JP2007091586A - Manufacture of optical component part for imaging lens system from melt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical component part, which is improved with respect to economical efficiency and the type of glass that can be processed. <P>SOLUTION: In the method for manufacturing the optical glass component part especially for an imaging optical system, a glass melt is allocated, and an allocated glass portion held by an allocating apparatus is supported on a floating cushion built on a floating support. The allocated glass portion is cooled, while being supported at the surface, until its viscosity reaches an adhesive viscosity or larger. At least a portion of the interior of the allocated glass portion has a viscosity no larger than that achieved at a softening point. The allocated glass portion is delivered to a press die and molded into a glass therein. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates generally to the manufacture of optical components, particularly imaging lens systems. The invention relates specifically to the production of optical components by thermoforming.

  The imaging lens system is incorporated for enlargement or reduction in an objective lens such as a camera, a projection device, a microscope, or a telescope. With regard to the quality of the enlarged or reduced imaging, there is always a growing demand. In this case, particularly sharpness, imaging fidelity and high resolution should be mentioned over the entire area of imaging. In parallel with this, imaging systems also require a strong reduction of the entire size, many times. An example of this is a digital camera and projection system integrated in a mobile phone. Imaging quality is often improved many times by special image processing software, but certainly these systems require high storage capacity and high energy consumption. Accordingly, a high standard is provided for the imaging properties of the optical module even in mass production. These criteria have so far been only partly guaranteed by special optical filters.

  The main requirement for imaging quality is the lens system. This means that not only reduction and enlargement need to be guaranteed, but also imaging defects need to be minimized or compensated, especially for the smallest possible objective lens size. These requirements can be met in particular by glass lens systems.

  Under these conditions, also for the mass market, high contour fidelity to the predicted contour, the possibility of economic creation of the desired aspherical contour, and the widest possible palette of different glasses, especially its refractive index The possibility of processing with respect to partial dispersion is particularly desirable. Additional requirements for such an imaging lens system manufacturing method are the low unit cost and the lot quantity of 1 for mass-produced products such as cameras in mobile phones, photographic video cameras, home theater projection systems, etc. It is to exceed 10,000.

The conventional method for manufacturing the imaging lens system is as follows.
1. Finish the green glass blank in the cooled or solidified state, such as allocation, grinding, and polishing.
2. For example, as described in Patent Document 1 and Patent Document 2, the glass preform is reheated in a press die and subsequently glass-molded.
3. For example, as described in Patent Document 3, Patent Document 4, and Patent Document 5, the glass preform or the glass soft mass is reheated on the outside of the press mold, and then in the preheated press mold. Glass molding with
4). For example, as described in Patent Document 6, it is directly formed from a glass melt by a hot forming method.

  In the case of grinding and polishing, the contour accuracy and economy of the aspheric contour depends on the size of the polishing tool and the number of optimized cycles. Contour accuracy> 5 μm is economical and suitable for the mass market, and this accuracy can be made with a large tool without optimized grinding. Contour accuracy of 1 μm or less can only be assured by introducing multiple minimum polishing tools and many optimization cycles for each individual lens. In this case, the manufacturing time and the cost corresponding to the manufacturing time are greatly increased to a range not suitable for profit. In particular, when high contour accuracy and high surface quality with roughness of 5 nm or less, that is, unevenness, are required, the final finishing must rely on more expensive methods such as ion beam etching. Further increases manufacturing costs.

  Furthermore, the choice of economical polishable glass for objective lenses for the end consumer area is limited to those that exhibit low thermal expansion. This makes it impossible to apply some types of glass having valuable optical properties, such as a special combination of refractive index and partial dispersion. Such glasses that are not meaningfully applicable to this method are, for example, fluoride crown glasses, fluoride phosphate glasses, and phosphate glasses, generally almost all modern optical glasses.

Reheating the glass preforms in the press mold and the subsequent glass mold represents a cheaper method than grinding and polishing for the production of the imaging lens system, but again the possible glass selection is economical. Limited from the point of view. The heating and cooling of the glass performed with the press mold defines process time and cost in this method. In this case, economics can only be achieved by introducing glass with a low transition point, in particular glass that can be extruded at 450 ° C. or below. Only in the case of this kind of glass, the heating time is short and sufficient. In the meantime, however, a series of glasses are known that exhibit the necessary properties with various optical constants, yet most optical glasses are still not economical to process in this way. In addition, most glasses with low transition points have insufficient surface stability against atmospheric humidity. Further, in the case of this method, the press mold is required not only with respect to the surface condition, contour accuracy, and long-term temperature fluctuation stability, but particularly in terms of hardness. The glass preform is placed in the mold in a cold and correspondingly hard state, where initially the contact surface between the glass and the mold is relatively small. The glass hardness during the entire deformation process is very high here. This is because the compressive viscosity of the glass is limited by the adhesive viscosity when the press mold is sufficiently heated (the glass and press mold adhere irreversibly together under this viscosity), which is 10 ⁸ dPa · s. It will be the best case. Processing such a material suitable for a hard precision press mold is time consuming and expensive. Thus, the cost of the processing mold can reach half of the total manufacturing cost of an imaging lens system manufactured in this format. In order to achieve high surface quality and contour accuracy in the case of a press, the pure and intact surface of the glass preform is the most important prerequisite. This precondition causes costly handling of glass preforms such as transport, cleaning, storage, and individual inspection. Long process times, high mold costs, narrow glass selection, and expensive handling of glass preforms limit the economics, shaping flexibility, and number of production in this method.

  The shortening of the process time and the increase in the life of the press die are the same as those described in Patent Document 3, Patent Document 4, and Patent Document 5, in order to restore the compressive viscosity of the glass preform outside the press mold to the compressive viscosity. Achieved by heating. There is no heating time in each press cycle, the press mold is preheated only at start-up, and no further large temperature exchanges will occur. The compressive viscosity is always still relatively high in this method as it is limited by the adhesive viscosity. In the case of reheating, the glass preform reaches the same temperature throughout the entire volume, or the outside is hotter than the inside. This is because heat acts on the glass from the outside and is transported inward only through the heat conduction of the glass. Therefore, the demand for material hardness for press dies is always high. The temperature stability of the ingot material with which the glass preforms are heated, and the structure of the packing and motion mechanism, also in this case, provides a range of economically processable glasses for those with low glass transition points. Restrict. Also in this case, the preparation of the glass preform, such as transport, cleaning, storage, individual inspection, etc. still gives a non-negligible negative contribution to the production costs.

  In the case of the internal punching press directly from the glass melt as described in Patent Document 6, there is no preparation for the glass preform. Nevertheless, the glass melt cannot be fed directly into the press mold and then pressed with very high accuracy. Supply and pressurization (conditioning of glass droplets) are required. Feeding and conditioning takes place on the air bearing, which avoids damage to the glass surface due to contact with the cooling mold. Certainly, it is possible to process a glass melt with a low viscosity exclusively and a small portion of 1-3 grams that can be formed and retained by surface stress. However, such small glass lumps are cooled relatively quickly on the air bearing, so that these lumps are always pressurized with a relatively high viscosity. As a result, the burden on the press die and its price are still relatively high.

Therefore, all of the above methods have technical limitations that strongly limit the production of imaging optics that simultaneously satisfy quality, flexibility, number and unit price.
U.S. Pat. No. 4,969,944 U.S. Pat. No. 4,734,118 US Pat. No. 5,873,921 US Pat. No. 6,0097,525 U.S. Pat. No. 4,854,958 US Pat. No. 5,762,673

  The present invention is therefore based on the problem of presenting an improved method for producing optical components with regard to economy and processable glass types. This problem has already been solved by the subject matter of the independent claims in a very surprisingly simple manner. Advantageous embodiments and further examples are presented in the dependent claims.

  Accordingly, the present invention assigns a glass melt, and the glass share obtained by the assignment is placed on a levitation cushion or gas cushion made on a levitation support, and the glass share Viscosity rises to or above the sticky viscosity by cooling while placed on the surface, the glass share shows a viscosity at least partially below the softening point inside, and the glass share is in the press mold. A method for producing optical glass components that are placed and glass-molded in a press mold is planned.

  It is particularly preferred at this stage that glass forming is performed on the final contour and surface quality, so that finishing of the glass components can be omitted.

  In order to maintain high contour accuracy and surface quality, the glass portion is allocated and sent to the press die so that the glass portion has a radius smaller than the radius of the curved ceiling of the press surface of the press die. In some cases, it is clear that it is particularly advantageous. In this way, air sealing between the press mold and the lens is avoided.

  In particular, an apparatus for producing an optical glass component arranged for carrying out the method according to the invention further comprises an allocating device for allocating a glass melt, a glass allocation maintained by the allocating device. It includes a levitation support, as well as a press die for performing glass forming, and an apparatus for transferring the glass portion from the levitation support to the press die. In this case, if the viscosity of the glass portion becomes sticky viscosity or higher on the surface of the glass portion during levitation support, the glass portion is then transferred to the press die by a device for controlling the process. Sent.

The adhesive viscosity is understood as the viscosity at which the glass comes to adhere to the press mold. At this time, generally in the case of glass, it is at a softening point of 10 ^7.6 dPa · s. In order to reliably prevent sticking to the press mold, it is preferable to lower the surface temperature of the glass allocation to a temperature at which the viscosity is at least 10 ^7.7 dPa · s. An apparatus for controlling the process progress in this case is that the glass share is pressed when the viscosity during support rises to a viscosity of at least 10 ^7.7 dPa · s on the surface of the glass share or higher. Configured to be delivered to.

  Thus, according to the present invention, as compared with the method described in Patent Document 6, no effort is made to obtain a uniform temperature distribution within the glass portion or the soft mass of the glass. In contrast, according to the present invention, a much more inhomogeneous temperature distribution is reached while being supported on the gas cushion, where the viscosity at the surface is greater than the viscosity inside the glass share. high. In this way, the subsequent glass forming is very fast and more important for the press mold. This is because here, only at the outer skin of the glass share, the high viscosity required for glass forming higher than the adhesive viscosity is achieved. The interior of the glass portion is more fluid and easier to deform, whereas the method described in US Pat. Is inherently more difficult.

  In order to prevent damage or deformation of the glass portion in the case of delivery from the levitation support to the press die, according to another preferred embodiment of the invention, the glass portion can be transferred without contacting the press die. Planned.

  One possibility to achieve this is to send the glass share to the press die by damping or deflection of the levitation support. Accordingly, in the device according to the invention according to this aspect, the device for delivering the glass share comprises a device for damping and / or pivoting of the levitation support. It is particularly advantageous if the levitation support moves downwards faster than if it is empty. Furthermore, the device for delivering the glass share includes a device for moving the levitation support downward with an acceleration higher than the gravitational acceleration. In this way, it is realized that the levitation support can move away from the freely falling glass allocation so fast that the glass allocation does not contact the levitation support. A recess for supporting the glass share so that the glass share can be stably supported on the gas cushion made on the float support during adjustment on the float support. It is particularly preferred to use a flotation support with a point.

  In order to improve the contour quality and surface quality of the glass components that can be produced according to the present invention, the position of the glass portion supported on the levitation support is pre-determined as accurately as possible during delivery to the press die. Obviously, it is very desirable. Thereby, the attitude | position for the glass allocation in a press die can also be defined correctly. This has proved as a surprisingly simple measure for quality improvement when the movement of the glass share on the levitation support is slowed down. Surprisingly, this has already been achieved by applying a concave aspheric shape to this. In particular, this movement can be decelerated through a recess, which has a smaller radius of curvature in the central region than in the surrounding region. The recess therefore makes its shape more like a hollow circle, a paraboloid or ellipsoid with a vertical major axis rather than a frying pan.

  According to yet another aspect of the present invention, the press mold is preheated to prevent the glass portion from being rapidly cooled in the case of pressing. However, it is advantageous to place the glass portion in a press mold having a temperature below the temperature of the glass tack viscosity in order to avoid the glass surface being heated to below the tack viscosity during glass forming. .

  According to yet another aspect of the present invention, glass forming is further performed with controlled process and force. By such combined control of process and force, the pressing process can be adjusted particularly precisely. In this case, process control and force control can be introduced simultaneously or one after the other.

The apparatus and method according to the present invention are hardly limited with respect to the choice of processable glass. However, it is particularly suitable for glasses having a viscosity of up to 10 ⁴ dPa · s at 1650 ° C. This method is also suitable for processing glass that is difficult to process by other pressing methods such as fluoride crown glass, fluoride phosphate glass, or phosphate glass. The present invention is very flexible with respect to the size of the components that can be manufactured, especially the size of the lens. The present invention is particularly suitable for processing glass quotas having a weight in the range of 0.1 grams to 150 grams. Furthermore, the glass melt can be assigned with a wide viscosity range, in particular with a viscosity in the range of ² dPa · s to 10 ⁴ dPa · s, and then formed into an optical component with high contour accuracy.

  It is also important that the glass share has the above-mentioned weight and volume in order to be able to produce optical components with high replicability and high contour accuracy. It is therefore particularly advantageous to plan an allocation device that can allocate as much an adjustable amount of glass allocation as possible from the glass melt. Needle tube feeders, in particular cycle needle tube feeders, are particularly suitable for this purpose.

Further glass quota, according to yet another aspect of the present invention, is also cooled to at least the transition temperature T _g in the interior under the adhesive contact with the press die. This is advantageous because it has been found that the contour accuracy is degraded when the contact between the glass and the mold is interrupted too early.
In addition, if the glass is allocated on a flotation support, it is advantageous to avoid temperature distribution inhomogeneities in the glass allocation caused by deformation of the allocation or contact with other parts of the apparatus. is there. For this purpose, according to this aspect of the invention, the assigning device is placed directly on the levitating support.

  Furthermore, it has been found that mucus can be avoided if adjustment of the levitation support is continued during supply. Thereby, the position of the levitation support can be changed with respect to the assignment device by a corresponding adjustment of the device during assignment on the levitation support.

  It is particularly advantageous when conditioning on the levitation support if the deformation of the glass share is avoided when supporting on a gas cushion. In addition, a particularly homogeneous pressure distribution is advantageous. This is achieved according to yet another aspect of the present invention by the levitation support having a porous material through which gas is replenished for the levitation cushion. This causes the gas to be evenly distributed over the surface of the porous material and flow into the gas cushion. Yet another procedure to achieve a uniform pressure distribution is to provide a single membrane on the levitation support. Sintered metal, preferably having a porosity of graphite, has proved particularly promising as a porous material.

  According to yet another aspect, it is planned to process many glass allocations simultaneously. In this case, it is particularly advantageous here to arrange many glass quotas on a common levitation support in order to achieve simultaneous conditioning for all glass quotas. Furthermore, the levitation support can also surround a single membrane. In this case, it has been found to be very advantageous to arrange the glass share, or a floating recess provided for receiving the glass share, along one circle. This type of arrangement surprisingly has an advantageous effect on the components produced according to the invention. The symmetrical arrangement of the buoyant recesses produced by this aspect serves to make the conditional deviation as small as possible during conditioning for individual glass allocations.

  In order to achieve uniform conditioning, it is further advantageous if the gas flow into the levitation cushion and / or the distance from the glass share to the levitation support is adjusted by a corresponding adjustment of the device. This is particularly effective even when assigned on a buoyant support.

  Furthermore, it is advantageous to carry out not only the cooling of the glass quota formed in the press mold. According to yet another aspect of the present invention, heat is removed, and even temporarily, heat is supplied during the pressing of the glass portion in the press mold. In particular, it is possible to remove heat during the press working for the glass quota in the press mold and to supply the heat thereafter. With the heat supplied, the temperature distribution in the glass share is homogenized and the stress in the glass can be removed. The supply of heat and the removal of heat can be replaced not only in time, but also according to a preferred embodiment of the invention can be carried out regionally along the pressing surface. In this case, it is planned that at least one region of the pressing surface is cooled and at least another region is heated. It is particularly advantageous to achieve a homogeneous temperature distribution in the glass soft mass if the central area of the pressing surface is cooled and the surrounding area is heated. In general, it is advantageous if the temperature of the pressing surface is set or adjusted so as to decrease from the central region towards the edge. This is not necessary depending on the occasion, but should be done by simultaneous cooling and heating. For this reason, according to this, an apparatus according to the invention can comprise a cooling device for cooling the central region of the press surface and a heating device for heating the region surrounding the central region of the press surface.

  A heating device for the press mold and, alternatively or in addition as an additional cooling device, so that the regional and temporal temperature distribution can be adjusted or adjusted, for example, during pressing as described above it can.

  The invention will now be described in more detail by way of example with reference to the drawings, in which the same and similar elements have the same reference numerals. It is possible to combine the features of the various embodiments with one another.

  1 to 3, the method steps of the production of optical glass components according to the invention are illustrated by partial views of the apparatus according to the invention for producing such optical glass components.

The device generally indicated by reference numeral 1 includes an assigning device which is illustrated as a cycle needle tube feeder 3 in the example shown in FIG. The needle tube feeder 3 of the device 1 further comprises a membrane 9 directly on the floating support 5. Thus, as shown in FIG. 1, a glass portion having a weight in the range of 1 gram to 150 grams to be pressed can be directly assigned onto the levitation support 5 by the needle tube feeder 3. In this case, a glass melt having a viscosity in the range of ² dPa · s to 10 ⁴ dPa · s is dispensed and squeezed from the outlet opening of the needle tube feeder 3 for the optical component to be manufactured. It is placed on the gas cushion until the glass quota of the expected amount is reached. It is preferred that a glass exhibiting a viscosity of up to 10 ⁴ dPa · s at 1650 ° C. is applied. Fluoride crown glass, fluoride phosphate glass, or phosphate glass can also be processed.

  The levitation support 5 further includes a membrane 9 formed in a single body with a recess 6 for receiving a glass share 7. The contours of the recesses 6 are shown for the feed viscosity, the desired amount of the glass quota 7, the desired heat distribution in the glass quota 7, the aerodynamics of the gas cushion, and the recess 6 when delivered to the press die. Suitable for vibration reduction and shock-free sliding.

  In order to reduce vibration, a recess formed in an aspherical shape is applied. In particular, this movement is damped by a recess having a smaller radius of curvature in the central region than in the surrounding region as shown in FIG. The recess shown in FIG. 1 has the shape of a paraboloid open upward or an ellipsoid with a vertical major semi-axis. This resembles a hollow cone rather than a frying pan. This shape with a smaller radius of curvature is designed so that the glass share is rather centered on the smaller central radius of curvature region of the recess, and thus in the case of frying pan or hemispherical recesses. Are well defined.

  The membrane 9 is made of a porous material, through which gas flows into the recess, thus forming a gas cushion 15 between the levitation support 5 or the membrane 9 and the glass portion 7. On top of this, the glass portion 7 is supported in the levitated state without any particular contact. Through a porous material combined with a single recess, a particularly homogeneous pressure distribution is achieved in the gas cushion. As the porous material, it is preferable to incorporate a sintered metal, and it is particularly preferable to have a porosity corresponding to graphite.

  The compressed gas is fed, for example, through one or more gas channels 11 in or below the membrane 9 and a pressurized air tube 13 connected to the one or more channels 11. The porosity of the membrane material is selected according to the viscosity of the glass. Furthermore, the porous material of the membrane is selected depending on the input temperature and the effect on the surface quality of this glass component.

  The levitation support 5 is further connected to an actuating unit 19 through a pivotable arm 17. The actuating unit 19 can carry out the horizontal and vertical movements of the levitation support 5 as well as the pivoting movement of the levitation support 5 around the horizontal axis 18 as indicated by the written arrows. Due to the horizontal and vertical mobility of the levitation support, the position of the levitation support can be changed during the assignment with respect to the assigning device or with respect to the needle tube feeder 3. Similarly, the gas flow into the levitation cushion 15 or the distance from the glass share 7 to the levitation support or in this example the recess 6 in the membrane 9 can also be adjusted. By re-adjusting the arrangement of the recesses 6 with respect to the position of the needle tube feeder 3, fringes in the glass are avoided. The readjustment by the actuating unit can be carried out vertically or horizontally, or a combined vertical and horizontal movement.

  The adjustment of these parameters, ie the gas flow or the distance to the recess, the horizontal position and the vertical position of the levitation support 5 with respect to the glass allocation device is controlled by the process control device 21. In particular, the process controller 21 adjusts the gas flow into the levitation cushion 15 or the distance from the glass allocation 7 to the levitation support 5 during the allocation on the levitation support. Assignment by the needle tube feeder 3 is also controlled by the process control device 21 as indicated by the connecting line of the needle tube feeder 3 to the process control device 21.

FIG. 2 shows the glass portion 7 supported on the gas cushion 15 made on the levitation support 5 at the end of the conditioning process. On the gas cushion 15, the glass portion 7 is conditioned so that, for its surface 71 and the area 72 close to the surface, the glass is cooled to a temperature at which the viscosity of the glass is higher or at most the same as the adhesive viscosity. . The viscosity in the region close to the surface is preferably at least 10 ^7.7 dPa · s. Nevertheless, in the middle or inner region 73 surrounded by the region 72, the temperature is still higher than the surface. According to the invention, here the viscosity is still below the softening point, so that the glass portion 7 can be easily deformed as a whole and only a small resistance is produced in the case of subsequent pressing. The cooling achieved by the present invention of the glass portion in the surface 71 and the region 72 near the surface below the temperature of the viscous viscosity is achieved by corresponding conditioning on the gas cushion. In addition, the gas flow and the temperature of the gas and / or the membrane can be adjusted, inter alia, according to the invention.

  FIG. 3 shows part of the apparatus during further process steps. After conditioning glass quota 7, glass quota 7 is delivered to press dies 27, 29. This delivery is performed in a non-contact manner, in particular in the example shown in FIG. 3, so that, in the sense of the invention, the glass portion 7 is in contact with the press surfaces 28 and / or 30 of the press dies 27 and / or 29. It is understood that it does not come into contact with another surface except. In this way, undesirable inhomogeneities of deformation or temperature distribution are avoided.

This delivery is controlled by the process control device 21. When the viscosity at the surface of the glass share reaches the state depicted by FIG. 2 having at least a sticky viscosity, preferably greater than 10 ^7.7 dPa · s, the process controller 21 causes the delivery mechanism depicted next. Is started. In the simplest case, delivery takes place after a predetermined time interval, but it is also possible to determine, for example, the temperature of the glass allocation, in particular its surface temperature, and start delivery according to the existing temperature. be able to.

  In the example shown in FIG. 3, the device for delivering the glass share is in particular an apparatus for lowering the levitation support 5 with an actuating unit and thereby a swivel arm 17 pivotable about a shaft 18. including. The actuating unit 19 can use a drive for the swivel arm, by means of which the levitation support 5 can be moved downward from the horizontal support position by swiveling, in which case the swivel movement is caused by gravity by acceleration. This is done faster than the acceleration, whereby the levitation support 5 is moved downward by free fall. Thus, the falling movement of the glass portion 7 accelerated by the acceleration of gravity is slower than the movement of the levitation support 5, and thus the glass portion 7 does not contact the levitation support when delivering to the press die 25. . Eventually, the glass quota 7 is placed on the press surface 28 of the lower press die 27. Subsequently, the upper press die 29 and the lower press die 27 move and overlap so that, in the example shown in FIG. 3, the hydraulic rod 31 is moved downward in the upper press die. With respect to the curved ceiling of the press surfaces 28, 30 of the press mold, the glass portion 7 is pre-allocated and conditioned so that the glass portion 7 has a radius smaller than the radius of the curved ceiling of the press die 25; It is advantageous if it can be placed in a press mold. In other words, the press surfaces 28, 30 have a curved ceiling that is shallower than the glass quota 7. In particular, the deformation of the glass component due to the confinement of the air between the glass share and the pressing surface is thus avoided.

  The next glass forming step in the press die 25 is shown in FIG. By glass forming, the glass component to be produced is formed with a final contour and good surface quality. This eliminates the need for additional glass processing. Of course, however, additional coatings such as, for example, special coating treatments or antireflective layers can be applied.

  Control of the press working process is also controlled by the process control device 21. This device also controls a hydraulic device 37 that causes the hydraulic rod 31 to act on the press die 29. In this case, a combination of stroke control and force control is input. This further distinguishes the present invention from previously known glass forming methods in which only force control is essentially a problem based on the high viscosity of the glass. On the other hand, the thickness of the optical component to be manufactured can be accurately adjusted by a combination of stroke control and force control.

  The press surfaces 28 and 30 of the press dies 27 and 29 are formed such that the lens is maintained by glass molding with a glass quota of 7. In the example shown in FIG. 4, the press surface is formed in an aspherical shape, for example, a hyperboloid, so that the aspherical lens is maintained during glass molding. The press dies 27 and 29 are provided with heating plates 34 each having a heating element 35 on the back side.

  For example, to avoid too fast cooling of the glass portion, it is preferable to place the glass portion in the press mold 25 preheated by the heating plate 34. However, in order to prevent the glass portion from sticking after delivery to the press mold 25, in this case the press mold is simply preheated until its temperature is below the glass adhesion viscosity temperature.

Then in the course of glass forming the glass quota is under the adhesive contact with the pressing surface 28, 30 of the press die 25, is also cooled to below the transition temperature T _g in the glass quota 7. The heating plates 34 further each have a central opening 33 in which fluid can be supplied by a fluid line 36. It is particularly preferred that air is supplied through the pipe 36 for the cooling of the press mold, in particular for the cooling of the central area of the press surfaces 28,30. Thereby, the device 1 passes through a cooling device for cooling the central area of the press surface of the press mold by the supply of cooling air through the pipe 36, as well as in the central area of this press surface 28, 30 in the form of a heating plate 34. It can be used through a heating device for heating the area surrounding.

Do not cool continuously during the pressing process. That is, it has been found to be advantageous if heat is removed and also supplied during the glass forming of the glass quota 7 in the press mold 25. Heat is supplied by the heating plate 34. In particular, according to another aspect of the method, it is planned to remove heat during the pressing of the glass share 7 in the press mold 25 and then temporarily supply heat. In this manner, a homogeneous temperature distribution can be adjusted temporarily while a heat flow is generated opposite to cooling through the heat supply. At this stage, the generated temperature stress can be equalized. In order to remove the temperature stress, for example, the cooling is braked through the heat supply, and the glass allocation is at a viscosity in the range of 10 ¹³ dPa · s to 10 ^14.5 dPa · s, the upper and lower cooling points. Can be kept at a certain temperature between. Subsequently, the glass share formed can be removed or further cooled prior to removal.

  Cooling and heating must not be replaced in time. The apparatus 1 has a cooling device for cooling the central region of the press surface of the press mold and a heating device 34 for heating the region surrounding the central region of the press surfaces 28, 30 so that the side of the press surface is located. It is possible to adjust the changing temperature profile. In this case, the central region of the press surfaces 28 and 30 of the press die 25 is cooled by the cooling air and the surrounding region is heated, so that the temperature of the press surfaces 28 and 30 of the press die 25 increases from the central region toward the edge. descend. This has been found to be particularly good in order to achieve as uniform a temperature distribution as possible along the surface of the glass quota 7 during glass forming.

  FIG. 5 is a partial schematic view of a further embodiment of the device 1 according to the invention. This device 1 is designed to process many glass quotas simultaneously. For this reason, the levitation support 5 includes a membrane 9 formed as a single body as in the example shown in FIG. 1, but in the embodiment shown in FIG. 5, each membrane 9 has a glass share. It has a number of recesses 6 for support. By supporting many glass allocations on one common levitation support 5 as in this example, it is possible to condition all glass allocations supported in parallel in the same way as possible. Is done. Moreover, a membrane formed as a single body is also particularly advantageous, since in this way the gas flow entering all the recesses can be adjusted in parallel by one adjusting device. The glass quota is also supplied through a number of cycle needle tube feeders 3, which in this embodiment are each arranged on one recess 6. The arrangement of the cycle needle tube feeder and the floating recess 6 along one circle has also proven particularly advantageous to achieve uniform conditioning, as shown in FIG.

  In this embodiment, the levitation support 5 is a swivel arm 171, 172 that can be rotated via the shafts 181, 182 of the actuating unit 19 to deliver the glass share to one or many unshown press dies. , 173, 174, whereby in this case the levitation support 5 is guided in parallel by the arrangement of the swivel arms 171, 172, 173, 174. This means that the arrangement direction of the levitating support is maintained during the turning. In this embodiment as well, the downward turn is performed at an acceleration higher than the acceleration of gravity in order to deliver the glass quota. During this advantageous parallel guidance, the movement of all the recesses 6 is the same speed during the turn.

  It will be apparent to those skilled in the art that the present invention is not limited to the embodiments described above and can be modified in various ways. In particular, the features of the individual embodiments can also be combined with one another.

Fig. 7 shows a method step of the method of the invention based on a schematic diagram of a part of the device according to the invention. Fig. 7 shows a method step of the method of the invention based on a schematic diagram of a part of the device according to the invention. Fig. 7 shows a method step of the method of the invention based on a schematic diagram of a part of the device according to the invention. Fig. 7 shows a method step of the method of the invention based on a schematic diagram of a part of the device according to the invention. FIG. 3 is a schematic partial view of an apparatus of the present invention according to another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus for manufacturing an optical component 3 Needle tube feeder 5 Levitation support base 6, 61 to 69 Recess 7 Glass allocation 9 Membrane 11 5 Gas supply channel in 9 13 Gas supply tube 15 Gas cushion 17 Swivel arm 171-174
18, 181 axis 182
DESCRIPTION OF SYMBOLS 19 Actuating unit 21 Process control device 25 Press die 27, 29 Press surface of press die 28, 30 27, 29 31 Opening in hydraulic rod 33 34 34 Heating element of heating plate 35 34 36 Fluid pipe 37 Hydraulic device

Claims (49)

  Method for manufacturing an optical glass component, in particular an imaging lens system, in which a glass melt is allocated and the glass portion obtained by the allocation is placed on a levitation cushion made on a levitation support And the viscosity of the glass portion increases to or above the adhesive viscosity by cooling while placed on the surface, the glass portion having a viscosity at least partially below the softening point inside, A method in which the allocated portion is placed in a press mold and glass molding is performed in the press mold.   2. A method according to claim 1, characterized in that the glass share is pressed into a final profile and good surface quality in a press mold. 3. A method according to claim 1 or 2, characterized in that the surface temperature of the glass share is lowered to a temperature at which the viscosity is at least ^107.7 dPa · s.   4. The method according to claim 1, wherein the glass portion is transferred without contacting the press die.   5. A method as claimed in claim 4, characterized in that the glass share is sent to the press die by damping or swiveling of the levitation support.   6. A method according to claim 4 or 5, characterized in that the levitation support moves downwards faster than free fall.   7. A method according to any one of the preceding claims, characterized in that the glass share is placed on a recess in a levitation support on a levitation cushion.   8. The method of claim 7, wherein movement of the glass share in the recess is moderated by the aspheric shape of the recess.   9. A method according to any one of claims 1 to 8, characterized in that the press mold is preheated.   10. A method according to any one of the preceding claims, wherein the glass portion is placed in a press mold having a temperature below the glass stick viscosity temperature. 11. A method according to any one of the preceding claims, characterized in that glass having a viscosity of up to 10 < ⁴ > dPa.s at 1650 [deg.] C. is processed.   12. A method according to any one of the preceding claims, characterized in that the glass is allocated by a needle tube feeder, in particular a cycle needle tube feeder. Glass quota is under the adhesive contact at the press-type method according to any one of claims 1 to 12 characterized in that it also being cooled to at least the transition temperature T _g in the interior particular.   The method according to claim 13, wherein the glass is assigned directly on the levitation support.   15. A method according to any one of the preceding claims, characterized in that the position of the levitation support is changed relative to the assignment device during assignment on the levitation support.   16. A method according to any one of the preceding claims, characterized in that the levitation support comprises a porous material through which gas for the levitation cushion is replenished.   17. A method according to any one of the preceding claims, characterized in that the gas flow entering the levitation cushion or the distance from the glass share to the levitation support is adjusted.   18. A method according to claim 17, wherein the gas flow entering the levitation cushion, or the distance from the glass allocation to the levitation support, is adjusted during the allocation to the levitation support.   19. A method according to any one of the preceding claims, wherein a number of glass quotas are processed simultaneously.   20. A method according to claim 19, wherein a number of glass quotas are placed on a common levitation support.   21. A method according to any one of the preceding claims, wherein a glass portion having a weight in the range of 0.1 grams to 150 grams is processed.   The method according to any one of claims 1 to 21, wherein heat is removed and further heat is supplied during pressing of the glass portion in the press mold.   The method according to any one of claims 1 to 22, wherein the temperature of the press surface of the press die is set or adjusted so as to decrease from the central region toward the edge.   24. A method according to any one of claims 1 to 23, wherein the central area of the pressing surface is cooled and the surrounding area is heated.   25. A method according to any one of claims 1 to 24, wherein heat is removed during the pressing of the glass quota in the press mold and then the heat is supplied. 26. The method according to any one of claims 1 to 25, wherein the glass melt is assigned with a viscosity in the range of ² dPa · s to 10 ⁴ dPa · s.   27. A method according to any one of claims 1 to 26, wherein the lens is formed in a press mold.   28. A method according to any one of claims 1 to 27, wherein the glass forming is performed with controlled process and force.   29. A glass portion according to any one of claims 1 to 28, wherein the glass portion is assigned and sent to the press die such that it has a radius smaller than the radius of the curved ceiling of the press surface of the press die. the method of.   30. An apparatus for producing optical glass components particularly adapted for carrying out the method according to any one of claims 1 to 29, maintained by an allocator for allocating glass melt, an allocator. Including a buoyancy support for placing a glass share, a press mold for performing glass forming, and a device for transferring the glass share from the levitation support to the press mold. An apparatus for producing an optical glass component, in which the glass share is transferred to a press mold by means of a device for controlling the process process when the adhesive viscosity becomes higher or higher on the surface of the glass share. . An apparatus for controlling the process so that the glass share is delivered to the press mold when the supporting viscosity rises to a viscosity of at least 10 ^7.7 dPa · s on the glass share surface. 32. The apparatus of claim 30, wherein the apparatus is configured.   32. Apparatus according to claim 30 or 31, wherein the apparatus for delivering the glass share comprises an apparatus for damping or pivoting the levitation support.   33. Apparatus according to any one of claims 30 to 32, wherein the apparatus for delivering the glass share comprises an apparatus for moving the levitation support table downward at an acceleration higher than the gravitational acceleration.   34. Apparatus according to any one of claims 30 to 33, characterized by a levitation support having a recess for supporting a glass share.   32. The apparatus of claim 30, wherein the recess has an aspheric shape.   32. Device according to claim 30 or 31, characterized in that the recess has a smaller radius of curvature in the central region than in the surrounding region.   37. Apparatus according to any one of claims 30 to 36, wherein the assigning device comprises a needle tube feeder.   38. Apparatus according to any one of claims 30 to 37, wherein the assigning device is arranged directly on the levitation support.   39. Apparatus according to any one of claims 30 to 38, wherein the levitation support comprises a porous material through which gas for the levitation cushion is replenished.   40. The apparatus of claim 39, wherein the levitation support comprises sintered metal as the porous material.   41. A device according to any one of claims 30 to 40, characterized in that the device is for changing the position of the levitation support with respect to the assigning device.   42. Apparatus according to any one of claims 30 to 41, characterized by a device for adjusting the gas flow entering the levitation cushion or the distance from the glass share to the levitation support.   43. Apparatus according to any one of claims 30 to 42, wherein the apparatus is adjusted to process a number of glass quotas simultaneously.   44. Apparatus according to any one of claims 30 to 43, characterized by a heating device for a press die.   45. Apparatus according to any one of claims 30 to 44, characterized by a cooling device for the press mold.   46. The cooling device for cooling the central region of the press surface of the press mold, and the heating device for heating the region surrounding the central region of the press surface, according to any one of claims 30 to 45. apparatus.   47. Apparatus according to any one of claims 30 to 46, characterized by a number of floating recesses arranged along a circle.   48. Apparatus according to any one of claims 30 to 47, wherein the press mold is made to form a lens.   49. Apparatus according to any one of claims 30 to 48, wherein the levitation support comprises a unitary membrane.

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