JPH049901A - Microoptical element, production thereof and display element - Google Patents

Abstract

PURPOSE:To obtain a bright display of good display quality and to prevent the elution of an alkali by forming arrayed microoptical elements on one surface of a transparent glass substrate and forming an alkali elution preventive layer on the other surface. CONSTITUTION:A metallic mold for plane molding, the transparent glass substrate 6 and a metallic mold for press forming are set and the substrate 6 is hot pressed for two minutes under prescribed conditions, by which concave microlenses are formed on the substrate 6. The transparent glass substrate 11 formed with a microlens array 19 in such a manner is built into the display element and the alkali elution preventive layer 7 is formed on the opposite surface. The light near apertures is condensed to the apertures of respective picture elements, by which the opening rate of the picture elements is substantially increased and a bright screen is obtd. Since the elution of the alkaline component is prevented, the degradation in specific resistance and the deterioration in display characteristics are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a micro optical element used in a display element having a bright screen, such as a liquid crystal display, a plasma display, an electroluminescent display, etc., a method for manufacturing the same, and a micro optical element. The present invention relates to a display element using an optical element.

Conventional technology In recent years, various thin display elements have been collected to replace CRTs (CATHOD ray tubes). Thin film transistor (
Active matrix type liquid crystal displays formed with TPT have been attracting particular attention.

In such a display element, light from a light source is transmitted through the aperture of each pixel, so the light transmittance depends on the aperture ratio of the pixel. In a high-precision liquid crystal display, when extremely small pixels are formed at high density, there is a limit to reducing the size of TPT, and the TP that occupies a pixel is limited.
The area of T becomes relatively large. In other words, the aperture through which light passes becomes smaller (decreased aperture ratio).
, the amount of transmitted light decreases. As the amount of transmitted light decreases, the screen becomes darker and the display quality deteriorates.

As a method to solve this problem, a method has been considered in which the light that was previously absorbed by the wiring and light shielding body necessary for TPT formation is condensed into the aperture of the pixel by a lens and used effectively. For example, Japanese Patent Application Laid-Open No. 165624/1983 describes that spherical microlenses are formed by subjecting the glass substrate itself to conventional mechanical processing. Furthermore, Japanese Patent Application Laid-Open No. 1-189685 describes that microlenses are formed by press-molding a thermally deformable resin onto an optically polished glass substrate.

Problems to be Solved by the Invention However, in the case of JP-A-60-165624,
For example, a 3-inch ultra-high-density liquid crystal display requires approximately 1 million microlenses, and it is difficult to process such a large number of microlenses, approximately 1 million microlenses. It is extremely difficult and impossible to mass produce such microlenses. On the other hand, in the case of JP-A-1-189685, the material of the microlens portion is a resin which is an organic compound. -Resins, which are organic compounds for boat fishing, have a coefficient of thermal expansion nearly an order of magnitude higher than glass substrates, and are more susceptible to expansion and contraction due to temperature changes. Therefore, when using a microlens formed on a glass substrate for a long period of time, the precise position between the pixel and the microlens may shift, the radius of curvature of the lens may change, or the microlens may peel off from the glass substrate. happens.

On the other hand, glass used as a transparent glass substrate is required to be highly durable and inexpensive, but glass often contains an alkali component in order to lower its melting temperature. In the case of a liquid crystal display element using a transparent glass substrate containing an alkaline component, the alkali component is eluted into the liquid crystal cell, lowering the specific resistance and deteriorating the display characteristics, and in active matrix type liquid crystal displays, thin film transistors There was a problem that (TPT) malfunctioned.

Means for Solving the Problems In order to solve the above problems, the present invention forms an array of micro optical elements on one surface of a transparent glass substrate, and prevents alkali elution from the transparent glass substrate on the other surface. A micro-optical element having an alkali elution prevention layer formed thereon, a method for manufacturing the same, and at least a display material constituting a pixel;
In a display element equipped with a transparent glass substrate holding a display substance, an array-shaped micro optical element is formed on one surface of the transparent glass substrate so as to correspond to each pixel, and an array of micro optical elements is formed on the other surface from the transparent glass substrate. The present invention provides a display element in which an alkali elution prevention layer is formed to prevent alkali elution.

Function: In the micro-optical element and display element of the present invention, the micro-optical element array formed on one surface of a transparent glass substrate condenses light at and near the aperture onto the aperture of each pixel. Therefore, the aperture ratio of the pixel is substantially increased, and a bright screen and display with high display quality can be obtained. Such display elements are hot-formed in a press-molding mold processed into the shape of a desired micro-optical element array, making it possible to manufacture highly accurate micro-optical element arrays and display elements with extremely high mass productivity. I can do it. Furthermore, the alkali elution prevention layer formed on the other surface of the transparent glass substrate can prevent elution of alkaline components normally contained in the transparent glass substrate.

Example An embodiment of the present invention will be described in detail below.

Example 1 FIG. 1 is a sectional view of a press molding die used in the present invention. Cemented carbide (WC-
5TiC-8Co) 50mm*40mm*10mm
It is cut into square plates, lapped and polished using ultra-fine diamond powder to improve the surface roughness (R).
MS) was made into a mirror surface of about 3 nm. Approximately 800,000 concave microlenses were formed in a lattice pattern at a pitch of 40 μm on the mirror-surfaced base material 1 using an indentation device using a highly precisely numerically controlled hemispherical diamond indenter with a radius of curvature of 400 μm. A thin film 2 of platinum-iridium-osmium alloy (Pt-Ir-Os) was coated thereon by the Svanta method to prepare a mold for press molding.

FIG. 2 is a sectional view showing a press molding method for a micro optical element array used in the present invention. In Figure 2, 6 is a transparent glass substrate with a polished surface (40mm*30w*
1.1m+ ), 30% by weight of silica (SiO It was a barium borosilicate glass consisting of.

4 is a base material of a flat press molding die, and 5 is a platinum-iridium-osmium alloy thin film on the base material 4, which was produced in the same manner as the press molding die described above.

As shown in Figure 2, a flat press mold, a transparent glass substrate 6, and a press mold with concave microlenses were set in this order from above, and nitrogen gas was flowed at 20 liters per minute. Hot press molding was carried out in a molding machine maintained in an atmosphere. The press molding conditions were a mold temperature of 560°C, a press pressure of 30 kg/cli, and a press time of 2 minutes. After press molding, it was slowly cooled to 300°C together with the press mold and taken out from the molding machine. A solution of isopropyl alcohol mixed with a small amount of Sing is applied to the opposite surface of the transparent glass substrate 6 on which the microlenses 19 are formed, and this is baked at about 40°C to form an alkali elution prevention layer 7 with a thickness of about 0.1 μm. was formed. FIG. 3 is a sectional view showing the micro optical element of the present invention. As shown in FIG. 3, a micro optical element was obtained in which an alkali elution prevention layer 7 and a microlens array 19 were formed on a transparent glass substrate 6.

FIG. 4 is a sectional view showing the display element of the present invention. As shown in FIG. 4, a thin film transistor (TPT) 13 made of amorphous silicon and a transparent electrode 14 made of ITO constituting a pixel are formed on the opposite surface of a transparent glass substrate 11 on which a microlens array 19 of micro optical elements is formed. Then, a deflection plate 1 is placed on the surface facing the microlens array 19.
I pasted the day.

A solution of isopropyl alcohol mixed with a small amount of 5 in 2 is applied to the entire surface of a flat transparent glass substrate 12 having the same composition as the transparent glass substrate 6, and this is baked at about 400°C to form an alkali film with a thickness of about 0.1 μm. An elution prevention layer 7 was formed (not shown). A common electrode 16 made of ITO is provided on one entire surface of the flat transparent glass substrate 12, and a color filter 21 is provided on the common electrode 16 at a position corresponding to the transparent electrode 14 constituting the pixel. A deflection plate 17 was attached. Transparent glass substrates 11 and 1 having such a structure
2 was fixed with an adhesive (not shown), and a liquid crystal material 15 was injected and filled into the gap. In such a display element, when the incident light 20 is incident in parallel and the voltage applied between the common electrode 16 and the transparent electrode 14 constituting the pixel is on, the light passing through the liquid crystal material 15 is polarized. The wavefront passes through unchanged and when the applied voltage is off, the liquid crystal material 15
The plane of polarization of the light passing through the liquid crystal material 15 is rotated by 90 degrees and cannot pass through the liquid crystal material 15.

The microlens array 19 has a transparent electrode 1 that constitutes a pixel.
The radius of curvature is determined so as to focus at the position 4, and the incident light 20 that has passed through the microlens array 19 is focused on the transparent electrode 14, which is an opening, and then the common electrode 16.
, transmits through the transparent glass substrate 12.

As is clear from FIG. 4, when the incident light 20 enters in parallel, almost all of the light passes through the transparent electrode 14 constituting the pixel, which is the aperture, without being blocked by the thin film transistor 13, and is displayed. contributed effectively to Therefore, the aperture ratio of the pixels is substantially increased, making it possible to create a bright screen and display with high display quality.

In addition, a transparent glass substrate 6 on which an alkali elution prevention layer 7 is formed
The alkali elution amount is determined by coating 0.3 μm of 5nOz on the transparent glass substrate 6 on which the alkali elution prevention layer 7 is formed, heating it at 550°C for 1 hour, and then peeling off the SnO□. Alkalinity was measured by atomic absorption spectrometry. As a result, the amount of alkali elution was 0.01μg/c
i, and the alkali elution from the large transparent glass substrate 6 could be significantly suppressed.

Example 2 Austenitic steel (S
US316) was cut into 50m * 40cm * 10cm square plates, which were then lapped and polished using ultra-fine diamond powder to achieve a surface roughness (RMS) of approximately 3n.
I made it a mirror surface of m. The base material 1 has a mirror surface, and the radius of curvature is 4.
Approximately 800,000 concave microlenses were formed in a lattice pattern with a pitch of 40 μm as shown in FIG. 1 using an indentation device using a highly accurate numerical control of a 00 μm hemispherical diamond indenter. This was coated with a thin film 2 of rhodium-gold-tungsten alloy (Rh-Au-W) by sputtering to form a press molding mold.

In Fig. 2, 6 is a transparent glass substrate with a polished surface (
40m*30*1.1m), and zirconia (Z
rO2) 8 weight percent, lanthanum oxide (La2O2
), 42 weight percent of boric acid (BzC)+), 5 weight percent of calcium oxide (Cab), 4 weight percent of sodium oxide (Na□0), and the balance was a lanthanum-based glass consisting of trace components. 4 is a base material of a flat press mold, and 5 is a rhodium-gold-tungsten alloy (Rh-Au-W) on the base material 4.
) It was a thin film and was produced in the same manner as the press molding die described above.

As shown in Figure 2, a flat press mold, a transparent glass substrate 6, and a press mold with concave microlenses are set in this order from above. Hot press molding was carried out in a molding machine maintained in an atmosphere in which gas was mixed at a rate of 1 liter/min. Press molding conditions are mold temperature 680°C, press pressure 10kg/d.
, the press time was 2 minutes. FIG. 3 is a sectional view showing the micro optical element of the present invention. After press molding, it was slowly cooled to 400°C together with the press mold and taken out from the molding machine. On the opposite side of the transparent glass substrate on which the convex microlenses 19 were formed, 60% by weight of silica (S i Ox ), 23% by weight of barium oxide (Bad),
5% by weight of boric acid (8,02), alumina (A
l zos) 10% by weight, the remainder consisting of trace components, using a high frequency sputtering method using barium borosilicate glass as a target at an RF power of 500 W and a substrate temperature of 3.
Under the film forming conditions of 00°C and argon gas pressure lXl0-'',
An alkali elution prevention layer 7 having a thickness of about 0.2 μm was formed. By this method, as shown in FIG. 3, a micro optical element was obtained in which a convex microlens array 19 was formed on a transparent glass substrate 6 and an alkali elution prevention layer 7 was formed on the opposite surface thereof.

FIG. 4 is a sectional view showing the display element of the present invention. As shown in Figure 4, a convex microlens array 1 of the micro optical element
A thin film transistor (TPT) 13 made of amorphous silicon and a transparent electrode 14 made of ITO constituting a pixel are formed on the alkali elution prevention layer 7, which is the opposite surface of the transparent glass substrate 11 on which the microlens 9 is formed. A deflection plate was attached to the surface facing array 19.

A common electrode 16 made of ITO is provided on one entire surface of a flat transparent glass substrate 12 (alkali-free glass, Asahi Glass AN, 40 m * 30 m * 1.1 m + a), and a color filter is provided at a position corresponding to the transparent electrode 14 constituting the pixel. 2
1 was provided on the common electrode 16, and a deflection plate 17 was attached to the other surface. Transparent glass substrate 11 with such a configuration
and 12 were fixed with an adhesive (not shown), and the liquid crystal material 15 was injected and filled into the gap. In such a display element, when the incident light 20 is incident in parallel and the voltage applied between the common electrode 16 and the transparent electrode I4 constituting the pixel is on, the light passing through the liquid crystal material 15 is polarized. The wavefront passes through unchanged, and when the applied voltage is off, the plane of polarization of the light passing through the liquid crystal material 15 is rotated by 90 degrees and cannot pass through the liquid crystal material 15.

The microlens array 19 has a transparent electrode 1 that constitutes a pixel.
The radius of curvature is determined so as to focus at position 4. The incident light 20 that passes through the microlens array 19 is focused on the transparent electrode 14, which is an opening, and then the common electrode 16.
, transmits through the transparent glass substrate 12.

As is clear from FIG. 4, when the incident light 20 is incident in parallel, almost all of the light is transmitted through the transparent type 8i14 that constitutes the pixel, which is the opening, without being blocked by the thin film transistor 13, and is displayed. contributed effectively to Therefore, in effect, the aperture ratio of the pixels increases, resulting in a brighter screen.
We were able to create a display with high display quality.

In addition, a transparent glass substrate 6 on which an alkali elution prevention layer 7 is formed
The alkali elution amount is determined by coating 5not with a thickness of 0.3 μm on the transparent glass substrate 6 on which the alkali elution prevention layer 7 is formed, heating it at 550°C for 1 hour, then peeling off the Snow, and removing the alkali contained in this Sn0w. Measured by atomic absorption spectrometry. As a result, the amount of alkali elution was 0.02μg/d
Therefore, alkali elution from the transparent glass substrate 6 could be significantly suppressed.

Example 3 Cermet (Tic-
10Mo-9Ni) 50mm + 140m * 10
It is cut into m-square flat plates, wrapped and polished using ultra-fine diamond powder to improve the surface roughness (
A mirror surface with a RMS) of approximately 2 nm was formed. Base material 1 with mirror surface
Next, approximately 800,000 concave microlenses were formed in a lattice pattern at a pitch of 40 μm as shown in FIG. 1 using an indentation device in which a hemispherical diamond indenter with a radius of curvature of 400 μm was controlled numerically with high precision. This was coated with a thin film 2 of platinum-tantalum-rhenium alloy (Pt-Ta-Re) by sputtering to form a press molding die.

In Fig. 2, 6 is a transparent glass substrate with a polished surface (
40mm*30stores*1.1M), and silica (Si
O□) 52% by weight, potassium oxide (KzO) 6
A lead glass containing 35% by weight of lead oxide (PbO), 5% by weight of sodium oxide (Nazo), and the balance consisting of trace components was used. 4 is a base material of a flat press mold, 5 is a platinum-tantalum-rhenium alloy (Pt-'Ta-Re) thin film on the base material 4, It was made in the same way as the mold.

As shown in Figure 2, a flat press mold, a transparent glass substrate 6, and a press mold with concave microlenses are set in this order from above, and 20 liters/min of helium gas and carbon dioxide are added. Hot press molding was carried out in a molding machine maintained in an atmosphere in which gases were mixed at a rate of 2 liters/min. Press molding conditions are mold temperature 520″C, press pressure 2
The weight was 0 kg/C1i and the press time was 1 minute. FIG. 3 is a sectional view showing the micro optical element of the present invention. After press molding, it was slowly cooled to 350°C together with the press mold and taken out from the molding machine. On the opposite side of the transparent glass substrate on which the convex microlenses 19 were formed, a film was formed with reactive gas SiH, -N by plasma CVD, under conditions of substrate temperature 3550°C, gas pressure ITORR, and RF power 100W, to a thickness of An alkali elution prevention layer 7 having a thickness of about 0.5 μm was formed. In this way, as shown in FIG.
A micro optical element was obtained in which a convex microlens array 19 was formed on the top and an alkali elution prevention layer 7 was formed on the opposite surface.

FIG. 4 is a sectional view showing the display element of the present invention. As shown in Figure 4, a convex microlens array 1 of the micro optical element
A thin film transistor (TPT) 13 made of amorphous silicon and a transparent electrode 14 made of ITO constituting a pixel are formed on the alkali elution prevention layer 7, which is the opposite surface of the transparent glass substrate 11 on which the microlens 9 is formed. A deflection plate 18 was attached to the surface facing the array 19.

Flat transparent glass substrate 12 (Corning 7059.4
ITO on one side of the entire surface (0mm*30mm*1.1um)
a common electrode 16 consisting of a transparent electrode 1 constituting a pixel;
Color filter 21 is placed at the position corresponding to common electrode 16.
, and a deflection vi17 was attached to the other side. The transparent glass substrates 11 and 12 having such a structure were fixed on the adhesive side (not shown), and a liquid crystal material 15 was injected and filled into the gap therebetween. In such a display element, incident light 20
When the light is incident in parallel, if the voltage applied between the common electrode 16 and the transparent electrode 14 constituting the pixel is on, the polarization plane of the light passing through the liquid crystal material 15 passes unchanged, and the applied light passes through the liquid crystal material 15 without changing. When the voltage applied to the liquid crystal material 15 is off, the plane of polarization of light passing through the liquid crystal material 15 is rotated by 90 degrees and cannot pass through the liquid crystal material 15.

The microlens array 19 has a transparent electrode 1 that constitutes a pixel.
The radius of curvature is determined so as to focus at the position 4, and the incident light 20 that has passed through the microlens array 19 is focused on the transparent electrode 14, which is an opening, and then the common electrode 16.
, transmits through the transparent glass substrate 12.

As is clear from FIG. 4, when the incident light 20 enters in parallel, almost all of the light passes through the transparent electrode 14 constituting the pixel, which is the aperture, without being blocked by the thin film transistor 13, and is displayed. contributed effectively to Therefore, the aperture ratio of the pixels is substantially increased, making it possible to create a bright screen and display with high display quality.

In addition, a transparent glass substrate 6 on which an alkali elution prevention layer 7 is formed
The alkali elution amount is determined by coating Sn○2 with a thickness of 0.3 μm on the transparent glass substrate 6 on which the alkali elution prevention layer 7 is formed, heating it at 550°C for 1 hour, peeling off SnO□, and injecting into this SnO□. The alkali content was measured by atomic absorption spectrometry. As a result, the amount of alkali elution was 0.005μg/
ctA, and was able to significantly suppress alkali elution from the transparent glass substrate 6.

Comparative Example A comparative example is shown in FIG. In Figure 5, convex lens array 1
9 is a resin material, and other than that, the structure was the same as in FIG. 4. When incident light 20 enters the display element having such a configuration in parallel, the radius of curvature of the lens changes due to temperature changes, the lens focuses at a position offset from the pixel, and the light reaches the non-aperture. and did not contribute to the display. Further, after using it for about one month, the convex lens array 19 made of a resin material peeled off from the transparent glass substrate 12.

Further, the alkali elution amount of the transparent glass substrate 6 made of barium borosilicate glass used in Example 1 was determined by coating the transparent glass substrate 6 with 5 nOz to a thickness of 0.3 μm.
After heating at 0°C for 1 hour, SnO□ was peeled off and this Sn
The alkali contained in O□ was measured by atomic absorption spectrometry. As a result, the amount of alkali elution was 3 μg/aa, and a large amount of alkali components were eluted from the transparent glass substrate 6, causing the thin film transistor (TPT) to malfunction.

In addition, in the micro optical element, its manufacturing method, and display element of the present invention, press molding conditions (temperature, time, pressure, and atmosphere), alkali elution prevention layer and its production method, press mold base material and thin film covering it The composition, the shape of the transparent glass substrate or the micro optical element array, the manufacturing method thereof, the display principle of the display element, the element configuration, etc. are not limited to the present example.

However, it is preferable that the thin film coated on the press molding die be made of noble metals such as tungsten, tantalum, rhenium, and hafnium, or alloys thereof, which do not react or fuse with the transparent glass substrate.

In addition, the atmosphere in which the transparent glass substrate and these thin films do not react or fuse together is an inert gas such as nitrogen, argon, or helium, or an inert gas containing hydrogen or -
Carbon oxide, carbon oxidation Th of carbon dioxide, hydrocarbons such as methane, ethane, ethylene and toluene, halogenated hydrocarbons such as trichloroethylene and trichlorotrifluoroethane, alcohols such as ethylene glycol and glycerin, F-13, A non-oxidizing atmosphere containing an appropriate mixture of fluorocarbons such as F-11 is desirable. These atmospheres or press molding conditions (temperature, time, and pressure) are appropriately selected depending on conditions such as the composition of the transparent glass substrate, the composition of the thin film coated on the press mold, or the shape of the optical micro optical element array.

As described in detail, the micro-optical element, the method for manufacturing the same, and the display element of the present invention utilize a micro-optical element array formed on one surface of a transparent glass substrate to separate light from the aperture and the vicinity of the aperture. The light is focused on the aperture of the pixel. Therefore, the aperture ratio of the pixel is substantially increased, and a bright screen and display with high display quality can be obtained. Such display elements are hot-formed in a press-molding mold processed into the shape of a desired micro-optical element array, making it possible to manufacture highly accurate micro-optical element arrays and display elements with extremely high mass productivity. I can do it. Further, the alkali elution prevention layer formed on the other surface of the transparent glass substrate can prevent elution of alkaline components normally contained in the transparent glass substrate.

[Brief Description of the Drawings] Fig. 1 is a sectional view of a press molding die, Fig. 2 is a sectional view showing a press molding method for a micro optical element array, Fig. 3 is a sectional view showing a micro optical element array, FIG. 4 is a sectional view showing a display element, and FIG. 5 is a sectional view showing a conventional micro optical element. 1...Base material, 2...Thin film, 4...
... Base material, 5 ... Thin film, 6 ... Transparent glass substrate, 7 ... Alkali elution prevention layer, 11.
. . . Transparent glass substrate, 12 . . . Transparent glass substrate, 13 . . . Thin film transistor, 14.
...Transparent electrode, 15 ...Liquid crystal material, 16
...Common electrode, 17...Deflection plate, 18
...... Deflection plate, 19... Microlens array, 20... Incident light, 21... Color filter.

Claims (3)

[Claims] (1) A micro optical element in which an array of micro optical elements is formed on one surface of a transparent glass substrate, and an alkali elution prevention layer for preventing alkali elution from the transparent glass substrate is formed on the other surface. (2) A micro-optical element in which a transparent glass substrate is hot press-molded using a press-molding die processed into the shape of a desired micro-optical element array, and then an alkali elution prevention layer is formed on the other surface of the transparent glass substrate. manufacturing method. (3) In a display element that includes at least a display material that constitutes a pixel and a transparent glass substrate that holds the display material, an array of micro optical elements is arranged on one surface of the transparent glass substrate to correspond to each pixel. and an alkali elution prevention layer formed on the other surface to prevent alkali elution from the transparent glass substrate.