JP2001270721A - Press molding apparatus for optical lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To find burning defects in its early stages, improve the stability of appearance quality without transporting lens for inspection and provide an optical lens at a low unit cost. SOLUTION: This press molding apparatus for optical lens is obtained by arranging an automatic lens inspection unit 12 equipped with an image processing unit 21 having an automatic judging treatment function to take in an image of the molded lens 1 and automatically judge defective factors of the molded lens 1 on a transporting rail 3 of the molded lens 1 and is capable of carrying out the quality inspection of the molded lens 1 molded in a molding chamber 11 on the transporting rail 3 in the press molding apparatus for optical lens for press molding glass lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical lens press forming apparatus used for optical equipment.

[0002]

2. Description of the Related Art In a press molding apparatus, a glass material (preform) which has been heated and softened is conveyed to a molding position, and the molded lens is taken out after press molding with a molding die. In general, the basic lens molding process using a transport unit involves storing the preform in a storage pallet → transporting the preform → preheating → main heating → pressing → cooling → transporting the molded lens → removing the molded lens. Has been widely proposed. After the basic molding step, a visual inspection of the molded lens (optical lens) by a skilled worker is performed as a part of a commercialization step.

Conventionally, as a press forming machine of this kind for a glass lens, an apparatus as disclosed in JP-A-5-17167 is known. According to the technology described in JP-A-5-17167, a preform taken out from a storage pallet (magazine) storing a plurality of preforms by a transfer arm is configured by a preheating furnace. Then, it is heated in the main heating furnace and press-formed in the forming chamber. The press-formed lens is taken out of the forming chamber by the transfer arm, cooled by exposing it to room temperature, and stored in a storage pallet.

[0004]

In order to provide a high quality lens to the market in manufacturing a lens, it is essential to inspect the appearance of the lens. However, in the conventional production process, a lens molding machine that produces a lens with a takt time of 20 seconds or less and a good production is a place where a lens molded by a press molding machine is inspected for quality separately from the press molding machine. In order to reduce the number of transportation steps, it was impossible to transport until a certain amount of lenses were stored in the storage pallet. Further, the visual sensory inspection of the lens is a factor that causes variation in quality, and the lens inspection process requires a large number of man-hours, which increases the cost of the lens unit.

[0005] In a molding process as disclosed in Japanese Patent Application Laid-Open No. 5-17167, in a molding method in which the same mold is continuously used, defective lenses are continuously removed due to the occurrence of image sticking due to early deterioration of the mold. It is highly likely that the lens will be manufactured at a low cost, and this will cause a rise in the cost of the lens unit due to a decrease in yield.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and enables early detection of burn-in failure, improvement in the stability of appearance quality without transporting the lens for inspection, and cost per lens. It is an object of the present invention to provide an optical lens press molding apparatus that can reduce the cost.

[0007]

According to a first aspect of the present invention, there is provided an optical lens press forming apparatus for pressing and forming a glass material. An automatic lens inspection unit provided with an image processing device having an automatic discrimination processing function for taking in an image and automatically discriminating the cause of a failure of the molded lens is provided on the lens transport line.

According to a second aspect of the present invention, there is provided an optical lens press-molding apparatus for pressing and molding a glass material, wherein an image of the molded lens is taken in, and the cause of the molded lens defect is automatically determined. An automatic lens inspection unit provided with an image processing apparatus having an automatic discrimination processing function provided on the lens transport line, and discharging the defective lens determined as a defective lens by the automatic lens inspection unit from the lens transport line. And a unit.

Further, a press molding apparatus for an optical lens according to claim 3 of the present invention is the press molding apparatus for an optical lens according to claim 1 or 2, wherein the automatic lens inspection unit comprises a camera for photographing, an illuminating device, An external light protection cover is provided.

That is, according to the optical lens press molding apparatus of the first aspect of the present invention, it is possible to determine whether the press molded lens is good or defective on the molded lens conveyance line.
As a result, defective lenses can be quickly removed, and the number of steps for transporting the lens to a quality inspection position provided at another position can be reduced.

Further, according to the press molding apparatus for an optical lens of the present invention, it is possible to determine whether the press-molded lens is good or defective on the conveying line of the molded lens, and take out the defective lens from the conveying line. Can be. As a result, non-defective lenses and defective lenses can be eliminated, and defective lenses can be eliminated at an early stage, and the number of steps for transporting the lenses to a quality inspection position provided at another position can be reduced.

Further, according to the press molding apparatus for an optical lens of the third aspect of the present invention, while preventing disturbance due to external light,
The image data on the surface of the lens captured by the photographing camera is binarized by the image processing device, and the quality of the lens can be determined.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, referring to FIGS. 1 to 3, which illustrate an outline of an optical lens press forming apparatus according to the present invention, an automatic lens inspection unit 12 penetrates a forming chamber 11 in which a pressing process is performed. Is provided in the middle of a transport rail 3 as a transport line for transporting a molded lens (hereinafter, simply referred to as a lens) 1, and above the transport rail 3,
A CCD camera 13 as a camera for photographing the lens surface is located. A CCD camera fixing jig 14 for fixing the CCD camera 13 and bypassing the conveying rail 3 so as not to contact the conveying rail 3 is fixed to the base 5 of the press forming apparatus.

The lens 1 mounted on the transport rail 3 is mounted on a ring-shaped holder 6 whose upper and lower parts are opened. The holder 6 is an extruding unit 7 composed of a cylinder or the like. Each time the preform 2 is formed by the molding die, the preform 2 is sequentially pressed, moved by a predetermined distance and stopped, and the lens 1 is positioned below the CCD camera 13.

The CCD camera 13 is connected to an image processing device 21 housed in a control box (not shown), and an image on the surface of the lens 1 is always sent to the image processing device 21.

A circular ring illuminating device 15 as an illuminating device for irradiating indirect light to the lens 1 stopped to be conveyed below the CCD camera 13 on the conveying rail 3 has a light source 15
Illumination means such as a red LED, a green LED, and a fluorescent lamp are used for a. The illumination device fixing jig 19 is arranged below the transport rail 3. The center of the CCD camera 13 is fixed via the fixing jig 19. The axis and the central axis of the ring illumination device 15 can be adjusted coaxially, and the position can be adjusted with an adjustment mechanism (not shown) that can move up and down. Ring lighting device 15
Is connected to a light amount adjuster 18 for adjusting the light amount of the light source 15a. Illumination means for irradiating the lens 1 with light from the ring illumination device 15 as indirect light includes a reflection plate 16
And the diffusion plate 17 are provided, but the reflection angle of the reflection plate 16 and the thickness of the diffusion plate 17 can be changed depending on the lens type (or may not be used). The ring illumination device 15 includes a light source 15a, a reflection plate 16, and a diffusion plate 17.

The CCD camera 13 and the ring illumination device 15
Is enclosed by a bottomed cylindrical external light prevention cover 20 provided with a minimum hole 20a through which the transport rail 3 can pass and does not hinder the transport of the lens 1. A discharge unit 27 for discharging the defective lens 22 is provided in the middle of the conveyance rail 3 in front of the automatic lens inspection unit 12 in the conveyance direction of the lens 1.

The lens 1 press-molded in the molding chamber 11
Is mounted on the transport rail 3 passing through the molding chamber 11. The mounted lens 1 is moved on the transport rail 3 by the push-out unit 7 while being placed on the holder 6. When the lens 1 moves below the CCD camera 13 and above the ring illuminator 15, that is, when the lens 1 moves to the center axis of the CCD camera 13 and stops, the image processing device 21 causes the surface of the lens 1 by the CCD camera 13 to move. Capture video from At this time, the ring illuminator 15 installed below the transport rail 3, that is, below the lens 1 irradiates the lens 1 with light.
Since 0 is set, there is no disturbance due to external light in the irradiation light.

The image once captured by the image processing device 21 is used to judge whether the photographed lens 1 is good or bad according to the processing contents input in advance for image processing, and to prevent the lens 1 from being exposed to external light. The non-defective lens is moved to the storage pallet 9 for accommodating the non-defective lens 1 after the non-defective lens is moved to the outside of the cover 20 on the conveying rail 3, and the defective lens is conveyed by the discharge unit 27. It is discharged from the rail 3 to a disposal 23 as a storage unit.

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is an overall perspective view showing a press molding apparatus, and FIGS. 2 and 3 are a perspective view and a sectional view showing a part of an automatic lens inspection unit.

As shown in FIG. 1, the transport rail 3 for moving and guiding the lens 1 and the preform 2 via the holder 6 is formed in a substantially U-shape with the preform supply side A and the lens take-out side B open. The base 5 is a square flat plate
It is fixed to a base 5 via a plurality of rail supports 4 erected above. The preform 2 is fitted into the recess formed in the disc-shaped holder 6 without any gap.
Further, in a state in which the lens 1 is stored, the holder 6 is regulated so that the holder 6 does not fall from the transport rail 3 by a shaft 3 a having the outer peripheral surface of the holder 6 fixed in parallel to both sides of the transport rail 3.

At the end of the transport rail 3 on the preform supply side A, a preform 2 placed on the transport rail 3
The preheating furnace 25 is continuously intermittently fed into the holder 6 accommodating the preform 2 by the time required for press-forming the preform 2 by the same distance as the outer diameter of the holder 6 (ie, the time of one molding cycle). An extruding unit 7 having a driving mechanism 7a such as a cylinder for pushing and pushing the side surface of the holder 6 is disposed on the side. At this time, the plurality of holders 6 on the transport rail 3 are arranged with their side surfaces in contact (close contact), and all the holders 6 are simultaneously moved by the pushing unit 7 by the distance.

The supply robot 8 is disposed on the open side of the U-shape of the transfer rail 3 and, for each molding cycle,
From a supply pallet 24 containing a large number of preforms 2 on one end side of the transport rail 3 (preform supply side A),
The holders 6 containing the preforms 2 can be sequentially gripped and supplied one by one. In addition, the hand 8a of the supply robot 8 can also store the holder 6 storing the molded non-defective lens 1 on the storage pallet 9 from the other end side of the transport rail 3 (lens extraction side B). .

The transport rail 3 is surrounded by the transport rail 3.
A preheating furnace 25 for heating the preform 2 is fixed on the base 5 on one arm side of the U-shaped (preform supply side A), and has a U-shaped bottom side (open side). (On the opposite side of the figure), a main heating furnace 26 for heating the preform 2 to a temperature at which the preform 2 can be molded and a molding chamber 11 provided with a molding die for press-molding the preform 2 into the lens 1 are respectively provided with the holder 6 (preform 2) 1 are fixedly arranged on the base 5 as shown in FIG.

Below the molding chamber 11, there is provided a driving device 10a containing a cylinder and the like fixed to the base 5, and a pair of upper and lower dies for pressing the preform 2 is provided on the top inside the driving device. A press mechanism 10 composed of a cylinder that presses the preform 2 with the lower mold is mounted on the lower mold (not shown). An upper die is attached downward on an inner upper surface of the molding chamber 11 via an upper shaft (not shown), and the upper die and the lower die are conveyed on the conveying rail 3 by the extrusion of the extrusion unit 7. In consideration of the size of the holder 6 and the length of the transfer rail 3, the center axis of the preform 2 and the center axis of the preform 2 stopped for molding and the center axes of the upper mold and the lower mold are matched. The position has been adjusted. Molding room 11
Is provided with a window 11a for internal observation.

An automatic lens inspection unit 12 is provided next to the molding chamber 11 along the transport direction of the holder 6 holding the press-molded lens 1. It is installed on the base 5 at a position (approximately 10 mm) away from the influence of heat from the outside. The automatic lens inspection unit 12 uses the CC
D camera 13, CCD camera fixing jig 14, circular ring illumination device 15 (here, red LED), reflection plate 16,
Diffusion plate 17, light amount adjuster 18, lighting device fixing jig 19,
The diffusion plate 17 is provided with a shielding plate 28 at the center thereof.

The CCD camera 13 is for photographing the surface of the lens 1 and is arranged above the transport rail 13. A CCD camera fixing jig 14 that fixes the CCD camera 13 downward and does not contact the transport rail 3 is fixed to the base 5.
The position and the inclination are adjusted so that the central axis (optical axis) of the lens 1 and the optical axis of the lens 1 placed on the holder 6 on the transport rail 3 are aligned. The CCD camera 13 is connected to an image processing device 21 installed in a control box such as a PC (personal computer) via a cable 29, and the surface image of the lens 1 is always sent to the image processing device 21. I have.

The ring illumination device 15 is a ring-shaped light source 15.
a, which is disposed on a lighting device fixing jig 19 fixed to the base 5 below the transport rail 3, the center axis of the CCD camera 13 and the center of the ring lighting device 15. The shaft can be adjusted coaxially, and has an adjusting mechanism (not shown) that can move up and down so that the position can be adjusted.
The lens 1 in the holder 6 conveyed on the conveyance rail 3 is stopped on the same axis of the CCD camera 13 and the ring illumination device 15. This stop position is
Is transported on the transport rail 3 with the side surfaces in close contact,
In consideration of the size (outer diameter) of the holder 6 and the length of the transport rail 3 up to the coaxial position, the distance is adjusted in advance similarly to the molding position.

The ring illuminator 15 is connected to a light amount controller 18 for adjusting the amount of light of the light source 15a. The ring illuminator 15 has a reflector 16 on the side and a diffuser 17 on the upper side. However, depending on the type of the lens 1, the reflection angle of the reflection plate 16 and the thickness of the diffusion plate 17 are changed.

As shown in FIG. 3, the reflecting plate 16 has a curved surface 16a having a substantially semicircular cross section so as to surround substantially half or more of the outer periphery of the ring-shaped light source 15a. It is formed by connecting the curved surfaces 16a with each other (a disk-shaped plane), and the light from the light source 15a reflected inside the curved surface 16a is irradiated upward from the opening.

The diffusion plate 17 is made of a translucent member such as frosted glass and the like.
6, and irradiates the lens 1 by diffusing light. At the center of the diffuser plate 17, a disc-shaped shielding plate 28 for reducing the light amount is provided at the center of the diffuser plate 17 because if the amount of light irradiated to the lens 1 is too large, observation with the CCD camera 13 becomes difficult. I have.

The reflector 16 has a curved surface 16a having a substantially semicircular cross section so as to surround substantially half or more of the outer periphery of the light source 15a.
Is formed into a donut shape having
The lower part may be opened similarly to the upper part, and an absorbing plate 28a that does not reflect light from a light source (including light reflected by the curved surface 16a) may be arranged below the reflecting plate 16. In this case, the installation of the shielding plate 28 provided on the diffusion plate 17 can be omitted.

The CCD camera 13 and the ring illumination device 15
Is surrounded by a cylindrical external light protection cover 20 provided with a minimum hole 20 a that does not hinder the conveyance of the lens 1, and the light emitted from the ring illumination device 15 to the lens 1 is disturbed by external light. Is not to receive.

A discharge unit 27 having a driving mechanism 27a such as a cylinder for discharging the holder 6 containing the defective lens 22 is provided near the end of the transport rail 3 on the rear side (lens extraction side B) of the automatic lens inspection unit 12. Is fixed to the base 5 via a fixture (not shown), and performs an operation of discharging the defective lens 22 together with the holder 6 from the transport rail 3 by a signal of the automatic lens inspection unit 12. Has become. At the front of the discharge unit 27, a disposal 23 in which the holder 6 on which the defective lens 22 is placed is discharged and stored is arranged on the base 5.

Next, the operation of the above configuration will be described. Preform 2 stored in large numbers on the supply pallet 24
One of the holders 6 accommodating the preform supply side A of the transport rail 3 is gripped by the hand 8a of the supply robot 8 and one of the holders 6 storing the preform is selected.
And is arranged on one end side of the U-shaped transfer rail 3.

The placed holder 6 and preform 2
Is in contact with the side surface of the front holder 6 in the direction of the preheating furnace 25 on the transport rail 3 by the extrusion unit 7 which operates in each press molding (each molding cycle) by the upper and lower dies in the molding chamber 11. , Is intermittently pushed out by the same distance as the outer diameter of the holder 6, and at the same time as the placed holder 6, the transfer rail 3 in front of the holder 6.
All the upper holders 6 move by the distance. By being sequentially extruded, the holder 6 and the preform 2 enter the preheating furnace 25 and are preheated for a certain distance. After passing through the preheating furnace 25, it enters the main heating furnace 26 arranged on the U-shaped bottom side of the transport rail 3, and
It is heated for a certain distance to the temperature required for substantial press molding.

The heated preform 2 and the holder 6 are pushed into the molding chamber 11 and stopped, and the press mechanism 10 is operated to press-mold the upper mold and the lower mold to form the lens 1. When the press molding is completed, the process proceeds to the cooling step. Forcible cooling means can be provided in the molding chamber 11, but the description is omitted here. That is, after the press molding is completed, the next preform 2 can be press-molded during natural cooling performed by discharging the lens 1 out of the molding chamber 11.

The lens 1 placed on the holder 6 is
In order to be sequentially pushed by the pushing unit 7, it is pushed in the direction of the automatic lens inspection unit 12,
The lens 1 is stopped on the central axis of the camera 13 and the ring illumination device 15. At this time, the holder 6 is
Since they move in a state where they are in close contact with each other, the relationship between the size of the holder 6 and the length of the transport rail 3 is taken into consideration beforehand.
The position of the lens 1 to be extruded is adjusted to the central axis of the CD camera 13 and the ring illumination device 15, and there is no need for positioning.

An image of the surface of the lens 1 is captured by the CCD camera 13 fixed to the CCD camera fixing jig 14. At this time, the ring illumination device 15 attached to the illumination device fixing jig 19 The current (or voltage) is adjusted by the adjuster 18 so that the light amount (irradiation amount) of the ring illumination device 15 is controlled, and the irradiation light is reflected by the reflection plate 16 and indirectly transmitted by the diffusion plate 17. The light is emitted from the back side of the lens 1 and reaches the CCD camera 13. Since the external light is prevented from being irradiated by the external light protection cover 20 that covers the CCD camera 13, the lens 1, and the ring illumination device 15, light other than the irradiation light does not impinge on the lens 1.

The image captured by the CCD camera 13 is
It is taken into the image processing device 21 via the cable 29,
The analysis is performed according to a series of processing contents programmed in advance. That is, the light is applied to the lens 1 and the CCD
The image of the surface of the lens 1 captured by the camera 13 is binarized by the image processing device 21 so that the defect content is recognized. Defects on the surface of the lens 1 include a crater in which a small dent is formed on the surface, and a case in which surface peeling occurs due to baking between the molding surface and the glass surface. At this time, the image processing device 21 analyzes the content of the defect based on the outline of the depression or the outline of the peeling, and determines whether the lens 1 is good or defective. In addition, on the display of the image processing device 21, the outline appears as a small bubble-shaped shadow (line) on the lens surface or a line generated as a result of peeling.

Since the time required to capture the image by the CCD camera 13 and the processing time required to determine the defect content by binarization are shorter than the molding tact, the same lens is formed while the lens 1 is being molded in the molding chamber 11. 2 for 1
By performing the repetition of about 30 repetitions, the number of times of retrieving is large, so that the analysis reliability can be improved.

The discharge unit 27 operates based on the result of the pass / fail judged by the image processing device 21. For example, when the result of the analysis is determined to be a defective lens 22, a good lens 1 is sequentially pushed out along with the lens 22 determined to be defective along with a series of molding operations of the lens 1.
When the defective lens 22 comes to the position of the discharge unit 27, the discharge unit 27 is operated to discharge the holder 6 together with the disposable 23 disposed on the base 5. On the other hand, if the analysis result indicates that the lens 1 is a non-defective lens, the discharge unit 27 is not operated, and the lens 1 moves along with the holder 6 on the transport rail 3 to pass through the discharge unit 27 and On the lens take-out side B, the holder 6 is held by the hand 8 a of the supply robot 8 and stored in the storage pallet 9 together with the holder 6. Also,
The failure factors obtained by the image processing are converted into data and fed back to a series of molding conditions, so that a lens 1 of higher quality can be obtained.
Can be formed.

According to this embodiment, the automatic lens inspection unit 12 by the image processing apparatus 21 is installed on the transport rail 3 during the transport process immediately after molding, so that the lens originally used for natural cooling can be used. Since the appearance inspection can be performed during the cooling step (1), early detection of burn-in failure and reduction of the quality inspection speed are realized.

The technical idea having the following configuration is derived from the specific embodiment described above. (Supplementary note) (1) An optical lens press-molding apparatus for pressing and molding a glass material, comprising an image processing apparatus having an automatic discrimination processing function for taking in an image of a molded lens and automatically discriminating a cause of a defect of the molded lens. The automatic lens inspection unit provided on the transport line of the above, a discharge unit for discharging a defective lens determined as a defective lens by the automatic lens inspection unit from the lens transport line, and a defective lens discharged by the discharge unit are stored. A press forming apparatus for an optical lens, comprising:

According to the optical lens press molding apparatus of the present invention (1), it is possible to determine whether the press molded lens is good or defective on the molded lens transport line, and take out the defective lens from the transport line and store it. Can be stored separately from the non-defective lens. As a result, non-defective lenses and defective lenses can be eliminated, and defective lenses can be eliminated at an early stage, and the number of steps for transporting the lenses to a quality inspection position provided at another position can be reduced.

[0046]

As described above, according to the press molding apparatus for an optical lens of the first aspect of the present invention, the automatic lens inspection unit by the image processing apparatus is installed on the transport line on the lens molding machine, so that the image sticking is performed. It is possible to reduce defective lenses by early detection of defects, abolish the lens transport process to the visual inspection process, improve the stability of visual quality by automatic visual inspection, and reduce the number of artificial visual inspections. It became possible to provide.

According to the optical lens press molding apparatus of the second aspect of the present invention, it is possible to distinguish a non-defective lens from a defective lens and to provide only non-defective lenses to the market reliably and at a lower cost. . Other effects are the same as those of the first aspect of the present invention.

Further, according to the optical lens press molding apparatus of the third aspect of the present invention, while preventing disturbance due to external light,
The image data on the surface of the lens captured by the photographing camera is binarized by the image processing device, and the quality of the lens can be determined.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a part of the automatic lens inspection unit according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a part of the automatic lens inspection unit according to the first embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens 2 preform 3 transfer rail 6 holder 7 push-out unit 12 automatic lens inspection unit 13 CCD camera 15 ring illuminator 16 reflector 17 diffuser 20 external light protection cover 21 image processing device 22 defective lens 23 disposable 27 discharge unit 28 Shield

Claims (3)

[Claims] An optical lens press-molding apparatus for pressing and molding a glass material, comprising: an automatic lens having an image processing apparatus having an automatic discrimination processing function for taking in an image of a molded lens and automatically discriminating a cause of a defect of the molded lens. An optical lens press-forming apparatus, comprising: an inspection unit on a lens transport line. 2. An optical lens press forming apparatus for pressing and forming a glass material, comprising: an image processing apparatus having an automatic discrimination processing function for taking in an image of the formed lens and automatically discriminating a cause of a defect of the formed lens. Press molding of an optical lens, comprising: an automatic lens inspection unit provided on a transport line; and a discharge unit for discharging a defective lens determined as a defective lens by the automatic lens inspection unit from the lens transport line. apparatus. 3. The apparatus according to claim 1, wherein the automatic lens inspection unit includes a camera for photographing, an illuminating device, and a cover for preventing external light.