JP2003145633A - Method for manufacturing composite precise optical element, and composite precise optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely manufacture an array-like plastic optical element comprising a light transmission part having a high light utility ratio (brightness) a high resolution with a lens pitch size of 1 m or less, an open area ratio of 90% or more and a shape accuracy of a lens of 0.1 μm or less and a non-light transmission part, and to devise a method for manufacturing for reducing the manufacturing cost as low as possible. SOLUTION: The method for manufacturing the composite precise optical element having the light transmission part having a mirror surface and the non-light transmission part for absorbing a light between the adjacent light transmission parts and its periphery comprises a step (primary working step) of forming a substantially final shape, and a step (secondary working step) of simultaneously performing narrowing the non-light transmission part and transferring the mirror surface shape to the surface of the light transmission part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-precision plastic molded product composed of a plurality of members (in particular, optical elements such as multi-lens and mirror), and is a copying machine, a facsimile, a solid scanning printer. The present invention can be applied to a plastic lens used in an optical scanning system such as the above and an optical transmission waveguide.

[0002]

2. Description of the Related Art In arrayed optical elements having a plurality of lenses and the like, higher resolution and higher light utilization rate (brightness) are required. To meet these requirements, it is necessary to reduce the pitch between lenses, increase the aperture ratio, and improve the shape accuracy. In order to increase the aperture ratio of the lens, it is necessary to narrow the aperture part (a part of the light shielding part), but if the aperture part is narrowed, the non-transmissive part inside the optical element is irradiated with light and total reflection occurs. (See Figure 1, Generation of Ghost Light). In order to eliminate this, it is necessary to make the difference in refractive index between the light transmitting portion having an optical function and the non-light transmitting portion extremely small. For example, when the incident angle is 1 degree, the difference in refractive index is 0.0002.
Must be within. There are almost no combinations of resins with such minute differences in refractive index (see Table 1). Conversely, it is necessary to use the same type of resin. For example, when PC (polycarbonate) is used as the light transmitting material, PC (containing carbon black) is also used as the non-light transmitting material.
Better to use.

Narrow pitch and high aperture ratio By narrowing the pitch, many lenses are provided in the same size or area. For example, when the dimension between lens pitches arranged one-dimensionally is 1 mm and the aperture ratio is 90%, the thickness of the non-light-transmitting portion is 0.1 mm. As mentioned above, it is best to use the same material for the light-transmissive member and the non-light-transmissive member, but if you use the same material, insert the non-light-transmissive member after injection molding the shape of the light-transmissive part. (In addition, a film-shaped non-transmissive member may be inserted, but in this case, it takes time, which is inefficient.) However, the thickness of the non-light-transmitting portion that can be realized by injection molding is limited to 0.1 mm, and it is very difficult to process the thickness less than this. Therefore, it is almost impossible to further reduce the pitch and increase the aperture ratio. Regarding the shape accuracy of the lens, for example, the dimension is 300 mm and the thickness is 2 m.
When an m-shaped arrayed optical element is injection-molded, the precision is 0.2 μm at a low position, and a higher precision than this is almost impossible by injection molding.

Next, a specific example of the prior art will be described. In the lens array manufacturing method described in Japanese Patent Laid-Open No. 2000-227505, the lens is first molded, and then the light-shielding portion is painted black. Although there is no description of a lens molding method in the publication, highly accurate molding cannot be obtained by injection molding. Further, although black coating is applied to the light-shielding portion, it is very costly to mix the materials so that the refractive indexes are the same. Alternatively, there is a drawback that only an optical element having a low aperture ratio and a low light effective utilization rate can be obtained.

On the other hand, the method disclosed in JP-A-55-90923 has the following problems 1 to 3. 1. In the method of compression-molding a block made by alternately laminating acrylic layers and light-shielding plates and adhering or fusing them together, it is possible to form a thin light-shielding part and to form a highly accurate lens. Is also possible, and also
It is also possible to reduce the pitch between the lenses and obtain a highly accurate optical element. However, the method of stacking layers alternately requires a very long time, and thus has a problem that processing efficiency (processing time) is poor. For example, total length 300mm, 1m
In the case of the m pitch, there are 600 laminated portions (see FIG. 2). 2. Acrylic resin (non-light transmitting member) is injected (injection molding) to cover the lens support (non-light transmitting portion),
This is a method of manufacturing by compression molding (heating and pressurization for lens molding). Since this uses injection molding, it is practically impossible to reduce the thickness of the non-light-transmitting portion to 0.1 mm or less, so that the aperture ratio cannot be further increased (see FIG. 3). 3. A manufacturing method in which a notch is formed between the lens pitches by cutting or laser processing, a light-shielding layer is formed on the notched portion by an opaque plate or inking, and compression molding is performed It takes time, the material is welded when cutting speed is increased,
There are problems such as chip disposal. In addition, cutting by laser processing has a problem that it takes a long time to process, the dimensional accuracy deteriorates due to thermal expansion of the material, and only linear processing is possible, while the method of inserting an opaque plate requires a long time for insertion. There is a problem that the black ink is required, and the black ink has the above problem (see FIG. 4).

[0006]

Therefore, according to the present invention, a light transmission with a high resolution and a high light utilization rate (brightness) of a lens pitch dimension of 1 mm or less, an aperture ratio of 90% or more, and a lens shape accuracy of 0.1 μm or less. It is an object of the present invention to devise a manufacturing method capable of easily and reliably manufacturing an array-shaped plastic optical element consisting of a light-transmitting portion and a non-light-transmitting portion and reducing the manufacturing cost as much as possible. is there.

[0007]

[Measures taken to solve the problem]

SOLUTION 1 (corresponding to claim 1) Means 1 taken for solving the above-mentioned problems is a light transmitting portion having a mirror surface, and a non-light transmitting portion that absorbs light between adjacent light transmitting portions and their surroundings. In a method for manufacturing a composite precision optical element including parts, a step of forming a substantially final shape (primary processing step), a narrowing of a non-light-transmitting portion region, and a mirror-like shape transfer to the surface of the light-transmitting portion. This is due to the simultaneous process (secondary processing process).

[0008]

The non-light-transmitting portion of the primary processed product is uniformly narrowed and compressed to an extremely thin thickness by the internal pressure of the light-transmitting portion due to the heating and pressing during the mirror surface transfer processing, so that the aperture ratio of the light-transmitting portion can be ensured. Can be 90% or more. In addition, since the mirror surface transfer processing and the constriction processing of the non-light-transmitting portion area of the first-processed product are performed at the same time, the transfer processing and molding processing accuracy can be improved, and the non-light-transmitting portion can be processed by the optical processing. It is processed extremely thin by the pressure of the permeation part, and there is little variation in the processing accuracy. Therefore, the lens pitch is 1 mm or less, the aperture ratio is 90% or more, and the lens shape accuracy is 0.1 μm or less.
It becomes easy to mold and process the array-shaped plastic optical element consisting of the light-transmitting portion and the non-light-transmitting portion of
Since the processing cycle of the transfer processing and the constriction processing of the non-light-transmitting portion region is shortened, the processing efficiency is improved, and since two molding processes are performed by a single molding device, these processes are performed separately. Compared with the case, the equipment cost of these processing devices is reduced. In order to perform the narrowing of the non-light-transmitting portion, it is not essential that the non-light-transmitting portion is softer than the light-transmitting portion at the time of heating and pressurizing, but the narrowing can be performed smoothly. To do so, it is necessary that the non-light-transmitting portion is softer than the light-transmitting portion, and therefore, the material of the non-light-transmitting portion is a material having a lower softening point than the light-transmitting portion, or A method is adopted in which only the non-light-transmitting portion is specially heated so that the temperature of this portion is higher than that of the light-transmitting portion.

[0009]

SOLUTION 2 (corresponding to claim 2) The solution means 2 is the manufacturing method of the solution means 1, in which (a) the processing method of the primary processing step is injection molding (primary molding) of a light transmitting portion. After that, the non-light-transmitting portion is injection-molded (secondary molding) on the primary molded product.

[0010]

When the material of the non-light-transmitting portion has a lower softening point than the material of the light-transmitting portion, the non-light-transmitting portion having a low softening point is injection-molded with respect to the light-transmitting portion having a high softening point. Therefore, the thermal influence on the light transmitting portion due to the injection molding of the non-light transmitting portion is reduced as much as possible.

[0011]

Solution means 3 (corresponding to claim 3) Solution means 3 is that, in solution means 1, the processing method of the secondary processing step is as described in (a) and (b) below. (A) After the primary processing step, a non-light-transmitting portion having a lower viscosity than the light-transmitting portion and a light-transmitting portion heated to a softening temperature or higher are added to the light-transmitting portion with a mold having a mirror surface. By pressing
By deforming the light transmitting part to widen the area, and by deforming the light transmitting part to stretch the non-light transmitting part to narrow the area, (b) Transfer the mirror surface shape to the surface of the light transmitting part, and thermally deform Remove from mold after cooling below temperature.

[0012]

When the light transmitting part is heated by the mold while being heated above the softening temperature, the transfer process is performed by the mold and it swells in the lateral direction, whereby the non-light transmitting part in the low viscosity state. Is laterally pressurized. Due to this lateral pressing action on the non-light-transmitting portion, the non-light-transmitting portion is easily constricted and smoothly stretched in the longitudinal direction with a low pressure. Therefore, the residual distortion of the light transmitting part due to the non-light transmitting part due to the applied pressure is reduced as much as possible, and high molding accuracy and optical characteristics can be obtained.

[0013]

Solution means 4 (corresponding to claim 4) Solution means 4 is that, in solution means 1, the processing method of the secondary processing step is as described in (a) and (b) below. (A) Softening temperature of the light-transmitting portion and the non-light-transmitting portion by heating by irradiation with light having a wavelength that is absorbed by the non-light-transmitting portion and generates heat at a high temperature as compared with the light-transmitting portion and by contact heating from the mold. By raising the temperature above and raising the temperature of the non-light-transmitting part compared to the light-transmitting part, and pressing the light-transmitting part with a mold having a mirror surface, the light-transmitting part is deformed and its area is expanded. Then, the non-light-transmitting portion is stretched by the expansion to narrow the area, and (b) the mirror-like shape is transferred to the surface of the light-transmitting portion and is taken out from the mold after being cooled to the heat deformation temperature or lower.

[0014]

[Function] The non-light-transmitting portion is heated by light irradiation, and the light-transmitting portion and the non-light-transmitting portion are heated above the softening temperature by heating the non-light-transmitting portion by contact with the mold, and the non-light-transmitting portion is light-transmitted. Since it can be heated to a higher temperature than the part,
The constriction processing of the non-light-transmitting portion can be performed more easily and quickly by the pressure applied to the light-transmitting portion by the mold for the transfer processing.

[0015]

SOLUTION 5 (corresponding to claim 5) is a method of irradiating light in the solution means 4, in which light of a wavelength having high absorptivity and high exothermicity in a non-light-transmitting portion is transmitted through the light-transmitting portion. It is a method of irradiating the non-light transmitting portion.

[0016]

[Function] Since the non-light-transmitting portion is irradiated with light by heating, the non-light-transmitting portion is irradiated with the light so that the non-light-transmitting portion is irradiated.
Since not only both ends of the non-light-transmitting portion sandwiched between the light-transmitting portions but also the inside thereof are irradiated and heated almost uniformly, the narrowing of the non-light-transmitting portion is performed uniformly and quickly, and the variation of the narrowing processing is performed. Variations in internal distortion due to the above are small, and adverse effects on optical characteristics due to uneven internal distortion are avoided.

[0017]

SOLUTION 6 (corresponding to claim 6) In the solution means 6, in the solution means 1, the non-light-transmitting part is a non-light-transmitting member in which a material absorbing light is dispersed in the same material as the light-transmitting part. That is.

[0018]

Since the base material of the non-light transmitting portion is the same as that of the light transmitting portion, the non-light transmitting portion and the light transmitting portion have the same thermal characteristics. Therefore, the temperature distribution and the internal stress in the light transmitting portion and the light non-transmitting portion are unlikely to occur, and therefore highly precise mirror surface transfer is realized. Further, since the light transmitting portion and the light non-transmitting portion have the same refractive index, internal reflection of the optical element (at the boundary surface between the light transmitting portion and the light non-transmitting portion) is performed regardless of the incident angle of light. Reflection) is almost completely suppressed. Furthermore, since there is no difference in the thermal expansion coefficient and the moisture absorption amount between the light transmitting portion and the light non-transmitting portion, variations in the internal stress of the optical element due to changes in environmental conditions such as temperature and humidity do not occur, and High shape accuracy is maintained regardless of fluctuations. The "light absorbing material" described above is a material that efficiently absorbs irradiated light and generates heat by irradiation, and various pigments having high light absorbing properties such as red and black correspond to this.

[0019]

SOLUTION 7 (corresponding to claim 7) In the solution means 7, the non-light-transmitting portion is made of a material having a refractive index difference of 0.1 or less with respect to the light-transmitting portion. That is, the non-light transmitting member is dispersed.

[0020]

[Function] Since materials having similar refractive indices are similar in other physical properties (shrinkage rate, thermal conductivity, thermal deformation temperature, etc.), the temperature distribution between the light transmitting portion and the non-light transmitting portion and the internal Variations in the stress distribution are unlikely to occur, and therefore high-precision mirror surface transfer is realized. Further, since the difference in the refractive index between the materials of the light transmitting portion and the non-light transmitting portion is 0.1 or less, the internal reflection of the optical element is almost completely suppressed by forming the aperture shape with the incident angle restricted to the minimum. can do.

[0021]

SOLUTION 8 (corresponding to claim 8) A solution means 10 is that the light absorbing material mixed in the material of the non-light transmitting portion in the solution means 6 or the solution means 7 is carbon black powder.

[0022]

[Function] Carbon black has a high light absorption property, and the powder thereof has a good compatibility with the material (plastic material) of the non-light-transmitting portion and is evenly dispersed in the non-light-transmitting portion. Irradiation heat generation is even and most efficient.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION From the viewpoint of processing efficiency (processing time), composite molding by injection molding is the best. However, the non-light-transmitting portion becomes thick, and the aperture ratio of the light-transmitting portion decreases. From the viewpoint of processing with high shape accuracy, a processing method including a secondary step in which a rough shape is formed by primary processing and the primary processed product is heated and pressed to a softening temperature to transfer a mirror surface is preferable. Therefore, taking advantage of these construction methods, a primary processed product having a light-transmitting portion where a lens portion is not formed and a non-light-transmitting portion is formed by two-color injection molding, and the above-mentioned method is performed by a mold having a mirror surface portion. In the secondary processing step of heating and pressing the primary processed product to form the lens portion, processing is performed to reduce the thickness of the non-light-transmitting portion.

The structure and operation of this processing will be described below. The method shown in FIG. 6 narrows the non-light-transmitting portion area and transfers the light-transmitting portion surface to a mirror-like shape after the step (primary processing step) of forming a substantially final shape (shape not reaching the mirror surface). This is a method for manufacturing a composite precision optical element by a step (secondary processing step) that simultaneously performs the above. Since the two molding processes of narrowing the non-light-transmitting part region and transferring the surface of the light-transmitting part to a mirror surface shape are performed at the same time, the processing cycle is shortened, and two molding processes are performed by a single molding device. Therefore, the apparatus cost is reduced as compared with the case where the molding apparatuses are used separately. Heating temperature required for mirror surface transfer processing,
It is necessary to select the material and heating temperature of the non-light-transmitting portion so that the constriction processing of the non-light-transmitting portion region is sufficiently completed depending on the pressing time.

Here, the material of the non-light-transmitting portion is the same as that of the light-transmitting member, or a material (for example, carbon black powder) that absorbs light is slightly (several) in the material having a refractive index difference of 0.1% or less. % By weight). As long as the material has a difference in the refractive index of the non-light-transmitting member from the light-transmitting member of 0.1% or less, the physical properties other than the refractive index (shrinkage rate, thermal conductivity, thermal deformation temperature, etc.) are almost the same. Moreover, variations in temperature distribution and internal stress due to locations (light-transmitting portion and non-light-transmitting portion) are unlikely to occur, and mirror surface transfer with extremely high shape accuracy can be performed. Since the same material as that of the light transmitting member has the same refractive index, reflection inside the optical element can be almost completely suppressed regardless of the incident angle of light. Moreover, if the same material as the light transmitting member is used, the coefficient of linear expansion and the amount of water absorption are almost the same, so the expansion and contraction of the material due to changes in temperature and humidity are the same, and variations in internal stress are less likely to occur, and environmental changes are less likely to occur. High shape accuracy can be maintained even at (temperature and humidity). When a material having a similar refractive index is used, the total internal reflection inside the optical element can be suppressed by forming the opening shape in which the incident angle is restricted to the minimum.

Next, the details of the processing steps will be described. Regarding the primary processing step: In the primary processing step, after the light transmission portion is injection molded (primary molding), the non-light transmission portion is injection molded (secondary molding) on the primary molded product. On the contrary, it is actually possible to injection-mold the light-transmitting portion after forming the non-light-transmitting portion.

Secondary Processing Step (See FIG. 5B) After the primary processing step, a non-light-transmitting portion having a lower viscosity than the light-transmitting portion and a light-transmitting portion heated to a softening temperature or higher are provided. By pressing at least the light transmitting part with a mold having a mirror surface,
The light-transmitting portion is deformed to expand its area, and the non-light-transmitting portion is narrowed (thinned) by the expansion, and the surface of the light-transmitting portion is transfer-molded to have a mirror-like shape. After cooling to the following, it is taken out from the mold.

Further, as a method of lowering the viscosity of the non-light-transmitting portion, light having a wavelength which is absorbed by the non-light-transmitting portion and generates heat at a high temperature is irradiated. This method has the advantage that the processing cycle can be shortened and the cost of the device can be reduced, but on the other hand, it is not necessary to deform the light transmitting portion and the non-light transmitting portion at the same time to form a predetermined shape. There is difficulty where it cannot be done. In short, a mold having a mirror surface portion is heated and pressed to transfer the mirror surface portion to the light transmitting portion, and at the same time, the light transmitting portion region is uniformly expanded in the lateral direction by the heat and pressure (installed and expanded. That is. As shown schematically in FIG. 6, when the resistance is very low (when there is no non-light-transmitting portion or when the viscosity of the non-light-transmitting portion is extremely low)
In the cross section of the light transmitting portion, the central portion swells and becomes a drum shape. When the resistance is high (when the viscosity of the non-light transmitting part is high)
The non-light-transmitting portion is not deformed, and the end portion of the light-transmitting portion region is deformed into a shape wrapping the non-light-transmitting portion (see FIG. 7).
In order to uniformly expand the light transmitting area in the lateral direction, it is necessary to appropriately control the viscosity of the non-light transmitting area. For that purpose, the temperature of the non-light transmitting portion may be raised. Solution 4
Adopts a method of irradiating light of a long wavelength as a method of causing the non-light transmitting portion to generate high heat. Here, in order to generate heat in the non-light-transmitting portion, as shown schematically in FIG. 8, long-wavelength light (for example, infrared rays) is irradiated, and this is absorbed by the non-light-transmitting portion and heated. . The non-light-transmitting part is preheated to a high temperature by light irradiation, and then it is heated and pressed by a transfer molding die to transfer the optical surface to a mirror surface, and the non-light-transmitting part is narrowed (or stretched). ) And then cool.

The light transmitting portion is a transparent plastic,
As shown in Table 1, the types are limited. And, although there is no material that absorbs far infrared rays among these materials, there is no material that efficiently absorbs near infrared rays. On the other hand, the carbon black used by being mixed in the non-light-transmitting portion absorbs light well in the near infrared region and efficiently generates heat. By irradiating near-infrared rays or the like, the temperature of the non-light-transmitting portion is higher than that of the light-transmitting portion and the viscosity is lowered. In this state, the non-light-transmitting portion easily flows with a small pressure, so that the non-light-transmitting portion can be selectively narrowed. At this time, by irradiating the near-infrared rays obliquely so as to pass through the light transmitting portion and reach the non-light transmitting portion, it is possible to heat more efficiently and raise the temperature.

In addition, as a means for decreasing the viscosity of the non-light-transmitting portion, there is also a method of using a material having a low softening temperature and bringing the non-light-transmitting portion into contact with a mold to raise the softening temperature. Since a uniform temperature distribution is obtained in mirror surface transfer, highly accurate transfer can be performed. Further, by adopting a mechanism (a gap is provided in a portion other than the lens) for allowing the residual pressure to escape, the pressure distribution during heating and pressurization can be reduced, and highly accurate transfer can be performed. Further, by lowering the material to a thermal deformation temperature and then taking it out, it is possible to prevent the material from being deformed due to frictional resistance at the time of taking it out. By using the above manufacturing method to reduce the thickness of the non-light-transmitting portion, the area of the light-transmitting portion is relatively increased, the effective utilization rate of light is increased, and a bright optical element is obtained. Moreover, since the step of transferring the shape of the lens portion and the step of narrowing and stretching the non-light-transmitting portion are performed at the same time, the process time is not so long and the processing cost thereof is reduced.

[0031]

EXAMPLE An example will be described with reference to FIGS. In this embodiment, a light-transmitting portion 10 composed of two lenses 1 and 2 and one prism 3 and a non-light-transmitting portion 11 that absorbs light around the light-transmitting portion 10 (one set) are arranged in a plurality. It is a precision optical element. The distance between the lenses, that is, one pitch (between the lenses and the lens) is 0.
8 mm, and the total length of 0.8 mm × about 400 sets is about 320 mm. Primary processed product by molding the light-transmitting portion 10 by primary molding using light-transmitting plastic (injection molding) and then molding the non-light-transmitting portion 11 by secondary molding using non-light-transmitting plastic (injection molding). Then, the primary processed product is heated and pressed to transfer-process the lens surface and the prism surface, and the non-light-transmitting portion (light-shielding portion) between the lenses is narrowed. At this time, the non-light-transmitting portion 11 between the lenses is narrowed from 0.15 mm or more in the primary processed product to 0.08 mm or less in the secondary processed product. The light-transmissive plastic in this example is a cycloolefin resin, and the non-light-transmissive plastic is the above polyolefin resin (transparent resin) containing 5% by weight of carbon black powder.

In the primary processed product, a gap, that is, an escape portion 11a is left at the lens-side end and the prism-side end so that the non-light-transmitting part is narrowed / stretched during pressurization in the secondary process. There is. The primary processing step is a molding step in which the light-transmitting portion is injection-molded (primary molding), and then the non-light-transmitting portion is injection-molded (secondary molding) on the primary molded product. The injection molding conditions such as are not particularly different from the conventional ones.

In the secondary processing step, the primary processed product is preheated to a temperature near the glass transition point (140 ° C.), and then the non-light-transmitting portion is heated by irradiation of near-infrared rays and heated to 180 to 220 ° C. After that, the mold and the primary processing step are instantly brought into contact with each other to heat the mold, and when the light transmitting part reaches the softening temperature or higher (160 ° C.), the mold having the lens surface (lens mirror surface piece)
15, a mold having a prism surface (prism mirror surface piece) 16
The light transmitting portion 10 is pressed with, and the pressure is applied to the light transmitting portion 10.
Are deformed to swell the region in the lateral direction, and the non-light-transmitting portion 11 is laterally narrowed and stretched in the longitudinal direction by the lateral expansion (bulging) of the light-transmitting portion 10. The area of the portion 11 is narrowed, and the surface of the light transmitting portion is transferred to a mirror surface shape. In this case, the non-light transmitting portion 1
1, the thickness of 0.15 mm is narrowed to 0.08 mm, and the length of 1.2 mm is stretched to 1.5 mm. The difference in length of the non-light-transmitting portion 11 is equal to the sum of the lengths of the upper and lower relief portions 11a and 11a. After that, it is taken out from the mold after being cooled to the heat distortion temperature or lower (120 ° C. or lower).

The heating pressure and the pressing time for the mirror surface transfer processing are set from the viewpoint of securing the molding accuracy and the optical characteristics of the light transmitting portion such as a predetermined mirror surface processing. The preheating temperature of the non-light-transmitting portion due to light irradiation should be adjusted so that the transmitting portion is constricted as planned. Since the necessary preheating temperature depends on various conditions such as the material and the lens thickness, there is no choice but to experimentally verify and adjust each complex precision optical element. As the material of the non-light-transmitting portion, cycloolefin containing 5% by weight of carbon black powder having a particle diameter of 0.24 μm can be used. Further, as a combination of the material of the light transmitting portion and the material of the non-light transmitting portion, the light transmitting member: PC and the non light transmitting member: PS can be adopted. In addition to the precision lens array, there is a two-dimensional precision lens array or the like as the complex precision optical element most suitable for applying the present invention.

[0035]

The effects of the present invention are summarized as follows according to the inventions according to the main claims. 1. Effect of the Invention According to Claim 1 Since the non-light-transmitting portion of the primary processed product can be narrowed and uniformly thinned by the internal pressure of the light-transmitting portion due to the heating and pressing during the mirror surface transfer processing, the opening of the light-transmitting portion can be made uniform. The rate can be certainly increased to 90% or more. Regarding the primary processed products, 2
Since the mirror surface transfer processing by the next processing and the narrowing processing of the non-light transmitting portion area are performed at the same time, the transfer processing and molding processing accuracy can be improved. The processing precision of these is high and the variations are small. Therefore, the lens pitch is 1 mm or less, the aperture ratio is 90% or more, and the lens shape accuracy is 0.1 μm or less, high resolution and high light utilization rate (brightness). The above-mentioned light-transmitting portion in the array-shaped plastic optical element composed of the light-transmitting portion and the non-light-transmitting portion can be highly and easily molded, and the transfer processing and the narrowing of the non-light-transmitting portion region can be performed. Since the processing cycle of processing is shortened, the processing efficiency is improved, and since two molding processes are performed by a single molding device, the equipment cost of these processing devices can be reduced.

2. When the material of the non-light transmitting portion has a lower softening point than the material of the light transmitting portion, the non-light transmitting portion having a lower softening point is higher than the light transmitting portion having a higher softening point. Since it is laminated by injection molding, the thermal influence on the light transmitting portion due to the lamination molding of the non-light transmitting portion is suppressed as much as possible, and the quality of the composite precision optical element is improved accordingly.

3. The effect of the invention according to claim 3 When the light transmitting portion is pressed by the mold while being heated to the softening temperature or higher, the transfer process is performed by the mold and the lateral bulge causes a decrease. The non-light transmitting part in the viscous state is laterally pressed. This lateral compression on the non-light-transmitting portion uniformly narrows the non-light-transmitting portion, so that the non-light-transmitting portion is smoothly stretched in the longitudinal direction with a low pressure. Therefore, the residual strain of the light transmitting portion due to the non-light transmitting portion due to the applied pressure is reduced as much as possible, and a composite precision optical element having high molding accuracy and optical characteristics can be obtained.

4. The effect of the invention according to claim 4 preheats the non-light-transmitting portion to a required temperature by irradiation with light,
Then, by contact heating with a mold, while heating the light-transmissive portion and the non-light-transmissive portion above the softening temperature,
Since the non-light-transmitting portion can be heated to a temperature higher than that of the light-transmitting portion, the non-light-transmitting portion can be easily and smoothly constricted under low resistance during transfer processing to the light-transmitting portion by the mold.

5. Advantageous Effects of the Invention According to Claim 5, Pre-heating of the non-light-transmitting portion due to light irradiation is effectively performed, and therefore, the non-light-transmitting portion can be swiftly specified while suppressing the temperature rise of the light-transmitting portion due to the pre-heating as much as possible. It can be heated to temperature. Therefore, the preheating cycle is shortened and the productivity is improved.

6. Effect of the Invention According to Claim 6 Since the base material of the non-light-transmitting portion is the same as that of the light-transmitting portion, variations in temperature distribution and internal stress between the light-transmitting portion and the non-light-transmitting portion are less likely to occur, and therefore high precision and high accuracy are achieved. Mirror transfer of the shape is realized. In addition, since there is no difference in the refractive index between the light transmitting portion and the non-light transmitting portion, internal reflection of the optical element (at the boundary surface between the light transmitting portion and the non-light transmitting portion) is performed regardless of the incident angle of light. Reflection) is almost completely suppressed. Furthermore, since there is no difference in the coefficient of thermal expansion and the amount of absorbed water between the light transmitting portion and the non-light transmitting portion, variations in internal stress of the optical element due to changes in environmental conditions such as temperature and humidity do not occur. Therefore, it is possible to obtain a complex precision optical element having high shape accuracy regardless of changes in environmental conditions.

7. The material of which the effect of the invention according to claim 7 is similar to the refractive index is other physical properties (shrinkage rate,
Since the thermal conductivity and the thermal deformation temperature are similar, the refractive index is similar to that of the light transmitting part and the non-light transmitting part. Therefore, other physical properties (shrinkage rate, thermal conductivity, thermal deformation) are similar. Temperature etc.)
Is also close. Therefore, variations in the temperature distribution and the internal stress distribution between the two are unlikely to occur, and as a result, the mirror surface transfer processing of a highly accurate shape is performed. Further, since the difference in the refractive index between the materials of the light transmitting portion and the non-light transmitting portion is 0.1 or less, the internal reflection of the optical element is almost completely suppressed by forming the aperture shape with the incident angle being restricted to the minimum. can do.

8. The effect of the invention according to claim 8 Since the carbon black powder has high light absorption, the heat generation effect by the light irradiation of the non-light transmitting portion is high. Also, because it has a good compatibility with plastic materials, it is uniformly dispersed and mixed,
The heat generated by light irradiation is uniform, and since the carbon black powder is mixed, the fluidity is increased, so that the constriction processing of the non-light-transmitting portion is facilitated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a state of internal reflection in a conventional complex precision optical element.

FIG. 2 is a perspective view showing an arrangement of light transmitting portions and non-light transmitting portions in a molding process of a conventional composite precision optical element.

FIG. 3 is a perspective view of a composite precision optical element according to the prior art.

FIG. 4 is a perspective view of another prior art compound precision optical element.

FIG. 5 is a perspective view of a composite optical member schematically showing the two-step processing of the present invention.

FIG. 6 is a cross-sectional view schematically showing the manner of working in the second working process of the present invention.

FIG. 7 is a cross-sectional view schematically showing another aspect of processing by the secondary processing step of the present invention.

FIG. 8 is a cross-sectional view schematically showing the manner of processing in the secondary processing step when the method of heating the non-light-transmitting portion by light irradiation is used.

FIG. 9 is a perspective view showing a processing step of the embodiment of the present invention.

FIG. 10 is a perspective view of a precision composite precision optical element of the example.

11A is a perspective view schematically showing a pressing direction in a secondary processing step in the example, and FIG. 11B is a cross-sectional view showing a heating state during light irradiation in the secondary processing step. It is a figure and (c) is sectional drawing which shows the pressurization state of the said secondary process process.

[Explanation of symbols]

1,2: Lens 3: Prism 10: Light transmission part 11: Non-light transmitting part 11a: relief section 15: Lens mirror piece 16: Prism mirror surface piece

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Claims (10)

[Claims] 1. A method of manufacturing a precision composite optical element comprising a light-transmitting portion having a mirror surface and a non-light-transmitting portion for absorbing light between adjacent light-transmitting portions and around the light-transmitting portion, wherein a substantially final shape is formed. Method of manufacturing complex precision optical element by step (primary processing step) and step (secondary processing step) of simultaneously constricting the non-light-transmitting portion region and transferring the mirror surface shape to the light-transmitting portion surface . 2. The method of processing in the above-mentioned primary processing step is a method of injection-molding (primary molding) a light-transmitting portion and then injection-molding (secondary molding) a non-light-transmitting portion on the primary molded product. 2. The method for manufacturing a complex precision optical element according to claim 1. 3. The processing method of the secondary processing step comprises: after the primary processing step, a non-light-transmitting portion having a lower viscosity than the light-transmitting portion and a light-transmitting portion heated to a softening temperature or higher, By pressing the light-transmitting portion with a mold having a mirror surface, the light-transmitting portion is deformed to widen the area, and the non-light-transmitting portion is stretched by the deformation of the light-transmitting portion to narrow the area, and 2. The method for producing a complex precision optical element according to claim 1, wherein the method is a method of transferring a mirror surface shape to the surface of the transmission part, cooling the surface to a temperature not higher than the thermal deformation temperature, and then taking it out from the mold. 4. The processing method of the secondary processing step is such that the light-transmitting portion and the non-light-transmitting portion are heated by irradiation with light having a wavelength that is absorbed by the non-light-transmitting portion and generates heat at a high temperature and contact heating from a mold. The light-transmitting portion is deformed by increasing the temperature above the softening temperature and increasing the temperature of the non-light-transmitting portion compared to the light-transmitting portion, and pressing at least the light-transmitting portion with a mold having a mirror surface. Then, the region is expanded, the non-light-transmitting part is stretched by the expansion to narrow the region, and a mirror-like shape is transferred to the surface of the light-transmitting part, cooled to a temperature below the heat deformation temperature, and then taken out from the mold. 2. The method for manufacturing a complex precision optical element according to claim 1. 5. The method of irradiating light is a method of irradiating the non-light-transmitting portion with light having a wavelength having a high absorptivity in the non-light-transmitting portion and having a high heat generation effect. Manufacturing method of complex precision optical element. 6. The method for manufacturing a complex precision optical element according to claim 1, wherein the non-light-transmitting portion is a non-light-transmitting member in which a material that absorbs light is dispersed in the same material as the light-transmitting portion. . 7. The non-light transmissive portion is a non-light transmissive member in which a material that absorbs light is dispersed in a material having a refractive index difference from the light transmissive portion of 0.1 or less. 1. A method for manufacturing the composite precision optical element of 1. 8. The method for manufacturing a complex precision optical element according to claim 6, wherein the material that absorbs light dispersed in the non-light transmitting portion is carbon black powder. 9. A composite precision optical element manufactured by the manufacturing method according to claim 1. 10. A composite precision optical element comprising a light-transmitting portion having a mirror surface and a non-light-transmitting portion that absorbs light between adjacent light-transmitting portions and its periphery, wherein the thickness of the non-light-transmitting portion is large. A complex precision optical element having a diameter of 0.08 mm or less.