JPH11142609A - Production of diffusion plate and diffusion plate as well as production of microlens array and microlens array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diffusion plate or microlens array which is free from unevenness of the individual indentation positions to be formed in spite of the random arrangements formed by machining and has good diffusivity without specifically controlling a machine tool and a process for producing the same. SOLUTION: The formation of the indentations of the same size adjacent to each other is averted in the process for producing the diffusion plate produced by forming the indentations on a workpiece by an indentation using (n) kinds of pressers varying in sizes or the microlens array produced by forming the indentations on a metal mold base material by the indentation method and using such metal mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffuser plate and a microlens array used for a screen of an optical apparatus or a single-lens reflex camera.

[0002]

2. Description of the Related Art It is conventionally known to provide a screen or a diffuser plate of an optical device in which a number of microlenses are arranged (hereinafter referred to as a microlens array). The screen of the microlens array has the advantage that there is less roughness and the appearance is brighter than the screen in which fine irregularities are transferred from the sanding surface of the mold, but if the microlenses are arranged periodically, diffraction will occur. There are drawbacks such that the direction of light is limited to a specific direction and the bokeh becomes unnatural, and when used in combination with a Fresnel lens, interference with the annular structure of the Fresnel lens causes moire fringes.

[0003] In addition, even if a minute concave portion is formed in a metal plate to form a diffusing plate for uniformly diffusing light throughout the screen,
A similar phenomenon occurs, making the image projected on the screen difficult to see. By the way, there is a method called an indentation method as a method of forming a concave portion in a mold or a workpiece used when manufacturing such a microlens array and a diffusion plate. This method is a method in which an indenter is pressed against the surface of a mold forming a microlens array or the surface of a metal plate serving as a diffusion plate to form an indentation. To achieve this, a machining center is used to
A mold or a metal plate is fixed to a table movably provided in the axial direction, and an indenter movably provided in the Z direction is pressed by a hydraulic cylinder or a moving coil to form an impression.

[0004]

By the way, the microlens array and the diffusion plate used for the above-mentioned applications are arranged by randomly arranging the microlenses and minute concave portions.
The above-mentioned problem can be solved. Therefore, it is necessary to form an indentation so that the regularity is lost. By the way, when a plurality of indenters having different diameters are used to form indentations of different sizes without regularity, for example, in the case of a machine that can perform indentation formation by computer control, a machining center that controls the entire machine is used. The indentation position must be entered for each individual, which requires a great deal of cost and time to create software for control. In addition, when the indentation is formed by a machine that cannot be controlled by a computer, the indentation must be formed while a person visually confirms the position of each one. In either case, a great deal of labor and time is required for the operator.

Accordingly, the present invention provides a method for inputting the positions of individual indentations to be formed or checking the positions by a human, without controlling a machine tool, even if the arrangement formed by machining is random. It is an object of the present invention to provide a diffusion plate or a microlens array having no diffusion and having good diffusivity, and a method for manufacturing the same.

[0006]

Therefore, in order to solve the above-mentioned problems, the present invention has a plurality of indenters having different diameters, a diffuser plate having an uneven shape on the surface, or a plurality of lens shapes. The present invention provides the following method for producing a microlens array using a plurality of indenters having different diameters.

First, when an indentation is formed on a workpiece such as a substrate of a diffusion plate or a mold for forming a microlens array by using a first indenter, a first starting position of a first row. Are formed on the workpiece at equal intervals in a predetermined direction. When all the indentations to be formed by the first indenter are formed in the first row, then in the second row next to the first row,
The indentation is started from a position that is not adjacent to the indentation present at the first start position, and the indentations are formed in a predetermined direction at the same intervals as the indentations formed in the first row.

The above operation is repeated, and the first
The indenter is formed by the indenter. Next, when forming an indentation on the workpiece using the second indenter having a diameter different from that of the first indenter, the second indentation is not formed on the first row from the second starting position. The indentations are formed in a predetermined direction and at the same interval as the indentations formed by the first indenter.

Then, when all the indentations to be formed by the second indenter are formed in the first row, then, in the second row, the indentations by the first indenter in the first row and the second indentation are formed. Starting from a position having a positional relationship different from the positional relationship with the indentation by the second indenter, the indentation by the second indenter is performed in a predetermined direction and at the same interval as the interval between the indentations formed by the first indenter. Is formed.

Further, when an indent is formed by another indenter, the starting position of the indentation in each row is arbitrarily determined, the indentation is started, and the indentation is started in a predetermined direction with the first indenter. Indentations were formed at the same intervals as the indentations formed, and indentations were formed on the workpiece. Further, in the second aspect of the present invention, the interval between the indentations is set such that the diameter of the indenter used for forming the indentations on the workpiece is shorter than the length obtained by adding all types of indenters, and the portion where the indentations are not formed is formed. Was reduced as much as possible.

According to a third aspect of the present invention, there is provided a diffusing plate or microlens in which a plurality of types of concave portions having different diameters or depths or a plurality of types of lenses having different diameters or heights are arranged in a two-dimensional direction. In the array, the arrangement interval between concave portions having the same diameter and depth is equal in one direction,
In the direction perpendicular to one direction, the recesses having the same diameter and height are formed so as not to be adjacent to each other. By doing so, the arrangement of the periodic indentations can be reduced as much as possible, and the data input to the machining center can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to embodiments. By the way, in the embodiment according to the present invention, the concave shape of the diffusion plate and the lens shape of the microlens array are all formed by the indentation method. The indentation method is a method in which an indenter is pressed against a substrate of a mold or a diffusion plate with a predetermined load to form a large number of indentations at predetermined intervals, thereby forming indentations of the indenter. When a microlens array is manufactured, the microlens array is formed by injection molding, compression molding, casting, or the like using a mold on which an indentation is formed. Next, the first of the present invention
The embodiment will be described with reference to a microlens array according to the present invention.

The microlens array according to the present invention is manufactured with the device configuration shown in FIG. Note that FIG.
1 is a schematic view of an indenter pressing device for manufacturing a reticle according to the present invention. After the indentation is formed by the indentation method, the mold base material 5 is mounted on the XY stage 6 by a mechanical method or a fixing method such as bonding. In the XY stage, the mold base material 5 can be two-dimensionally moved by an X-direction driving stage motor 7X and a Y-direction driving stage motor 7Y. The stage movement motors 7X and 7Y are controlled by the stage drive circuit 20. The position of the XY stage 6 can be detected by the digital micrometer 8X for the X direction and the digital micrometer 8Y for the Y direction. The output signals obtained from the digital micrometers 8X and 8Y are input to the stage movement amount detection circuit 21, and the stage movement amount detection circuit 21 can monitor the drive amounts of the stage movement motors 7X and 7Y.

Next, the moving coil device 2 shown in FIG. 2 is fixed to the lying body 4 of the indenter pressing device, and applies a force to the indenter 1 to press the mold base material 5. By the way, the moving coil device 2 has a structure shown in FIG. A shaft 11 is attached to the moving coil device 2 as shown in FIG.
The indenter 1 is attached to 1. The moving coil device 2 includes a shaft 11 to which the indenter 1 is attached.
Is provided with a motor 3 for rotating. This motor 3
Is a stepping motor whose rotation angle is controlled by the number of pulses from the rotation angle determination circuit 23 as shown in FIG. The moving coil drive circuit 22 is a circuit for driving the shaft of the moving coil device 2 in the vertical direction, and is controlled by an output signal from the computer 24. Similarly, a signal for control is output to the other stage drive circuit 20, movement amount detection circuit 21, and rotation angle determination circuit 23. Further, since the computer 24 is provided with an input device (not shown), it is possible to input work conditions with the input device. The input device includes a keyboard, a recording medium reading device, and the like.

The structure of the moving coil driving device 2 will be described with reference to FIG. The moving coil driving device 2 is provided with a cylindrical permanent magnet 12, provided so as to be extrapolated to the shaft 11, and fixed to the base plate 10 c. And the coil support frame 1
3 is attached to the shaft 11 so as to be extrapolated to the permanent magnet, and the coil 14 is wound around the coil support frame 13 in an annular shape. An annular permanent magnet 15 is provided so as to be extrapolated to the coil 14, and the permanent magnet 15 is fixed to the base plate 10a.

The moving coil driving device 2 includes:
Leaf springs 9a and 9b are provided, and a base end of the leaf spring 9a is attached to a block 17 fixed to a base plate 10c by a pressing plate 17a.
a and bolts. And leaf spring 9a
Is connected to the shaft 11 by being sandwiched between the holding plate 16a and the block 16 together with the connecting ring 18 integrated with the shaft 11 by the pin 18a. On the other hand, the base end of the leaf spring 9b is fixed to the block 17 fixed to the base plate 10a by a holding plate 17a and a bolt. The distal end of the leaf spring 9b is connected to the shaft 11 by being sandwiched between the holding plate 13a and the support frame 13 together with the connection ring 18.

Therefore, the shaft 11 is provided with the leaf springs 9a,
The shaft 11 is elastically supported so as to reciprocate on a vertical line by 9b, but the shaft 11 itself can rotate. The upper end of the shaft 11 is connected to the indenter rotation motor 3 via a joint 19. Since the joint 19 has rigidity in the rotational (radial) direction and has a flexible structure in the vertical (thrust) direction, the rotation of the motor 3 is transmitted to the shaft 11, but the vertical movement of the shaft 11 is There is no transmission to the motor 3.

Next, the details of the shaft driving section of the moving coil device 2 will be described with reference to FIG. As shown in FIG. 4, the lower portion of the permanent magnet 15 has an S pole, and the upper portion has an N pole.
The lower part of the permanent magnet 12 is magnetized to the N pole, and the upper part is magnetized to the S pole, and the direction of the magnetic force line is vertically downward on the center axis of the shaft 11 as shown by the arrow B. Here, when a current is applied so that the magnetic lines of force generated by the coil 14 are directed vertically downward as indicated by an arrow B at the center axis of the shaft 11, a vertically downward force acts on the coil 14 to move the shaft 11 vertically downward. Moving. On the other hand, when a current in the opposite direction is applied to the coil 14, a vertically upward force acts to move the shaft 11 vertically upward. The moving coil drive circuit 22 has a variable pulse current generator (not shown), and moves the indenter 1 up and down at a high speed by outputting a pulse wave-shaped current whose polarity changes periodically to the coil 14. Can be.
The cycle of this vertical movement can be set to 0.1 to 50 Hz. The upper and lower strokes are about 50 μm. The pressing force of the indenter 1 can be changed by changing the magnitude of the current supplied to the coil 14.

In this manner, the indenter 1 is pressed against the mold base material 5 to form an indent on the mold base material 5. In addition,
In the present invention, the XY stage is moved every time an impression is formed, and after the mold base material is moved in a predetermined direction by a predetermined amount,
The next indentation is formed. Next, the mold base material 5
Next, a method of forming an indentation will be described.

The microlens array according to the present invention is manufactured as follows in order to prevent irregularities in the arrangement of the microlenses and uneven light to such an extent that a phenomenon such as moire fringes does not occur. Is done. First, in order to first form the microlens array 30 of the present invention,
The indentation forming surface of the mold base material 5 is mirror-finished by metal polishing. As a material of the mold base material, a martensitic stainless steel which is a crystalline material is suitable. In addition, in order to obtain a microlens array determined by the optical design, test hitting is performed using a test piece of the same material as the material used for the mold in advance, and a coil necessary to obtain a predetermined pushing depth is obtained. Check the supply voltage value.
In the microlens array according to the embodiment of the present invention, it is necessary to form a plurality of types of indentations so that diffused light has no unevenness and moire fringes do not occur. Therefore, it is necessary to check the supply voltage value to the coil in accordance with each type of indentation.

Next, the computer 24 is operated using the input device.
Then, the position where the indentation is first formed in each row of each indenter and the interval between the indentations formed by the same indenter are input. In addition, the position where the first indentation is formed in each row using the same indenter is such that the first indentation formed in a certain row and the first indentation formed in a row adjacent to a certain row are as small as possible. What should I do? However, it is often the case that the required performance of the microlens array manufactured therefrom is ensured even if the same indentations are not all adjacent.

Therefore, in the first embodiment of the present invention,
Indentation A1 formed by the first largest indenter used
The formation start position of the indentation A1 is set so that they are not adjacent to each other, and the positional relationship between the indentation A2 formed by the second largest indenter and the indentation A1 formed by the largest indenter is different in each adjacent row. Thus, the formation start position of the indentation A2 is set.

FIG. 1 shows a state in which indentations are formed in the mold base material 5 according to the first embodiment of the present invention. , Parallel to the X axis. Thus, one arrangement on the same straight line is referred to as a “column”. In the method of forming a microlens array, the intervals between indentations formed by the same indenter are the same. The position where the indentation is formed at the beginning of each indenter in each row is set so that at least a part of the indentation overlaps the adjacent indentation in the same row. This is because a microlens array with good diffusibility can be manufactured by minimizing the area where no indentation is formed. The intervals between the rows are set so that the indents partially overlap each other for the same reason.

In the embodiment of the present invention, indentations are formed by using four types of indenters. Therefore, for each row, a position where an indentation is first formed is input for each indenter, and furthermore, The interval between indentations formed by the same indenter is input. Specifically, as shown in FIG. 1, first, the supply voltage value V1 to the moving coil device 2 is supplied to the computer 24.
(For processing indentation A1), V2 (for processing indentation A2), ...
.., Vn (for indentation An processing), moving distance Pμ in the X direction
m (constant), the coordinates (x1
1, y1), the coordinates (x12,
y2),..., the coordinates (x1m, ym) of the start position of the mth column of the indentation A1, the coordinates (x21, y1) of the start position of the first column of the indentation A2, and the start of the second column of the indentation A2 Position coordinates (x22, y2), ..., coordinates (x2m, ym) of the start position of the mth column of the indentation A2, ..., coordinates (xn1, y1) of the start position of the first column of the indentation An, Coordinates (xn2, y2) of the starting position of the second row of the indent An, m of the indent An
The coordinates (xnm, ym) of the start position of the column are input. In the first embodiment of the present invention, since there are four types of indenters, n = 4. The distance Pm in the X direction is set to be shorter than the sum of the sizes of all the indentations A1, A2, to An.
This is because indentations adjacent to each other in the same row are formed so as to partially overlap each other. In the first embodiment of the present invention, the start position is determined by the indentation A1.
Only in the case of, it was set not to be adjacent to the same indentation in the adjacent row. Regarding other indentations, the same indentations are not arranged at least in parallel to the X-axis direction or parallel to the Y-axis direction.

At the same time, the range in which indentations are formed on the mold base material 5 is also input to the computer 24. Next, the mold base material 5 is placed at a predetermined position on the XY stage 6, and the start is started. Then, after the origin is found on the mold base material 5, the coordinates (x11,
y1) The indenter 1 is moved so as to be positioned thereon. When the movement is completed, the voltage V1 is supplied to the moving coil device 2, and the indenter 1 forms an impression A1 on the mirror surface of the mold base material 5. The XY stage 6 moves the mold base material 5 in the X direction.
Move micrometer (μm). If the mold base material 5 is within the predetermined range, the voltage V1 is supplied to the moving coil device 2 again, and the indenter 1 forms an indentation A1 on the mirror surface of the mold base material 5. In this way, if the movement in the X direction is within the range where the indentation is formed, the above-described operation is repeated. However, when the movement exceeds the range, the XY stage 6 moves to the second row of the indentation A1 (on the Y axis in FIG. y2) start position coordinates (x
(12, y2) The indenter 1 is moved so as to be positioned above.

The voltage V is applied to the moving coil device 2.
1 is supplied, and the indenter 1 forms an impression A1 on the mirror surface of the mold base material 5. The XY stage 6 moves the mold base material 5 by P μm in the X direction. Then, it is determined whether or not the area is within the range where the indentation is formed. If the area exceeds the range, the area is moved further to the next row to the movement start position. Perform the above operation m
Indentations A1 are formed in a desired range on the surface of the mold base material by repeating the process up to the row.

Next, instead of the indenter forming the indentation A2,
The indenter is mounted on the moving coil device 2. Then, the XY stage 6 moves so that the indenter 1 is positioned on the coordinates (x21, y1) of the start position of the first row of the indentation A2. The voltage V2 is supplied to the moving coil device 2, and the indenter 1 forms an indentation A2 on the mirror surface of the mold base material 5. Next, the XY stage 6 moves the mold base material 5 by P micrometers (μm) in the X direction. If the mold base material 5 is within the predetermined range, the voltage V2 is supplied to the moving coil device again, and the indenter 1 forms an indentation A2 on the mirror surface of the mold base material 5. In this way, if the movement in the X direction is within the range where the indentation is formed, the above-described operation is repeated.
The indenter 1 moves so as to be located on the coordinates (x22, y2) of the start position of the second row of the second row (y2 on the Y axis in FIG. 1). Thereafter, the voltage V2 is supplied to the moving coil device 2, and the indenter 1 forms an impression A2 on the mirror surface of the mold base material 5. Then, the mold base material 5 is moved by P μm in the X direction by the XY stage 6.

In the same manner, up to the indentation An is formed in a desired range on the surface of the mold base material. The mold base material 5 on which the indentations are formed in this manner has the shape shown in FIG. next,
The mold is formed by using the mold base material 5 as a part of the mold.
Then, a microlens array is manufactured by enclosing an acrylic resin in the formed mold and performing compression molding.

By the way, a method of manufacturing a diffusion plate that diffuses incident light while reflecting it is to use a metal that constitutes the diffusion plate instead of a metal mold and to use a metal until a dent is formed on a predetermined surface of the diffusion plate. What is necessary is just to perform the same process as the manufacturing method of a lens array. The diffusion plate manufactured in this manner has the same shape as that of FIG. Note that the coordinates of the indentation position are input directly to the computer 24 using CAD data obtained by optical design.
Can be simplified. Even in such a case, since the number of data input to the computer 24 is much smaller than that of the conventional one, the transfer time can be reduced.

It is also possible to perform an intermittent operation in which the processing of the indentations A1 to An is not performed continuously, the state of formation is confirmed when the indentation A1 is completed, the processing is started again, and the processing of the indentation A2 is started. it can. Further, in the present invention, when one type of indentation is formed in each row, the indenter may be replaced and the indentation may be formed in each row. But,
When the indentation is formed in this way, there is a disadvantage that the number of times of changing the indenter increases. However, when the position is corrected for each row, such a method may be used.

[0031]

Next, the present invention will be described with reference to examples. FIG. 5 is a plan view of one embodiment of the microlens according to the present invention. For indenting the mold, a diamond indenter having a hemispherical tip with a curvature of 30 μm is used. With this indenter, indentation A1 size φ22 μm, depth 2.1 μm, indentation A2 size φ20 μm, depth 1.7 μm, indentation A3 size φ18 μm, depth 1.4 μm, indentation A4 size φ16
Four types of indentations having a thickness of 1.1 μm and a depth of 1.1 μm are formed on the die surface in a range of 27 mm long and 44 mm wide at a pitch of 68 μm in the X direction. A microlens array 30 composed of four types of microlenses L1, L2, L3, and L4 was manufactured by compression molding an acrylic resin using this mold.

[0032]

As described above, according to the present invention, it is possible to manufacture a microlens array having no unevenness and excellent diffusibility by a simple method.

[Brief description of the drawings]

FIG. 1 is a plan view of a mold used to manufacture a microlens array according to the present invention.

FIG. 2 is a perspective view schematically showing an indenter pressing device.

FIG. 3 is a sectional view showing details of a moving coil device 2;

FIG. 4 is a diagram illustrating the operation of the moving coil device 2.

FIG. 5 is a plan view of one embodiment of a microlens array according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Indenter 2 ... Moving coil device 3 ... Motor 5 ... Die base material, Die 6 ... XY stage 20 ... Stage drive circuit 21 ... Stage movement amount detection circuit 22: Moving coil drive circuit 23: Rotation angle indexing circuit 24: Computer 30: Micro lens array

Claims (8)

[Claims] 1. A method for manufacturing a diffusion plate manufactured by forming indentations on a workpiece by using an indentation method by using three or more types of indenters having different diameters, wherein the indentations are formed by a first indenter. When forming on the object, indentations are formed on the workpiece at equal intervals in a predetermined direction from the first start position of the first row, and the indentations to be formed by the first indenter are First
When all of the indentations are formed in the row, then in the second row adjacent to the first row, indentation is started from a position not adjacent to the indentation at the first start position, and Then, indentations are formed at the same intervals as the indentations formed in the first row. Next, when forming indentations on the workpiece using a second indenter having a diameter different from that of the first indenter From the second starting position where no indentations are already formed on the first row,
Indentations are formed in the predetermined direction and at the same intervals as the indentations formed by the first indenter, and the indentations to be formed by the second indenter are formed by the first indenter.
When all of the indentations are formed in the second row, in the second row, a position different from the positional relation between the indentation by the first indenter and the indentation by the second indenter in the first row is obtained. Indentation formation is started, and the second indentation is formed in the predetermined direction at the same interval as the interval between the indentations formed by the first indenter.
When forming an indentation using another indenter having a diameter different from that of the first indenter and the second indenter, the indentation starting position in each row is formed. Arbitrarily determined to start indentation, and in the predetermined direction and the first direction.
Forming an indent at the same interval as the interval between the indents formed by the indenter, and forming an indent on the workpiece. 2. The diffusion plate according to claim 1, wherein the interval between the indentations is shorter than a length obtained by adding all kinds of diameters of an indenter used for forming an indentation on the workpiece. Production method 3. The method according to claim 1, wherein the X-axis is a direction parallel to the predetermined direction, and the Y-axis is a direction perpendicular to the predetermined direction on the surface of the workpiece. When the number of types of indentations is n, the X coordinate components of the positions of the indentations formed by the other indenters in the first to n-th columns are formed differently. A method for manufacturing a diffusion plate according to claim 1, wherein 4. A method for manufacturing a microphone lens array using three or more types of indenters having different diameters, forming indentations on a mold base by an indentation method, and using the mold bases, wherein the first indenter When forming indentations on the mold base material, indentations are formed on the mold base material at equal intervals in a predetermined direction from a first start position in the first row, and the first indenter is formed. The indentation to be formed by the first
When all the rows are formed, the second row adjacent to the first row starts indentation formation from a position not adjacent to the first start position, and the first row is formed in the predetermined direction. Indentations are formed at the same intervals as the intervals of the indentations formed in the rows. Next, when forming indentations on the workpiece using a second indenter having a diameter different from that of the first indenter, From the second starting position on the first row where no indentations have already been formed,
Indentations are formed by the second indenter in the predetermined direction and at the same intervals as the intervals of the indentations formed by the first indenter, and should be formed by the second indenter in the first row. After all of the indentations are formed, the second row starts from the position where the positional relationship between the indentation by the first indenter and the indentation by the second indenter in the first row is different. Starting the formation, forming indentations by the second indenter in the predetermined direction and at the same interval as the interval of the indentations formed by the first indenter, further comprising: the first indenter and the second indenter; When forming an indentation with another indenter having a diameter different from the diameter of the indenter, the start position of the indentation formation in each row is arbitrarily determined, indentation formation is started, and in the predetermined direction and The first
Forming an indent at the same interval as the indent formed by the indenter, and forming an indent on the mold base material. 5. An interval between indentations formed by the first indenter is equal to a length obtained by adding all kinds of diameters of an indenter used for forming an indentation on the workpiece. The method of manufacturing a microlens array according to claim 4. 6. An X-axis in a direction parallel to the predetermined direction,
When the number of types of indentations formed on the mold base material is n on a coordinate set on the mold base material as a Y axis in a direction perpendicular to the predetermined direction, from the first column The X coordinate component of the position where the other indenter is formed up to the n-th column is
5. The method of manufacturing a microlens array according to claim 4, wherein the microlens arrays are formed differently. 7. A diffusion plate in which n types of recesses having different diameters or depths are arranged in a two-dimensional direction, wherein the arrangement intervals of the recesses having the same diameter and depth are equal in one direction, and are in the one direction. Characterized in that the recesses having the same diameter and height are formed so as not to be adjacent to each other in a direction perpendicular to the diffusion plate. 8. In a microlens array in which n types of microlenses having different diameters or heights are arranged in a two-dimensional direction, microlenses having the same diameter and height are arranged at equal intervals in one direction. In a direction perpendicular to the one direction,
A microlens array wherein microlenses having the same diameter and height are formed so as not to be adjacent to each other.