JP2010036112A - Method for processing light emitting diode (led)-built-in product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of processing LED-built-in products which enable advantageous utilization resources contained in LED backlight modules built in the LED-built-in products. <P>SOLUTION: The method for processing LED-built-in products involves a step of disassembling a wiring board from an LED-built-in product, a step of disassembling an LED module from the wiring board, a crushing step of crushing the LED module, a separation step of separating a compound semiconductor material and metals from the crushed debris of the LED module, and a recovery step of recovering metals from the metals-containing crushed debris. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a processing method particularly effective for effective use of resources contained in a product equipped with a light emitting diode (LED).

  Light Emitting Diodes (LEDs) are mainly used as backlight sources for small and medium-sized liquid crystal displays in mobile phones, car navigation systems, personal digital assistants (PDAs), notebook computers, and some liquid crystal televisions. in use. In the future, it is predicted that the replacement of conventional incandescent lamps and fluorescent lamps will progress rapidly due to improved performance as a light source by improving the luminous efficiency and color rendering of LEDs, and will rapidly spread as a light source for general lighting equipment. In addition, low environmental load performance, such as energy saving, has a boost at the policy level, and it is predicted that the spread of lighting fixtures using LEDs as light sources will be accelerated.

  By the way, the demand for liquid crystal display devices including liquid crystal televisions and liquid crystal monitors, which are one of the main uses of LEDs, has become a recent global environmental problem due to the power saving, space saving, light weight and suitable for receiving digital broadcasting images. With the growing interest in Japan and the digitization of television broadcasts, it is increasing rapidly. In particular, the demand for large-screen LCD TVs with large LCD panels, LCD monitors for information displays and computers is increasing dramatically. Liquid crystal display devices such as liquid crystal televisions and liquid crystal monitors are non-light emitting types that do not emit light themselves, and there are those that use LEDs or cold cathode fluorescent lamps (CCFLs) as light sources, Conventionally, most of them use CCFLs. However, backlights using LEDs are expected to increase rapidly in the future due to demands for thinning liquid crystal display devices and improving color reproducibility.

  As mentioned above, with the rapid spread of lighting fixtures and liquid crystal display devices using LEDs, the amount of waste is expected to increase rapidly in the future, and the recycling society is expected to coexist with the environment. In the formation of the above, it is desired to recycle the lighting apparatus and the liquid crystal display device on which the LED is mounted and to effectively use the resources. In particular, the LED uses a light emitting material whose main component is a compound semiconductor such as GaAs (gallium arsenide), GaP (gallium phosphide), GaN (gallium nitride) or the like. Of these, gallium is a rare metal. Some of them use copper as a terminal material. Furthermore, some LED packages use precious metals and expensive gold as wire bond materials. Therefore, it is desired to efficiently treat a product equipped with LEDs (LED-equipped product) and recover metal resources such as gallium, copper and gold.

  As a method of recycling lighting fixtures, some methods have been implemented in which the fluorescent tube is removed, the fluorescent tube is crushed, mercury is removed from the fluorescent tube glass, and the recovered glass is recycled to glass wool or fluorescent tube glass. .

  Japanese Patent Laid-Open No. 6-168253 (Patent Document 1) discloses a method for displaying a processing method and used material information on a part of a liquid crystal television product as a bar code, and dismantling at a dismantling line when dismantling at a recycling plant. Discloses a method and a system for reading a bar code or the like and developing a dismantling operation.

  In JP 2000-44237 (Patent Document 2), as a method for treating semiconductor scrap mainly composed of GaP discharged when manufacturing an LED, the scrap is vacuum-heated and decomposed into gallium and phosphorus. A method for recovering gallium is disclosed.

Japanese Patent Application Laid-Open No. 2001-115289 (Patent Document 3) discloses a method for treating semiconductor scrap containing GaP as a main component by heating and melting the scrap together with a eutectic salt composed of sodium hydroxide and potassium hydroxide. A method of completely decomposing and recovering gallium by electrowinning is disclosed.
JP-A-6-168253 JP 2000-44237 A JP 2001-115289 A

  Liquid crystal display devices equipped with LED lighting fixtures and LED backlights can contribute to power saving and resource saving while increasing attention to global environmental problems. In the future, the number and quantity of LED-mounted products to be discarded are expected to increase rapidly.

  Conventionally, an appropriate processing method for recycling an LED-mounted product has not been established, and the actual situation is that technology establishment is delayed as compared with recycling of a product including a fluorescent tube as a light source. Therefore, in the future, establishment of a processing method for recycling in preparation for an increase in the number of products with LED to be discarded will be urgently required.

  Here, some LEDs use rare metals such as gallium and noble metals such as copper and gold. Therefore, it is desired to efficiently dismantle LED-mounted products and recover metal resources such as gallium, copper and gold. However, currently practiced methods for recycling lighting fixtures are directed to those in which the light source is a fluorescent tube, and recycling of lighting fixtures in which the light source is an LED has hardly been implemented. In addition, the method disclosed in Patent Document 1 described above does not describe a method for processing a backlight module used in a liquid crystal display device, and an LED cannot be effectively used as a resource.

  In LED mounted products, the wiring board on which the LED module is mounted is fixed to the housing or chassis of the product, and in order to efficiently recover metal resources such as gallium, gold and copper contained in the LED It is necessary to separate the LED module from the product casing or chassis. However, the methods disclosed in Patent Documents 2 and 3 are intended for defective process materials discharged from the LED manufacturing process, and do not describe a method for taking out semiconductor scrap such as LEDs from the final product.

  In addition, when looking at operations at home appliance recycling plants, it is desirable to have a method for processing LED-equipped products that do not use energy from heating and combustion as much as possible and do not use difficult-to-process chemicals such as strong acids and strong alkalis. Yes.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to enable effective use of resources included in an LED backlight module mounted on an LED-mounted product. It is providing the processing method of LED mounting products.

  The processing method of the LED mounting product of the present invention includes a step of removing the wiring board from the LED mounting product, a step of removing the LED module from the wiring board, a crushing step of crushing the LED module, and a compound semiconductor from the crushed LED module. The method includes a separation step of separating the material and the metal, and a recovery step of recovering the metal from the crushed material containing the metal.

  The LED-mounted product in the present invention is preferably an LED lighting device or a liquid crystal display device.

  In the method for treating an LED-mounted product according to the present invention, the separation step separates the crushed LED module obtained in the crushing step into a compound semiconductor material and metal, plastic, and ceramics by a separation method using a specific gravity difference. It is preferable that it is a process to perform.

  Moreover, the separation step in the processing method of the LED-mounted product of the present invention includes the LED module crushed material obtained in the crushing step, heavy specific gravity particles containing compound semiconductor material and metal, and light specific gravity particles containing plastic and ceramics. More preferably, it is a step of separating into types.

  The separation method using the specific gravity difference in the separation step in the present invention is a method using thin flow sorting in which water and crushed material are supplied onto an inclined rocking table and classified into heavy specific gravity particles and light specific gravity particles. It is preferable that

  In addition, the separation method using the specific gravity difference in the separation step of the present invention may be a method of supplying water and crushed material into a rotating water tank and sorting the specific gravity difference using a centrifugal field.

  ADVANTAGE OF THE INVENTION According to this invention, the processing method of the LED mounting product for recycling which can collect | recover resources efficiently from LED mounting product can be provided. Moreover, according to the processing method of the LED mounting product of this invention, since the material is separated and collected from the LED mounting product, it is possible to process the LED mounting product that generates almost no waste.

  FIG. 1 is a flowchart showing a preferred example of the processing method of the LED mounted product of the present invention. As shown in FIG. 1, the processing method of the LED mounting product of the present invention includes a step of removing the wiring board from the LED mounting product (step S1), a step of removing the LED module from the wiring board (step S2), and an LED module. A crushing step (step S3), a separation step (step S4) for separating the compound semiconductor material and the metal from the crushed product of the LED module, and a recovery step (step S5) for recovering the metal from the crushed product containing the metal. Is basically included. With such a method for treating an LED-mounted product of the present invention, resources used in the LED can be efficiently recovered. Moreover, according to the processing method of the product which mounts such LED of this invention, resources can be efficiently collect | recovered from the disassembled components and materials.

  Prior to specific description of the above steps, a typical structure of an LED-mounted product used in the processing method of the present invention will be described first. FIG. 2 is an exploded perspective view schematically showing the structure of an LED lighting apparatus which is an example of a product equipped with a typical LED used in the present invention. As shown in FIG. 2, a typical LED lighting apparatus provided for the present invention basically includes an LED module 1, a wiring board 2, a housing 3, a lens 4 and a cover 5.

  FIG. 3 is an exploded perspective view schematically showing the structure of a liquid crystal display device which is another example of the LED-mounted product. As shown in FIG. 3, a typical liquid crystal display device used in the present invention as an LED-mounted product is arranged between the rear cabinet 11, the stand 12, the front cabinet 13, and between the rear cabinet 11 and the front cabinet 13. The control board 14 and the liquid crystal panel module 15 are basically provided. Among these, the liquid crystal panel module 15 includes a backlight chassis 16, an LED backlight 17 (configured from an LED module 17 a and an LED substrate 17 b), an optical system sheet 18 (configured from a prism sheet, a diffusion sheet, etc.), and a liquid crystal panel unit 19. (Consisting of a liquid crystal driver substrate 19a, a plastic case 19b, a bezel 19c and a panel glass 19d). A liquid crystal material, a transparent electrode, and the like are enclosed between two panel glasses 19d. The backlight chassis assembly 20 is composed of a combination of components such as the backlight chassis 16 and the LED backlight 17.

  The processing method of LED mounting products of this invention can be applied suitably to the waste of LED mounting products of the structure as shown in FIGS. Hereinafter, a method for treating a product equipped with the LED of the present invention will be described with reference to FIGS. 1, 2, and 3.

[1] Step of Removing LED Board from Product Body First, a wiring board (wiring board 2 in the example shown in FIG. 2 and LED board 17b in the example shown in FIG. 3) is removed from the product body of the LED-mounted product (step S1). Specifically, as a method of removing the wiring board 2, a screw that fastens the casing (the casing 3 in the example shown in FIG. 2 and the backlight chassis 16 in the example shown in FIG. 3) and the wiring board 2 is used. Remove the wiring board manually using an electric screwdriver.

  When the wiring board (wiring board 2 in the example shown in FIG. 2 and LED board 17b in the example shown in FIG. 3) is covered with a cabinet or the like, the wiring board is removed before removing the wiring board 2 or the LED board 17b from the product body. 2 or the member covering the LED substrate 17b is removed. Specifically, in the case of LED illumination having a structure as shown in FIG. 2, first, the cover 5 and the lens 4 are removed, and then the wiring board 2 is removed from the housing 3. In the case of the liquid crystal display device as shown in FIG. 3, after removing the cabinet (rear cabinet 11 and front cabinet 13) and removing the control board 14, the liquid crystal panel module 15 is assembled with the liquid crystal panel unit 19 and the backlight chassis assembly. After separation into the product 20, the LED board 17b is removed from the backlight chassis 16.

  In this way, first, the wiring board is recovered from the LED-mounted product. Resources are recovered from the recovered wiring board in a process described later.

[2] Step of removing LED module Next, the LED module is removed from the wiring board (step S2). As a specific method for removing the LED, first, from the wiring board (wiring board 2 in the example shown in FIG. 2, LED board 17b in the example shown in FIG. 3) to the LED module (LED module 1 in the example shown in FIG. 2, FIG. In the example shown in FIG. 3, the LED module 17a) is removed.

  As a method for removing the LED module, the LED module mounted on the wiring board is mechanically removed by an external force. The LED module is usually mounted on the wiring board by solder, and the solder is a tin-based material, which is relatively soft. Therefore, the LED module is separated by mechanically cutting using a press cutting blade made of a carbide tool. be able to. As means for applying an external force, a rotating brush or a hammer can be used.

  Moreover, it is also possible to remove the LED module by applying an external force while heating. Heating the solder joint portion to 150 ° C. or higher, more preferably 180 ° C. or higher, deteriorates the joint strength and promotes removal of the LED module. As a heating method, a method of blowing hot air, a method using a panel heater, an infrared heater, or the like can be used. When heated, since the bonding strength between the LED module and the wiring board is reduced, the LED module can be removed with a relatively small external force. For example, the LED module can be removed by vibrating the wiring board or applying a shearing force with a rotating brush or the like. The LED module removed from the wiring board is collected and used for a crushing process described later.

  Here, FIG. 4 is a cross-sectional view schematically showing the structure of a typical example of the LED modules 1 and 17a used in the present invention. The LED module refers to an integrated component made up of an LED chip, a package material that seals the LED chip, and a terminal material that is electrically connected to the outside. For example, as shown in FIG. 4, the LED modules 1 and 17a include an LED chip 21 made of a compound semiconductor material, a bonding wire 22 made of gold, a package 23 made of plastic, and a terminal material 24 made of copper. And a sealing resin material 25 made of epoxy resin, silicone resin or the like, and a reflector 26 made of plastic or ceramics. Among these, for example, the LED chip 21 contains gallium which is a rare metal as a main component. Therefore, it is desired to efficiently recover a metal material from an LED-mounted product that is no longer needed and to effectively use resources.

  The wiring board 2 and the LED board 17b are made of a substrate material such as glass fiber reinforced epoxy and a wiring material such as copper. The wiring board after the LED module is removed is put into a non-ferrous smelting furnace, and copper is recovered by a conventionally known non-ferrous smelting technique, and organic substances are decomposed to recover heat, and glass fiber components are recovered into slag. And used for cement materials. Glass fiber reinforced epoxy can also be used as a reinforcing material for the molding material.

[3] Crushing step Next, the LED module is crushed to recover metal from the LED module. As a crushing method, it can crush by using a conventionally known crushing means. For example, by crushing the resin package using a shearing type crusher, the compound semiconductor material, the package material, and the lead frame material that are sealed are separated at the bonding interface due to the difference in physical properties. Even if the compound semiconductor material, the package material, and the lead frame material are not completely separated, the resin package can be divided into a portion containing a large amount of the compound semiconductor material and a portion containing a large amount of the package material. The crushing size is preferably 500 μm or less, and more preferably 100 μm or less. As a crushing method, a ball mill, a hammer mill, a tower mill, or the like can be used.

  The LED module crushed material obtained in the crushing process is separated into metals, compound semiconductor materials, plastics, ceramics, and the like in the separation process and the recovery process described later.

[4] Separation Step Next, the LED module crushed material obtained in the crushing step is separated into a compound semiconductor material and metal, and plastic and ceramics by a separation method using a specific gravity difference. Here, in the crushed product of the LED module, the metal is included in the bonding wire material and the terminal material. In the crushed LED module, plastics and ceramics are included in the sealing material and the reflector material.

  By passing through such a separation step, the metal and the compound semiconductor material are concentrated, so that it is possible to recover the metal more efficiently in the recovery step described later than when recovering the metal directly from the LED module. . Moreover, since the separation process does not use energy for heating or combustion, and does not use chemicals that are difficult to process, it can be implemented in a home appliance recycling plant. Moreover, since the metal and the compound semiconductor material are concentrated, when carrying out the recovery process described later in the non-ferrous smelter, the transport efficiency of the recovered material from the home appliance recycling plant to the non-ferrous smelter is improved.

  Here, the specific gravity of metal copper is 8.9, the specific gravity of gold is 19.3, the specific gravity of GaN of the compound semiconductor material is 6.1, and the specific gravity of plastics and ceramics is about 1 to 2. . Therefore, when the crushed LED module obtained in the crushing process is separated into, for example, two types of heavy specific gravity particles and light specific gravity particles, the heavy specific gravity particle portion contains metal and compound semiconductor material, and the light specific gravity particle portion Includes plastics and ceramics. Thereby, it can divide into the heavy specific gravity particle | grains containing many metals and compound semiconductors, and the light specific gravity particle | grains containing a plastic and ceramics from the crushed product of the LED module obtained at the crushing process. Hereinafter, the method in the case of separating into two types of heavy specific gravity particles and light specific gravity particles will be described. Furthermore, even when the specific gravity is separated into many types, separation can be performed by the same operation by making the operation multistage.

  FIG. 5 is a diagram schematically showing a thin flow sorting method that can be suitably employed in the separation step of the present invention. As a separation method using the specific gravity difference, for example, a thin flow sorting method can be used. The method of throwing the crushed material of the LED module obtained at the crushing process into the water which flows along the table surface on the inclined vibration table is mentioned. In such a method, since the light specific gravity particles travel farther on a thin stream, they can be separated from the heavy specific gravity particles. By using a Wilfrey table as shown in FIG. 5 in which a plurality of bars are provided in parallel on the vibration table, it is possible to use a method in which heavy specific gravity particles settle in the gaps between the bars.

  When performing thin flow sorting using a Wilfrey table as in the example shown in FIG. 5, the table 31 has a table surface (upper surface) 3 from the upper side to the lower side as it goes from the right side to the left side with respect to the paper surface of FIG. It is inclined by -5 ° and is configured such that water supplied from above flows downward. Further, the table 31 is provided with a plurality of low bars 32 arranged in the horizontal direction, and for supplying the crushed LED module above the right portion of the table 31 with respect to the paper surface of FIG. A supply port 33 is provided.

  In the thin flow sorting using such a Wilfrey table, heavy specific gravity particles of the supplied LED modules settle into the gaps of the bars 32. The heavy particles having settled in the gaps of the crosspieces 32 move fast to the left and slowly to the right, and thus move to the left due to inertial force. On the other hand, the light specific gravity particles do not settle but ride in a thin stream and flow downward with water. In this way, with respect to the paper surface of FIG. 5 of the table 31, the heavy specific gravity particles are separated on the left and the light specific gravity particles on the lower side.

  Moreover, FIG. 6 is a figure which shows typically the specific gravity selection method using the centrifugal field which can be employ | adopted suitably for the isolation | separation process in this invention. As a separation method using the specific gravity difference, for example, a specific gravity selection method using a centrifugal field can be used. A method using a Falcon sorter will be described with reference to FIG. 6 as an example of specific gravity sorting using a centrifugal field. For example, the water containing the crushed LED module obtained in the crushing process is supplied from the supply port 42 to the center of the inverted conical water tank 41 that rotates at high speed. The supplied water containing the crushed material of the LED module creates an upward thin flow along the side surface of the water tank. Light specific gravity particles ride out in a thin stream and overflow from the container. Since heavy specific gravity particles receive a large centrifugal force, they flow along the wall surface and are separated by providing grooves 43 for separating heavy particles.

  Further, as a separation method using the specific gravity difference, a jig sorter, an air table, or the like can be used.

  In this way, the LED module crushed material obtained in the crushing process is separated into heavy specific gravity particles containing a large amount of metal and compound semiconductors and light specific gravity particles containing plastic and ceramics by a separation method using a specific gravity difference. Can do. Since the separated metal and the compound semiconductor material have a high metal content and are concentrated as compared with the state of the LED module, the metal can be efficiently recovered in a recovery process described later.

  According to this method, energy by heating and combustion is not required, and chemicals that are difficult to process such as strong acid and strong alkali are not used, so it is a low environmental load method and can be implemented in home appliance recycling plants, etc. Separation becomes possible.

  The separated plastics and ceramics can be recycled to heat recovery or cement material.

[5] Recovery Step Next, the metal is recovered from the metal and compound semiconductor material separated in the separation step. A conventionally known smelting method can be used as the metal recovery method. Regarding the recovery process, capital investment for processing chemicals is enormous, and the environmental burden is large, so it is not preferable to implement it in a home appliance recycling plant. In plants equipped with waste liquid processing equipment, such as non-ferrous smelters, etc. It is desirable to do.

  As a specific method of metal recovery, for example, a metal component is eluted (leached) from a mixture of a metal and a compound semiconductor material using an acid solution. The acid solution used for elution preferably contains hydrochloric acid, phosphoric acid, nitric acid, or hydrofluoric acid. Specifically, (1) an acid solution containing hydrochloric acid and nitric acid as main components, (2) an acid solution containing hydrofluoric acid and nitric acid as main components, and (3) an acid solution containing phosphoric acid as main components are suitable. Used.

  Here, the compound semiconductor material is preferably made of gallium phosphide, gallium arsenide, or gallium nitride. When (1) the acid solution mainly composed of hydrochloric acid and nitric acid is used, gallium phosphorus is eluted from the compound semiconductor material, and (2) the acid solution mainly composed of hydrofluoric acid and nitric acid is used. In this case, gallium arsenide is eluted from the compound semiconductor material, and (3) when an acid solution containing phosphoric acid as a main component is used, gallium nitride is eluted from the compound semiconductor material. In addition, elution of the luminescent material from the compound semiconductor material using an acid solution is usually performed in a leaching tank equipped with a stirring means.

  After the elution using the acid solution described above, the residue and the metal-containing acid solution can be obtained by separating the mixture of the leaching residue and the acid solution by solid-liquid separation means such as a filter. The metal-containing acid solution contains a metal such as gallium or copper ((1) also contains gold when an acid solution containing hydrochloric acid and nitric acid as main components is used), and recovers the metal from this solution. As a method for concentrating and recovering gallium and copper (and gold) from a metal-containing acid solution, for example, an ion exchange method, a sulfide method, a hydroxide method, a displacement precipitation method, a solvent extraction method, an electrowinning method, or the like is used. Can do.

It is a flowchart which shows a preferable example of the processing method of the LED mounting product of this invention. It is a disassembled perspective view which shows typically the structure of the LED lighting fixture which is a typical example LED mounted product provided to this invention. It is a disassembled perspective view which shows typically the structure of the liquid crystal display device which is a typical example LED mounted product provided to this invention. It is sectional drawing which shows typically the structure of the LED module 17a of a typical example with which this invention is provided. It is a figure which shows typically the thin flow selection method which can be employ | adopted suitably for the isolation | separation process in this invention. It is a figure which shows typically the specific gravity classification method using the centrifugal field which can be employ | adopted suitably for the isolation | separation process in this invention.

Explanation of symbols

  1 LED module, 2 wiring board, 3 housing, 4 lens, 5 cover, 11 rear cabinet, 12 stand, 13 front cabinet, 14 control board, 15 LCD panel module, 16 backlight chassis, 17 LED backlight, 17a LED Module, 17b LED board, 18 Optical system sheet, 19 Liquid crystal panel unit, 19a Liquid crystal driver board, 19b Plastic case, 19c Bezel, 19d Panel glass, 20 Backlight chassis assembly, 21 LED chip, 22 Bonding wire, 23 Package, 24 terminals, 25 sealing resin, 26 reflectors, 31 tables, 32 bars, 33 supply ports, 41 water tanks, 42 supply ports, 43 grooves.

Claims (6)

Removing the wiring board from the LED mounted product;
Removing the LED module from the wiring board;
Crushing step of crushing the LED module;
A separation step of separating the compound semiconductor material and the metal from the crushed LED module;
The processing method of LED mounting products including the collection | recovery process of collect | recovering metals from the crushed material containing a metal.   The processing method of LED mounting products of Claim 1 whose said LED mounting products are LED lighting fixtures or a liquid crystal display device.   3. The separation step is a step of separating the crushed LED module obtained in the crushing step into a compound semiconductor material and metal, plastic, and ceramics by a separation method using a specific gravity difference. The processing method of LED mounting products as described in 2.   The separation step is a step of separating the crushed LED module obtained in the crushing step into two types of heavy specific gravity particles including compound semiconductor material and metal and light specific gravity particles including plastic and ceramics. 3. A method for treating an LED-mounted product according to 3   The separation method using the specific gravity difference in the separation step is a method using thin flow sorting in which water and crushed material are supplied onto an inclined rocking table and classified into heavy specific gravity particles and light specific gravity particles. The processing method of LED mounting products of Claim 3 or 4.   5. The LED according to claim 3, wherein the separation method using the specific gravity difference in the separation step is a method in which water and crushed material are supplied into a rotating water tank and the specific gravity difference is selected using a centrifugal field. Processing method of on-board products.

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