KR20120024698A - Imaging device and method of producing imaging device - Google Patents

Abstract

An object of the present invention is to provide an imaging device and a method of manufacturing the same, which can increase the manufacturability and reduce the cost. In the present invention, the resin imaging lens is heated from the outside of the light shielding frame in the reflow tank, but is effectively shielded by the heat resistant light shielding frame and the space, so that the temperature rise of the internal imaging lens can be suppressed. . In addition, the temperature rise of the imaging lens can be suppressed by constructing the base frame from a material having a low thermal conductivity. By the above, an imaging lens can be formed from the resin material with low heat resistance, and cost reduction can be aimed at.

Description

Imaging device and manufacturing method of imaging device {IMAGING DEVICE AND METHOD OF PRODUCING IMAGING DEVICE}

TECHNICAL FIELD This invention relates to the imaging device and the manufacturing method of an imaging device. Specifically, It is related with the imaging device provided with the resin imaging lens and imaging element, and the manufacturing method of an imaging device.

In recent years, portable telephones to which a photographing function is provided by incorporating an imaging device have become popular. In addition, in order to facilitate the embedding of a shooting function in a small electronic device such as a mobile phone, an optical module in which an imaging lens is built in, and a camera module in which a mounting board provided with a solid-state imaging element and a control circuit are assembled and unitized are provided. It is becoming.

Here, in the conventional imaging device, transmission and reception of signals between the substrate and the imaging device are performed through a plurality of wires connected to each other. However, wire bonding to connect the wires is required, and thus, labor and time are required. There is a problem. On the other hand, Patent Literature 1 discloses a technique capable of performing wiring connection without using wire bonding by directly mounting an imaging device on the back surface of a glass substrate.

Japanese Patent Publication No. 2007-288755

By the way, in patent document 1, when mounting an image pick-up element on the back surface of a glass substrate, a solder ball is arrange | positioned in several places to be wired, and it internally flows through the reflow tank to which the solder ball melted. By the wiring connection, it is described that the manufacturing process can be simplified and the number of steps can be reduced. By the way, the resin (PC etc.) with high optical performance used for an imaging lens has the problem that it is comparatively low in heat resistance, and deforms when it passes a reflow tank, and deteriorates an optical characteristic. On the other hand, although it can be considered that forming an imaging element from the glass material which has heat resistance, it will be sufficient, but the other problem of causing high cost of an imaging lens arises.

This invention is made | formed in view of such a trouble of the prior art, and an object of this invention is to provide the imaging device which can raise cost, and can reduce cost.

The imaging device of claim 1,

A transparent substrate having a wiring section on one side;

An imaging device disposed on the one side of the substrate so as to be connected to the wiring portion;

An imaging lens made of resin disposed on the other side of the substrate;

An imaging device having a housing surrounding the imaging lens,

The manufacturing process of the imaging device includes at least a step of exposing to a high temperature environment in a state where the imaging lens and the housing are disposed with respect to the substrate,

The housing includes a base frame having a low thermal conductivity provided on the substrate, and a heat resistant light shielding frame which is assembled to the base frame and extends in an optical axis direction to cover the imaging lens, and between the light blocking frame and the imaging lens. A space is provided.

According to the present invention, the housing includes a base frame having a low thermal conductivity installed on the substrate, and a heat resistant light blocking frame which is assembled to the base frame and extends in an optical axis direction to cover the imaging lens. Since a space is provided between the imaging lenses, at the time of manufacture, even if the process of being exposed to a high temperature environment with the imaging lens and the housing disposed with respect to the substrate is performed, the imaging lens is provided by the housing and the space. Can be shielded, and the base frame can suppress that external heat is conducted to the imaging lens. Thereby, thermal distortion of the said imaging lens can be suppressed and deterioration of optical performance can be suppressed.

Therefore, it is possible to pass a reflow process, for example, with the said imaging lens assembled, and it can manufacture an imaging device in a short time and at low cost. In addition, "high temperature environment" means the environment maintained at least 200 degreeC or more, and "material with low thermal conductivity" means a material of 10 W / m * K or less, for example, there are ceramics, such as silicon nitride and zirconia. In addition, the material which has heat resistance means the raw material which does not deform | transform at 260 degreeC, for example. Although there exist metals, such as aluminum, for example, heat resistant resins, such as a thermosetting resin, may be sufficient.

The imaging device according to claim 2, in the invention according to claim 1, wherein the base frame has a recess coupled to a leg portion of the imaging lens and / or a projection coupled to at least two edges intersecting the substrate, By engaging the imaging lens to the concave portion of the base frame or engaging the projection of the base frame to at least two edges intersecting the substrate, the imaging lens is at least in the optical axis direction and the optical axis orthogonal direction with respect to the substrate. It is characterized by positioning in one direction. As a result, by simply assembling the imaging lens to the base frame, the center of the imaging surface of the imaging device can be accurately positioned at the focal position of the imaging lens, and the manufacturing process can be simplified.

In the imaging device according to claim 3, in the invention according to claim 2, the material of the base frame is ceramic, and the material of the light shielding frame is metal or heat resistant resin.

The imaging device according to claim 4 is the invention according to any one of claims 1 to 3, wherein the light shielding frame has an opening through which object light passes to the imaging lens, and the imaging lens and the housing with respect to the substrate. In the process of exposing to a high temperature environment in the state of arranging, the opening is shielded by the lid member. Thereby, it is possible to suppress that external heat is conducted to the imaging lens through the opening of the light shielding frame.

The manufacturing process of the imaging device of Claim 5 is

A transparent substrate having a wiring section on one side;

An imaging device disposed on the one side of the substrate so as to be connected to the wiring portion;

An imaging lens made of resin disposed on the other side of the substrate;

It is a manufacturing method of the imaging device which has the housing made of resin surrounding the said imaging lens,

A first step of forming an intermediate assembly in which the imaging element, the imaging lens, and the housing are disposed on the substrate;

A second step of exposing the intermediate assembly to a high temperature environment with a heat-resistant cap around the housing;

And after cooling of the intermediate assembly, a third process of removing the cap.

According to the present invention, the intermediate assembly is exposed to a high temperature environment in a state where a heat-resistant cap is wrapped around the housing, whereby the cap can be shielded to shield the housing and the imaging lens, thereby capturing the image. The thermal deformation of the lens can be suppressed and the deterioration of optical performance can be suppressed.

The manufacturing method of the imaging device of Claim 6 is the invention of Claim 5 WHEREIN: The said 2nd process is a reflow process which electrically connects the wiring part of the said board | substrate with the said imaging element by soldering, It is characterized by the above-mentioned.

According to the present invention, it is possible to provide an imaging device and a method of manufacturing the same, which can increase the manufacturability and reduce the cost.

1 is a perspective view of an imaging device 50 according to the present embodiment.
FIG. 2 is a cross-sectional view taken along the line of arrow II-II and viewed in the direction of the arrow. FIG.
3 is a diagram illustrating a manufacturing method of the imaging device according to the present embodiment.
4 is a diagram illustrating a manufacturing method of an imaging device according to another embodiment.
FIG. 5 is a diagram showing a state where the imaging device 50 is equipped with the mobile telephone 100 as a mobile terminal.
6 is a control block diagram of the mobile phone 100.
FIG. 7: (a) is the figure which looked at the unit with which the image sensor 51 was assembled with respect to the glass substrate GP, (b) is the figure which looked at the structure of (a) in the arrow XB direction.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. FIG. 1 is a perspective view of an imaging device 50 according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II of the configuration of FIG. 1 and viewed in an arrow direction. As shown in Fig. 2, the imaging device 50 includes a CMOS image sensor 51 serving as a solid-state imaging device having a photoelectric conversion section 51a, and a subject to the photoelectric change section 51a of the image sensor 51. An imaging lens 10 for forming an image, a transparent glass substrate GP that is a parallel plate in a rectangular plate shape having the image sensor 51 attached to the back, and a housing 20 covering the imaging lens 10. have. In FIG. 2, HB is the solder ball fixed to the wiring part of glass substrate GP, and the solder ball HB which contact | connects the back surface of glass substrate GP is shown by the dotted line.

The image sensor 51 has a photoelectric conversion section 51a serving as a light receiving section in which a pixel (photoelectric conversion element) is two-dimensionally arranged in the center of the light receiving side plane, and a signal processing circuit (shown in the periphery thereof). Not formed) is formed. Such a signal processing circuit includes a driving circuit section for sequentially driving each pixel to obtain signal charges, an A / D converter for converting each signal charge into a digital signal, a signal processing section for forming an image signal output using the digital signal, and the like. It consists of. Moreover, many terminal 5lb (refer FIG.7 (b)) is formed in the vicinity of the outer edge part of the plane on the light receiving side of the image sensor 51, On the back (lower surface) of the glass substrate GP The wiring portion GPa which is the printed wiring is formed by metal deposition or the like. The terminal 5lb of the image sensor 51 is electrically connected to the wiring portion GPa via the stud bump SB (see FIG. 7A).

The image sensor 51 converts the signal charge from the photoelectric conversion section 51a into an image signal such as a digital YUV signal, or the like, and uses an external circuit (not shown) (not shown) via the wiring section GPa. And a supply of a voltage and a clock signal for driving the image sensor 51 from an external circuit. Here, Y is a luminance signal, U (= B-Y) is a color difference signal Cb of blue and luminance signals, and V (= R-Y) is a color difference signal Cr of red and luminance signals. In addition, an imaging element is not limited to the said CMOS image sensor, You may use another thing, such as CCD.

The housing 20 which consists of a light shielding material consists of the base frame 21 made from ceramics, and the light shielding frame 22 of the substantially cylindrical shape made from aluminum. The base frame 21 has a rectangular flat plate-shaped body 21a, projections 2lb projecting downward from the side edges of the body 21a so as to surround the glass substrate GP, and the body 21a. It has the annular wall 21c which protrudes from an upper surface. A rectangular opening 21d is formed in the center of the main body 21a. The inner side of the annular wall 21c constitutes a recess.

When the base frame 21 and the glass substrate GP have assembled the base frame 21 to the glass substrate GP, the lower surface of the main body 21a contacts the upper surface of the glass substrate GP, and protrusions 2lb. ) Contacts the side edge portion of the glass substrate GP so as to be positioned in the optical axis direction and the optical axis orthogonal direction in the imaging lens 10. Moreover, you may fix the base frame 21 to the glass substrate GP with the heat resistant adhesive agent which is not shown in figure. In addition, although the protrusion 2lb is configured to surround the glass substrate GP, that is, is coupled to the four peripheral edges of the glass substrate GP, it is coupled to at least two edges intersecting the glass substrate GP. You may turn it. In this case, it is suitable to couple to the edge of the glass substrate GP by adhesion or spring pressing.

The light shielding frame 22 has a cylindrical body 22a, a flange portion 22b formed so as to extend radially inward from the upper end of the body 22a, and a circular opening 22c formed in the center of the flange portion 22b. Has By fitting the lower end of the main body 22a to the outer periphery of the annular wall 21c of the base frame 21, the light shielding frame 22 is coaxially attached to the base frame 21. As shown in FIG. Moreover, you may fix the light shielding frame 22 to the base frame 21 with the heat resistant adhesive agent which is not shown in figure.

The imaging lens 10, which is a surface side (upper side) of the glass substrate GP and is provided at the center of the housing 20, has a first lens L1, a second lens L2, and a third lens L3 from an object side. ), The flange portions extending in the axial direction are bonded together and fixed to each other by an adhesive, thereby ensuring a high accuracy between the lenses. The end surface of the flange portion L3a of the third lens L3 closest to the image sensor 51 contacts the upper surface of the main body 21a of the base frame 21, and the outer circumference of the flange portion L3a is annular. It is fitted to the inner periphery of the shape wall 21c.

As a result, the imaging lens 10 is accurately positioned with respect to the base frame 21. That is, if the optical axis direction length (position of the end surface with respect to the lens part) of the flange part L3a, the thickness of the main body 21a of the base frame 21, and the thickness of the glass substrate GP are managed, an imaging lens 10 and the image sensor 51 can be positioned with high accuracy in the optical axis direction. In addition, if the outer circumferential surface of the flange portion L3a, the annular wall 21c of the base frame 21 to which it is coupled, the projection 2lb, and the dimensional shapes of the glass substrate GP to which it is coupled are managed, imaging The lens 10 and the glass substrate GP1 can be accurately positioned in the optical axis orthogonal direction. Therefore, by assembling the image sensor 51 to the glass substrate GP with high accuracy, the focal position of the imaging lens 10 passes through the glass substrate GP, so that the photoelectric conversion section 51a of the image sensor 51 is formed. It is made to match with high precision in the center. In addition, a peripheral groove 21e (not shown) is formed inside the annular wall 21c of the base frame 21, and the third lens is formed by a heat resistant adhesive filled in the peripheral groove 21e. L3) is fixed to the base frame 21.

Here, the flange portion L3a of the third lens L3 constitutes a leg portion of the imaging lens 10, which leg portion is in contact with the main body 21a of the base frame 21, and further has an annular wall 21c. ) Can be positioned in the optical axis direction and the optical axis orthogonal direction. In addition, in this embodiment, although positioning is carried out in both directions of an optical axis direction and an optical axis orthogonal direction, positioning in only one direction by this structure is performed, and positioning in another direction may be used by another method.

A donut plate-shaped light blocking member SH1 is fixed to the upper portion of the flange portion L1a of the first lens L1, and a donut plate-shaped aperture member is fixed to the upper portion of the flange portion L2a of the second lens L2. AP is fixed, and the annular light blocking member SH2 is fixed to the upper portion of the flange portion L3a of the third lens L3. By the light blocking members SH1 and SH2, unnecessary light is prevented from entering the inside of the housing 20, and generation of ghosts and flares can be suppressed. Light rays (subject light) incident on the imaging lens 10 through the center opening 22c of the light shielding frame 22 pass through the opening 21d of the base frame 21 and are transmitted through the glass substrate GP. Thus, an image is formed in the photoelectric conversion section 51a of the image sensor 51.

Although it is clear from FIG. 2, the cylindrical space SP is provided between the light shielding frame 22 and the imaging lens 10, and is ensuring heat shielding by this.

Next, with reference to FIG. 3, the manufacturing method of the imaging device which concerns on this embodiment is demonstrated. 3 is a diagram illustrating a manufacturing method of the imaging device according to the present embodiment. First, as shown in FIG. 7, the image sensor 51 is assembled so that it may become parallel with the glass substrate GP, and is unitized. Specifically, for example, a stud bump SB made of gold is formed on the inner end of the wiring portion GPa, which is a plurality of printed wirings formed by metal deposition or the like, on the back surface of the glass substrate GP. The bump SB is vibrated in contact with the terminal 5lb of the image sensor 51 and welded with frictional heat. Thereby, the terminal 5lb and the wiring portion GPa can be connected.

Next, the solder balls HB are fixed to the outer ends of the wiring portions GPa, respectively. In addition, although the terminal 5lb and the wiring part GPa may be connected using solder plating instead of the stud bump, the solder plating in this case needs to have a higher melting temperature than the solder balls HB.

In addition, as shown in Fig. 3A, the base frame 21 and the imaging lens 10 are assembled and fixed on the glass substrate GP having the image sensor 51 assembled on the back side. The light shielding frame 22 is fixed to the base frame 21. The circular opening 22c of the light shielding frame 22 is covered with aluminum cover member DP (1st process). An aluminum tape may be attached instead of the lid member DP. The above is called intermediate assembly MA. In addition, the solder ball HB fixed to the wiring portion GPa of the glass substrate GP is brought into contact with the printed wiring LF of the printed circuit board CB on which other electronic circuit components (not shown) are mounted. The intermediate assembly MA is loaded onto the printed board CB.

Subsequently, as shown in FIG. 3B, in the reflow tank RB heated by the heater HT, at 240 ° C. for 10 seconds (for example, time and temperature at which the operation of the electronic component is guaranteed). The intermediate assembly MA is held together with the printed circuit board CB (the process exposed to a high temperature environment or the second process). As a result, the solder balls HB are melted by the heat of the heater HT and the printed wirings LF of the printed circuit board CB are electrically connected to each other at the same time as the connection of other electronic circuits (not shown). do. However, adhesion between the stud bump SB and the terminal 5lb, which has a higher melting temperature than the solder ball HB, does not peel off. As mentioned above, the connection of an external electronic circuit and the image sensor 51 is performed, and the trouble of connection can be reduced significantly.

At this time, the imaging lens 10 is heated from the outside of the light shielding frame 22 in the reflow tank RB, but is effectively shielded by the aluminum light shielding frame 22 and the space SP. The increase in temperature of the internal imaging lens 10 can be suppressed. In addition, since the base frame 21 is made of ceramic, the heat transfer property is low, and the temperature rise of the imaging lens 10 can be suppressed. Thereby, the thermal deformation of the imaging lens 10 can be suppressed. Therefore, the imaging lens 10 can be formed with the resin material with low heat resistance, and cost reduction can be aimed at.

Thereafter, as shown in Fig. 3C, the molten solder ball is solidified (H) by taking out the intermediate granules MA from the reflow tank RB and cooling them (third step). The terminal of the image sensor 51 is permanently connected to the printed wiring LF of the printed circuit board CB via the wiring portion GPa. In addition, the imaging device 50 can be manufactured by removing the cover member DP. The removed cover member DP can be reused.

4 is a diagram illustrating a manufacturing method of an imaging device according to another embodiment. In the present embodiment, the light shielding frame 22 may be made of a resin having low heat resistance. First, as mentioned above, the image sensor 51 is assembled and unitized with respect to the glass substrate GP.

In addition, as shown in Fig. 4A, the base frame 21 and the imaging lens 10 are assembled and fixed on the glass substrate GP having the image sensor 51 assembled on the back side. The light shielding frame 22 is fixed to the base frame 21. In addition, a ceramic cap CP (cylindrical shape or cylindrical shape in which the upper end is closed) is covered on the outside of the light shielding frame 22 and the base frame 21. In such a state, it is preferable that a gap Δ is formed between the cap CP and the light shielding frame 22, but may be in contact with the base frame 21. In addition, the solder ball HB fixed to the wiring portion GPa of the glass substrate GP is brought into contact with the printed wiring LF of the printed circuit board CB on which other electronic circuit components (not shown) are mounted. The intermediate assembly MA is loaded onto the printed board CB.

Subsequently, as shown in FIG. 4B, in the reflow tank RB heated by the heater HT for 10 seconds at 240 ° C. (for example, time and temperature at which the operation of the electronic component is guaranteed). The intermediate assembly MA is held together with the printed circuit board CB (the process exposed to a high temperature environment or the second process). As a result, the solder balls HB are melted by the heat of the heater HT and the printed wirings LF of the printed circuit board CB are electrically connected to each other at the same time as the connection of other electronic circuits (not shown). do. However, adhesion between the stud bump SB and the terminal 5lb, which has a higher melting temperature than the solder ball HB, does not peel off. As mentioned above, the connection of an external electronic circuit and the image sensor 51 is performed, and the trouble of connection can be reduced significantly.

At this time, the imaging lens 10 is heated from the outside of the cap CP in the reflow tank RB, but is internally shielded by the ceramic cap CP and the light shielding frame 22, so that The temperature rise of the imaging lens 10 can be effectively suppressed. In addition, since the base frame 21 is made of ceramic, the heat transfer property is low, and the temperature rise of the imaging lens 10 can be suppressed. Thereby, the thermal deformation of the imaging lens 10 can be suppressed. Therefore, the imaging lens 10 can be formed with the resin material with low heat resistance, and cost reduction can be aimed at.

Thereafter, as shown in FIG. 4C, the molten solder ball solidifies (H) by taking out the intermediate granules MA from the reflow tank RB and cooling (third step). The terminal of the image sensor 51 is permanently connected to the printed wiring LF of the printed circuit board CB via the wiring portion GPa. In addition, the imaging device 50 can be manufactured by removing the cap CP. The removed cap CP can be reused. The cap CP may not be made of ceramic, but may be made of metal such as aluminum, for example.

The usage form of the imaging device 50 mentioned above is demonstrated. FIG. 5 is a diagram showing a state where the imaging device 50 is equipped with the mobile telephone 100 as a mobile terminal. 6 is a control block diagram of the mobile telephone 100.

In the imaging device 50, for example, the object-side end surface of the housing 20 in the imaging lens is provided on the rear surface of the mobile phone 100 (with the liquid crystal display side in front), and corresponds to the lower side of the liquid crystal display. It is arrange | positioned so that it may become a position.

The imaging device 50 is connected to the control part 101 (refer FIG. 6) of the mobile telephone 100 via the wiring part GPa (FIG. 2) of glass substrate GP, and is a luminance signal, a chrominance signal, etc. Is output to the control unit 101 side.

On the other hand, as shown in FIG. 6, the mobile phone 100 collectively controls each unit, and inputs a control unit (CPU) 101 for executing a program according to each process, a number, and the like by keys. An input unit 60 for displaying, a display unit 70 for displaying captured images, images, etc. in addition to predetermined data, a wireless communication unit 80 for realizing various information communication with an external server, and a mobile telephone ( A storage unit (ROM) 91 storing necessary data such as a system program of 100, various processing programs, and terminal ID, various processing programs and data executed by the control unit 101, or processing data; or The imaging device 50 is provided with a temporary storage unit (RAM) 92 which is used as a work area for temporarily storing image data or the like.

When the photographer holding the cellular phone 100 faces the imaging lens 10 of the imaging device 50 with respect to the subject, an image signal is introduced into the image sensor 51. At a desired shutter chance, the release is performed by the photographer pressing the button BT shown in Fig. 5, and the image signal is introduced into the imaging device 50. The image signal input from the imaging device 50 is transmitted to the control system of the mobile phone 100, stored in the storage unit 92 or displayed on the display unit 70, and further via the wireless communication unit 80. The image information is transmitted to the outside as image information.

As mentioned above, although this invention was demonstrated with reference to embodiment, this invention should not be interpreted limited to the said embodiment, Of course, change and improvement are possible suitably. The light shielding frame 22 may be formed with heat resistant resin. In addition, you may provide an IR cut filter film in the upper surface of glass substrate GP.

10 Imaging Lens
20 housing
21 base frame
21a main body
21b turning
21c annular wall
21d opening
Home around 21e
22 shading frame
22a body
22b flange
22c circular opening
50 imaging device
51 image sensor
51a photoelectric converter
AP aperture member
CP cap
DP cover member
GP glass substrate
GPa wiring section
HB solder ball
HT heater
L1 first lens
L1a Flange
L2 second lens
L2a flange
L3 third lens
L3a flange
MA intermediate assembly
RB Reflow Jaw
SH1 shading member
SH2 shading member
SP space
Δ gap

Claims (6)

A transparent substrate having a wiring section on one side;
An imaging device arranged on the one side of the substrate so as to be connected to the wiring portion;
An imaging lens made of resin disposed on the other side of the substrate;
An imaging device having a housing surrounding the imaging lens,
The manufacturing process of the imaging device includes at least a step of exposing to a high temperature environment in a state where the imaging lens and the housing are disposed with respect to the substrate,
The housing includes a base frame having a low thermal conductivity installed on the substrate, and a heat resistant light blocking frame assembled to the base frame and extending in the optical axis direction to cover the imaging lens, wherein the light blocking frame and the imaging lens An imaging device, characterized in that a space is provided. The method of claim 1, wherein the base frame has a concave portion coupled to the leg portion of the imaging lens and / or projections coupled to at least two edges of the substrate,
By engaging the imaging lens to the concave portion of the base frame or engaging the projection of the base frame to at least two edges intersecting the substrate, the imaging lens is at least in the optical axis direction and the optical axis orthogonal direction with respect to the substrate. Positioning in the one direction characterized by the above-mentioned. The imaging device according to claim 2, wherein the base frame is made of ceramic and the light blocking frame is made of metal or heat resistant resin. The said light shielding frame has an opening which passes the object light to the said imaging lens,
And the opening is shielded by a lid member in a step of exposing the imaging lens and the housing to the substrate to a high temperature environment. A transparent substrate having a wiring section on one side;
An imaging device disposed on the one side of the substrate so as to be connected to the wiring portion;
An imaging lens made of resin disposed on the other side of the substrate;
It is a manufacturing method of the imaging device which has the housing made of resin surrounding the said imaging lens,
A first step of forming an intermediate assembly in which the imaging element, the imaging lens, and the housing are disposed on the substrate;
A second step of exposing the intermediate assembly to a high temperature environment with a heat-resistant cap around the housing;
And a third step of removing the cap after cooling the intermediate assembly. The method of manufacturing an image pickup apparatus according to claim 5, wherein the second step is a reflow step of electrically connecting a wiring portion of the substrate and the image pickup device by soldering.

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