JPH06208005A - Microlens array, microelenses and their manufacture, and stamper for manufacturing microlenses - Google Patents

Abstract

PURPOSE:To make the top surface of a lens body nearly equal in curvature between two directions wherein the lens diameter is different by forming the lens body in a specific shape on a substrate from above a curvature adjustment part so that the lens body crosses the curvature adjustment part different in height from the top surface of the substrate. CONSTITUTION:A microlens 1 consists of the transparent substrate 2 and lens body 4 and the refractive index of the substrate 2 is equal to the refractive index of the lens 4. On the substrate 2, the curvature adjustment base 3 which is trapezoidally sectioned and has thickness dp is projected, the width Lb of the curvature adjustment base 3 is narrower than the major axis directional length Wy the length of the curvature adjustment base 3 is longer than at least the minor axis directional length Wx of the lens body 4. The top surface of the curvature adjustment base 3 consists of a top surface 3a which has width La and slanting surfaces 3b on both its sides. The lens body 4 is formed on the top surface of the substrate 2 from above the curvature adjustment base 3 while crossing the curvature adjustment base 3, and major axis direction of the lens body 4 crosses the length direction of the curvature adjustment base 3 almost at right angles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens array, a microlens and a manufacturing method thereof, and a stamper for manufacturing the microlens array.
More specifically, the present invention relates to a microlens array and a microlens for use in a liquid crystal display panel to focus a light beam on a pixel opening region. Further, the present invention relates to a manufacturing method for manufacturing these and a stamper used for mass-producing the microlens array.

[0002]

[Background Art and its problems] Microlens arrays are expected to grow in demand in the future as important optical elements in fine optics and other fields. Hereinafter, an application example to a liquid crystal television projector and its problems will be described.

As shown in FIG. 13, a liquid crystal television projector 31 includes a backlight light source 35 including a white lamp 33 with a reflecting mirror 32 and a condenser lens 34, and a backlight light source 35.
The liquid crystal display panel 37 is sandwiched between the polarizing plates 36 and the projection lens 38.

FIG. 14 is a plan view schematically showing the structure of the liquid crystal display panel 37, and FIG. 15A shows the liquid crystal display panel 3.
7 is a sectional view specifically showing the structure of almost one pixel 40 of FIG.
FIG. 15B is a sectional view taken along line MM of FIG.
This is the liquid crystal display panel 37, the transparent electrode 42 on the glass substrate 41 are formed in a matrix, the display electrodes Y ₁ in the transverse direction between the transparent electrodes 42, Y _2, ..., Y _j is wired, The scanning electrodes X ₁ , X ₂ ,
..., X _i are wired. A switching thin film transistor 44 having a semiconductor layer 48 is provided near each transparent electrode 42.
A drain electrode 45 of being connected to the transparent electrode 42, the source electrode 46 scan electrodes X _1, X _2, ..., are connected to the X _i, the gate electrode 47 display electrode Y _1, Y _2, ..., connected to the Y _j Has been done. Further, above the glass substrate 41, a counter glass substrate 49 having a counter transparent electrode 50, an insulating film 51 and a color filter 52 on the lower surface is provided via a spacer 53, and the glass substrate 41 and the counter glass substrate 49 are provided. The liquid crystal 54 is sealed between them.

Therefore, by applying a scanning voltage to the scanning electrodes X ₁ , X ₂ , ..., X _i and sending an image signal to the display electrodes Y ₁ , Y ₂ , ..., Y _j in synchronism with the scanning voltage. The thin film transistor 44 at the intersection (selection point) is turned on, and the liquid crystal 5
It is possible to display the pixels 40 by changing the polarization characteristics of No. 4 and to display a two-dimensional moving image on the liquid crystal display panel 37. Then, as shown in FIG. 13, when the backlight light source 35 is turned on and the liquid crystal display panel 37 sandwiched between the two polarizing plates 36 is illuminated by the light flux α from the backlight light source 35, the liquid crystal display panel 37
The moving image displayed on the screen is magnified by the projection lens 38 and projected on the screen 39.

In such a liquid crystal television projector 31, the pixel size of the liquid crystal display panel 37 is being reduced in order to increase the image resolution (increase the display capacity), but the scanning electrodes X ₁ , X _2, ..., X _i and the display electrodes Y _1, Y _2, ..., the Y _j or the like to reduce the wiring area 55 are wired, since they produce adverse effects such as increased reduction in walking blind or an electric resistance, transparency The pixel size is reduced by reducing the area of the pixel opening region 56 in which the electrode 42 is arranged.

However, as shown in FIG. 18, the pixel aperture region 5 of the light flux α entering the liquid crystal display panel 37 is shown.
The light flux α incident on the scanning electrode X ₁ ,
X _2, ..., X _i and the display electrodes Y _1, Y _2, ..., are shielded to the Y _j like, can not pass through the screen 39 side. For this reason,
As is clear from 8 (the light flux α that enters and passes through the area for one pixel is shaded by a broken line), the effective aperture ratio of the pixel 40 is: effective aperture ratio of the pixel 40 = pixel aperture region 56 Area / total area of the pixel 40. As a result, when the area of the pixel aperture region 56 is reduced, the effective aperture ratio of the pixel 40 is reduced, so that the transmittance of illumination light is reduced and the screen becomes dark.
For example, in FIG. 16, the transparent electrodes 42 and the scan electrodes X ₁ , X ₂ , ..., X _i , the display electrodes Y ₁ , Y ₂ , ..., In the liquid crystal display panel 37 in which the pixels 40 are arranged in a delta arrangement (triangular arrangement).
Although a specific layout pattern such as Y _j is shown, even if all the pixels 40 of the liquid crystal display panel 37 are turned on, the light emitting area of the liquid crystal display panel 37 is the white area (light emitting area) in FIG. The pixel opening region 56, which is a region, is shown in white. On the other hand, the wiring region 55 that becomes a shadow is shaded.), And if the transparent electrode 42 is made smaller, the screen of the liquid crystal display panel 37 becomes smaller. It was dark.

FIG. 19 is a perspective view of another conventional example, showing a liquid crystal display panel 37 having a microlens array 57. In FIG. 19, one pixel 40 is shaded, and the corresponding microlens body 58 is also shaded. In this conventional example, a microlens array 57 in which microlens bodies 58 each having a circular lens shape are arranged similarly to the pixels 40 of the liquid crystal display panel 37 is installed on the backlight light source 35 side of the liquid crystal display panel 37. Therefore, the screen is brightened by condensing the light from the backlight light source 35 on the pixel opening region 56.

However, in the liquid crystal display panel 37 having such a microlens array 57 having a circular lens shape, there is a dead space (that is, the microlens body 58 and the microlens body 5) that does not contribute to light collection.
8 is large, the effective aperture ratio of the microlens array 57 (= area of the microlens body 58 [hatched area in FIG. 19] / microlens array 5)
The total area of 7) was low, and the light utilization efficiency could not be improved so much.

FIG. 20 shows a further conventional example. In the microlens array 59 used in this conventional example, the lens shape of the microlens body 60 is made rectangular (rectangular). The gap between the bodies 60 is eliminated to increase the effective aperture ratio. The microlens bodies 60 are arranged at the same pitch as the pixels 40 of the liquid crystal display panel 37. When the pixels 40 are arranged in matrix, the microlens bodies 60 are arranged in matrix, and when the pixels 40 are arranged in delta. As shown in FIG. 21, the microlens bodies 60 are also arranged in delta. If such a microlens array 59 is used, the dead space of the microlens array 59 can be eliminated, and as shown in FIG. 22, all the illumination light from the backlight light source 35 is condensed on the pixel opening region 56. Therefore, the light utilization efficiency can be made extremely high.

However, in practice, if the area of the pixel opening region 56 is reduced in order to improve the resolution of the image, the illumination light cannot be focused on the pixel opening region 56 for the following reason, and the light Usage efficiency deteriorates. That is, such a microlens array is manufactured by melting the lens base material arranged on the glass substrate and cooling and hardening when the melted lens base material becomes a lens shape due to surface tension. If the shape is not circular, the curvature difference of the lens surface becomes large in each radial direction passing through the center of the lens, and astigmatism occurs, so that the light cannot be condensed at one point.

FIG. 23 (a) is a front view of a microlens body 60 having a rectangular lens shape, and FIGS. 23 (b) and 23 (c) are sectional views taken along the line PP and QQ of FIG. FIG. When the lens shape is rectangular, as shown in FIG.
The radius of curvature Ry in the major axis direction of the microlens body 60 becomes much larger than the radius of curvature Rx in the minor axis direction, and astigmatism occurs. Therefore, as shown in FIG. 24A, the light ray 61 that has passed through the rectangular microlens body 60 connects two different focal points F1 and F2 at the focal lengths fx and fy,
The light ray 61 becomes a slit light as shown in FIGS. 24B and 24C at both the focal points F1 and F2 in the x direction and the y direction. Therefore, spot light cannot be obtained even though the light passes through the microlens body 60, and the pixel opening region 56
If the area of the
Even if the distance between the liquid crystal display panel 37 and the liquid crystal display panel 37 is adjusted, the light ray 61 cannot be contained in the pixel opening region 56, and the light cannot be effectively used.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the conventional examples, and its object is to provide a large effective aperture ratio and a small curvature difference between lens surfaces. It is to provide a microlens array, a microlens, and the like.

[0014]

According to the first microlens array of the present invention, a large number of curvature adjusting portions having a height different from that of the substrate are formed on a substrate so as to intersect the curvature adjusting portions. It is characterized in that a plurality of lens bodies having a predetermined shape are formed on the substrate from above each curvature adjusting portion.

The second microlens array of the present invention is
Curvature adjusting parts having different heights from the substrate are formed in a lattice shape on the substrate, and a plurality of lens bodies having a predetermined shape are formed on the substrate from above each intersection of the curvature adjusting parts. Is characterized by.

In each of the above microlens arrays,
The curvature adjusting table may have a substantially arcuate cross section. Further, the material of the curvature adjusting table may be the same as the material of the lens body.

It is preferable that the shape of the lens body in the microlens array has at least two line symmetry axes having different lengths, and the curvatures of the lens body surface in the two line symmetry axis directions are equal.

In the first method of manufacturing a microlens array of the present invention, a plurality of curvature adjusting portions having different heights from the substrate are formed on the substrate, and each curvature adjusting portion intersects with the curvature adjusting portion. A plurality of lens base materials having a predetermined shape are formed on the substrate from above the adjusting part, and the shape of the lens base material is not deformed, and the surface of the lens base material is curved due to surface tension. Is melted, and the lens base material is formed by curing the lens base material in a state where the shape of the lens base material is not collapsed and the surface of the lens base material is a curved surface.

Further, in the second method for manufacturing a microlens array of the present invention, the curvature adjusting portions having different heights are formed on the substrate so as to intersect each other in a lattice shape, and the curvature adjusting portions of the curvature adjusting portion are formed. Forming a plurality of lens base materials of a predetermined shape on the substrate from above each intersection, the shape of the lens base material is not collapsed, and
The lens base material is melted so that the surface of the lens base material becomes a curved surface due to surface tension, the shape of the lens base material is not collapsed, and the surface of the lens base material is a curved surface. It is characterized in that the lens body is formed by curing the base material.

In the method of manufacturing each of the microlens arrays described above, the curvature adjusting portion can be formed in a substantially arcuate shape by melting the same material as the lens base material.

In the microlens of the present invention, a curvature adjusting portion having a height different from that of the substrate is formed on the substrate, and the curvature adjusting portion intersects with the curvature adjusting portion so that the curvature adjusting portion is formed on the substrate from above the curvature adjusting portion. It is characterized in that a lens body having a predetermined shape is formed.

In the method of manufacturing a microlens of the present invention, a curvature adjusting portion having a height different from that of the substrate is formed on the substrate,
A lens base material of a predetermined shape is formed on the substrate from above the curvature adjustment portion so as to intersect with the curvature adjustment portion, the shape of the lens base material is not collapsed, and the surface of the lens base material has a surface tension. The lens base material is melted so that it becomes a curved surface, and the lens base material is cured while the shape of the lens base material is not collapsed and the surface of the lens base material is a curved surface. It is characterized by forming a body.

The stamper of the present invention is characterized in that the concave-convex inversion shape of the surface on which the lens body of the microlens array serving as the master is formed is transferred.

Further, in the microlens array of the present invention, a microlens material is injected into the stamp transfer surface of the stamper and the microlens material is cured to transfer the concavo-convex inversion shape of the stamper transfer surface. It can also be manufactured by

[0025]

In the microlens array and the microlens of the present invention, a lens body having a predetermined shape is provided on the substrate from above the curvature adjusting portion so that the surface of the substrate intersects with the curvature adjusting portion having a different height. Since it is formed, even in the case of a lens body having a different lens diameter depending on the direction, such as a rectangle or an ellipse, the direction crossing the curvature adjusting portion and the size of the step between the curvature adjusting portion and the substrate surface are adjusted appropriately. By doing so, it is possible to make the curvature of the lens body surface in two directions with different lens diameters substantially equal.

For example, when the curvature adjusting portion is projected higher than the surface of the substrate, it is arranged so that the major axis direction of the lens body intersects the curvature adjusting portion having an appropriate thickness.
The curvature in the major axis direction and the minor axis direction of the lens body can be made substantially equal. Therefore, astigmatism can be reduced even in the case of a lens body having a lens shape with a large aspect ratio.

Further, if the curvature adjusting portions are formed by intersecting each other in a lattice shape and the lens body having a predetermined shape is formed on the substrate from above each intersection of the curvature adjusting portions, each of the curvature adjusting portions in two directions is formed. The shape and curvature of the lens body in two directions can be controlled by the cross-sectional shape, and a microlens array having excellent aberration characteristics can be obtained.

In particular, when the curvature adjusting portion having a substantially arcuate cross section is used, the surface of the curvature adjusting portion is gently changed, so that the edge of the lens body formed thereon can be smoothly changed, which is ideal. A lens body having a shape similar to a conventional aperture lens can be easily formed by a fusion method, and a microlens array having high light condensing characteristics and high light utilization efficiency can be obtained.

In each of the microlens array and microlens manufacturing method of the present invention, the lens base material having a predetermined shape is formed on the substrate so as to intersect the curvature adjusting portion, and the shape of the lens base material is formed. Since the lens base material is melted so that the surface of the lens base material does not collapse and the surface of the lens base material becomes a curved surface due to surface tension, the lens base material is cured in that state to form a lens body. The microlens array and microlens described above can be easily manufactured without molding or polishing the lens body.
In addition, the microlens array and the microlens manufactured in this way, like the above-mentioned microlens array and microlens, also in the case of a lens body having a different lens diameter depending on the direction, the curvature of the lens body surface in two directions having different lens diameters. Can be adjusted to be approximately equal.

Further, if the microlens array is duplicated by using a stamper obtained by reversing and transferring the microlens array as a master, the microlens array can be easily mass-produced.

[0031]

1 (a), 1 (b) and 1 (c) are plan and sectional views showing a microlens 1 according to an embodiment of the present invention, which is used as a single lens element or a microlens array. It is a microlens used as one unit. The microlens 1 is made of glass, silicon,
A transparent substrate 2 made of optical plastic or the like, and a lens having a rectangular shape (length Wx in the minor axis direction, length W in the major axis direction).
y; Wx <Wy), and the refractive index of the substrate 2 is equal to the refractive index of the lens body 4. A curvature adjusting table 3 having a trapezoidal cross section and a thickness of dp is projectingly provided on the substrate 2.
Lb is narrower than the length Wy of the lens body 4 in the major axis direction (Lb <Wy), and the length of the curvature adjusting base 3 is at least longer than the length Wx of the lens body 4 in the minor axis direction. . The surface of the curvature adjusting table 3 is composed of a top surface 3a having a width La and inclined surfaces 3b on both sides thereof. The lens body 4 is formed on the surface of the substrate 2 from above the curvature adjusting base 3 so as to intersect with the curvature adjusting base 3.
The major axis direction of is substantially orthogonal to the length direction of the curvature adjusting table 3. That is, the lens body 4 straddles the curvature adjustment base 3 in the major axis direction, and the curvature adjustment base 3 penetrates the lower surface of the lens body 4 in the minor axis direction of the lens body 4.

The lens body 4 has a surface curvature in the major axis direction and a surface curvature in the minor axis direction substantially equal to each other. That is, in a section passing through the center of the lens and parallel to the minor axis direction, as shown in FIG. 1C, the surface of the lens body 4 draws an arc having a radius of curvature Rx with the point O as the center of curvature. The thickness at the center is dx. On the other hand, in a cross section that passes through the center of the lens and is parallel to the long axis direction,
As shown in (b), the surface of the lens body 4 draws an arc having the same radius of curvature Ry (= Rx) with the same point O as the center of curvature, and the thickness of the lens center is also dx, and the thickness of the entire lens is It is dy (= dx + dp). Therefore, although the lens body 4 has different lengths in the major axis direction and the minor axis direction, the curvature of the lens surface is substantially equal in the major axis direction and the minor axis direction, and astigmatism is increased. Has been reduced.

In order to obtain the microlens 1 as described above, it is necessary to properly select the thickness dp of the curvature adjusting base 3, but the thickness dp of the curvature adjusting base 3 is the radius of curvature Rx of the lens body 4. = Ry and the dimensions Wx and Wy. For example,
If the radius of curvature Rx = Ry of the lens body 4 is determined, the thickness dx of the lens center can be determined from the length Wx of the lens body 4 in the minor axis direction. Similarly, the radius of curvature Rx of the lens body 4
= Ry and the length Wy in the major axis direction, the thickness dy of the entire lens can be determined. Therefore, the thickness dp of the curvature adjusting table 3 is determined by dp = dy−dx.

Further, in this microlens 1,
The refractive index of the lens body 4 and the substrate 2 (at least the curvature adjustment table 3
Since the refractive index of the part (1) is the same, unnecessary optical disturbances such as refraction and reflection do not occur at the interface between the lens body 4 and the curvature adjusting base 3, and the decrease in light utilization efficiency is prevented. can do. Further, since both sides of the curvature adjusting base 3 are inclined surfaces 3b, when the lens body 4 is formed on the substrate 2, the corners formed by the stepped portions of the curvature adjusting base 3 are separated from the lens body 4. It is possible to prevent air gaps from being generated between the substrate 2 and the substrate 2.

2 (a) (b) (c) and FIG. 3 (a)
4 (b) (c) and FIGS. 4 (a) (b) (c) are plan views or sectional views showing a method for manufacturing a microlens array 5 in which a plurality of the microlenses 1 are arranged in a matrix. Hereinafter, a method for manufacturing the microlens array 5 in which the microlenses 1 having a rectangular lens shape (aperture shape) are arranged in m rows and n columns (where m and n are positive integers) will be described with reference to FIGS.

First, what is shown in FIGS. 2 (a), (b) and (c) is a substrate 2 for producing a microlens array, on the surface of which a curvature adjusting table 3 having a width Lb of m lines and a space S. (<W
y-Lb) are provided so as to be parallel to each other and project over the entire width of the substrate 2 from one end to the other. The curvature adjusting table 3 may be formed by any method, for example, the substrate 2 may be formed by etching or cutting. Alternatively, the curvature adjusting table 3 may be added on the substrate 2.

Next, the entire surface of the substrate 2 on which the curvature adjusting base 3 is formed is covered with, for example, a positive type photoresist film 6, and a photomask 7 is provided above this, as shown in FIG. 3B. It is placed, exposed, and developed. As a result,
As shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the lens base material 8 of m rows and n columns is arranged on the substrate 2 so as to straddle the curvature adjusting table 3.
Is formed. At this time, each lens base material 8 is patterned so that its center line in the minor axis direction is aligned with the center line of the curvature adjustment base 3, and the surface of each lens base material 8 remains flat.

Next, the lens base material 8 is heated to be liquefied. When liquefied, the surface of the lens base material 8 rises into a substantially spherical shape due to surface tension, and the lens base material 8 becomes a lens shape. At this time, if the curvature adjusting table 3 is placed on the substrate 2,
If there is not, the curvature radius Ry in the major axis direction of the lens base material 8 becomes larger than the curvature radius Rx in the minor axis direction, but in the present embodiment, the presence of the curvature adjustment table 3 causes the lens thickness dy in the major axis direction to be Since the lens thickness dx in the minor axis direction is different, the curvature of the lens surface can be made isotropic.

Theoretically speaking, the radius of curvature Rx in the minor axis direction and the radius of curvature Ry in the major axis direction of the lens surface are expressed by the following equations. Rx = [dx ² + (Wx / 2) ² ] / 2dx ... Ry = [dy ² + (Wy / 2) ² ] / 2dy = [(dx + dp) ² + (Wy / 2) ² ] / 2 (dx + dp) Therefore, if the thickness dp of the curvature adjusting base 3 is set so that Rx = Ry from the formulas and formulas, the curvature of the lens surface of the lens body 4 can be made substantially isotropic.

When a predetermined lens shape is formed in this way, the lens base material 8 is cooled and hardened as it is. As a result, the desired lens body 4 is obtained by the cured lens base material 8, and the microlens array 5 as shown in FIGS. 4A, 4B, and 4C is manufactured.

According to the above manufacturing method, the curvature of the lens surface can be made isotropic, so that the light beam can be condensed in a smaller area. In addition, by making the lens shape of the lens rectangular, the lens bodies 4 can be arranged with almost no space therebetween, so that the effective aperture ratio of the microlens array 5 can be improved. Therefore, even when used in a liquid crystal display panel having a very small pixel, for example, the illumination light can be condensed in the pixel opening region, and the light utilization efficiency can be improved.

5 and 6 are cross-sectional views showing a method of mass producing the microlens array. FIG. 5 is a diagram showing a method for producing a stamper for duplicating a microlens array by electroforming. First, for example, the microlens array 5 produced by the above-described method is prepared as a master disk, and sputtering or The silver thin film 10 is formed so as to cover the entire surface of the microlens array 5 by vapor deposition or the like. Then, by using this silver thin film 10 as an electrode by electroforming, nickel is deposited on the silver thin film 10 until it becomes a plate shape, and the nickel stamper 9 is manufactured. Then, the nickel stamper 9 is peeled off from the silver thin film 10, and the nickel stamper 9 having the surface shape of the microlens array 5 transferred thereto is separated to obtain the desired nickel stamper 9.

FIG. 6 is a cross-sectional view showing a method of replicating the microlens array 5 using the nickel stamper 9, which is a so-called 2P method (Photo-polymerization Metho).
d) is shown. That is, this nickel stamper 9
A UV-curable photopolymer 11 is dropped on the mold transfer surface, and a smooth plate 12 such as an acrylic plate or a glass plate, which is transparent and has good flatness, is pressed onto the photopolymer 11 and ultraviolet rays are emitted from above the smooth plate 12. Irradiate photopolymer 1
After curing No. 1, the photopolymer 11 is removed from the nickel stamper 9. After that, the surface of the photopolymer 11 is sufficiently irradiated with ultraviolet rays to completely cure the photopolymer 11, and the substrate 2 and the many lens bodies 4 are integrally molded with the photopolymer 11. Next, by peeling off the microlens array (replica) 13 from the smooth plate 12, a replica of the original microlens array 5 can be obtained.

By duplicating the microlens array 5 using the stamper 9 in this manner, the microlens array 13 can be easily mass-produced. Also, the lens body 4
The curvature adjusting table 3 and the curvature adjusting table 3 can be integrally molded simultaneously with one type of photopolymer 11. Therefore, due to the difference in refractive index between the lens body 4 and the curvature adjusting table 3, optical disturbance such as reflection or refraction occurs at the interface. There is no fear.

7A, 7B and 7C are a plan view and a sectional view showing another example of the microlens 15 (or a part of the microlens array) according to the present invention. In this microlens 15 (or microlens array), the depth of the surface of the transparent substrate 2 having the same refractive index as that of the lens body 4 is formed in the shape of a groove having a trapezoidal cross section that is slightly wider on the opening side. A curvature adjusting recess 14 having a depth dp is provided as a recess.
It is composed of a and inclined surfaces 14b on both sides thereof. Also,
The lens body 4 has an elliptical (ellipsoidal) shape and is formed on the substrate 2 so as to intersect with the curvature adjusting recess 14, and the minor axis direction of the lens body 4 is the length of the curvature adjusting recess 14. It is almost orthogonal to the direction. That is, the lens body 4 straddles the curvature adjustment recess 14 in the minor axis direction thereof, and the curvature adjustment recess 14 penetrates the lower surface of the lens body 4 in the major axis direction of the lens body 4.

Also in the microlens 15 having such a structure, the lens body 4 has substantially the same surface curvature in the major axis direction and in the minor axis direction. That is, in the cross section that passes through the center of the lens and is parallel to the major axis direction, as shown in FIG.
A circular arc having a radius of curvature Rx with the center of curvature as the center of curvature is drawn, and the thickness of the lens center is dx. On the other hand, in a cross section passing through the center of the lens and parallel to the minor axis direction, as shown in FIG. 7B, the surface of the lens body 4 has an arc of the same radius of curvature Ry (= Rx) with the same point O as the center of curvature. I'm drawing
The thickness of the lens center is also dx, and the thickness of the entire lens is dy (= dx-dp). Therefore, although the lens body 4 has different lengths in the major axis direction and the minor axis direction, the curvature of the lens surface is substantially equal in the major axis direction and the minor axis direction.

In the above embodiments, the microlens array for use in the liquid crystal display panel in which the pixels are arranged in a matrix pattern has been described. However, the microlens array of the present invention has a structure as shown in FIG. Needless to say, it can be implemented as a microlens array as shown in FIG. 21 in which the lens bodies are arranged in delta for use in the liquid crystal display panel in which delta is arranged. The shape of the lens body is not limited to a rectangle or an ellipse (oval), but may be a polygon such as a rhombus, a hexagon, or an octagon.

FIG. 8 is a perspective view showing an ideal shape of the rectangular aperture lens 16. The surface of the rectangular aperture lens 16 has rotational symmetry about the axis and has the same surface curve in any cross section passing through the axis.
7a and 17b are arcuate surfaces, and side end surfaces 17a and 17b
The height of 17b changes smoothly. Since this rectangular aperture lens 16 is excellent in aberration characteristics (convergence characteristic for one point), it is preferable that the shape of the lens body manufactured by the fusion method is also close to this rectangular aperture lens 16.

FIG. 9 is a perspective view showing a microlens array 18 according to still another embodiment of the present invention. The microlens array 18 has a lens body having a shape similar to that of the rectangular aperture lens 16 shown in FIG. is there. In this microlens array 18, a plurality of curvature adjusting bases 19 each having an arcuate cross section are provided in parallel at a constant interval on the upper surface of a transparent substrate 2 made of glass, silicon, optical plastic, or the like. The lens bodies 4 are formed on each curvature adjusting table 19 at a constant pitch so as to straddle the curvature adjusting table 19. The curvature adjusting table 19 is made of a material having at least the same refractive index as that of the lens body 4, and its cross-sectional shape is an arcuate surface similar to the ideal shape of the side end surface 17a or 17b of the rectangular aperture lens 16. . Therefore, the lens body 4 and the curvature adjusting table 19 therebelow
The side end surface (that is, the cross section of the curvature adjusting table 19) in the length direction of the curvature adjusting table 19 of the lens portion configured by a part of the above is also arcuate. Further, in the width direction of the curvature adjusting table 19, the edge of the lens body 4 protruding from the edge of the curvature adjusting table 19 has an arc shape.

10 (a), (b), (c) and (d) are views showing a method for manufacturing the microlens array 18 of the above.
First, for example, a positive photoresist film made of the same material as the lens body 4 is formed on the surface of the substrate 2, and the photoresist film is exposed to light through a photomask and developed to form a cross section as shown in FIG. A long curvature adjustment table 19 having a rectangular shape or a trapezoidal cross section is formed. Next, when the curvature adjusting base 19 is heated and liquefied so that its shape does not collapse, the curvature adjusting base 19 is rounded by the surface tension, and is cured as it is, so that the cross section as shown in FIG. A curvature adjusting table 19 having an arcuate surface is formed. The curvature adjusting table 19 having an arcuate cross section formed in this way
After the substrate is post-baked, the substrate 2 is
The entire surface of the lens is covered with, for example, a positive photoresist film, exposed through a photomask, developed, and patterned, and the lens mother is arranged at constant pitches so as to straddle the curvature adjusting table 19 as shown in FIG. The material 8 is formed. Although the surface of this lens base material 8 is flat, if it is heated and liquefied so as not to lose its shape, the surface of the lens base material 8 rises into a substantially spherical shape due to surface tension and is cured as it is. The lens body 4 is shaped as shown in FIG. Due to the surface tension when the lens base material 8 is liquefied, the edge of the lens body 4 is formed in an arc shape along the surface of the curvature adjusting base 19 in the length direction of the curvature adjusting base 19, and the curvature adjusting base 19 has a curved shape. Even the part protruding in the width direction spreads in an arc shape.

By using the curvature adjusting base 19 having an arcuate cross section whose surface height changes smoothly in this way, a lens body similar to the rectangular aperture lens 16 having an ideal shape as shown in FIG. 8 is used. 4 can be easily manufactured by the melting method, and the microlens array 18 having good aberration characteristics and good light utilization efficiency can be obtained.

FIGS. 11 and 12 are a plan view showing a microlens array 20 and a perspective view showing one lens body 4 according to still another embodiment of the present invention. In this microlens array 20, a plurality of curvature adjusting bases 19 each having an arc-shaped cross section on the upper surface of the transparent substrate 2 are provided.
a and 19b are arranged in a grid pattern. As shown in FIG. 12, a lens body 4 is formed on each intersection of the curvature adjustment bases 19a and 19b arranged vertically and horizontally by a fusion method. The curvature adjusting bases 19a and 19b are formed of a material having at least the same refractive index as the lens body 4, and the cross-sectional shape thereof is formed into an arcuate surface similar to the shape of the side end surface 17a or 17b of the ideal rectangular aperture lens 16. ing. Further, the center of the lens body 4 and the center of the intersection of the curvature adjusting bases 19a and 19b are vertically overlapped with each other. Therefore, the lens body 4 located at the intersection of the curvature adjusting bases 19a and 19b is formed into a rectangular aperture lens shape by the curvature adjusting bases 19a and 19b, and the shape of the four sides is also the curvature adjusting bases 19a and 19b.
It is formed in an arc shape in conformity with b. The curvature adjusting bases 19a and 19b and the lens body 4 can be manufactured in the same manner as the method shown in FIG.

In this microlens array 20, the shape of the lens body 4 and the curvature in the two directions can be controlled by the curvature adjusting tables in the two directions, vertical and horizontal. That is, by making the width and height of the one curvature adjustment table 19a different from the width and height of the other curvature adjustment table 19b,
A rectangular lens body 4 can be formed, and further, a lens body 4 having the same curvature in the short side direction and the long side direction can be easily formed, and a lens body closer to an ideal rectangular aperture lens 16 can be formed. 4 can be produced.

[0054]

According to the microlens array and the microlens of the present invention, in a lens body having a different lens diameter depending on the direction, such as a rectangle or an ellipse, the curvature of the lens body surface in two directions having different lens diameters is almost the same. Can be equal. Therefore, the curvature of the lens body having an anisotropic shape can be made isotropic, and the astigmatism of such a lens body can be reduced.

In particular, if the curvature adjusting portions are formed to intersect in a grid pattern and the lens body is formed on each intersection of the curvature adjusting portions, a rectangular lens body having a constant curvature can be accurately manufactured by the melting method. . Further, if a curvature adjusting table having a substantially arcuate cross section is used, the edge of the lens body formed thereon can be made smooth, and a lens body having a shape close to an ideal aperture lens can be easily formed by the melting method.

Since the astigmatism of the light beam after passing through the lens body can be reduced in this way, the focused spot after passing through the lens body can be narrowed down, and when used in a liquid crystal display panel, the liquid crystal Even if the pixel aperture area is reduced in order to reduce the pixel size of the display panel, light ray eclipse is less likely to occur in the pixel wiring area, and the liquid crystal display panel can have a high-resolution and high-luminance screen.

In each of the method of manufacturing a microlens array and a microlens of the present invention, the lens base material 8 formed on the substrate 2 so as to intersect the curvature adjusting portion is melted and then left as it is. The microlens array and the microlens can be easily manufactured by curing in the state. In addition, the microlens array and the microlens manufactured in this way, like the above-mentioned microlens array and microlens, also in the case of a lens body having a different lens diameter depending on the direction, the curvature of the lens body surface in two directions having different lens diameters. Can be adjusted to be approximately equal.

Further, if the microlens array is duplicated by using a stamper which is obtained by reversing and transferring the microlens array as a master, the microlens array can be easily mass-produced.

[Brief description of drawings]

1A is a plan view showing a microlens according to the present invention, FIG. 1B is a sectional view taken along line AA of FIG. 1A, and FIG. 1C is a sectional view taken along line BB of FIG. .

FIG. 2A is a plan view showing a substrate used for manufacturing a microlens array according to the present invention. (B) is (a)
6 is a sectional view taken along line C-C of FIG.

FIG. 3A is a plan view showing a substrate provided with a lens base material in the manufacture of the above microlens array;
(B) is a sectional view taken along the line EE of (a), and (c) is an F of (a).
It is a -F line sectional view.

FIG. 4A is a plan view showing a substrate on which a lens body is formed in the manufacture of the above-mentioned microlens array;
(B) is a sectional view taken along line GG of (a), and (c) is H of (a).
It is a -H line sectional view.

FIG. 5 is a cross-sectional view showing a method of manufacturing a nickel stamper used for manufacturing a microlens array.

FIG. 6 is a cross-sectional view showing a method of replicating a microlens array by using the above nickel stamper.

7A is a plan view showing another microlens according to the present invention, FIG. 7B is a sectional view taken along line JJ of FIG. 7A, and FIG. 7C is a sectional view taken along line KK of FIG. Is.

FIG. 8 is a perspective view showing the shape of an ideal rectangular aperture lens.

FIG. 9 is a partially cutaway perspective view showing still another microlens array according to the present invention.

10 (a), (b), (c), and (d) are explanatory views showing a method for manufacturing the above microlens array.

FIG. 11 is a plan view showing still another microlens array according to the present invention.

FIG. 12 is a perspective view showing one lens body formed at the intersection of the curvature adjusting bases in the above microlens array.

FIG. 13 is a schematic configuration diagram showing a configuration of a liquid crystal television projector.

FIG. 14 is a plan view schematically showing a configuration of a conventional matrix array type liquid crystal display panel.

15A is a cross-sectional view specifically showing the above liquid crystal display panel, and FIG. 15B is a cross-sectional view taken along line MM of FIG. 15A.

FIG. 16 is a partially cutaway plan view showing a conventional delta arrangement type liquid crystal display panel.

FIG. 17 is a diagram showing a light emitting portion and a shadow portion when an image is displayed on the liquid crystal display panel.

FIG. 18 is an explanatory diagram showing illumination light and transmitted light of a liquid crystal display panel.

FIG. 19 is a partially cutaway perspective view showing a structure in which a microlens array having circular microlenses is mounted on a liquid crystal display panel.

FIG. 20 is a partially cutaway perspective view showing a structure in which a microlens array having rectangular microlenses is mounted on a liquid crystal display panel.

FIG. 21 is a partially cutaway plan view showing a microlens array in which rectangular microlenses are arranged in a delta arrangement.

FIG. 22 is an explanatory diagram showing illumination light and transmitted light of a liquid crystal display panel equipped with a microlens array having a rectangular lens shape.

23A is a front view showing a rectangular microlens, FIG. 23B is a sectional view taken along the line PP of FIG. 23A, and FIG.
FIG. 8 is a sectional view taken along line QQ of FIG.

24 (a) is a perspective view for explaining the focusing principle of a rectangular microlens, FIG. 24 (b) is a diagram showing a cross-sectional shape of a light beam in the x ₁ -y ₁ plane of FIG. 24 (a), and FIG. x of a) ₂ -y ₂
It is a figure which shows the cross-sectional shape of the light beam in a plane.

[Explanation of symbols]

 1,15 Microlens 2 Substrate for producing microlens array 3 Curvature adjusting table 4 Lens body 5 Microlens array 8 Lens base material 9 Nickel stamper 14 Curvature adjusting concave portion

Claims (13)

[Claims] 1. A plurality of curvature adjusting portions having a height different from that of the substrate are formed on the substrate, and a predetermined shape is formed on the substrate from above the curvature adjusting portions so as to intersect the curvature adjusting portions. A microlens array comprising a plurality of lens bodies. 2. A lens body having a predetermined shape formed on a substrate by intersecting a curvature adjusting portion having a height different from that of the substrate in a lattice pattern, and above the intersection of the curvature adjusting portions. A microlens array having a plurality of formed. 3. The microlens array according to claim 1, wherein the curvature adjusting table has a substantially arcuate cross section. 4. The microlens array according to claim 3, wherein the material of the curvature adjusting table is the same as the material of the lens body. 5. The shape of the lens body has at least two line symmetry axes having different lengths, and the curvatures of the lens body surface in the two line symmetry axis directions are equal to each other. , 3 or 4, the microlens array. 6. A plurality of curvature adjusting portions having different heights from the substrate are formed on the substrate, and a predetermined shape is formed on the substrate from above the curvature adjusting portions so as to intersect the curvature adjusting portions. Forming a plurality of lens base materials, the shape of the lens base material is not collapsed, and the lens base material is melted so that the surface of the lens base material becomes a curved surface due to surface tension, and the shape of the lens base material is collapsed. A method of manufacturing a microlens array, characterized in that the lens body is formed by curing the lens base material in a state where the surface of the lens base material is curved. 7. A curvature adjusting part having a height different from that of the substrate is formed on the substrate so as to intersect in a grid pattern, and a lens mother having a predetermined shape is formed on the substrate from above each intersection of the curvature adjusting parts. Forming a plurality of materials, the shape of the lens base material is not collapsed, and the lens base material is melted so that the surface of the lens base material is a curved surface due to surface tension, the shape of the lens base material is not collapsed, A method of manufacturing a microlens array, characterized in that a lens body is formed by curing the lens base material while the surface of the lens base material is curved. 8. The method of manufacturing a microlens array according to claim 6, wherein the curvature adjusting portion is formed in a substantially arcuate shape by melting the same material as the lens base material. 9. A lens body having a predetermined shape formed on a substrate from above the curvature adjusting part so that a curvature adjusting part having a height different from that of the substrate is formed on the substrate so as to intersect the curvature adjusting part. A microlens characterized by being formed. 10. A curvature adjusting part having a height different from that of the substrate is formed on the substrate, and a lens mother having a predetermined shape is formed on the substrate from above the curvature adjusting part so as to intersect with the curvature adjusting part. Forming a material, the shape of the lens base material does not collapse, and the lens base material is melted so that the surface of the lens base material becomes a curved surface due to surface tension, and the shape of the lens base material does not collapse, and A method for manufacturing a microlens, comprising forming a lens body by curing the lens base material in a state where the surface of the lens base material is a curved surface. 11. A stamper to which a concavo-convex inverted shape of a surface of a microlens array serving as a master disk on which a lens body is formed is transferred. 12. A microlens material is injected into the mold transfer surface of the stamper according to claim 11, and the microlens material is cured to transfer the inverted shape of the stamper mold transfer surface. A method for manufacturing a characteristic microlens array. 13. A microlens array in which the concavo-convex inverted shape of the mold transfer surface of the stamper according to claim 11 is transferred.