホログラムの表面に、蒸着法や無電解めっき法により導電性金属被膜を形成して同図（Ｂ）の状態にした後、該金属被膜を電極としてニッケル等の金属を厚くめっきし、同図（Ｃ）に示すような金属スタンパを作成する。その後、レジスト面から剥離した上記金属スタンパを用いて熱可塑性樹脂からなるフィルムを熱プレスするエンボス複製により、計算機ホログラム（エンボスホログラム）を量産する。
【００４５】
実際のプレス装置では、多面付けされたスタンパを用いて、フィルム原反（例えば、ＰＥＴ／アクリル樹脂／アルミ蒸着によりなる多層構造のフィルム）に対して、プレスしてホログラムが作成される。
【００４６】
このようにして作成された計算機ホログラムに対しては、必要に応じてシール加工が施される。これは、粘着剤（例えば、塩化ビニル／酢酸ビニル共重合体を主成分とするもの）を、上記多層構造の場合はプレス後のアルミ蒸着面に塗布して、剥離紙（例えば、ＰＥＴ）を張り付けることにあたる。
【００４７】
以上詳述した如く、この実施の形態によれば、計算機によって作成される干渉縞データに、媒体にホログラムとして記録した際に回折格子又は凸レンズ列等の一方向性光学素子と同様に機能させるデータを混在させることができる。従って、このデータを荷電粒子ビーム描画装置を用いて２値パターンとして物理的媒体に描画することにより、垂直方向に回折効果の高い計算機ホログラムを作成することができる。
【００４８】
以上、本発明を具体的に説明したが、本発明は、前記実施の形態に示したものに限られるものでなく、その要旨を逸脱しない範囲で種々変更可能である。
【００４９】
例えば、前記実施の形態では、２値化部３０がデータ複写部３２の前に設けられ、干渉縞データの２値化を複写する前に実行する場合を示したが、逆に、２値化部をデータ複写部３２の後方に設置し、干渉縞データをコピーする作業が完了した後に２値化を行うようにしてもよい。但し、前記実施の形態のように先に２値化する方が、処理を短時間で行うことができる。
【００５０】
又、前記実施の形態では、要素領域に形成する干渉縞列について、幅と間隔の寸法を具体例を挙げて示したが、この間隔等は回折効果を生じさせるものであれば、任意の寸法でよい。
【００５１】
【発明の効果】
以上説明したとおり、本発明によれば、水平方向のみの干渉縞を記録する計算機ホログラムに対して光が垂直方向に回折する効果を高めることができるため、該ホログラムによる再生像を上下方向の広い視域範囲にわたって観賞することができる。
【図面の簡単な説明】
【図１】本発明に係る一実施の形態の計算機ホログラムを模式的に示す説明図
【図２】要素領域に形成された回折格子による作用を示す線図
【図３】要素領域に形成されたフレネルゾーンプレートとその作用を示す線図
【図４】本発明に係る一実施形態の計算機ホログラム作成装置の概略構成を示すブロック図
【図５】対象物データと干渉縞計算領域及び要素領域の関係を示す説明図
【図６】この実施の形態における計算ホログラムの作成工程を示すフローチャート
【図７】干渉縞データの計算モデルを示す説明図
【図８】干渉縞データを計算する基本単位を示す説明図
【図９】干渉縞データ、バイナリデータ、描画データの関係を示す線図
【図１０】干渉縞データ列の作成の仕方を模式的に示す説明図
【図１１】計算機ホログラムの量産化までの処理手順を示す説明図
【図１２】光学ホログラムを模した計算モデルを示す説明図
【図１３】図１２の計算モデルと、再生光による像の再生を示す説明図
【図１４】水平方向のみ相関を有する物体光を用いた計算モデルを示す説明図
【図１５】図１４の計算モデルを基に作成された計算機ホログラムを模式的に示す説明図
【図１６】図１４の計算モデルと、再生光による像の再生を示す説明図
【符号の説明】
１０…計算機ホログラム
１０Ａ…干渉縞計算領域
１２…要素領域
１２Ａ…データ上の要素領域
１４…干渉縞列
２０…対象物データ作成部
２２…初期条件設定部
２４…要素領域設定部
２６…干渉縞データ計算部
２８…光学素子選定部
３０…干渉縞２値化部
３２…干渉縞データ複写部
３４…データ変換部
３６…描画装置
３８…後加工装置[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a data creation method及BiSo location suitable computer hologram beam applied to a display hologram for viewing a reproduced image.
[0002]
[Prior art]
Three-dimensional information of an object is recorded on a physical medium such as a film using an interference phenomenon between the object light that is reflected light from the object and the reference light, and the reproduction light similar to the reference light is irradiated to the recording medium. There is holography as a technique for reproducing and displaying an object image by utilizing the diffraction phenomenon of light. A hologram obtained by recording the three-dimensional information of an object on a physical medium by utilizing such a light interference phenomenon is called a hologram.
[0003]
In addition to the hologram that is actually created by utilizing the light interference phenomenon, the interference fringes are represented as digital data on the computer based on the three-dimensional object data corresponding to the object. A so-called computer generated hologram that creates interference fringe data and records it on a physical medium is also known.
[0004]
In this computer generated hologram, as schematically shown in FIG. 12, a calculation model simulating an optical hologram, a point light source (sample point) in which object light, which is reflected light from the surface of an object, is indicated by a circle on the surface. Assuming that the light from the object light from each point light source (shown in two dimensions for convenience) having a three-dimensional spread, the interference fringe between the reference light and the reference light is obtained on a computer, and is obtained from the physical medium. A computer generated hologram is created by recording at each of the above sample points (in the figure, only the state of interference at one point is shown as a representative). The computer generated hologram can be observed as a three-dimensional object image because light from each sample point on the hologram is incident on the pupil when irradiated with reproduction light as shown in FIG.
[0005]
As described above, it is assumed that the object light is incident on the medium from the point light source having a three-dimensional spread on the object, that is, the computer intends to reproduce an image having parallax both in the horizontal direction and in the vertical direction. When a hologram is created, a hologram image that is three-dimensionally expanded in any direction can be observed depending on the hologram. However, in order to create interference fringe data based on object light from a point light source having a three-dimensional spread in this way on a computer, the amount of computation becomes enormous.
[0006]
Therefore, in the computer generated hologram, a calculation model is schematically shown in FIG. 14 with the intention of reproducing an image having parallax only in the horizontal direction of the object at the expense of the three-dimensional expansion of the hologram image in the vertical direction. As described above, object light having a correlation only in the horizontal direction is virtually generated on the computer, and interference fringe data is generated for each horizontal line of the interference region, and this is made to correspond to 1: 1 on the medium. A computer generated hologram is created by recording each line in the horizontal direction.
[0007]
FIG. 15 schematically shows a computer generated hologram (interference fringe formation region) 10 created in this manner and a part thereof enlarged, and this enlarged view shows the formation of interference fringes in the horizontal direction. An element area corresponding to one line as a unit and a part of another element area located above and below the element area are shown. The interference fringes referred to here are stripe patterns composed of a number of strips arranged in the horizontal direction and having the width of the element region as a length.
[0008]
Since the computer generated hologram is created by ignoring the interference in the vertical direction, as shown in FIG. 16, when the image is reproduced by irradiating the reproduction light, the vertical direction is three-dimensional. Although a spread image is not observed, the amount of data can be greatly reduced, so that hologram data can be easily created, so that it is generally used.
[0009]
[Problems to be solved by the invention]
However, the computer generated hologram that records interference fringe data with parallax only in the horizontal direction created by the above method on the physical medium is weak in the effect of light diffracting in the vertical direction, so that the reproduced image can be observed in the vertical direction. There was a problem that the viewing angle of was narrow and difficult to watch.
[0010]
The present invention has been made to solve the above-mentioned conventional problems, and enhances the effect of diffracting light in the vertical direction with respect to a computer generated hologram that records interference fringes only in the horizontal direction. It is an object of the present invention to provide a computer generated hologram that can be viewed over a wide vertical viewing area, a data creation method thereof, and a creation apparatus thereof.
[0012]
[Means for Solving the Problems]
The present invention, in the interference fringe computing region that describes the interference fringe data of the entire holograms, in units of element regions on the data obtained by dividing the same area in the horizontal direction is calculated based on the corresponding object data In the computer hologram data creation method that describes the horizontal interference fringe data, the interference fringe data calculated for the representative horizontal line for each element area is copied to the array that constitutes the unidirectional optical element in the vertical direction. and by creating an interference fringe data sequence is obtained by solving the previous SL problems.
[0013]
The present invention further provides a computer generated hologram for generating a computer generated hologram in which interference fringes are formed in an interference fringe forming region constituting the entire hologram as a unit of an element region obtained by dividing the region in the horizontal direction. , A means for creating object data corresponding to an object to be recorded as a hologram, and an interference fringe calculation region describing the object fringe data on the object data and the interference fringe data of the entire hologram are set as initial conditions, respectively. Means for dividing an interference fringe calculation area and setting element areas; means for calculating interference fringe data for a representative line in the horizontal direction for each element area; and a unidirectional optical element formed in the element area The interference fringe data of the representative line calculated for each element region is duplicated in an array constituting a unidirectional optical element in the vertical direction. The above problem is similarly solved by providing copying means for creating an interference fringe data string and means for converting the created interference fringe data string into data for a hologram creating device. .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a diagram corresponding to FIG. 15 schematically showing the characteristics of the computer generated hologram according to the embodiment of the present invention.
[0016]
This computer generated hologram 10 is an element region 12 formed by dividing the region in the horizontal direction into an interference fringe forming region on a physical medium constituting the entire hologram, like the conventional one shown in FIG. Interference fringes are formed in units of. Moreover, in this computer generated hologram 10, the interference fringe array 14 having the same pattern in the horizontal direction is arranged for each element region 12 to form a diffraction grating that is a unidirectional optical element in the vertical direction, that is, in the vertical direction. Interference fringe rows 14 having the same width are formed at the same interval.
[0017]
The computer generated hologram 10 will be described in detail. The element region 12 has a vertical width A of, for example, about 80 μm and a width B of the interference fringe array 14 arranged so as to form a stripe pattern in the horizontal direction. The formation intervals C are each 0.5 μm, for example, and the unit of the stripe pattern indicated by D in the drawing can be formed, for example, 0.15 μm.
[0018]
In this way, by forming the interference fringe rows 14 having the same stripe pattern in the horizontal direction with the above dimensions, a hologram structure in which diffraction gratings of about 80 interference fringe rows 14 are formed in each element region 12. FIG. 2 schematically shows an enlarged cross-sectional view (corresponding to the cross-sectional view taken along the line II-II in FIG. 1). Assuming that parallel light is incident, the light is diffracted in the vertical direction. And can be diffused. As a result, it is possible to widen the viewing angle in the vertical direction in which the computer generated hologram 10 can be observed. Therefore, by using this computer generated hologram 10, it is possible to provide a display hologram that is easy to watch.
[0019]
The unidirectional optical element formed in the element region 12 may be a Fresnel zone plate (Fresnel zone plate) in addition to the diffraction grating. The Fresnel zone plate has a plan view as shown in FIG. 3 (A), an interference fringe row with diagonal lines, and a sectional view as shown schematically in FIG. 3 (B). It can be configured by increasing the width as it approaches. By forming the interference fringe array with such an arrangement, the function of diffusing incident light in one direction can be given to each element region as shown by the arrow in FIG. Can diffuse. In this case, the width and the arrangement interval of the interference fringe array 14 are not limited to the Fresnel zone shape, and may have a function of diffusing light in the vertical direction. For example, the width may be changed little by little at equal intervals. Further, the width may be narrowed as it approaches the center.
[0020]
FIG. 4 is a block diagram showing an apparatus for creating the computer generated hologram. This creation apparatus has an object data creation unit 20, an initial condition setting unit 22, an element region setting unit 24, and an interference fringe data calculation unit having a function (to be described in detail later) for performing each process until creation of computer generated hologram data. 26, a computer generated hologram data creating unit including an optical element selecting unit 28, an interference fringe data binarizing unit 30, and an interference fringe data copying unit 32. The creation device also includes a data converter 34 that converts the created hologram data into drawing device data, a drawing device 36 that creates a hologram using the converted data, and the created hologram as an original. And a post-processing device 38 for commercializing a computer generated hologram.
[0021]
In the above computer generated hologram data creation unit, an interference fringe calculation area describing the interference fringe data of the entire hologram is used as a unit based on the corresponding object data with the element area on the data obtained by dividing the area in the horizontal direction as a unit. Data of a computer generated hologram is created by describing the calculated horizontal interference fringe data.
[0022]
This will be described with reference to FIG. 5 schematically showing the relationship between the object data and the interference fringe calculation area. The object data shown in FIG. 5A is object data described by three-dimensional coordinate values. Based on this object data, when creating computer generated hologram data in the interference fringe calculation area 10A describing the interference fringe data of the entire hologram shown in FIG. 5B, the area 10A is divided in the horizontal direction. Based on the corresponding object data (corresponding to one line indicated by hatching in the figure, which is the same as one line in the conventional calculation unit) Horizontal interference fringe data is calculated and described in the same element region 12A. By the same method, interference fringe data is obtained for all other element regions 12A, and the computer generated hologram data is created by sequentially describing the interference fringe data.
[0023]
At that time, as will be described in detail below, the interference fringe data calculated by copying the interference fringe data calculated for the representative line in the horizontal direction for each element region 12A to the array constituting the unidirectional optical element in the vertical direction is copied. A row (corresponding to an interference fringe row in the hologram) is created.
[0024]
Next, the process of creating a computer generated hologram will be described based on the flowchart shown in FIG.
[0025]
First, in step 1, the object data creating unit 20 is used to create object data as shown in FIG. 5A on the computer. This object data is data that defines an object for calculating interference fringe data, and this object may be digital data sampled at an arbitrary number of sample points. Therefore, the object may be any character, pattern, image, plane, or solid. For example, a character or image displayed on a monitor of a personal computer may be defined as an object, or three-dimensional computer graphics may be created and defined as an object. Therefore, any digital data having a value at each sample point may be used, and a commercially available image creation tool may be used as the creation unit 20.
[0026]
Next, in step 2, the initial condition setting unit 22 is used to set an object region and an interference fringe calculation region as initial conditions for creating computer generated hologram data. The object area is set by designating the coordinate range in which the interference fringe calculation is performed with the data shown in FIG. 5A. The interference fringe calculation area is set by the interference fringe calculation shown in FIG. This corresponds to designating the size of the area 10A.
[0027]
Next, in step 3 , using the element region setting unit 24, the interference fringe calculation region 10A set above is divided into a predetermined number in the horizontal direction. The number of divisions is changed depending on the size of the computer generated hologram.
[0028]
Next, in step 4, using the interference fringe data calculation unit 26, for each element region 12A on the data determined above, the representative line, for example, the center line is used as the interference fringe data calculation line, which corresponds to that line. Based on the object data, interference fringe data for one line is obtained by calculation.
[0029]
The calculation performed by the interference fringe data calculation unit 26 will be described with reference to a cross-sectional view of the calculation model shown in FIG. 7. The sample point (x, y) of the interference fringe calculation region 10A shown in FIG. The interference fringe data I (x, y) at is calculated by the following equation (1) using the object light O (x, y) and the reference light R (x, y) that have reached the sample point (x, y). Is done. The calculation according to this formula is performed for each line, that is, with y fixed during one calculation.
[0030]
I (x, y) = | O (x, y) + R (x, y) | ² (1)
[0031]
The object light O (x, y) is a composite wave from each of N sample points (point light sources) on the object data shown in FIG. 7, and is expressed as the following equation (2). be able to.
[0032]
[Expression 1]

Here, Oi: amplitude of object light (point light source) at sample point i ri (x, y): distance from sample point i k: wave number (2π / λ)
φi: initial phase of object light (point light source) at sample point i
Furthermore, in this embodiment, since parallel light is used as the reference light, this can be expressed as in equation (3).
[0034]
R (x, y) = Ro exp (jkxsin (θ) + jφr) (3)
Here, Ro: amplitude θ: incident angle φr of reference light: initial phase
In this embodiment, as described in FIG. 5, the object light shown in FIG. 7 is treated as a wave that travels only in the xz plane of FIG. Accordingly, there is no correlation with other cross sections (xz plane) in the y direction, and as described above, the interference fringes are calculated independently for each cross section, that is, with y fixed. Accordingly, the interference fringe calculation area 10A is divided into element areas 12A on the data, which are a plurality of stripe-like areas.
[0036]
FIG. 8 schematically shows a relationship between one horizontal line of the object data, which is a basic unit for calculating the interference fringe data, and the element region 12A on the data corresponding thereto. In the figure, a small square located at the front indicates a unit of object data, and the data units are arranged in a plane here for convenience, but actually, the object data shown in FIG. As in the case of (3), the three-dimensional data is changing in the z direction.
[0037]
The object light is calculated on the assumption that it is light from a point light source indicated by a circle at the center of the data unit. That is, due to interference of light from a point light source located at the center of each unit of object data arranged in the horizontal direction, interference occurs on the center line (representative line) of one element region 12 on the computer hologram 10 located behind. As fringes are generated, the data is calculated. FIG. 9A schematically shows the interference fringe data for one line obtained by this calculation.
[0038]
Next, in step 5, the optical element selection unit 28 is used to set the width and interval for copying the interference fringe data. That is, when the diffraction grating is selected, the dimensions are set so as to have the same width and the same interval, and in the case of the Fresnel zone plate, the width becomes wider toward the center and, in some cases, the width becomes narrower toward the center. Here, the following description will be made assuming that a diffraction grating is selected.
[0039]
In the next step 6, the interference fringe data for one line as shown in FIG. 9A obtained by the binarization unit 30 and calculated by the interference fringe calculation unit 26 is stored in a predetermined manner. The binary value is set to binary data as shown in FIG.
[0040]
Next, in step 7, using the data copying unit 32, FIG. 10 conceptually shows the element region 12A on the data having the same size as FIG. As described above, when the interference fringe data for one center line binarized for each element region 12A is converted into a hologram, it is intermittently copied so as to exhibit a diffraction function. FIG. 10 schematically shows a state in which four interference fringe data for one center line are copied in an area above the center. Thereafter, four copies are similarly made in the lower area. In the case of this figure, assuming that copying is performed with the same width at the center, a total of nine interference fringe data strings are created in one element region 12A. By the copying process by the data copying unit 32, the creation of the computer generated hologram data according to this embodiment is completed.
[0041]
Next, in step 8, the computer generated hologram data created by the data copying unit 32 is binary data on the computer using the data conversion unit 34, so that the charged particle beam drawing device 36 is controlled and driven. Is converted into data for a drawing apparatus format for use as drawing data. FIG. 9C schematically shows this drawing data.
[0042]
Next, in step 9, the drawing device 36 is used to drive the device using the drawing data, and a physical medium is drawn by a charged particle beam to create a computer generated hologram. As a result, although the number of interference fringe strings is different from the number of interference fringe data strings shown in FIG. 10, the computer generated hologram shown in FIG. 1 is obtained.
[0043]
As the drawing device 36, for example, an electron beam drawing device manufactured by JEOL Ltd. can be used. The drawing device 36 is driven while being controlled by the above-described drawing data whose format has been converted, and the resist film (physical medium) coated on the glass substrate is drawn with an electron beam to cure the resist film into a predetermined pattern. Then, the computer generated hologram is completed by performing development to remove the uncured portion. In the computer generated hologram as described above, the interference fringe array 14 having the same pattern is intermittently formed for each element region 12 as described above. The cross section of the pattern is shown in FIG. ).
[0044]
Next, in step 10, the post-processing device 38 is used to perform a process for mass production using the computer generated hologram as described above as an original plate. Specifically, after drawing by the drawing device 36 shown in FIG. 11 (A), a conductive metal film is formed on the surface of a computer generated hologram made of a resist created by development by vapor deposition or electroless plating. After the formation and the state shown in FIG. 5B, a metal stamper as shown in FIG. 5C is formed by thickly plating a metal such as nickel using the metal coating as an electrode. Thereafter, computer generated holograms (embossed holograms) are mass-produced by emboss replication in which a film made of a thermoplastic resin is hot-pressed using the metal stamper peeled from the resist surface.
[0045]
In an actual pressing apparatus, a hologram is created by pressing a film original (for example, a film having a multilayer structure formed by PET / acrylic resin / aluminum deposition) using a multi-faced stamper.
[0046]
The computer generated hologram is sealed as necessary. This is done by applying a pressure-sensitive adhesive (for example, a vinyl chloride / vinyl acetate copolymer as a main component) to the aluminum vapor-deposited surface after pressing in the case of the multilayer structure described above, and applying release paper (for example, PET). It corresponds to sticking.
[0047]
As described above in detail, according to this embodiment, the interference fringe data created by the computer is made to function in the same manner as a unidirectional optical element such as a diffraction grating or a convex lens array when recorded as a hologram on a medium. Can be mixed. Therefore, by drawing this data on a physical medium as a binary pattern using a charged particle beam drawing apparatus, a computer generated hologram having a high diffraction effect in the vertical direction can be created.
[0048]
Although the present invention has been specifically described above, the present invention is not limited to that shown in the above embodiment, and various modifications can be made without departing from the scope of the invention.
[0049]
For example, in the above-described embodiment, the binarization unit 30 is provided in front of the data copying unit 32, and the binarization of interference fringe data is executed before copying. May be placed behind the data copying unit 32, and binarization may be performed after the operation of copying the interference fringe data is completed. However, the process can be performed in a shorter time by binarization first as in the embodiment.
[0050]
In the above embodiment, the width and interval dimensions of the interference fringe array formed in the element region are shown by way of specific examples. However, these intervals are arbitrary dimensions as long as they cause a diffraction effect. It's okay.
[0051]
【The invention's effect】
As described above, according to the present invention, it is possible to enhance the effect of light diffracting in the vertical direction with respect to a computer generated hologram that records interference fringes only in the horizontal direction. Appreciate over the viewing area.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram schematically showing a computer generated hologram according to an embodiment of the present invention. FIG. 2 is a diagram showing the action of a diffraction grating formed in the element region. FIG. 3 is formed in the element region. FIG. 4 is a block diagram showing a schematic configuration of a computer generated hologram according to an embodiment of the present invention. FIG. 5 is a relationship between object data, interference fringe calculation region, and element region. FIG. 6 is a flowchart showing a process of creating a calculated hologram in this embodiment. FIG. 7 is an explanatory diagram showing a calculation model of interference fringe data. FIG. 8 is an explanation showing a basic unit for calculating interference fringe data. FIG. 9 is a diagram showing the relationship between interference fringe data, binary data, and drawing data. FIG. 10 is an explanatory diagram schematically showing how to create an interference fringe data string. FIG. 11 is a mass production of computer generated holograms. FIG. 12 is an explanatory diagram showing a calculation model simulating an optical hologram. FIG. 13 is an explanatory diagram showing a calculation model of FIG. 12 and image reproduction by reproduction light. FIG. FIG. 15 is an explanatory diagram schematically showing a computer generated hologram based on the calculation model of FIG. 14; FIG. 16 is an explanatory diagram showing a calculation model using the object light having only correlation; Explanatory drawing showing image reproduction by reproduction light [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Computer hologram 10A ... Interference fringe calculation area | region 12 ... Element area | region 12A ... Element area | region 14 on data ... Interference fringe string 20 ... Object data creation part 22 ... Initial condition setting part 24 ... Element area | region setting part 26 ... Interference fringe data Calculation unit 28 ... Optical element selection unit 30 ... Interference fringe binarization unit 32 ... Interference fringe data copying unit 34 ... Data conversion unit 36 ... Drawing device 38 ... Post-processing device

Claims (3)

Horizontal interference fringes calculated based on the corresponding object data in the interference fringe calculation area that describes the interference fringe data of the entire hologram, with the element area on the data obtained by dividing the same area in the horizontal direction as a unit In the method of creating computer hologram data describing data,
An interference fringe data calculated for a representative line in the horizontal direction for each element region is copied to an array constituting a unidirectional optical element in a vertical direction to create an interference fringe data string. Data creation method. In a computer generated hologram for creating a computer generated hologram in which interference fringes are formed, with an element region formed by dividing the same region in the horizontal direction in the interference fringe forming region constituting the entire hologram,
Means for creating object data corresponding to an object to be recorded as a hologram;
Means for setting an interference fringe calculation region describing the object fringe data on the object data and the interference fringe data of the entire hologram as initial conditions,
Means for dividing the interference fringe calculation area and setting the element area;
Means for calculating interference fringe data for a representative line in the horizontal direction for each element region;
Means for selecting the type of unidirectional optical element formed in the element region;
Copying means for copying the interference fringe data of the representative line calculated for each element region to an array constituting a unidirectional optical element in the vertical direction to create an interference fringe data string;
And a means for converting the generated interference fringe data string into data for the hologram creating apparatus. In claim 2 ,
A computer generated hologram data generating apparatus, wherein means for binarizing interference fringe data is installed before the copying means.

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