JP2010145730A - Method for producing optical ceramic lens and optical ceramic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical ceramic lens, in which the efficiency in a production process is made high and the production cost of the optical ceramic lens is reduced. <P>SOLUTION: The method for producing the optical ceramic lens 1 includes steps of: fabricating a powdery raw material to prepare a temporarily-molded article; subjecting the temporarily-molded article to hot press molding to form such a lens array 10 that a plurality of optical ceramic lenses are arranged collectively; and dividing the lens array 10, for example, by using a vertical tangent line 6 or a horizontal tangent line 7 as a boundary to obtain the optical ceramic lenses 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical ceramic lens manufacturing method and an optical ceramic lens.

  For example, in home appliances such as an air conditioner or home security equipment installed in a house or the like, a sensor that detects the location of a person may be used. In such a sensor, an optical ceramic lens for collecting infrared rays or the like is used. Conventionally used optical ceramic lenses have a diameter of the optical curved surface portion in the direction along the main surface of about 6 mm to 30 mm. Here, the main surface refers to the surface having the largest projected area among the surfaces in the respective directions of the optical ceramic lens.

  However, in order to arrange the sensor in the above-described home appliances and home security equipment, it is necessary to downsize the sensor. For this reason, it is required to reduce the size of the optical ceramic lens used in the sensor. Specifically, it is required to provide an optical ceramic lens in which the diameter of the optical curved surface portion in the direction along the main surface is about 1 mm to 5 mm.

For example, as disclosed in Patent Document 1 below, such an opto-ceramic lens is obtained by pressure-molding, for example, zinc sulfide (ZnS) powder as a molding object, and then pre-sintering a temporary molded product. It is formed by pressure molding while heating using a mold composed of an upper mold and a lower mold.
JP 2006-45038 A

  As described above, when an optical ceramic lens is formed using, for example, zinc sulfide powder as a raw material, powder pressing and temporary firing are first performed in order to form the raw material powder into a desired shape. The powder used here may be granulated as a pretreatment. Thus, after forming the temporary molded product which has a shape close | similar to a desired shape, in order to shape | mold this into the final desired shape, the hot mold shaping which applies temperature and pressure simultaneously is performed. For example, when an optical ceramic lens is formed using the mold disclosed in Patent Document 1, only one optical ceramic lens can be formed by one molding, which may lead to a decrease in production efficiency and high cost. There is. For this reason, for example, in the case of mass-producing an optical ceramic lens, there is a limit to improving the production efficiency of the optical ceramic lens.

  On the other hand, in the case of a small lens as described above, a large number of lenses can be arranged independently in the mold. If a large number of lenses are arranged independently, the quality variation of the temporary molded product and the error in the arrangement are reflected, and the quality variation of the obtained optical ceramic lens tends to increase. It is difficult to produce with high efficiency. As described above, it has been difficult to achieve both quality and cost.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an optical ceramic lens manufacturing method formed by processing a powder raw material, which can improve production efficiency and reduce costs, and It is to provide an optoceramic lens formed using a manufacturing method.

  The method of manufacturing an optical ceramic lens according to the present invention includes a step of processing a powder raw material to prepare a temporary molded product, and a lens in which a plurality of optical ceramic lenses are collectively arranged by hot press molding the temporary molded product An optical ceramic lens manufacturing method comprising the steps of forming an array and obtaining an optical ceramic lens by dividing the lens array.

  The process of preparing the above-mentioned powder raw material to prepare a temporary molded product is, for example, for forming a powder adjusted by granulation into a temporary shape in order to form the raw material powder into a desired shape. It refers to the step of performing powder pressing and pre-baking. A lens array is a plurality of lenses having the same shape and size arranged in a two-dimensional direction along a predetermined plane, that is, one direction and two directions intersecting the one direction. The lens is arranged in the shape of an assembly of lenses formed by doing so.

  That is, in the method of manufacturing an optical ceramic lens according to the present invention, a temporary molded product is hot press-molded using a molding die in which a plurality of molding surfaces corresponding to individual optical ceramic lenses are arranged in a two-dimensional direction. Thus, a lens array having a shape as an optical ceramic lens arranged in a two-dimensional direction can be formed. Then, the lens array is divided into portions for forming the optical ceramic lens, for example, by dicing with a diamond blade. In this way, the number of optical ceramic lenses equal to the number of molding surfaces arranged in the molding die can be obtained by performing the press molding process using the molding die described above only once. Therefore, if the method for producing an optical ceramic lens according to the present invention is used, it is possible to produce an optical ceramic lens with higher efficiency than in the case of using a conventional method in which only one optical ceramic lens can be formed by one treatment. For this reason, the cost of the said optical ceramic lens can be reduced.

  In the above-described optical ceramic lens manufacturing method, the raw material powder is preferably zinc sulfide powder having a purity of 99% or more. By forming an optical ceramic lens using zinc sulfide, it is possible to provide an optical ceramic lens that transmits infrared rays used for the sensor at a high rate.

  In the step of forming the lens array in the above-described method of manufacturing an optical ceramic lens, the circular diameter in plan view of the optical curved surface portion of the optical ceramic lens is made smaller than the distance between the centers of adjacent optical ceramic lenses in the lens array. It is preferable that a lens array is formed on the surface.

  If the arrangement of the lens array is as described above, it is arranged next to the circular shape in plan view of the optical curved surface portion, which is an effective portion that acts as a lens of one optical ceramic lens to be formed, and next to the one optical ceramic lens. There is a gap region that is not used as an optical ceramic lens between the circular shape in plan view of the optical curved surface portion of another optical ceramic lens. Here, the circular shape in plan view of the optical curved surface portion is a circular shape formed by the outer peripheral portion of the optical curved surface portion when the optical curved surface portion is viewed from a direction intersecting the main surface on which the optical curved surface portion is disposed. Say. In this case, for example, when the lens array is divided into individual optical ceramic lenses by dicing, the region that can be divided is the entire gap region that is not used as the above-described optical ceramic lens. Therefore, for example, compared with the case where the gap does not exist, the range in which the division can be performed is widened, and the division processing can be easily performed. As a result, since an optical ceramic lens can be produced with higher efficiency, the cost of the optical ceramic lens can be further reduced.

  In the step of forming the lens array in the above-described method of manufacturing an optical ceramic lens, the circular diameter in plan view of the optical curved surface portion of the optical ceramic lens is made equal to the distance between the centers of adjacent optical ceramic lenses in the lens array. A lens array may be formed.

  If the arrangement of the lens array is as described above, it is arranged next to the circular shape in plan view of the optical curved surface portion, which is an effective portion that acts as a lens of one optical ceramic lens to be formed, and next to the one optical ceramic lens. There is no gap area that is not used as an optical ceramic lens between the optical curved surface portion of another optical ceramic lens in a plan view. Therefore, it is possible to increase the ratio of the region that can be effectively used for obtaining the optical ceramic lens in the lens array, and to further increase the number of the optical ceramic lenses that can be obtained by one processing. Therefore, since the optical ceramic lens can be produced with higher efficiency, the cost of the optical ceramic lens can be further reduced.

  In the step of forming the lens array in the above-described method of manufacturing an optical ceramic lens, the circular diameter of the optical curved surface portion of the optical ceramic lens in plan view is larger than the distance between the centers of adjacent optical ceramic lenses in the lens array. A lens array may be formed.

  If the arrangement of the lens array is as described above, it is arranged next to the circular shape in plan view of the optical curved surface portion, which is an effective portion that acts as a lens of one optical ceramic lens to be formed, and next to the one optical ceramic lens. The circular shape in plan view of the optical curved surface portion of the other optical ceramic lens partially overlaps. Therefore, in this case, for example, as compared to the case where the lens array is formed so that the circular diameter in plan view of the optical curved surface portion is equal to the distance between the centers of the adjacent optical ceramic lenses in the lens array, for example, Since the area occupied by one optical curved surface portion is reduced, a larger number of optical curved surface portions can be formed from a lens array having the same diameter.

  The optical ceramic lens according to the present invention is manufactured by using the above-described optical ceramic lens manufacturing method. In this case, it is possible to obtain an optical ceramic lens having a manufacturing cost reduced as compared with the prior art.

  According to the method for producing an optical ceramic lens of the present invention, an optical ceramic lens can be produced with high efficiency, and the cost of the optical ceramic lens can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, elements having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

  FIG. 1 is a flowchart showing a method for manufacturing an optical ceramic lens according to an embodiment of the present invention. The opto-ceramic lens according to the present embodiment is used, for example, in a human sensor that detects the location of a human being to detect infrared rays emitted from the sensor by collecting reflected light reflected by the human body. It is a lens.

As a method for producing the optical ceramic lens, first, a raw material preparation step (S10) is performed as shown in FIG. Specifically, this is a step of preparing a raw material to be a base constituting the optical ceramic lens. The optical ceramic lens manufacturing method is a method of forming an optical ceramic lens by processing a powder raw material. For example, it is preferable to use zinc sulfide (ZnS) powder. Instead of zinc sulfide, for example, calcium fluoride (CaF ₂ ), YAG (3Y ₂ O ₃ .5Al ₂ O ₃ ), magnesium oxide (MgO), spinel (MgAl ₂ O ₄ ), yttrium oxide (Y ₂ O The powder of ₃ ) may be used. If these raw material powders are used, it is possible to form an optical ceramic lens having good transparency to light rays such as infrared rays used in the sensor.

  In addition, the powder raw material for forming the above-mentioned optical ceramic lens is prepared by performing a granulation process, which is a process for adjusting the size, shape and purity suitable for the intended use as a solid substance. You may perform the process which refines the powder grain of a raw material, and the process which adds an impurity. In this way, it is possible to obtain a powder raw material having a desired size and purity, such as zinc sulfide powder having a purity of 99.7% and an average particle diameter of 2 μm.

  Then, a powder press process (S20) and a temporary baking process (S30) are implemented. In the case of the step of forming by processing the powder raw material as in the method of manufacturing the optical ceramic lens according to the present embodiment, before performing the step of forming the powder raw material to have a desired shape, the powder raw material It is preferable to perform a process of processing so as to form a temporary molded product (solid lump) having a temporary shape. For this reason, it is preferable to perform a powder press process (S20) and a temporary baking process (S30) in this Embodiment. By performing the powder pressing step (S20) and the pre-baking step (S30), it is possible to easily perform processing with higher accuracy in the step of forming a lens array corresponding to the product shape later. In addition, the temporary molded product formed here may be a flat plate shape whose main surface is circular, for example, or may be a flat plate shape whose main surface is rectangular or elliptical. Or you may form the said temporary molded product so that it may become a near net shape which has a form close | similar to the optical curved surface part which the optical ceramic lens to form has.

  The above-described powder pressing step (S20) is preferably performed by applying a certain pressure to the powder raw material by, for example, double-shaft cold mold press molding. The treatment is performed at room temperature, and the applied pressure is, for example, 50 MPa when the powder is zinc sulfide, 150 MPa when the powder is, for example, spinel, YAG, or magnesium oxide. Any pressure required to shape can be used. In the temporary firing step (S30), the temporary molded product formed in the powder pressing step (S20) is put into a vacuum furnace and, for example, when the powder is zinc sulfide, the temperature is 700 ° C. or higher and 900 ° C. or lower. Arbitrary temperature and time conditions necessary for making a temporary molded product can be used, such as heating for about 5 hours and heating to 1500 ° C. when the powder is spinel, YAG, or magnesium oxide. Here, it is preferable that the vacuum furnace has a vacuum degree of 0.1 Torr or less.

  More specifically, first, a temporary molded product subjected to the above-described pressing is put into a vacuum furnace. Here, when moisture and impurities contained in the temporary molded product are preferentially removed, it is preferable that the vacuum furnace has a vacuum degree of 0.1 Torr or less. Further, when preferentially uniformizing the heating of the temporary molded product, the treatment may be performed while introducing an inert gas such as argon or nitrogen into the vacuum furnace. It is preferable to select the degree of vacuum in the vacuum furnace and the conditions for introducing the gas depending on which of the above-mentioned preferential treatments is performed for the temporary molded product.

  The temporary firing step (S30) is performed to remove moisture and volatile impurities in the powder press after the powder pressing step (S20) and ensure the strength of the temporary molded product. When the amount of is originally small, or when the preliminary baking step is performed in the subsequent hot molding step (S40), the preliminary baking step (S30) may be omitted.

  By performing the above steps, it is possible to form a temporary molded product for facilitating processing from a powder raw material into a desired optical ceramic lens shape.

  Subsequently, a hot molding step (S40) is performed as shown in FIG. Specifically, this is a step of raising the temperature of the provisional molded article prepared in the previous step in the mold, pressurizing it when reaching a certain temperature, and molding. A plurality of desired optical curved surfaces (molding surfaces) are formed on the molding die, and a lens array sheet on which a plurality of optical ceramic lenses are arranged can be formed by transferring them to a temporary molded product.

  In the hot molding step (S40), for example, an optical curved surface portion corresponding to the shape of the molding surface of the molding die is formed on the main surface of the temporary molding using a molding die such as a mold. In this process, a mold process is performed using a mold in which a plurality of molding surfaces corresponding to the surface shape of each optical ceramic lens are arranged in a two-dimensional direction. In this way, it is possible to form a surface shape in which the structures (optical curved surface portions) of the optical ceramic lens are collectively arranged in the two-dimensional direction on the main surface of the temporary molded product. As a result, it is possible to form a fly-eye lens-like lens array in which a plurality of optical ceramic lenses are arranged in a two-dimensional direction. In addition, the size of the temporary molded product contracts mainly in the press axis direction and becomes thin by heat sintering in the hot molding step (S40).

  Here, the hot molding step (S40) is a step of performing hot press molding, which has both the function of heating and sintering the temporary molded product and the function of finishing the temporary molded product into a desired shape (lens array) using a mold. It is. The step of performing the pressing in the hot molding step (S40) is performed by using, for example, the mold for forming the lens array described above and applying a pressure of, for example, 50 MPa to the main surface of the temporary molded product. It can be performed using any pressure condition necessary for forming a lens array having a desired shape and size on the main surface of the temporary molded product with high accuracy.

  Here, for example, when the temporary molded product is made of zinc sulfide, it is preferably heated at 900 ° C. to 1000 ° C. for 30 seconds to 10 minutes. Further, for example, when the temporary molded product is made of spinel, it is heated to 1650 ° C, for example. As described above, the heating can be performed using any heating conditions necessary for forming a lens array having a desired shape and size on the main surface of the temporary molded product with high accuracy.

  The application of the pressing pressure in the hot molding step (S40) is basically performed at a temperature at which sintering and plastic deformation of the temporary molded product occur. However, if there is no problem with the strength of the temporary molded product, pressure may be applied before heating.

  FIG. 2 is a schematic plan view of a lens array in which individual optical curved surface portions are arranged in a hexagonal lattice shape. FIG. 3 is a schematic plan view of a lens array in which individual optical curved surface portions are arranged in a square lattice pattern. FIG. 4 is a schematic plan view of a lens array in which a part of each optical curved surface portion arranged in a square lattice shape overlaps. On the main surface of the temporary molded product (circular main surface in FIGS. 2 to 4), an optical curved surface portion (the optical ceramic lens 1 in FIGS. 2 to 4) that is an effective portion as the plurality of optical ceramic lenses 1. When the lens array 10 is formed by forming a circular inner region), a plurality of optical ceramic lenses 1 may be arranged so as to form a hexagonal lattice as shown in FIG. As shown in FIG. 3, they may be arranged so as to form a substantially square lattice. Further, among the lens arrays 10 arranged so as to form a substantially square lattice, they may be arranged more densely than FIG. 3 as shown in FIG.

  The plurality of vertical tangent lines 4 and oblique tangent lines 5 of the optical ceramic lens 1 in FIG. 2 are arranged such that the shape of the region surrounded by these vertical tangent lines 4 and oblique tangent lines 5 is a hexagon. Further, the plurality of vertical tangent lines 6 and horizontal tangent lines 7 of the optical ceramic lens 1 in FIG. 3 are arranged so that the shape of the region surrounded by the vertical tangent lines 6 and the horizontal tangent lines 7 is a square. Also, the plurality of vertical lines 11 and horizontal lines 12 of the optical ceramic lens 1 in FIG. 4 are straight lines connecting the intersections of the circumferences of the optical ceramic lens 1 that are superimposed on the plan view of FIG. They are arranged to form a square lattice.

  That is, it is preferable to perform the hot molding step (S40) using a molding die in which a plurality of molding surfaces are arranged so that the lens array 10 as shown in FIGS. 2 to 4, the circular diameter in plan view in the direction along the main surface of the lens array 10 formed by the optical curved surface portion of each optical ceramic lens 1 is the size of the optical ceramic lens 1 to be formed. In addition, the thickness is preferably set to 1 mm or more and 5 mm or less.

  FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. 6 is a schematic sectional view taken along line VI-VI in FIG. 5 and 6, a part of the number of the optical ceramic lenses 1 actually arranged in each cross-sectional view is omitted.

  In the arrangement of the hexagonal lens array 10 in FIG. 2, the circular outer peripheral portions in plan view of the optical curved surface portions of the individual optical ceramic lenses 1 are in direct contact with each other even if they are arranged next to each other. Not done. More specifically, as shown in the cross-sectional view of FIG. 5, the circular diameter D in the plan view of the optical curved surface portion of the optical ceramic lens 1 is the center distance LR ( The distance between the centers of the optical curved surface portions of the adjacent optical ceramic lenses 1 is smaller.

  More specifically, the center-to-center distance LR is the distance between the centers of, for example, spherical surfaces formed by the optical curved surface portions of the adjacent optical ceramic lenses 1, in other words, the adjacent optical ceramic lenses 1 in the plan views shown in FIGS. This is the distance between the centers of the circles. As shown in FIG. 5, an optical curved surface portion that is an effective portion that functions as a lens of one optical ceramic lens 1, and an optical curved surface portion of another optical ceramic lens 1 arranged next to the one optical ceramic lens 1 The lens array 10 may be formed so that there is a gap region 2 that is not used as an optical ceramic lens. In this way, when the lens array 10 is divided into the individual optical ceramic lenses 1 in the subsequent process, the dividing area 8 (that is, the dividing line 8 that is a position to be divided by a method such as dicing) is formed. The region that can be arranged) is the entire gap region 2. Therefore, if the gap region 2 is provided, the range in which the division can be performed is wider than that in the case where the gap region 2 does not exist, and therefore the division operation can be easily performed. As a result, the optical ceramic lens 1 can be produced with higher efficiency, and the cost of the optical ceramic lens 1 can be further reduced.

  On the other hand, in the arrangement of the rectangular lattice-shaped lens array 10 in FIG. 3, among the individual optical ceramic lenses 1, the circular outer peripheral portions in a plan view of the optical curved surface portion are in contact with each other. . The vertical tangent 6 and the horizontal tangent 7 in FIG. 3 are tangents formed by connecting the circular contacts formed by the adjacent optical ceramic lenses 1. More specifically, as shown in the sectional view of FIG. 6, the circular diameter D formed by the optical curved surface portion of the optical ceramic lens 1 in the direction along the main surface of the lens array 10 is adjacent to the optical element in the lens array 10. The distance LR between the centers of the ceramic lenses 1 is equal to the distance between the centers formed by the optical curved surface portions of the adjacent optical ceramic lenses 1.

  In the case of the lens array 10 shown in FIGS. 3 and 6, since the gap region 2 as shown in FIG. 5 does not exist, the ratio of the region that can be effectively used to obtain the optical ceramic lens 1 in the temporary molded product is increased. The number of the optical ceramic lenses 1 that can be obtained by one treatment can be further increased. Therefore, the optical ceramic lens 1 can be produced with higher efficiency, and the cost of the optical ceramic lens 1 can be further reduced.

  Further, in the arrangement of the lens array in FIG. 4, among the individual optical ceramic lenses 1, the circular outer peripheral portions in plan view of the optical curved surface portions of those arranged adjacent to each other overlap. That is, a part of the optical curved surface portions arranged next to each other overlap each other. Therefore, the arrangement of the lens array 10 in FIG. 4 is such that the individual optical ceramic lenses 1 are arranged more densely than the arrangement of the lens array 10 in FIG. More specifically, referring to FIG. 4 and FIG. 7, the circular diameter D in the plan view of the optical curved surface portion of the optical ceramic lens 1 is the distance LR (center-to-center between adjacent optical ceramic lenses 1 in the lens array 10. The distance between the centers formed by the optical curved surface portions of the adjacent optical ceramic lenses 1 is larger. In the case of FIG. 4 (FIG. 7), the center-to-center distance LR is equal to the distance between the adjacent vertical line 11 and horizontal line 12.

  FIG. 7 is a three-dimensional perspective view in which the region VII in FIG. 4 is enlarged. As shown in FIG. 7, the arrangement of the lens array 10 in FIG. 4 is such that, for example, the optical curved surface portion of each optical ceramic lens 1 in the lens array 10 in FIG. 3 is arranged on a plane along the main surface of the lens array 10. It is moved in the direction along the vertical line 11 or the horizontal line 12 and arranged so that parts of the optical curved surface portions of the adjacent optical ceramic lenses 1 overlap each other. Therefore, the lens array 10 in FIG. 4 can have a larger number of optical curved surface portions of the optical ceramic lens 1 than the lens array 10 in FIG. That is, in the case of the lens array 10 shown in FIGS. 4 and 7, the number of the optical ceramic lenses 1 that can be obtained from one lens array 10 can be further increased as compared with the lens array 10 shown in FIGS. 3 and 6. it can. Therefore, the optical ceramic lens 1 can be produced with higher efficiency, and the cost of the optical ceramic lens 1 can be further reduced.

  4 and 7, the circular shape of the optical curved surface portion of the optical ceramic lens 1 is superimposed in both the direction of the vertical line 11 and the direction of the horizontal line 12 intersecting with the vertical line 11. However, the circular shape of the optical curved surface portion is overlapped only in one of the direction of the vertical line 11 or the direction of the horizontal line 12, and the other direction has an arrangement as shown in FIGS. 3 and 6, for example. The lens array 10 may be formed. Even in this case, the number of the optical ceramic lenses 1 that can be obtained from one lens array 10 can be further increased as compared with the lens array 10 shown in FIGS.

  The optical ceramic lens 1 obtained by the arrangement of the lens array 10 in FIGS. 4 and 7 has areas forming individual optical curved surface portions as compared to the optical ceramic lens 1 obtained by the arrangement of the lens array 10 in FIGS. Get smaller. However, the arrangement of the lens array 10 in FIGS. 4 and 7 is very effective when a sufficient lens is produced with a small optical curved surface due to the requirement of imaging accuracy.

  When the optical ceramic lens 1 having a desired shape and size can be formed into a fly-eye lens shape by the above method, a cleaning step (S50) is performed as shown in FIG. In this cleaning step (S50), any conventionally known cleaning method may be applied to remove foreign matter from the surface of the lens array 10. Thereafter, a process of coating a thin film on the surface of the optical curved surface portion of each optical ceramic lens 1 is performed by the AR coating step (S60). This thin film means that when the optical ceramic lens 1 is irradiated with light such as infrared rays so that the optical ceramic lens 1 is used for, for example, the human sensor described above, the infrared rays are not reflected on the surface of the optical ceramic lens 1. It is a thin film formed in order to suppress the occurrence of a phenomenon of reflection that is necessary. Note that these steps (S50) and step (S60) may be omitted.

  Then, a dividing step (S70) is performed. This is a process of dividing the lens array 10 into individual optical ceramic lenses 1. For example, a diamond blade having a thickness of about 50 to 200 microns is rotated at a high speed. For example, in the sectional view of FIG. 5, the dividing line 8 of the gap region 2 and in the sectional view of FIG. Cut at tangent 6 (and transverse tangent 7 in FIG. 3). Also, in the perspective view of FIG. In this way, the optical ceramic lenses 1 are individually divided from the lens array 10.

  As described above, the cutting process in the dividing step (S70) may be performed by dicing with a diamond blade. In particular, when emphasizing the outer tolerance and eccentricity of the formed optical ceramic lens 1, it is preferable to cut with a diamond blade having high positioning accuracy. The cutting speed at this time is preferably 3 mm / sec, for example. However, arbitrary conditions of 0.5 mm or more and 40 mm or less can be used depending on the thickness of the lens array 10. However, the dividing step (S70) may be performed using a method such as laser dicing, water jet, blade dicing using ultrasonic waves, electric discharge machining, etching, or the like instead of the above-described diamond blade dicing.

  For example, in the case of using a method in which one lens is formed by a single process as in the conventional manufacturing method, the powder pressing step (S20), temporary firing step (S30), and hot molding step (S40) in FIG. Must be repeated a number of times equal to the number of optical ceramic lenses 1 to be formed. However, in the case of using the manufacturing method of the present embodiment, although the dividing step (S70) is newly added, the above-described steps (S20), (regardless of the number of the optical ceramic lenses 1 formed from one lens array 10). If S30) and (S40) are performed once, the optical ceramic lens 1 equal to the number of optical curved surface portions included in one lens array 10 can be formed. Further, since the cleaning step (S50) and the AR coating step (S60) can be performed in the state of the lens array 10, the work is easier than when processing is performed for each single optical ceramic lens. Can be done. In particular, when the size of the optical ceramic lens is small, such an effect of improving workability is remarkable. Therefore, if all processes are considered comprehensively, using the manufacturing method of the present embodiment will increase the work efficiency and greatly reduce the cost of the product compared to the case of using the conventional manufacturing method. Can do.

  Further, in the case of a small lens, it is conceivable to develop a conventional manufacturing method, provide a plurality of lens surfaces on a mold, arrange independent temporary molded products, and perform hot molding. In that case, since the temporary molded product is independent, the influence of the variation in the shape and the set error on the mold is large, and the quality variation of the formed optical ceramic lens may be large. However, when the manufacturing method of the present embodiment is used, it is possible to simultaneously mold a large number of optical ceramic lenses 1 as an integrated sheet by a single process. For this reason, the quality deviation between the individual optical ceramic lenses 1 to be formed depends on the accuracy of the molding surface of the mold. Therefore, it is possible to minimize deviations in quality such as shape accuracy and light transmittance in the optical curved surface portion formed in the hot molding step (S40) for forming the optical curved surface portion. In particular, when the size of the optical ceramic lens 1 is small, such a quality stabilizing effect becomes remarkable.

  Furthermore, in the manufacturing method of the present embodiment, the lot is managed as the lens array 10 until the last division step (S70), and the lot is not divided into individual lenses. For this reason, the management of the product in the middle of a manufacturing process becomes easy.

  Moreover, if the manufacturing method of this Embodiment is used, the quality of the optical ceramic lens 1 formed can be stabilized. For this reason, if the cutting in the dividing step (S70) is performed with a precise positioning, it is performed after forming the individual optical ceramic lenses 1, for example, to reduce deviations in product quality such as a centering step. Processing can be omitted. Also from this fact, by using the manufacturing method of the present embodiment, it is possible to increase work efficiency as compared with the case of using the conventional manufacturing method.

  By the above procedure, a plurality of optical ceramic lenses 1 having desired dimensions and shapes are formed. Here, the formed optical ceramic lens 1 will be described in detail. Each divided optical ceramic lens 1 is divided by, for example, the dividing line 8 or the longitudinal tangent 6 in FIGS. 5 and 6.

  By the way, for example, if a mold for forming the lens array 10 is used only on one main surface (upper side in FIGS. 5 to 7) of the temporary molded product, as shown in the sectional views of FIGS. The optical ceramic lens 1 having convex curved surfaces 1a and 1c as optical curved surface portions is formed only on one side (upper side in FIGS. 5 to 7). In this case, no optical curved surface portion is formed on the lower main surface of the optical ceramic lens 1 in FIGS. 5 to 7, and the flat surface 9 forming the main surface of the temporary molded product is the optical ceramic lens 1. One main surface is constituted.

  The optical ceramic lens 1 may be a plano-convex lens having an optical curved surface portion only on one main surface of a temporary molded product, which can be formed by individually dividing the above-described forms shown in FIGS. Good. However, for example, if the mold is used for both one main surface of the temporary molded product and the other main surface (the upper side and the lower side in FIGS. 5 to 7) opposite to the one main surface, both main surfaces are used. An optical ceramic lens 1 having an optical curved surface portion on the surface is formed. Therefore, the optical ceramic lens 1 may be a biconvex lens having optical curved surface portions on both main surfaces. Alternatively, the optical ceramic lens 1 may be a meniscus lens having an optical curved surface portion on one main surface and a concave shape portion bent in the opposite direction to the optical curved surface portion on the other main surface. Furthermore, the optical ceramic lens 1 may be a biconcave lens having concave portions on the main surfaces on both sides. FIG. 8 is a cross-sectional view of the optical ceramic lens 1 divided from the lens array of FIG. 2 having optical curved surface portions on both main surface sides in a direction intersecting the main surface. 9 is a cross-sectional view of the optical ceramic lens 1 divided from the lens array of FIG. 3 (FIG. 4) having optical curved surface portions on both main surface sides in a direction intersecting the main surface.

  An optical ceramic lens 100 shown in FIG. 8 is formed from a lens array (see FIGS. 2 and 5) arranged so as to include the gap region 3. The cross-sectional view in FIG. 8 is a cross-sectional view of the optical ceramic lens 100 cut substantially parallel to the longitudinal tangent line 4 or the oblique tangent line 5 as seen from the direction intersecting the main surface. Then, a convex curved surface 1a as an optical curved surface portion is arranged on the upper side in FIG. 8, and a convex curved surface 1b as an optical curved surface portion is arranged on the lower side in FIG. . The left end and the right end in FIG. 8 are dividing lines 8 divided from the lens array in the dividing step (S70).

  On the other hand, the optical ceramic lens 200 shown in FIG. 9 is formed from a lens array that does not include a gap region (see FIGS. 3, 4, 6, and 7). 9 is a cross-sectional view of the optical ceramic lens 200 cut substantially parallel to the vertical tangent line 6 or horizontal tangent line 7 of FIG. 3 and the vertical line 11 or horizontal line 12 of FIG. 4 as viewed from the direction intersecting the main surface. It is. A convex curved surface 1c as an optical curved surface portion is arranged on the upper side in FIG. 9, and a convex curved surface 1d as an optical curved surface portion is arranged on the lower side in FIG. . The left end and the right end in FIG. 9 are the vertical tangent line 6 or the horizontal tangent line 7 divided from the lens array in the dividing step (S70). The optical ceramic lens 1 as shown in FIGS. 8 and 9 can also be manufactured using the manufacturing method according to the present invention described above.

  The convex curved surfaces 1a, 1b, 1c, and 1d shown in FIGS. 5 to 9 may be spherical surfaces, but may be aspherical surfaces or diffractive surfaces, for example.

  Below, an example of the optical ceramic lens formed in the manufacturing method of this Embodiment described above is demonstrated. The lens array 10 is, for example, a sheet whose main surface is a circle having a diameter of 50 mm. Then, on the main surface of the lens array 10, for example, the optical ceramic lenses 1 arranged in a square lattice shape as shown in FIG. 4 so that the interval between the adjacent vertical lines 11 and horizontal lines 12 is 2 mm are arranged in 17 rows × 17 columns. = 289. The optical curved surface portion of the optical ceramic lens 1 is a plano-convex lens in which one main surface is a spherical surface having a radius of 3 mm and the other main surface is a plane, and the thickness (center thickness) at the highest (largest) portion of the optical curved surface portion is 2 mm. The PV value, which is the width between the maximum value and the minimum value of the deviation from the design value of the optical curved surface portion, is 1.5 μm. The lens array 10 thus formed with the optical curved surface portion has the optical curved surface portion shown in the perspective view of FIG. By dividing this into individual optical ceramic lenses, a square lens is formed.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly excellent as a technique for improving efficiency and reducing costs in the manufacturing process of an optical ceramic lens.

It is a flowchart which shows the manufacturing method of the optical ceramic lens which concerns on embodiment of this invention. It is a schematic plan view of a lens array in which individual optical curved surface portions are arranged in a hexagonal lattice shape. It is a schematic plan view of a lens array in which individual optical curved surface portions are arranged in a square lattice pattern. It is a schematic plan view of a lens array in which a part of each optical curved surface portion arranged in a square lattice shape overlaps. FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. 2. FIG. 4 is a schematic sectional view taken along line VI-VI in FIG. 3. It is the three-dimensional perspective view which expanded the area | region VII in FIG. It is sectional drawing in the direction which cross | intersects the main surface of the optical ceramic lens 1 divided | segmented from the lens array of FIG. 2 which has an optical curved surface part in both main surface sides. It is sectional drawing in the direction which cross | intersects the main surface of the optical ceramic lens 1 divided | segmented from the lens array of FIG. 3 (FIG. 4) which has an optical curved surface part in both main surface sides.

Explanation of symbols

  1, 100, 200 Optical ceramic lens, 1a, 1b, 1c, 1d Convex curved surface, 2, 3 Gap region, 4, 6 Long tangent, 5 Diagonal tangent, 7 Horizontal tangent, 8 Dividing line, 9 Plane, 10 Lens array, 11 Vertical line, 12 Horizontal line.

Claims (6)

Processing the powder raw material to prepare a temporary molded product;
Forming a lens array in which a plurality of optical ceramic lenses are collectively arranged by hot press molding the temporary molded article;
Obtaining the optical ceramic lens by dividing the lens array.   The method for producing an optical ceramic lens according to claim 1, wherein the raw material powder is zinc sulfide powder having a purity of 99% or more.   In the step of forming the lens array, the lens array is formed such that a circular diameter of the optical curved surface portion of the optical ceramic lens in plan view is smaller than a center-to-center distance between adjacent optical ceramic lenses in the lens array. The method for producing an optical ceramic lens according to claim 1 or 2, wherein:   In the step of forming the lens array, the lens array is formed such that a circular diameter of the optical curved surface portion of the optical ceramic lens in plan view is equal to a center-to-center distance between adjacent optical ceramic lenses in the lens array. The method for producing an optical ceramic lens according to claim 1 or 2, wherein:   In the step of forming the lens array, the lens array is formed such that a circular diameter of the optical curved surface portion of the optical ceramic lens in a plan view is larger than a center-to-center distance between adjacent optical ceramic lenses in the lens array. The method for producing an optical ceramic lens according to claim 1 or 2, wherein:   The optical ceramic lens manufactured using the manufacturing method of any one of Claims 1-5.

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