JPH0483725A - Lens molding machine - Google Patents

Abstract

PURPOSE:To reduce producing cost by controlling a high-frequency coil with a temperature sensor fitted at a part of a specific heater and performing temperature control with temperature sensors fitted to each part of plural upper and lower molds. CONSTITUTION:Heaters 14 and 15 are heated with a high-frequency heating coil 16 and glass material P and upper and lower molds 11 and 12 are heated with the heaters. Temperatures of the heater are detected by temperature sensors 17, 19 and 20 and inputted into E controlling part 26. Temperatures of the heaters 14 and 15 are raised to a fixed temperature and the high-frequency heating coil 16 is controlled, then flow- proportional valves 23 and 24 are controlled in opened state to feed cooling air to control, the mold temperature. On the other hand, a space between the upper and lower molds 11 and 12 is filled with glass material P and lens thickness is decided, then a body 18 is brought into contact with a side part of the glass material P, thus a cylindrical side face of the lens is formed by an inner peripheral face of the body. Next, the lower mold 12 is moved by a servo motor 28 to press the glass material and a molding face of the mold is transferred on the upper and lower faces of the glass material P, then the material is cooled to a fixed temperature, and pressure by the servo motor 28 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens molding device used for example in optical communications and optical disc players.

[Prior Art] As a conventional device of this type, there is a glass lens press molding device disclosed in Japanese Patent Laid-Open No. 64-42334. Fourth
The figures are the main drawings attached to the same specification.

The glass lens press molding apparatus disclosed in the same specification is a glass lens molding apparatus using induction heating means, in which at least one set of glass lenses is formed by sintering and molding ceramics and is provided with a cavity surface corresponding to the lens surface of the glass lens. It includes a cavity die 12, molds 3 and 4 that fit and hold the outer periphery of the cavity die 1.2, and a gouie plate 5.6 that supports the mold 3.4 and the back surface of the cavity die 1.2. However, a blind hole 7.8 is formed on the back side of the cavity die 1.2.

With such a configuration, regardless of the increase in lens diameter,
It is believed that the cavity portion can be heated effectively and uniformly, and a glass lens with good surface precision can be molded.

[Problems to be Solved by the Invention] Incidentally, there has been a desire to reduce manufacturing costs by press-molding a large number of glass lenses at once.

In response to this request, we prepared a large number of the cavity guides,
It is thought that this can be achieved by heating at the same time using a common induction heating means.

However, when induction heating is performed at the same time, each individual cavity guide is not necessarily heated uniformly, and for this reason, it is necessary to place a temperature measurement sensor in each cavity part, and furthermore, each temperature sensor needs to be placed in each cavity part. Even if it is detected that the temperatures of the two are different, it is impossible to deal with this using a common induction heating means. Further, when an induction heating means is provided separately, there is a problem in that the manufacturing cost increases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lens molding device that can simultaneously mold a large number of lenses with a simple molding device, thereby reducing manufacturing costs.

[Means for Solving the Problems] The configuration of the present invention for achieving the above object is to mold a lens by pressurizing a lens material with an upper mold and a lower mold that are arranged facing each other so as to be able to press and separate. A heating body consisting of a lens molding part, a plurality of ring-shaped heating bodies arranged on the same circumference and at equal angular intervals around the lens molding part, and a ring-shaped heating body coaxial with the lens molding part surrounding this heating body. a high-frequency heating coil; a single heating-body temperature sensor attached to a part of the heating body to measure the temperature; and controlling the high-frequency output of the high-frequency heating coil based on the measurement results of the heating body temperature sensor. A heating element temperature control means, a pair of upper and lower mold temperature sensors that are respectively attached to an arbitrary set of upper and lower molds to measure their temperatures, and the upper and lower molds. The apparatus is equipped with mold temperature control means for controlling the temperature of the upper and lower molds, respectively, based on the measurement results of the temperature sensors.

[Function] The function of the present invention having the above configuration is that a single temperature sensor is attached to a part of the heating body in which a plurality of lens molded parts are formed, the temperature is measured, and the high-frequency heating is performed based on the measurement result. The heating temperature of the heating element by the coil is controlled. On the other hand,
A pair of temperature sensors is attached to only one set of both the upper and lower molds, each consisting of a plurality of molds, to measure the temperature, and the temperatures of the upper and lower molds are controlled based on the measurement results. This allows a large number of lenses to be molded simultaneously using a simple molding device, thereby reducing manufacturing costs.

[Example 1 Hereinafter, the present invention will be explained with reference to the drawings.

Fig. 1 shows a pressure molding section which is the main part of a lens molding apparatus as an embodiment. FIG. 1 is an enlarged detailed view of the portion indicated by A-A of the lens molding section shown in FIG.

The pressure molding section 10 shown in FIG. 1 is located on the same circumference as the lens molding section 13 shown in detail in FIG. A plurality of ring-shaped heating elements 14 and 15 are arranged at equal angular intervals, and a high-frequency ring-shaped heating element coaxial with a lens molding part 13, which will be described in detail later, surrounds the opposing part of the heating elements 14 and 15. It includes a heating coil 16 and a single heating element temperature sensor 17 that is attached to a part of the negative heating element 15 and measures the temperature thereof.

The lens molding section 13 is connected to the heating body 1 as shown in FIG.
4.15, which are integrally pressed and releasably arranged to face each other, are used to form an upper mold 11 for molding the upper surface of an aspherical lens, etc., and a lower mold 12 for molding the lower surface similarly to the lower mold 12, which is extrapolated to the upper mold 11. For example, it includes a cylindrical body mold 18 made of a cemented carbide such as WC-Ni cemented carbide material.

Among these, the lower mold 12 is movable in the vertical direction in the figure, and when heating the lens material (glass material) P,
The glass material P is held at a position facing the protrusion 14a of the heating body 14, and when pressurizing the glass material P, a servo motor 28, which will be described later, moves the lower mold 12 toward the upper mold 11 (as shown in the figure). (upward).

Further, an upper mold temperature sensor 19 is provided only in the illustrated upper mold 11, and a lower mold temperature sensor 20 is provided only in the illustrated lower mold 12. That is, in this embodiment, a plurality of upper and lower molds are provided on the heating element 14 side and the heating element 15 side, but a single mold is used to measure the temperature of only the upper and lower molds of the - set. A mold temperature sensor is installed.

Furthermore, air nozzles 21 and 22 are provided in the upper mold 11 and the lower mold 12, respectively. Cooling air is sent to each air nozzle 21, 22 via each flow rate proportional valve 23, 24 shown in FIG.
1.12 temperatures can be adjusted individually.

Next, referring to FIG. 3, the explanation will be mainly focused on the electrical system.

At the subsequent stage of each of the temperature sensors 17, 19, and 20, there is a temperature amplifier 33 for amplifying the output current, and this temperature amplifier 3.
An analog/digital converter 25 that converts the analog signal output from 3 into a digital signal, and a control section 26 that includes a CPU that functions as a control center for the entire device, a ROM in which a program is recorded, etc. It is connected.

Furthermore, a servo motor 28 is connected to one output side system of the control section 26 via a servo controller 27, and a high frequency current is connected to the high frequency heating coil 16 via a digital/analog converter 29 to another system. A high-frequency power supply 30 that supplies the flow rate proportional valve 23.24 is connected to a proportional valve amplifier 31.32 that amplifies the output signal to operate the flow rate proportional valve 23.24.

By the way, in addition to the above-mentioned functions, the control unit 26 shown in this embodiment controls the temperature of the heating element 14 and 15 for the high-frequency power source 30 that supplies power to the high-frequency heating coil 16 based on the measurement result of the heating element temperature sensor 17. a function of sending a control signal for control, and a temperature sensor 19 for the upper and lower molds;
It has a function of sending control signals to the proportional valve amplifiers 31 and 32 based on the measurement results of 20 to control the temperatures of the upper and lower molds 11 and 12, respectively.

In this embodiment, the control unit 26. Heating body temperature control means 3 by digital analog converter 29 and high frequency power supply 30
4, and the control unit 26. Digital analog converter 29, proportional valve amplifier 31°32, flow rate proportional valve 23.24
The air nozzles 21 and 22 constitute a mold temperature control means 35.

The operation of an embodiment of the apparatus having the above configuration will be explained with reference to FIGS. 1 to 3.

First, the glass material P is placed on the upper surface of the lower mold 12, and then the lower mold 12 itself is moved to a position where the glass material P faces the protrusion 14a of the heating element 14.

In this state, power is supplied from the high frequency power source 30 to the high frequency heating coil 16 to heat the heating elements 14 and 15. The heated heating elements 14 and 15 directly heat the glass material P facing them and the upper and lower molds 11 and 12, respectively.

The temperatures of the upper and lower molds 11 and 12 and the heating elements 14 and 15 are detected by the temperature sensors 17, 19 and 20, respectively, and these detection signals are amplified by the temperature amplifier 33 and then sent to the control unit 26. is input.

Regarding the heating element 14.15, the control unit 26 energizes the high-frequency heating coil 16 so that the temperature of the heating element 14.15 rises to a predetermined value so as to maintain the temperature at that value. A control signal for controlling the amount of current is sent to the high frequency power source 30.

Regarding the upper and lower molds 11.12, each flow rate proportional valve 23.24 is controlled to be open from the time the temperature rises to a predetermined value below the glass transition point until several seconds before the start of pressurization. cooling air is supplied, which causes the upper and lower molds 1 to
1. Control the temperature in step 12 so that it does not rise above that value. Note that the pressurization start point is a point in time when the temperature of the glass material P is increased to a predetermined temperature equal to or higher than the glass softening point.

Also, from a certain point on, the supply of the cooling air to the upper and lower molds 11.12 is stopped or the supply amount is reduced, and the upper and lower molds 11.12 are heated to a required temperature above the glass transition point and below the glass yield point. Raise the temperature to The temperature is maintained at the same temperature until several seconds have passed after the start of pressurization. Further, from the above point on, the supply of current to the high-frequency heating coil 16 is stopped or the supply amount is reduced, and the current supply to the heating body 1415 is stopped.
The temperature is reduced.

Next, the pressurizing operation will be explained.

After heating the glass material P to a predetermined temperature above the glass softening point using the upper and lower molds 11 and 12 heated to a required temperature above the glass transition point and below the glass yield point as described above,
From the time when the glass material P is heated to a predetermined temperature equal to or higher than the glass softening point, the servo motor 28 is driven in response to a signal from the servo controller 27, thereby moving the lower mold 12 as shown in FIGS. 1 and 2. From the position shown in , the barrel mold 18 is raised to a predetermined position facing the side of the glass material P.

This raising operation of the lower mold 12 is performed all at once by the servo motor 28 within a short time.

As a result, the glass material P is filled between the upper and lower molds 11 and 12, and the lens thickness is determined. Further, the side portion of the glass material P is in contact with the barrel mold 18, and the inner peripheral surface forms a cylindrical side surface of an aspherical lens or the like.

Next, the lower mold 12 is gradually pressed upward in the figure by the servo motor 28, so that the molding surfaces of the upper and lower molds 11 and 12 are transferred to the upper and lower surfaces of the glass material P, respectively. Then, the servo motor 28 continues until the glass material P cools down to a predetermined temperature below the glass transition point.
Pressure is maintained by Then, the holding pressure by the servo motor 28 is released, and the lower mold 12 is returned to the position shown in FIGS. 1 and 2.

According to the embodiment detailed above, heating can be performed simultaneously by a common induction heating means, and a plurality of upper and lower molds are provided on the common heating body at equal angular intervals on the same circumference. This allows for uniform heating. Therefore, the temperature of the plurality of upper molds only needs to be measured by a single temperature sensor, and similarly, the temperature of the lower molds only needs to be measured by a single temperature sensor. As a result, it is only necessary to prepare a minimum number of temperature sensors, and since a common induction heating means can be used, the control system can be simplified, and manufacturing costs can be reduced.

It should be noted that the present invention is not limited to the embodiments described above, and that various modifications can be made within the scope of the gist.

[Effects of the Invention] According to the present invention described in detail above, a large number of lenses can be molded simultaneously with a simple molding device, thereby providing a lens molding device that reduces manufacturing costs.

[Brief explanation of the drawing]

Fig. 1 shows a pressure molding section which is the main part of a lens molding apparatus as an embodiment. 1 is an enlarged detailed view of the portion indicated by A-A of the lens molding section shown in FIG.
FIG. 4 is a sectional view showing the structure of a conventional glass lens press molding apparatus. DESCRIPTION OF SYMBOLS 11... Upper mold, 12... Lower mold, 13... Lens molding part, 14.15... Heating body, 16... High frequency heating coil, 17... Temperature sensor for heating body , 19.2
0...Temperature sensor for upper and lower molds, 26...Control unit,
34°35... Heating body temperature control means, mold temperature control means, P... Lens material.

Claims (1)

[Claims] 1. A lens molding section where a lens material is molded by pressurizing a lens material with an upper mold and a lower mold that are placed opposite each other so as to be able to press and separate, and this lens molding section is arranged on the same circumference and at equal angular intervals. a ring-shaped heating element arranged in plurality, a ring-shaped high-frequency heating coil coaxial with the lens molding part surrounding the heating element, and a ring-shaped high-frequency heating coil attached to a part of the heating element to measure the temperature. a single heating element temperature sensor for heating, a heating element temperature control means for controlling the high frequency output of the high frequency heating coil based on the measurement result of this heating element temperature sensor, and an arbitrary set of upper and lower molds. A pair of upper and lower mold temperature sensors are attached to both sides to measure the temperature, and a mold temperature control device that controls the temperature of the upper and lower molds based on the measurement results of the upper and lower mold temperature sensors. A lens molding device characterized by comprising a control means.