JPH055922A - Optical integrated optical system integrated with flat plate type optical element and production thereof - Google Patents

Abstract

PURPOSE:To form the small-sized optical system having excellent adhesion by forming the films of the optical elements of a flat plate type by a sol-gel method directly on a transparent substrate and integrating these elements. CONSTITUTION:A transparent glass substrate 1 having a reflection layer 13 in the lower part is masked by a resist 8. Lens parts and photodetecting parts are then masked by a hot meltable plastic film 10 and slit type polarizers 9 are deposited by evaporation to input parts and filter parts. After a PLZT soln. is applied thereon from above, the coating is dried and is further heated. PLZT sintered bodies 11 are formed by repeating the operations from the coating up to the sintering and electrodes 12 of a comb shape are deposited thereon. The plastic film 10 is then peeled and an SiO2 soln. is applied to the lens parts. After transfer is executed by using a stamper, the sintering is similarly executed to form the Fresnel type lenses 4, 6 are formed. A reflection layer is deposited thereon. Finally, photodetectors 7 are laminated by alignment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical integrated optical system in which flat plate type optical elements for handling optical information are integrated and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, an optical integrated optical system has performed processing such as interference and correlation by arranging a bulk optical element in a space, but recently, a similar function has been integrated in a waveguide to reduce the size. Things are made. As an example of producing a flat plate type optical element on one transparent substrate, J. Jahn
s and A. Huang; “Planer int
integration of free-space op
mechanical components ", Appl. Op.
t. 28, No. 9,1602 (1989) has been reported. Generally, in a bulk optical system, positioning of each optical element requires precision because precision is required, but currently, a stage or a jig is used. However, in the above-mentioned miniaturized optical system, it is more difficult to align the respective optical elements, and there is a demand for more efficient positioning work, but an effective method has not been proposed yet.

[0003]

An object of the present invention is to provide an optical system in which flat plate optical elements are integrated on a single transparent substrate and to efficiently provide flat plate optical elements that are excellent in adhesion, small in size, and accurate in positioning. And

[0004]

According to a first aspect of the present invention, at least a light emitting element, a flat plate type lens, a flat plate type spatial modulation element and a light receiving element are arranged on one transparent substrate, and at least one of them is formed by a sol-gel method. An optical integrated optical system characterized by being directly formed on a substrate (hereinafter referred to as the optical integrated optical system 1
That) and its manufacturing method. A second aspect of the present invention is characterized in that at least a light emitting element, a flat plate type lens and a flat plate type spatial modulation element are arranged on one transparent substrate, and a light receiving element is arranged on the opposite surfaces with the transparent substrate interposed therebetween. Optical integrated optical system (hereinafter referred to as optical integrated optical system 2) and its manufacturing method. The light-emitting element used in the present invention means an input pattern, but an element which emits light to form a pattern may be used, and a signal such as light intensity when transmitting a light-emitting body and light incident from the light-emitting body. You may use the combination with the substance which changes. Further, the flat plate type lens in the present invention must be a reflection type lens. For example, a Fresnel zone type lens having a reflective layer on its surface can be used. In this case, it is preferable that a variable substance is used in the form of a Fresnel zone plate and its pattern is variable because the size of the lens aperture and the focal length can be controlled. The flat-plate type spatial modulation element used in the present invention is a reflection type spatial modulation element in which the directions of input light and output light are the same. It is preferable to use a substance having an electro-optical effect for this because various treatments can be performed by one optical system without changing the optical system. As the light receiving element used in the present invention, a general element is used. For example, photodiodes and charge transfer devices are used, but since these devices cannot be directly formed on a transparent substrate, they can be easily and accurately manufactured by arranging them on the surface facing the substrate of other optical devices. Can be done. Since the photodiode and the charge transfer device are made of silicon doped with impurities, they are also used as the reflective layer of the substrate (optical integrated optical system 2). The transparent substrate in which light is handled in the present invention is a medium having a constant refractive index and having a thickness and a size capable of utilizing a normal light propagation phenomenon. Examples include glass and crystal. In the present invention, the sol-gel method, which is a method of directly forming a film on an optical element on a substrate, generally means that a metal-organic compound such as a metal alkoxide is hydrolyzed in a solution system and polycondensed to form a metal-oxygen-metal bond. This is a method for producing an inorganic oxide, which is completed by growing and finally sintering. The feature of the sol-gel method is that a uniform film can be obtained at a low substrate temperature. Further, since the film is formed from the solution, it has excellent adhesion to the substrate and easy alignment. Specifically, a solution containing a metal organic compound is applied onto the substrate, dried and then sintered. Examples of the metal organic compound used include alkoxides such as methoxides, ethoxides, propoxides, butoxides, etc., of metals constituting an inorganic oxide, and acetate compounds. Inorganic salts such as nitrates, oxalates and perchlorates may be used. In order to produce an inorganic oxide from these compounds, it is necessary to proceed with hydrolysis and polycondensation reactions, and therefore it is necessary to add water to the coating solution. The amount of addition varies depending on the system, but if it is too large, the reaction proceeds rapidly and the quality of the film obtained tends to be non-uniform, and it is difficult to control the reaction rate. If the amount of water added is too small, it is difficult to control the reaction, and there is an appropriate amount. Furthermore, a reaction rate and a reaction form can be controlled by adding a hydrolysis acceleration catalyst or a chelating agent which coordinates with a metal atom. As the hydrolysis, acids and bases usually used in the hydrolysis reaction are used.
It is said that the acid catalyst is easy to form a linear polymer and the basic catalyst is easy to form a three-dimensional polymer, but it cannot be said unconditionally because of the balance with the concentration and pH of the whole solution. Further, examples of the chelating agent include acetylacetone, ethylacetoacetate, diethyl malonate and the like. As the solvent, those in which the above materials do not precipitate, that is, those having excellent compatibility are desirable. The solution concentration depends on the coating method, but in the case of the spin coating method, it is preferable to adjust the solution viscosity to be several cP to several tens of cP. Sintering of the coated film promotes desorption and crystallization of organic substances. Although the sintering temperature varies depending on the material, the sintering can be performed at a temperature lower than the temperature required for firing the usual metal oxide powder. Depending on the device configuration, there are many cases in which reaction, composition change, or structure change occurs at high temperature, and therefore the possibility of use is expanded by using this method. A general photolithography technique is used as a patterning method for film formation. Particularly, if all the optical elements constituting the optical system are aligned at the same time with one photomask, highly accurate and efficient patterning can be performed. Specifically, the transparent substrate is masked with a resist, leaving the optical element portion to be arranged, to form a desired inorganic oxide film by the sol-gel method. However, the optical element is S
When a commercially available product, which is not produced by the ol-Gel method, is adhered and used, an alignment mark for facilitating alignment at the time of adhering may be provided in the process of photolithography. A film is obtained by applying the above solution, drying and sintering. Other patterning methods using the photolithography technology include, for example, a method of performing selective coating by processing the substrate into a desired pattern and changing the wettability, or a surface-roughening process to the substrate desired pattern and selecting A method of patterning through etching may be used. In the optical integrated optical system 2, a light receiving element is formed on the surface of the substrate (for example, ion-doped on a silicon substrate), and this is attached to a transparent substrate, and then another optical element is formed on the opposite surface of the transparent substrate. It is provided by the above patterning. An example of the optical integrated optical system 1 of the present invention is shown in FIG. In the figure, 1 is a transparent substrate provided with a reflective layer on one side, 3 is an input pattern, 4 is a reflection type lens, 5 is a flat plate type spatial modulation element, 6 is a reflection type lens, and 7 is a light receiving element. The operation is as follows. Light travels while being reflected in the substrate as shown by the arrow in the figure. A light source such as a semiconductor laser is collimated and is incident on the input pattern of 3 at a certain incident angle. This light is reflected by the reflective layer of the substrate 1 and 4
The light enters the lens of No. 2 and becomes convergent light, which is reflected again by the reflection layer and enters the spatial filter of No. 5. Here, spatial frequency filtering, for example, high-pass filtering for edge extraction, is emitted, reflected by the reflection layer, and incident on the flat-plate type reflective lens 6 to be collimated light, which then enters the light-receiving element 7. Next, an example of the optical integrated optical system 2 of the present invention is shown in FIG. In the figure, 1 is a transparent substrate, 2 is a silicon substrate, 3 is an input pattern, 4 is a reflection type lens, 5 is a flat-plate type spatial modulation element, 6 is a reflection type lens showing a focal length different from 4, and 7 is light receiving. It is an element. The operation is as follows.
Light travels while being reflected in the substrate as shown by the arrow in the figure. A light source such as a semiconductor laser is collimated and is incident on the input pattern of 3 at a certain incident angle. This light is reflected by the reflective layer of the substrate 1 and is incident on the lens 4 to be converged light, which is reflected again on the reflective layer and is incident on the spatial filter 5.
Here, spatial frequency filtering, for example, high-pass filtering for edge extraction, is emitted, reflected by the reflection layer, and incident on the flat-plate type reflective lens 6 to be collimated light, which then enters the light-receiving element 7.

[0005]

【Example】

Example 1 This example is a manufacturing example of the optical integrated optical system 1. The optical system of FIG. 1 was created. The creation procedure is shown as a to e in FIG. The transparent glass substrate 1 having the aluminum reflective layer 13 underneath was masked with a resist 8 in a pattern as shown in FIG. 2a. Next, the lens portion and the light receiving portion are masked with a heat-fusible plastic film 10, and the slit type polarizer 9
Was formed on the input part and the filter part by vapor deposition (Fig. 2
b). From there, a PLZT solution having the composition shown below was applied. A methoxyethanol solution (0.25 mol) of lanthanum acetate 0.1 mol, titanium tetraisopropoxide 0.35 mol, and zirconium tetrapropoxide 0.65 mol per mol of lead acetate (0.25
(mol / liter), water was added in an amount equal to that of the -OR group, and nitric acid as a catalyst was added in an amount of 0.1 mol / liter (here, -O).
The R group represents an organic compound bonded to a metal organic compound. ). After the solution was applied onto the substrate, it was dried at 120 ° C. for 1 hour and further heated at 600 ° C. for 1 hour. The process from coating to sintering is repeated 10 times and the thickness of PLZT is 1 μm.
A sintered body 11 was prepared, and a comb-shaped electrode 12 was attached to the upper portion of PLZT (FIG. 2c). Next, the plastic film 10 was peeled off, and the reflective lenses 4 and 6 were prepared by the following procedure. A SiO ₂ solution having the following composition was applied to the lens portion. A solution of tetraethoxysilane, water, nitric acid, and polyethylene glycol (molecular weight 600) dissolved in methoxyethanol was applied, transferred using a stamper, and then sintered in the same manner to create a Fresnel lens. A reflective layer was applied on top of (Fig. 2d). Finally, the photodiodes 7 as light receiving elements were laminated by alignment to form a flat plate type optical system (FIG. 2e). An optical system was obtained in which the alignment of each optical element was precise, stable, and small. Example 2 This example is a manufacturing example of the optical integrated optical system 2. The integrated optical system of FIG. 3 was created. The creation procedure is shown in FIGS. A light receiving element 7 is manufactured by ion-doping the light receiving portion of the silicon substrate 2 and is bonded to the transparent glass substrate 1 (see FIG. 4).
a) The resist 8 was used to mask the pattern as shown in FIG. 4b. Next, the lens portion was masked with the heat-fusible plastic film 10, and the slit-type polarizer 9 was formed on the input portion and the filter portion by vapor deposition (FIG. 4c). From this, a PLZT solution having the composition shown below was applied. A methoxyethanol solution (0.25 mol / liter) in which lanthanum acetate 0.1 mol, titanium tetraisopropoxide 0.35 mol, and zirconium tetrapropoxide 0.65 mol were prepared per 1 mol of lead acetate. Water equal to -OR group, nitric acid 0.1m as catalyst
ol / liter was added (here, the —OR group represents an organic compound bonded to a metal organic compound). After the solution was applied onto the substrate, it was dried at 120 ° C. for 1 hour and further heated at 600 ° C. for 1 hour. The process from application to sintering is repeated 10 times to form a PLZT sintered body 11 having a thickness of 1 μm, and the electrodes 1 are arranged in a matrix on the upper portion of PLZT.
2 was attached (Fig. 4d). Next, plastic film 10
Then, the reflective lenses 4 and 6 were prepared by the following procedure. A SiO ₂ solution having the following composition was applied to the lens portion.
A solution of tetraethoxysilane, water, nitric acid, and polyethylene glycol (molecular weight 600) dissolved in methoxyethanol was applied, transferred using a stamper, and then sintered in the same manner to create a Fresnel lens. A reflective layer was applied on top of (Fig. 4e). An optical system was obtained in which the alignment of each optical element was precise, stable, and small.

[0006]

The optical integrated optical system 1 of the present invention is (1) a compact and excellent in adhesion by at least one flat plate type optical element being directly formed on a transparent substrate by a sol-gel method to be integrated. An optical system can be created, and (2) all optical elements on the substrate forming the optical system are simultaneously patterned by using a single mask to form a film, so that the flat optical element can be formed with high accuracy. In addition, it is possible to align the position efficiently. In the integrated optical system 2 of the present invention, (1) at least a light emitting element, a flat plate type lens, and a flat plate type spatial modulation element are arranged on one transparent substrate, and a light receiving element is arranged on the surfaces facing each other across the transparent substrate. By doing so, accurate alignment can be achieved. (2) A flat optical element is directly formed on a transparent substrate by a sol-gel method to form a film, and the small optical system having excellent adhesion is produced. In addition, (3) all optical elements on the substrate constituting the optical system are simultaneously patterned using a single mask to form a film, so that the optical elements can be aligned with high precision and efficiency. Made possible

[Brief description of drawings]

FIG. 1 is a perspective view of one specific example of an optical integrated optical system of the present invention in which a light emitting element, a flat plate type lens, a flat plate type spatial modulation element and a light receiving element are arranged on a transparent substrate.

2A to 2E are manufacturing process diagrams of the optical integrated optical system of FIG.

FIG. 3 is an optical integrated optical system of the present invention in which a light emitting element, a flat plate type lens and a flat plate type spatial modulation element are arranged on a transparent substrate, and a light receiving element is arranged on opposite substrate surfaces with a transparent substrate interposed therebetween. 3 is a perspective view of one specific example of FIG.

4A to 4F are manufacturing process diagrams of the optical integrated optical system of FIG.

[Explanation of symbols]

 1 Transparent Glass Substrate 2 Silicon Substrate 3 Input Pattern 4 Flat Plate Lens 5 Flat Plate Spatial Modulator 6 Flat Plate Lens 7 Photoreceptor 8 Resist 9 Slit Polarizer 10 Thermal Fusion Plastic Film 11 PLZT Sintered Body 12 Comb Electrode 13 Aluminum reflective layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Fujimura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (1)

Claims: 1. At least a light emitting element, a flat plate lens, a flat plate spatial modulation element and a light receiving element are arranged on one transparent substrate, and at least one of the optical elements is a sol-gel (Sol-gel). An optical integrated optical system characterized in that a film is directly formed on a substrate by the Gel method. 2. A light comprising at least a light emitting element, a flat plate type lens and a flat plate type spatial modulation element arranged on one transparent substrate, and a light receiving element arranged on a surface facing each other across the transparent substrate. Integrated optics. 3. At least one of flat plate type optical elements provided on one transparent substrate is directly formed on the substrate by a sol-gel method, and all the optical elements on the transparent substrate use one mask. 3. The method for producing an integrated optical system according to claim 1, wherein the film is formed by patterning at the same time.