JPH112704A - Optical element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely form an optical element having both the condenser function of a minute lens and the spectroscopic function of a color filter with a simple process by arranging and constituting plural convex colored minute lenses on a transparent substrate. SOLUTION: This optical element is constituted by arranging plural convex colored minute lenses 2-4 on a transparent substrate 1. In this manufacture of this optical element, for arranging many colored minute lenses 2-4 on a plane, an ink-jet method is used and liquid colored transparent materials 24-26 are arranged selectively on a part becoming the lenses. That is, the liquid colored transparent materials 24-26 colored so as to transmit only respective colors of R, G, B through from ink-jet nozzles 21-23 are applied onto the transparent substrate 1. The liquid colored transparent material 24-26 to be used are constituted of a cured resin raw material for fixing a colorant, pigments or dyestuffs as the colorant for transmitting only a specified color such as R, G, B through and forming the convex lenses and a solvent, etc., dissolving the resin material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element comprising a lens array having a color filter function in which a number of colored microlenses are arranged on a transparent substrate surface, and an optical element for manufacturing the optical element with high precision. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, with the development of multimedia, large-screen display devices such as color liquid crystal projectors and various devices around an integrated optical fiber have been attracting attention in the field of optical communication.

A liquid crystal projector generally includes a light source 31, a condenser lens 32, a liquid crystal panel 33, a projection lens 34, and a screen 35, as shown in FIG. Light source 31
The light exiting from is converted into parallel light by the condenser lens 32 and enters the liquid crystal panel 33. The liquid crystal panel 33 forms an image by transmitting or blocking the light of each pixel corresponding to the image. The light transmitted through the liquid crystal panel 33 is transmitted to a projection lens 34.
By forming an image on the screen 35, a large screen image can be obtained.

When a color image is formed by a liquid crystal projector, there is a method of arranging a color filter on one side of a liquid crystal panel 33 as used in a normal color liquid crystal display device. Further, as a configuration for realizing a brighter color display, the light of the light source 31 is divided into three primary colors of red, blue, and green, an image is formed on the liquid crystal panel 33 for each light, and finally synthesized on the screen 35. Also, a method of obtaining a color image is generally performed.

A liquid crystal projector generally employs a thin film transistor (TFT) liquid crystal panel.
The T liquid crystal panel is for driving TFT and wiring,
Light transmission parts are reduced. Therefore, as shown in FIG. 4, by arranging a minute convex lens 42 corresponding to each pixel on the transparent substrate 41, the light-shielding region 43 formed by the TFT or the wiring is avoided, and the effective (light-transmitting) region 44 of the pixel is formed. There are also ways to collect light and increase brightness.

[0006] In the field of optical communication, interest in parallel optical fiber communication has increased, and integrated array devices have been used. A lens array is effective for connecting such an array of devices. As shown in FIG. 5, when the lens array 52 is used, the integrated elements can be aligned at once. In FIG. 5, reference numeral 51 denotes a semiconductor laser array, and 53 denotes a fiber array.

As described above, in the field of liquid crystal projectors and optical fiber communication, a highly accurate and inexpensive lens array having a large number of microlenses arranged on a plane is required.

Conventionally, as a method of manufacturing a lens array used for such an application, a method of molding a glass material using a mold described in Japanese Patent Publication No. 6-24990,
Japanese Patent Application Laid-Open No. 8-207159 discloses a method of sandwiching and molding a resin between a stamper and a substrate.
A method using a photolithography method described in JP-A-73003 and a method for changing the refractive index through a mask opening described in JP-A-5-157924 have been proposed.

[0009]

The microlens arrays used for alignment of the liquid crystal projector and the integrated device for optical fiber communication are all formed of a colorless and transparent material. Therefore, when a color image is formed by using white light as a light source, or when only light having a specific wavelength is selected and transmitted, it is necessary to disperse the light using a member different from the microlens array. .

In the case of a color liquid crystal projector, as described above, in order to perform color display, a method of separately arranging a color filter or dividing a light source into three primary colors and synthesizing them on a screen is generally performed. Therefore, a light-splitting member is required in addition to the microlens array, so that an increase in the size and cost of the apparatus is inevitable.

In the field of optical fiber communication devices, a single wavelength semiconductor laser or LED is generally used as a light source.
However, in order to form an inexpensive system, it is also possible to use white light as a light source and split the light with a filter. Also in this case, there is a problem that a light separating member is required in addition to the micro lens array.

On the other hand, as for the method of manufacturing a microlens array, any of the above-mentioned methods requires a mold and a mask, and it is difficult to easily manufacture a lens array having an arbitrary shape and an arbitrary arrangement. In addition, there is also a problem that the production cost is increased due to the production of the mold and the mask.

An object of the present invention is to provide an optical element having both a light collecting function of a minute lens and a spectral function of a color filter.
An object of the present invention is to form a lens array with high accuracy and a simple process, and specifically, to provide a lens array having a color filter function and in which micro lenses of an arbitrary shape are arbitrarily arranged at low cost.

[0014]

The first aspect of the present invention is an optical element having a plurality of convex colored microlenses arranged on a transparent substrate.

A second aspect of the present invention is to manufacture an optical element characterized in that a liquid colored transparent material is applied to the surface of a transparent substrate by an ink-jet method, adhered and cured to form a convex colored microlens. Is the way.

That is, the optical element of the present invention is provided with a color filter function by coloring the microlenses of the lens array, and the manufacturing method of the present invention uses the above-mentioned liquid colored transparent material by an ink-jet method. By providing it on the surface of a transparent substrate, it is possible to easily form a microlens of any shape at any place.

[0017]

FIG. 1 is a schematic cross-sectional view of one embodiment of the optical element of the present invention. In FIG. 1, reference numeral 1 denotes a transparent substrate, and reference numerals 2 to 4 denote colored microlenses colored so as to transmit only red (R), green (G), and blue (B), respectively. Reference numeral 5 denotes white light, and reference numerals 6 to 8 denote focal points of the light condensed by the colored microlenses 2 to 4, respectively.

When white incident light 5 enters the transparent substrate 1 of the optical element of the present invention, the colored minute lenses 2 to 4
The light is divided into light of each color of R, G, and B, and emitted as light condensed at focal points 6 to 8. As described above, since the optical element of the present invention is constituted by the minute lenses that are colored so as to transmit only a specific color, the incident parallel white light is condensed and simultaneously split into the specific color light. Can be accomplished with the same components.

Next, a method for manufacturing the optical element of the present invention will be described.

In the present invention, an ink jet method is used to arrange a large number of colored microlenses on a plane.
A liquid colored transparent material is selectively disposed on a portion to be a lens.

The ink-jet method is a technique used in printers and the like in recent years, and has been used for industrial purposes such as production of color filters for liquid crystal displays and the like. The advantage of the ink jet method is that when forming a fine pattern, a mask or a mold required by a photolithography method, a printing method, a molding method, etc. is unnecessary, and a pattern of an arbitrary shape can be formed quickly. is there.

FIG. 2 schematically shows the formation of colored microlenses by the ink-jet method. In the figure, 21-2
Reference numeral 3 denotes an ink jet nozzle, and liquid colored transparent materials 24 to 26 colored so as to transmit only R, G, and B colors are applied on the transparent substrate 1 from the respective nozzles.

The transparent substrate 1 used in the present invention is generally made of optical glass polished to a flat surface, but plastics such as polyethylene terephthalate and polycarbonate can also be used, provided that they have desired optical performance and strength. The material is not particularly limited. Also, the transparent substrate 1
In order to increase the adhesion strength to the microlenses formed on the surface, it is preferable to sufficiently perform degreasing and cleaning.

The liquid colored transparent materials 24 to 26 used in the present invention are formed on the transparent substrate 1 by an ink jet method.
It is a material that is applied above and that can be cured after application. Specifically, for example, a dye or a pigment is fixed as a colorant for transmitting only a specific color such as R, G, and B, and the colorant is fixed. And a curable resin material for forming a convex lens,
It is composed of a solvent for dissolving the resin material, water for setting the curvature and improving the ejection performance of the ink jet, and in some cases, additives.

The above dye is appropriately selected from, for example, anthraquinone dye, azo dye, triphenylmethane dye, polymethine dye and the like.

The above-mentioned curable resin material is a resin or a monomer agent which is cured by crosslinking, for example, a thermosetting resin or an energy-curable resin. Specifically, acrylic resins such as polymethyl methacrylate and polycyclohexyl methacrylate, allyl resins such as diethylene glycol bisallyl carbonate, and polycarbonate, and methacrylic resins are used.

As the solvent, for example, isopropyl alcohol, ethylene glycol, N-methyl-2-pyrrolidone and the like are used.

As an additive, acetylenol or the like may be added for the purpose of adjusting the surface tension.

The radius of curvature of the colored microlenses is determined by the viscosity of the liquid colored transparent materials 24 to 26 and the wettability of the transparent substrate 1 to the liquid colored transparent materials 24 to 26. For example, if the transparent substrate 1 is easily wet, the inkjet nozzle 2
The materials 24 to 26 discharged from 1 to 23 spread on the surface of the transparent substrate 1 and have a gentle convex shape with a large radius of curvature. Conversely, if the transparent substrate 1 is difficult to wet, the liquid colored transparent materials 24 to 26 are easily repelled on the substrate surface, and have a convex shape with a small radius of curvature. Therefore, in order to obtain a desired radius of curvature, the transparent substrate is subjected to cleaning or surface modification treatment,
The wettability can be controlled by coating the surface with a material having water repellency.

The size of the colored microlenses 2 to 4 can be changed by changing the amount of the liquid colored transparent material applied to the same place. For example, a large-diameter lens can be formed by using a large-diameter nozzle or by repeatedly applying the nozzle at the same location.

The liquid colored transparent material provided on the transparent substrate 1 has a convex shape due to viscosity and surface energy. Thereafter, the material is cured by heat, ultraviolet light, or the like. In the curing process, since the solvent and the like contained in the material evaporate and the shape changes, it is desirable to set the surface energy and the amount of application in consideration of the change in advance.

As the ink jet system, a bubble jet type using an electrothermal converter as an energy generating element, a piezo jet type using a piezoelectric element, or the like can be used. Can be set arbitrarily.

FIG. 2 shows a mode in which the liquid colored transparent materials of R, G, and B are simultaneously applied, but the application and curing steps may be repeated for each color.

The optical element of the present invention is suitably used as a microlens array having a spectral function in the liquid crystal projector shown in FIG. 3 or the connection device for optical fiber communication shown in FIG.

[0035]

【Example】

[Example 1] An optical glass BK7 polished to a flat surface was used as a transparent substrate, and alkali cleaning and UV treatment were performed to increase the adhesion strength to a colored microlens.

A red ink was applied to a desired position on the substrate using an ink jet apparatus (trade name: BJ10E, manufactured by Canon Inc.). The red ink is obtained by dispersing a red dye in a self-crosslinking thermosetting resin mainly composed of an acrylic silicone graft polymer and dissolving it in ethylene glycol.

The amount applied at one time is 50 ng, and 1
It was applied 0 times. The applied ink became convex on the substrate surface due to surface tension.

Next, the substrate is placed on a hot plate,
It was dried and cured at 100 ° C. for 20 minutes.

The above steps are repeated for a blue ink using a blue dye and a green ink using a green dye,
A lens array provided with colored microlenses of three colors of R, G and B was obtained.

The above-mentioned lens array is used for a liquid crystal projector T.
When an image was formed on the screen after being arranged in front of the FT liquid crystal panel, an image having sufficient brightness could be obtained.

Example 2 A polycarbonate substrate was used as a transparent substrate, and a sufficient cleaning and UV ozone treatment were performed. As the liquid colored transparent material, a material in which a dye was dispersed in a monomer agent of a polycarbonate resin was used. Using the same ink jet apparatus as in Example 1, 50 ng of ink was applied to the same spot 10 times at a time. The applied ink became convex on the substrate surface due to surface tension.

Next, the substrate is placed on a hot plate,
It was dried and cured at 120 ° C. for 20 minutes.

The above process was repeated for the blue ink and the green ink to obtain a lens array provided with colored microlenses of three colors of R, G and B.

When the lens array thus manufactured was used for a liquid crystal projector, desired performance was obtained.

Example 3 A glass substrate was used as a transparent substrate, and after sufficient washing and UV ozone treatment, a colored microlens was formed using an ink jet apparatus in the same manner as in Example 1. The ink used was a red ink in which Pigment Red 177 was dispersed as a pigment in an ammonium salt of a styrene-acrylic acid copolymer and dissolved in isopropyl alcohol, and pigments of blue and green were used. Each time each ink was applied, it was dried and cured at 120 ° C. for 20 minutes.

When the lens array thus manufactured was used for a liquid crystal projector, desired performance was obtained.

Example 4 As in Example 3, colored microlenses were formed by aligning the optical axes on both sides of the glass substrate, and a lens array having lenses on both sides was manufactured.

When this lens array is used in a connection portion of an optical fiber communication device in which a light source as shown in FIG. 5 is converted into white parallel light, good spectral performance is obtained and the light is efficiently introduced into the optical fiber. Was completed.

[0049]

As described above, according to the present invention,
A lens array having a spectral performance and a lens of an arbitrary size at an arbitrary position can be accurately formed by a simple process. Therefore, an optical element having both a spectroscopic function and a condensing function is provided at a low cost, and the size and the price of an optical device such as a liquid crystal projector and an optical fiber communication device can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an optical element of the present invention.

FIG. 2 is a schematic view showing a state of manufacturing an optical element of the present invention.

FIG. 3 is a schematic view showing a liquid crystal projector which is one application of the optical element of the present invention.

FIG. 4 is a partially enlarged view of the liquid crystal projector shown in FIG.

FIG. 5 is a schematic view showing a parallel optical fiber which is another application of the optical element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2-4 Colored micro lens 5 White light 6-8 Focus 21-23 Ink jet nozzle 24-26 Liquid colored transparent material 31 Light source 32 Condensing lens 33 Liquid crystal panel 34 Projection lens 35 Screen 41 Transparent substrate 42 Micro lens 43 Light shielding Area 44 Effective (light-transmitting) area 51 Semiconductor laser array 52 Lens array 53 Fiber array

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nagato Osano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kenichi Iwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (2)

[Claims] 1. An optical element comprising a transparent substrate on which a plurality of convex colored microlenses are arranged. 2. A method for producing an optical element, comprising applying a liquid colored transparent material to a surface of a transparent substrate by an ink-jet method, and attaching and curing the liquid colored transparent material to form a convex colored microlens.