JP3289202B2 - Microlens array, microlens, and method of manufacturing microlens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a microlens array, a microlens, and a method for manufacturing a microlens.
I do. Specifically, the present invention relates to a microlens array and a microlens used for a liquid crystal display panel for condensing a light beam on a pixel opening region. Furthermore, this
The present invention relates to a method for manufacturing a microlens.

[0002]

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

As shown in FIG. 13, a liquid crystal television projector 31 has a backlight light source 35 comprising a white lamp 33 having a reflector 32 and a condenser lens 34,
It comprises a liquid crystal display panel 37 sandwiched between two polarizing plates 36 and a projection lens 38.

FIG. 14 is a plan view schematically showing the structure of the liquid crystal display panel 37, and FIG.
7 is a cross-sectional view specifically showing the structure of almost one pixel 40;
FIG. 15B is a cross-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, Scan 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.
, The source electrode 46 is connected to the scan electrodes X ₁ , X ₂ ,..., X _i , and the gate electrode 47 is connected to the display electrodes Y ₁ , Y _{2 ,.} Have been. An opposing glass substrate 49 provided with an opposing transparent electrode 50, an insulating film 51, and a color filter 52 on the lower surface is provided above the glass substrate 41 via a spacer 53, and the glass substrate 41 and the opposing glass substrate 49 are provided. The liquid crystal 54 is sealed between them.

A scanning voltage is applied to the scanning electrodes X ₁ , X ₂ ,..., X _i , and an image signal is sent to the display electrodes Y ₁ , Y _{2 ,.} The thin film transistor 44 at the intersection (selection point) is turned on, and the liquid crystal 5
The pixel 40 can be displayed by changing the polarization characteristics of the pixel 4, and a two-dimensional moving image can be displayed 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
Is enlarged by the projection lens 38 and projected on the screen 39.

[0006] In the liquid crystal TV projector 31 as this enhances the resolution of the image but reduction of the pixel size of the (display capacity increase) for the liquid crystal display panel 37 has been advanced, the scan electrodes X _1, If the wiring area 55 in which X ₂ ,..., X _i and the display electrodes Y ₁ , Y ₂ ,..., Y _j are wired is reduced, adverse effects such as a decrease in yield and an increase in electric resistance occur. 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 incident on the liquid crystal display
6 is transmitted through the liquid crystal display panel 37, but the light flux α incident on the wiring region 55 is not scanned by the scanning electrodes X ₁ and 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. Therefore, FIG.
8 (the luminous flux α that enters and passes through the area of one pixel is indicated by oblique lines with broken lines), the effective aperture ratio of the pixel 40 is: effective aperture ratio of the pixel 40 = pixel aperture area 56 Area / total area of pixel 40. As a result, when the area of the pixel opening region 56 is reduced, the effective aperture ratio of the pixel 40 is reduced, so that the transmittance of the illumination light is reduced and the screen becomes dark.
For example, FIG. 16 shows a transparent electrode 42 and scan electrodes X ₁ , X ₂ ,..., X _i , display electrodes Y ₁ , Y ₂ ,.
Although a specific arrangement pattern such as _Yj is shown, even if all the pixels 40 of such a liquid crystal display panel 37 are turned on, the light emitting area of the liquid crystal display panel 37 has a white area (light emitting area) in FIG. The pixel opening area 56, which is an area, is shown in white. On the other hand, the wiring area 55 serving as a shadow is shaded.) When 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 provided with a microlens array 57. In FIG. 19, one pixel 40 is hatched, and the corresponding microlens body 58 is also hatched. In this conventional example, a microlens array 57 in which microlenses 58 having a circular lens shape are arranged in the same manner as 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. In this case, the screen is brightened by condensing the light from the backlight light source 35 into the pixel opening area 56.

However, in the liquid crystal display panel 37 including the microlens array 57 having such a circular lens shape, a dead space that does not contribute to light collection (that is, the microlens body 58 and the microlens body 5).
8, the effective aperture ratio of the microlens array 57 (= the sum of the areas of the microlens bodies 58 [shaded area in FIG. 19]) / the microlens array 5
7 as a whole) was low, and the light use efficiency could not be increased so much.

FIG. 20 shows still another conventional example. In a microlens array 59 used in this conventional example, the microlens body 60 has a rectangular (rectangular) lens shape. The gap between the bodies 60 is eliminated, and the effective aperture ratio is increased. 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 a matrix, the microlens bodies 60 are also arranged in a matrix, and when the pixels 40 are arranged in a delta arrangement. As shown in FIG. 21, the microlens bodies 60 are also arranged in a delta arrangement. By using such a microlens array 59, 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 focused on the pixel opening area 56. Light utilization efficiency can be extremely increased.

However, when the area of the pixel opening area 56 is actually reduced to increase the resolution of the image, the illumination light cannot be focused on the pixel opening area 56 for the following reasons. The usage efficiency becomes poor. That is, such a microlens array is manufactured by melting a lens base material arranged on a glass substrate and cooling and hardening when the molten lens base material becomes a lens shape due to surface tension. If the shape is not circular, the difference in curvature of the lens surface becomes large depending on each radial direction passing through the center of the lens, and astigmatism occurs, so that light cannot be focused on one point.

FIG. 23 (a) is a front view of a microlens body 60 having a rectangular lens shape, and FIGS. 23 (b) and (c) are cross-sectional views taken along line PP and line QQ of FIG. 23 (a). It is sectional drawing. 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 considerably larger than the radius of curvature Rx in the minor axis direction, and astigmatism occurs. For this reason, as shown in FIG. 24A, the light beam 61 that has passed through the rectangular microlens body 60 forms two focal points F1 and F2 having different focal lengths fx and fy.
At both the focal points F1 and F2 in the x direction and the y direction, the light beam 61 becomes slit light as shown in FIGS. Therefore, a spot light cannot be obtained even when the light passes through the microlens body 60, and the pixel aperture region 56
When the area of the micro lens array 5 is reduced,
Even if the distance between the liquid crystal display panel 9 and the liquid crystal display panel 37 is adjusted, the light ray 61 cannot be contained in the pixel opening area 56, and the light cannot be used effectively.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to provide a large effective aperture ratio and a small difference in the curvature of the lens surface. Microlens arrays and microlenses and their
An object of the present invention is to provide a method for manufacturing a microlens .

[0014]

A first microlens array according to the present invention has a plurality of curvature adjusting portions formed on a substrate at different heights from the substrate, and a plurality of curvature adjusting portions which are in contact with the curvature adjusting portions. A plurality of lens bodies of a predetermined shape formed ,
Some of the lens bodies are different from each other around the lens body.
At least two or more lens bodies adjacent in the direction
Are connected via the different curvature adjusters.
You.

[0015] The second microlens array of the present invention comprises:
A plurality of lens bodies formed on a substrate and arranged at intersections of a lattice , any one of the lens bodies, and the lens
At least two or more adjacent in different directions around the body
The lens body is the same height as the substrate and the lens body.
Are connected by a plurality of connecting portions formed differently,
The connecting portion has a substantially circular cross section.

In the first microlens array, the curvature adjusting section may have a substantially arc-shaped cross section. Further, in each of the microlens arrays, the same material as the material of the lens body can be used as the material of the curvature adjusting portion or the connecting portion .

Preferably, the shape of the lens body in the microlens array has at least two line-symmetric axes having different lengths, and the curvature of the lens body surface in the two line-symmetric axis directions is preferably equal.

In the microlens array of the present invention, a large number of curvature adjusting portions having different heights from the substrate are formed on the substrate,
A plurality of lens base materials of a predetermined shape are formed on the substrate from above each curvature adjustment unit so as to intersect with the curvature adjustment unit, the shape of the lens base material does not collapse, and the surface of the lens base material is Melting the lens preform so that the lens preform is curved by surface tension, and curing the lens preform in a state where the shape of the lens preform is not deformed and the surface of the lens preform is curved; in particular to form the lens body by
Can be manufactured.

Also, the microlens array of the present invention
A curvature adjusting portion having a height different from that of the substrate is formed on the substrate so as to intersect in a lattice shape, and a plurality of lens base materials having a predetermined shape are formed on the substrate from above each intersection of the curvature adjusting portion. Melting the lens preform so that the shape of the lens preform does not collapse, and the surface of the lens preform becomes a curved surface due to surface tension; the shape of the lens preform does not collapse; in a state where the surface of the is a curved surface, by forming the lens body by curing the lens base material
Can be manufactured.

Thus, a microlens array is manufactured.
In the case of manufacturing, by melting the same material as the lens base material, the curvature adjusting portion can be formed to have a substantially arc-shaped cross section.

The microlens of the present invention forms a first curvature adjustment unit that different from the substrate and height on the substrate, the second curvature adjusting unit so as to intersect with the curvature adjustment unit
And forming an intersection of the first curvature adjustment section and the second curvature adjustment section.
A lens body having a predetermined shape is formed at the difference point position and in the vicinity thereof.

According to 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,
Touch the curvature adjustment unit and straddle the curvature adjustment unit
Forming a lens preform having a predetermined shape from above the curvature adjustment unit on the substrate, the lens base material is not broken shape, and the lens base so that the surface of the lens base material is curved by surface tension Melting the material, the shape of the lens base material does not collapse,
In addition, a lens body is formed by curing the lens base material in a state where the surface of the lens base material is curved.

[0023]

Further, the microlens array of the present invention forms the lens body of the microlens array serving as the master.
Using a stamper that transfers the inverted shape of the uneven surface,
The stamper can also be manufactured by injecting a microlens material into the mold transfer surface and curing the microlens material so as to transfer the inverted shape of the mold transfer surface of the stamper.

[0025]

According to the microlens array of the present invention, a plurality of curvature adjusting portions formed on a substrate at different heights from the substrate, and a predetermined shape formed so as to be in contact with the curvature adjusting portion. Any one of the lenses having a plurality of lens bodies
And a small number of adjacent lenses in different directions about the lens body.
At least two or more of the lens bodies are different
Are connected via the rate adjustment section, also, in the micro-lens, the it was different from the substrate and height on the substrate 1
Is formed, and crosses with the curvature adjusting section.
Thus, a second curvature adjusting section is formed, and the first curvature adjustment section is formed.
Since a lens body having a predetermined shape is formed at the intersection of the adjusting section and the second curvature adjusting section and in the vicinity thereof, even if the lens body has a different lens diameter depending on the direction, for example, a rectangular or elliptical lens body, it has a curvature. Les by adjusting the size of the step between the adjustment portion and the intersecting direction and the curvature adjustment unit and the substrate surface appropriately
The curvature of the lens body can be adjusted in two directions, and the curvature of the lens body surface in two directions having different lens diameters can be made substantially equal.

For example, when the curvature adjusting portion protrudes higher than the surface of the substrate, the lens body is arranged so that the major axis direction 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, even in the case of a lens body having a lens shape with a large aspect ratio, astigmatism can be reduced.

Further , the microlens array of the present invention comprises:
A plurality of grids formed on the substrate and arranged at the intersections of the grid
A lens body, next to the lens body formed on the substrate
And a curvature adjustment unit arranged to connect
With such a configuration, the shape and curvature of the lens body in two directions can be controlled by each cross-sectional shape of the two-direction curvature adjustment unit, and a microlens array having excellent aberration characteristics can be obtained.

In particular, if a curvature adjusting portion having a substantially arc-shaped cross section is used, since the surface of the curvature adjusting portion changes gently, the edge of the lens body formed thereon can also change smoothly. A lens body having a shape close to a typical aperture lens can be easily formed by a melting method, and a microlens array having high light-collecting characteristics and light use efficiency can be obtained.

In the method of manufacturing a microlens according to the present invention, a lens base material having a predetermined shape is formed on a substrate so as to intersect with the curvature adjusting portion, and the shape of the lens base material does not collapse. Since the lens base material is melted so that the surface of the lens base material becomes a curved surface due to surface tension, and then the lens base material is cured as it is to form a lens body, the lens body is formed. The microlens can be easily manufactured without performing polishing or polishing. Moreover, the micro lens manufactured in this way
Similarly to the above-described microlens, in the case of a lens body having a different lens diameter depending on the direction, it is possible to adjust the curvature of the lens body surface in two directions having different lens diameters to be substantially equal.

Further, by replicating the microlens array using a stamper obtained by inverting and transferring the microlens array serving as the master, the microlens array can be easily mass-produced.

[0031]

1 (a), 1 (b) and 1 (c) are a plan view and a sectional view showing a microlens 1 according to an embodiment of the present invention, which is used as a single lens element or a microlens array. This is a microlens used as one unit. The micro lens 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 short axis direction, length W in the long axis direction)
y; Wx <Wy), and the refractive index of the substrate 2 is equal to the refractive index of the lens body 4. The substrate 2 is provided with a curvature adjusting table 3 having a trapezoidal cross section and a thickness dp, which protrudes.
Is smaller than the length Wy of the lens body 4 in the long axis direction (Lb <Wy), and the length of the curvature adjusting table 3 is at least longer than the length Wx of the lens body 4 in the short 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 adjustment table 3 so as to intersect with the curvature adjustment table 3.
Is substantially orthogonal to the length direction of the curvature adjusting table 3. That is, the lens body 4 straddles the curvature adjusting table 3 in the major axis direction, and the curvature adjusting table 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 substantially the same surface curvature in the major axis direction as in the minor axis direction. That is, in a cross section passing through the lens center and parallel to the short 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 passing through the center of the lens and parallel to the long axis direction, FIG.
As shown in (b), the surface of the lens body 4 describes an arc having the same radius of curvature Ry (= Rx) with the same point O as the center of curvature, the thickness of the lens center is also dx, and the thickness of the entire lens is reduced. 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 in the major axis direction and the minor axis direction is substantially equal, and astigmatism is obtained. Has been reduced.

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

In this micro lens 1,
The refractive index of the lens body 4 and the substrate 2 (at least the curvature adjusting table 3)
Since the refractive index of the portion (3) is equal, unnecessary optical disturbances such as refraction and reflection do not occur at the interface between the lens body 4 and the curvature adjusting table 3, thereby preventing a decrease in light use efficiency. can do. Further, since both sides of the curvature adjusting table 3 are inclined surfaces 3b, when the lens body 4 is formed on the substrate 2, the lens body 4 and the lens body 4 are formed at the corners formed by the steps of the curvature adjusting table 3. A gap can be prevented from being generated between the substrate 2 and the air due to air biting.

FIGS. 2 (a), 2 (b), 2 (c), 3 (a)
(B), (c) and FIGS. 4 (a), (b), and (c) are plan views or cross-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 of manufacturing the microlens array 5 in which the microlenses 1 having a rectangular lens shape (opening shape) are arranged in m rows and n columns (where m and n are positive integers) will be described with reference to FIGS.

First, FIG. 2A, FIG. 2B, and FIG. 2C show a substrate 2 for manufacturing a microlens array, on the surface of which a curvature adjusting table 3 having an m-width Lb is provided with an interval S. (<W
They protrude in parallel with each other at intervals of y-Lb) and over the entire width from one end of the substrate 2 to the other. The curvature adjusting table 3 may be formed by any method, for example, by etching or cutting the substrate 2. 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 table 3 is formed is coated with, for example, a positive type photoresist film 6, and a photomask 7 is placed above the photoresist film 6 as shown in FIG. Place and expose, then develop. As a result,
As shown in FIGS. 3 (a), 3 (b) and 3 (c), a lens base material 8 of m rows and n columns is provided 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 short axis direction is aligned with the center line of the curvature adjusting table 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 in 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
If there is no curvature radius Ry in the major axis direction of the lens base material 8 becomes larger than the radius of curvature Rx in the minor axis direction, but in the present embodiment, the lens thickness dy in the major axis direction is reduced by the presence of the curvature adjusting table 3. Since the lens thickness dx in the minor axis direction is different, the curvature of the lens surface can be made isotropic.

To put it theoretically, the radius of curvature Rx in the short axis direction and the radius of curvature Ry in the long 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 table 3 is set so that Rx = Ry from the formula and the formula, 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 cured as it is. As a result, a desired lens body 4 is obtained from 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 focused on a smaller area. Further, since the lens bodies 4 can be arranged with almost no gap by making the lens shape of the lens rectangular, the effective aperture ratio of the microlens array 5 can also be improved. Therefore, for example, even when used for a liquid crystal display panel having a very small pixel, the illumination light can be condensed in the pixel opening region, and the light use efficiency can be improved.

FIGS. 5 and 6 are sectional views showing a method for mass-producing the microlens array. FIG. 5 is a diagram showing a method of manufacturing a stamper for duplicating a microlens array by an electroforming method. First, for example, a microlens array 5 manufactured by the above-described method is prepared as a master, and sputtering or the like is performed. 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. Next, nickel is deposited on the silver thin film 10 by using the silver thin film 10 as an electrode by electroforming until the nickel thin plate 10 is formed into a plate shape, thereby producing a nickel stamper 9. Thereafter, the nickel stamper 9 is peeled off from the silver thin film 10, and the nickel stamper 9 to which the surface shape of the microlens array 5 is transferred is separated to obtain a target 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 method).
d) is shown. That is, this nickel stamper 9
A UV-curable photopolymer 11 is dropped on the mold transfer surface of, and a transparent plate 12 such as an acrylic plate or a glass plate having good transparency and flatness is pressed from above the photopolymer 11, and ultraviolet light is irradiated from above the smooth plate 12. Irradiate photopolymer 1
After curing the photopolymer 1, the photopolymer 11 is released from the nickel stamper 9. Thereafter, ultraviolet rays are sufficiently irradiated from the surface side of the photopolymer 11 to completely cure the photopolymer 11, and the substrate 2 and a number of lens bodies 4 are integrally formed by the photopolymer 11. Then, if the microlens array (replica) 13 is peeled off from the smoothing plate 12, a duplicate of the original microlens array 5 can be obtained.

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

FIGS. 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), a transparent substrate 2 having a refractive index equal to that of the lens body 4 has a concave groove having a trapezoidal cross section slightly wider on the opening side. The curvature adjusting recess 14 having a width dp is provided, and the curvature adjusting recess 14 has a bottom surface 14 having a width La.
a and the inclined surfaces 14b on both sides thereof. Also,
The lens body 4 has an elliptical (elliptical) shape and is formed on the substrate 2 so as to intersect with the curvature adjusting recess 14. The minor axis direction of the lens body 4 is equal to the length of the curvature adjusting recess 14. It is almost perpendicular to the direction. That is, the lens body 4 straddles the curvature adjusting recess 14 in the short axis direction, and the curvature adjusting recess 14 penetrates the lower surface of the lens body 4 in the long axis direction of the lens body 4.

Also in the microlens 15 having such a structure, the surface curvature of the lens body 4 in the major axis direction is substantially equal to the surface curvature in the minor axis direction. That is, in a cross section passing through the center of the lens and parallel to the long axis direction, as shown in FIG.
Are drawn with an arc having a radius of curvature Rx with the center of curvature as, and the thickness at the center of the lens is dx. On the other hand, in a cross section passing through the lens center and parallel to the short axis direction, as shown in FIG. 7B, the surface of the lens body 4 forms an arc having the same radius of curvature Ry (= Rx) with the same point O as the center of curvature. I'm drawing
The thickness at the center of the lens 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 embodiment, a microlens array for use in a liquid crystal display panel in which pixels are arranged in a matrix pattern in a grid pattern has been described. However, the microlens array of the present invention has a structure as shown in FIG. Can be implemented as a microlens array as shown in FIG. 21 in which lens bodies are arranged in a delta arrangement in order to use the liquid crystal display panel in a delta arrangement. The shape of the lens body is not limited to a rectangle or an ellipse (ellipse), but may be a polygon such as a rhombus, a hexagon, or an octagon.

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

FIG. 9 is a perspective view showing a microlens array 18 according to still another embodiment of the present invention, which is a microlens array 18 having a lens body similar in shape to the rectangular aperture lens 16 shown in FIG. is there. In this microlens array 18, a plurality of curvature adjusting tables 19 having a circular cross section are provided in parallel at regular intervals 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 the curvature adjusting tables 19 at regular intervals so as to straddle the curvature adjusting tables 19. The curvature adjusting base 19 is formed of a material having a refractive index at least equal to that of the lens body 4, and its cross-sectional shape is formed into an arc-shaped surface similar to the ideal shape of the side end face 17 a or 17 b of the rectangular aperture lens 16. . For this reason, the lens body 4 and the curvature adjustment table 19 thereunder
A side end face (that is, a cross section of the curvature adjusting table 19) in the length direction of the curvature adjusting table 19 of the lens portion formed by the part of the lens section is also arc-shaped. 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.

FIGS. 10 (a), 10 (b), 10 (c) and 10 (d) are views showing a method of manufacturing the microlens array 18 of the above.
First, a positive photoresist film, for example, 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 adjusting table 19 having a rectangular or trapezoidal cross section is formed. Then, when the curvature adjusting table 19 is heated and liquefied so as not to lose its shape, the curvature adjusting table 19 is rounded due to surface tension, and is cured as it is to obtain a cross section as shown in FIG. An arc-shaped surface curvature adjusting table 19 is formed. The curvature adjusting table 19 of the arcuate cross section formed in this way.
Is post-baked, the substrate 2 is placed on the curvature adjusting table 19 from above.
Is coated with, for example, a positive-type photoresist film, exposed through a photomask, developed and patterned, and, as shown in FIG. The material 8 is formed. The surface of the lens base material 8 is flat, but if heated and liquefied so as not to lose its shape, the surface of the lens base material 8 rises to a substantially spherical shape due to surface tension and is hardened as it is. The lens body 4 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 adjustment table 19 in the length direction of the curvature adjustment table 19, and the curvature adjustment table 19 The part that protrudes in the width direction also spreads in an arc shape.

The use of the curvature adjusting table 19 having an arcuate cross section whose surface height changes smoothly in this manner enables a lens body similar to the rectangular aperture lens 16 having an ideal shape as shown in FIG. 4 can be easily manufactured by a melting method, and a microlens array 18 having good aberration characteristics and good light use 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 tables 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 lattice pattern. As shown in FIG. 12, a lens body 4 is formed on each intersection of the curvature adjusting tables 19a and 19b arranged vertically and horizontally by a melting method. The curvature adjusting tables 19a and 19b are formed of a material having a refractive index at least equal to that of the lens body 4, and the cross-sectional shape thereof is formed in an arc-shaped surface similar to the ideal shape of the side end face 17a or 17b of the rectangular aperture lens 16. ing. The center of the lens body 4 and the center of the intersection of the curvature adjusting stands 19a and 19b overlap in the vertical direction. For this reason, the lens body 4 located at the intersection of the curvature adjusting stands 19a and 19b is formed in a rectangular aperture lens shape by the curvature adjusting stands 19a and 19b, and the shape of the four sides is also the curvature adjusting stands 19a and 19b.
It is formed in an arc shape corresponding to b. The curvature adjusting tables 19a and 19b and the lens body 4 can be manufactured in the same manner as in the method shown in FIG.

In the microlens array 20, the shape of the lens body 4 and the curvature in two directions can be controlled by the curvature adjusting tables in two directions. That is, by making the width and height of 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 the lens body 4 having the same curvature in the short side direction and the long side direction can be easily formed. 4 can be produced.

[0054]

According to the microlens array and microlens of the present invention, in a lens body having a different lens diameter depending on the direction, for example, a rectangular or elliptical lens body, the curvature of the lens body surface in two directions having different lens diameters is substantially reduced. 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 so as to intersect in a grid pattern, and a lens body is formed on each intersection of the curvature adjusting portions, a rectangular lens body having a constant curvature can be manufactured accurately by a melting method. . In addition, if a curvature adjusting table having a substantially arc-shaped 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 a melting method.

In this way, the astigmatism of the light beam after passing through the lens body can be reduced, so that the condensed spot after passing through the lens body can be narrowed down. Even if the pixel aperture area is reduced in an attempt to reduce the size of the pixels of the display panel, the vignetting of light rays hardly occurs in the wiring area of the pixels, and the liquid crystal display panel can have a high resolution and a high brightness screen.

In the method of manufacturing a microlens according to the present invention, the substrate 2 is made to cross the curvature adjusting section.
After melting the lens base material 8 formed thereon , and curing it as it is , a microlens can be easily manufactured. In addition, similarly to the above-described microlenses , even in the case of a lens body having a different lens diameter depending on the direction, the microlens thus manufactured is adjusted so that the curvatures of the lens body surfaces in two directions having different lens diameters are substantially equal. be able to.

Further, by replicating the microlens array using a stamper obtained by inverting and transferring the microlens array serving as the master, the microlens array can be easily mass-produced.

[Brief description of the 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)
(C) is a cross-sectional view taken along line DD in (a).

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

FIG. 4A is a plan view showing a substrate on which a lens body is formed in manufacturing the microlens array according to the first embodiment;
(B) is a sectional view taken along the line GG of (a), and (c) is an H of (a).
FIG. 4 is a sectional view taken along line -H.

FIG. 5 is a cross-sectional view illustrating a method for 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 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. It is.

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

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

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

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 an intersection of a curvature adjusting table in the microlens array according to the first embodiment.

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

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

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

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

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

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

FIG. 19 is a partially broken 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 broken 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 broken 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 micro lens, FIG. 23B is a cross-sectional view taken along line PP of FIG. 23A, and FIG.
FIG. 3 is a sectional view taken along line QQ of FIG.

[Figure 24] (a) is a perspective view illustrating a light collecting principle of rectangular microlenses, (b) is a view showing a sectional shape of a light beam in the x ₁ -y ₁ plane (a), (c) is ( x of a) ₂ -y ₂
It is a figure showing the section shape of the light flux in a plane.

[Explanation of symbols]

 Reference Signs List 1,15 microlens 2 substrate for producing microlens array 3 curvature adjusting stand 4 lens body 5 microlens array 8 lens base material 9 nickel stamper 14 curvature adjusting recess

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-140611 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 3/00

Claims (7)

(57) [Claims] 1. A semiconductor device comprising: a plurality of curvature adjusting portions formed on a substrate at different heights from the substrate; and a plurality of lens bodies having a predetermined shape formed so as to be in contact with the curvature adjusting portions , Any one of the above-mentioned lens bodies,
At least two or more lens bodies adjacent in the direction
Are connected to each other via the different curvature adjusting units.
A microlens array , characterized in that: 2. A formed on a substrate having a plurality of lens body disposed at the intersection positions of the grating, and one of the lens body, different around the said lens body
At least two or more lens bodies adjacent in the direction
Is formed at a different height from the substrate and the lens body.
Are connected by a plurality of connected portions, and the connected portion has a cross-sectional shape.
Is a substantially arc shape . 3. The microlens array according to claim 1 , wherein the curvature adjusting section has a substantially arc-shaped cross section. 4. The microlens array according to claim 2 , wherein a material of the curvature adjusting portion or the connecting portion is the same as a material of the lens body. 5. The lens body according to claim 1, wherein the shape of the lens body has at least two axes of symmetry having different lengths, and the curvature of the surface of the lens body in the directions of the two axes of symmetry is equal. 5. The microlens array according to claim 3, 3 or 4. 6. A first substrate having a height different from that of the substrate on the substrate .
Curvature adjusting unit is formed of the second curvature adjustment unit is formed so as to intersect with the curvature adjustment unit, the first curvature regulation
A microlens, wherein a lens body having a predetermined shape is formed at an intersection position between the adjusting unit and the second curvature adjusting unit and in the vicinity thereof. 7. A curvature adjusting portion having a height different from that of the substrate is formed on the substrate so that the curvature adjusting portion contacts the curvature adjusting portion and straddles the curvature adjusting portion.
Forming a lens preform having a predetermined shape from above the curvature adjustment unit on the substrate, the lens base material is not broken shape, and the lens base so that the surface of the lens base material is curved by surface tension Melting the material, forming a lens body by curing the lens base material in a state where the shape of the lens base material does not collapse and the surface of the lens base material is a curved surface. Manufacturing method of micro lens.