JP2013120940A - Optocoupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optocoupler with a light guide having a consistent shape where a shape of a light guide between an optical transmitter die and an optical receiver die is controlled.SOLUTION: An optocoupler 100 has an optical transmitter die 120, an optical receiver die 130, a light guide 140, a limiting element 150, and a body 170. The light guide 140 is confined to an upper portion 171 of the body 170 by using the limiting element 150. The limiting element 150 is: a dielectric tape; or a pre-molded plastic attached to a lead frame via non-conductive epoxy.

Description

  This application is a continuation-in-part of US application Ser. No. 12 / 945,474, filed Nov. 12, 2010. The U.S. Application No. 12 / 945,474 is a continuation-in-part of U.S. Application No. 12 / 729,943 filed on March 23, 2010, all of which are incorporated herein by reference. And

  A galvanic isolator provides a means for transmitting a signal from one electrical circuit to the other when the two electrical circuits need to be electrically isolated from each other. Usually, these two electrical circuits operate at different voltages, so that they need to be electrically isolated. For example, consider an application where a 5V battery powered controller board is used to control a motor circuit operating at 240V. In this example, it is essential to electrically isolate the 240V motor circuit from the 5V controller circuit while allowing the 5V controller circuit to send or receive signals to the 240V motor circuit. In this type of application, galvanic isolators can be used to allow voltage and noise to be isolated while exchanging information between the two circuit systems. For electrical systems with more than two circuits operating at different voltages, multi-channel galvanic isolators can be used.

  There are three main types of galvanic isolators. The first type is a radio frequency transceiver that allows signals to be sent from one circuit to another via a radio signal. The second type is a magnetic isolator in which a signal is sent from one circuit to another by a magnetic field. The third type is an optocoupler (also referred to as an optical coupling element or an optoisolator) in which a signal is transmitted between circuits by light waves. Galvanic isolators can be used in applications that require operating voltages in kilovolts. Magnetic isolators and radio frequency isolators have limitations in shielding noise from one circuit system to another. This is because the entire circuit in the isolator is susceptible to strong magnetic or radio frequency waves that can induce voltage or current. However, optocouplers that combine signals by light waves do not induce noise in the same way that magnetic isolators and radio frequency transceivers induce noise.

  In general, an optocoupler comprises an optical transmitter die and an optical receiver die. The optical transmitter die and the optical receiver die can be contained in one package (eg, a container). A multi-channel optocoupler can have two or more pairs of an optical transmitter die and an optical receiver die. Usually, the signal is transmitted from the optical transmitter die to the optical receiver die. A light guide is typically used to prevent light loss. In most cases, the light guide is formed by adding a clear liquid encapsulant (or capsule material) over the light transmitter and light receiver dies. Next, this transparent encapsulant is cured by a curing process to form a light guide. The shape of the light guide may depend on the viscosity of the encapsulant, and therefore it may be difficult to control the shape of the light guide. This problem with controlling the shape of the light guide may be more severe in the case of optocouplers with large dies or multichannel optocouplers.

  Non-limiting exemplary embodiments are shown in the accompanying drawings. Throughout this specification and the drawings, the same reference numerals are used to identify similar elements.

It is sectional drawing of the optocoupler in a lead frame package (lead frame package). 1 is a cross-sectional view of an optocoupler in a leadframe package having an optical transmitter die and an optical receiver die attached to a common conductive pad. FIG. One embodiment of a partially completed multi-channel optocoupler with two optical transmitters and one optical receiver on a printed circuit board encapsulated by a transparent encapsulant, but without wire bonding and encapsulant Indicates. 3 is a cross-sectional view of an optocoupler with a light guide defining element in a leadframe package. FIG. FIG. 3 is a cross-sectional view of an optocoupler with a light guide defining element and tape in a leadframe package. FIG. 2 is a cross-sectional view of an optocoupler having an optical transmitter die and an optical receiver die attached to a common conductive pad and an optical guide defining element. FIG. 3 is a cross-sectional view of an optocoupler with a light guide defining element attached to a printed circuit board. A is a perspective view of the light guide defining element, B is a cross-sectional view of the light guide defining element along line 3-3 of A, and C is a top view of the light guide defining element. 1 is a top view of a multi-channel optocoupler comprising a light guide defining element having two cavities. FIG. FIG. 6 is a top view of a light guide defining element for a multi-channel optocoupler having a light separating element. 1 is a top view of a multi-channel optocoupler with a light guide defining element having one cavity. FIG. FIG. 6 is a perspective view of a light guide definition element having a channel configured to be cascaded to another light guide definition element of an adjacent optocoupler. 1 shows one method for making an optocoupler with light guide defining means. 2 is a cross-sectional view of an optocoupler having a limiting element bonded to a lead frame package, where the optical transmitter die and the optical receiver die are located on different leads of the lead frame. FIG. FIG. 3 is a cross-sectional view of an optocoupler having a limiting element attached to a leadframe package using epoxy, wherein the optical transmitter die and the optical receiver die are each disposed on different conductors of the leadframe. 1 is a cross-sectional view of an optocoupler having a limiting element bonded to a leadframe package, where the optical transmitter die and the optical receiver die are disposed on one conductive pad. FIG. 16B is a perspective view of the partially completed optocoupler shown in FIG. 16A without wire bonding and opaque encapsulant. FIG. 3 is a top view of a multi-channel optocoupler having two cavities using two limiting elements. 1 is a top view of a multi-channel optocoupler with one cavity, without wire bonding and opaque encapsulant. FIG. Fig. 4 shows a limiting element having an inconsistent shape. Fig. 3 shows a surface for receiving a light guide including a limiting element and a portion of a plurality of conductors.

  FIG. 1 is a cross-sectional view of an optocoupler 100 in a lead frame package. The optocoupler 100 includes a plurality of conductors 111 and 112, an optical transmitter die 120 and an optical receiver die 130. The plurality of conductors 111 and 112 are made of a conductive material, and the plurality of conductors can be formed from a lead frame. The plurality of conductors 111, 112 are known as leads or conductive traces. The conductors 111, 112 can be extended to form conductive pads 118, 119, thereby configuring the conductive pads 118, 119 to hold the optical transmitter die 120 and the optical receiver die 130. can do. The plurality of conductors 111, 112 can be configured as a means for connecting the dies 120 and 130 to an external circuit (not shown). For example, by extending the plurality of conductors 111 and 112 to the edge or bottom of the optocoupler 100, the plurality of conductors can function as electrical contacts to an external circuit (not shown).

  The optical transmitter die 120 can be a light emitting diode (hereinafter referred to as an LED) or any light source capable of emitting light. The optical transmitter die 120 can be an integrated circuit with embedded LEDs and drive circuitry. Depending on design requirements, the control circuitry can be integrated into the optical transmitter die 120. The optical transmitter die 120 can be configured to be powered by a first power source (not shown) via a conductor 111. The optical transmitter die 120 can operate to emit light in accordance with a logic signal from an external circuit (not shown) that operates from the first power source (not shown). For example, a logic signal “high” can be transmitted to optical transmitter die 120 via conductor 111. In response, the optical transmitter die 120 emits an optical output indicative of a “high” signal.

  The optical receiver die 130 can include a photodetector 135 such as a photodiode or phototransistor. The optical receiver die 130 can be an embedded photodetector 135 or an integrated circuit having an amplifier circuit (not shown) for amplifying the photocurrent generated by the photodetector 135. Depending on design requirements, control circuitry can be integrated into the optical receiver die 130 to provide signal processing. The optical receiver die 130 can be configured to be powered by a second power source (not shown) via the conductor 122. The optical receiver die 130 is operable to receive a signal in the form of light emitted from the optical transmitter die 120.

  In order to form the light guide 140, the optical transmitter die 120 and the optical receiver die 130 are made of a transparent encapsulant such as transparent epoxy (epoxy is also referred to as an epoxy resin, hereinafter the same), silicon or other similar material ( In the present invention, the encapsulant can be used as a capsule material). Next, the transparent encapsulant is encapsulated with an opaque (i.e., light impermeable) encapsulant to form a body 170 comprising an upper portion 171 and a lower portion 172. The upper portion 171 and the lower portion 172 can be made using two different tools (e.g., a stamp) in the molding process. The opaque encapsulant can be a plastic, ceramic, or any other substantially opaque or black compound used to form the body 170 of the packaging (package structure). Optionally, the transparent encapsulant reflects light before being encapsulated in the opaque encapsulant, such as white epoxy (white epoxy), metallic materials, or other reflective materials similar to them The reflective material 150 can be covered.

  The transparent encapsulant forms a light guide 140 for sending light emitted from the light transmitter die 120 to the light receiver die 130. A transparent encapsulant can be formed by adding a liquid encapsulant to encapsulate both the optical transmitter die 120 and the optical receiver die 130. Next, the light guide 140 is formed by curing the liquid transparent encapsulant into a solid. The size (ie, size) of the light guide 140 is controlled by controlling the amount of liquid encapsulant added, but the size can be greatly dependent on the viscosity of the liquid encapsulant. In the case of a small light guide 140, by adjusting the viscosity and amount of clear epoxy added, the size and shape is substantially consistent (ie uniform or identical) without undue process variation. Can be realized. However, in the case of relatively large dies 120 and 130 and multi-channel optocouplers, process variations with respect to the size and shape of the light guide 140 become large and the size and shape of the light guide become inconsistent (ie, size And variation in shape).

  One way to obtain a more consistent light guide 140 is to reduce the distance (spacing) between the light transmitter die 120 and the light receiver die 130 so that the light guide 140 is smaller. This can be accomplished by mounting the dies 120, 130 on a common conductive pad 118, 119 as shown in FIG. However, since the optical transmitter die 120 and the optical receiver die 130 can be connected to two different power sources (power supply sources), appropriate electrical insulation and noise isolation between the two dies 120, 130 are provided. It is essential to ensure.

  FIG. 2 is a cross-sectional view of the optocoupler 200 in the lead frame type package. The optocoupler 200 includes a body 270 having a plurality of conductors 211, 212, an optical transmitter die 220, an optical receiver die 230, a light guide 240 formed by a transparent encapsulant, and an upper portion 271 and a lower portion 272. I have. The optical receiver die 230 further includes a photodetector 235. As shown in the embodiment of FIG. 2, one of the conductors 211, 212 extends to form a conductive pad 218. The optical transmitter die 220 and the optical receiver die 230 are attached to a common conductive pad 218. The optocoupler 200 of FIG. 2 is similar to the optocoupler 100 of FIG. 1, except that both the optical transmitter die 220 and the optical receiver die 230 are attached to a common conductive pad 218. It differs from the optocoupler 100 at least. In the embodiment shown in FIG. 2, the optical transmitter die 220 can be electrically connected to the conductor 211 and the optical receiver die 230 can be connected to the conductor 212.

  In the embodiment shown in FIG. 2, the optical transmitter die 220 is attached to the conductive pad 218 via three material layers 225, which are between two securing layers. It consists of an isolation layer (also called an insulating layer) sandwiched between. The isolation layer has the function of electrically insulating the optical transmitter die 220 from the conductive pads 218 that are electrically connected to the optical receiver die 230. The isolation layer can be a layer of glass, polyimide, or similar electrically insulating material. The isolation layer may or may not have sufficient adhesion (or adhesion) to hold the optical transmitter die 220 on the conductive pad 218.

  The pinned layer can be silicon dioxide, silicon (silicon), nitride, benzocyclobutane (BCB), or any other suitable layer of insulating adhesive. The pinned layer can be an epoxy material suitable for die attach applications. Such epoxies include, but are not limited to, epoxies sold by Tra-con, Massachusetts, USA. The pinned layer has sufficient adhesion to hold the optical transmitter die 220 and the isolation layer on the conductive pad 218. The three material layers 225 can be electrically insulating, so that the voltage and noise of the optical transmitter die 220 are removed from the conductive pads 218 that are electrically connected to the optical receiver die 230. Can be separated.

  The pinned layer may be liquid at the beginning of the manufacturing process (or at the beginning of the manufacturing process), but may be cured later in the manufacturing process, for example, by exposure to heat or UV light (ie, ultraviolet light). Thus, a solid layer can be formed. The isolation layer may prevent the optical transmitter die 220 from physically contacting the conductive pad 218 at the beginning of the manufacturing process (or at the beginning of the manufacturing process) where the pinned layer may be liquid.

  In the embodiment shown in FIG. 2, the optical transmitter die 220 is attached to the conductive pad 218 via three layers of material 225 and the optical receiver die 230 is attached directly to the conductive pad 218. This (attachment) configuration can also be reversed. Which configuration is selected can be determined based on various design considerations such as the relative height profile of each die 220, 230, heat transfer requirements, power supply and grounding requirements.

  An optocoupler having two or more pairs of a transmitter die 220 and a receiver die 230 is known as a multi-channel optocoupler. FIG. 3 shows a partially completed multi-channel optocoupler 300 without wire bonding or opaque encapsulant. The multi-channel optocoupler 300 includes a substrate 310, two optical transmitter dies 320, 321, and an optical receiver die 330. The dies 320, 321, and 330 are encapsulated by a transparent encapsulant that forms a light guide 340. The substrate 310 can be a printed circuit board (hereinafter referred to as a PCB). The substrate 310 further includes a plurality of conductors 311 to 316. In the case of a PCB, conductors 311-316 are also known as conductive traces. One of the conductors 311-316 can be extended to form a conductive pad 318. Optical transmitter dies 320, 321 and optical receiver die 330 can be attached to conductive pads 318. One of the dies 320, 321 and 330 can be attached directly to the conductive pad 318, and the other dies 320, 321 and 330 are attached to the conductive pad 318 by the three insulating material layers 225 shown in FIG. be able to.

  By attaching multiple dies 320, 321, and 330 to the same conductive pad 318, the size of the light guide 340 can be reduced, but the number of dies 320, 321, and 330 increases, making the light guide 340 consistent. It can still be difficult to achieve size (ie uniform or constant size). In order to enclose all of the dies 320, 321 and 330, it will be inevitable that the size of the light guide 340 will increase. One effective way to create a light guide 340 having a consistent size and shape is to use a light guide defining element 460 as shown in the embodiment of FIG.

  The optocoupler 400 of FIG. 4 includes a plurality of conductors 411 and 412, which can be lead wires of a lead frame, an optical transmitter die 420, an optical receiver die 430, and dies 420 and 430 that can include a photodetector 435. It comprises a light guide 440 formed by a transparent encapsulant to be encapsulated, a light guide defining element 460 and a body 470 formed by an opaque encapsulant comprising an upper portion 471 and a lower portion 472. The upper portion 471 and the lower portion 472 of the main body 470 can be formed using two different tools (eg, a stamper) in the molding process. Similarly, the light guide 440 can be divided into an upper portion 441 and a lower portion 442. Some of the conductors 411, 412 can be extended to form conductive pads 418, 419 for receiving the dies 420, 430. Similar to the optocouplers 100 and 200 shown in the embodiments of FIGS. 1 and 2, respectively, the optical transmitter die 420 can be connected to a first power source (not shown), while the optical receiver die 430. Can be connected to a second power source (not shown) separated from the first power source (not shown).

  As shown in FIG. 4, the light guide defining element 460 can have a cavity (ie, a cavity) having a reflective surface 450 that defines the light guide 440 formed by a transparent encapsulant. The light guide defining element 460 can define any suitable shape. However, the cavity can define a shape suitable for the light guide 440, which is generally substantially dome-shaped. The light guide defining element 460 can be formed of polycarbonate, high refractive index plastic, acrylic plastic (or acrylic synthetic resin), or any other material similar thereto. Optionally, a micro-optical element can be formed on the reflective surface 450 to better control the light adjustment by the reflective surface 450. The light guide defining element 460 can be attached to the plurality of conductors 411, 412 via a non-conductive epoxy 480. Such non-conductive epoxy 480 can include, but is not limited to, epoxy sold by Henkel, Sumitomo Metal Mining, METAL MINING, and Epoxy Technology. The light guide demarcating element 460 can be attached to the plurality of conductors 411, 412 using other attachment methods such as die attach with a non-conductive adhesive or heat staking.

  One possible method of making the embodiment optocoupler 400 shown in FIG. 4 is to first attach the dies 420, 430 to one of the conductive pads 418, 419. The next step can be a wire bonding process, in which the dies 420, 430 can be coupled to their respective conductors 411, 412 to establish an electrical connection. Note that there may be more conductors 411, 412 than the conductors shown in the drawing. After wire bonding, the light guide defining element 460 can be attached to the conductors 411, 412 via the non-conductive epoxy 480 so that the dies 420, 430 are near the cavity defined by the reflective surface 450. Placed in. Next, a liquid transparent epoxy is injected into the cavity to form the light guide 440.

  The upper portion 441 of the light guide 440 is bounded by a light guide defining element 460. In order to increase reliability and completely encapsulate the dies 420, 430, the amount of transparent encapsulant injected can be greater than the volume defined by the cavity of the light guide defining element 460. As shown in the embodiment of FIG. 4, the light guide 440 further includes a lower portion 442 disposed outside the cavity of the light guide defining element 460. The shape and size of the lower portion 442 has a relatively small effect on optical performance because the lower portion 442 is disposed on the opposite side of the optical dies 420, 430. In view of cost, the size and shape of the lower portion 442 may not be strictly controlled.

  Next, the liquid transparent encapsulant can be cured to a solid state. The light guide defining element 460 and portions of the conductors 411, 412 can then be encapsulated with an opaque encapsulant to form the lower portion 472 of the body 470 by a first molding process. The lower portion 472 of the main body 470 may be referred to as a substrate. Next, the lower portion 472 of the main body 470 can be subjected to a second molding process to form the upper portion 471 of the main body 470. Finally, the conductors 411, 412 can be separated from the lead frame (not shown) and bent into the required shape.

  As shown in the embodiment of FIG. 4, the shape of the upper portion 441 of the light guide 440 can be substantially dome-shaped to match the shape of the light guide defining element 460. Technically, the lower portion 442 of the light guide 440 can be substantially flat or can be any other convenient and cost effective shape. However, to increase reliability and to prevent arching and delamination, the lower portion 442, like the upper portion 441, is smaller and substantially dome-shaped. be able to. Alternatively, tape 590 (see FIG. 5) formed from Mylar ™, polyimide, Melinex ™, or any other similar material may be attached to the lower portion 442 of the light guide 440. Or attached to the lower portion 442 for increased reliability. This is illustrated in FIG. 5, in which part or all of the lower portion 442 has been substantially replaced by the tape 590.

  FIG. 5 illustrates one embodiment of an optocoupler 500 that is similar to optocoupler 400, but differs from optocoupler 400 in that tape 590 is used to increase reliability. The optocoupler 500 includes a plurality of conductors 511, 512, an optical transmitter die 520, an optical receiver die 530 having at least one optical detector 535, an optical guide 540, an optical guide defining element 560, and an upper portion 571 and a lower portion. A body 570 having a portion 572 is provided. The light guide defining element 560 is attached to the conductors 511, 512 via a non-conductive epoxy 580. Optionally, the reflective surface 550 of the light guide defining element 560 can include a micro-optic element configured to direct light emitted from the light transmitter die 520 to the light receiver die 530. As shown in FIG. 4, unlike the optocoupler 400 having a fairly large bottom 442, the light guide 540 of the optocoupler 500 is a half that does not have the lower portion 442 shown in FIG. Defines a semi-dome shape. On the other hand, the tape 590 is used to strengthen the structure of the light guide 540. The tape 590 can be made of an adhesive material (eg, an adhesive) and can be attached to the light guide 540 after the transparent encapsulant is cured. Another advantage of using the tape 590 is that the lower portion 442 (see FIG. 4) can be made substantially flat by the tape 590, thereby increasing the efficiency of the light guide 540. is there. Since the tape 590 can be substantially flat on the lower portion 442, the height of the optocoupler 500 can be reduced. In another embodiment, the optocoupler 500 shown in FIG. 5 may not include the light guide defining element 560. The shape of the light guide 540 depends on the viscosity of the encapsulant. However, the tape 590 can reduce process variations related to the shape and size of the light guide 540.

  FIG. 6 shows an optocoupler 600, which is another embodiment similar to the optocoupler 400 shown in FIG. Optocoupler 600 includes a plurality of conductors 611, 612 (one of these conductors 611, 612 extending to form a common conductive pad 618), an optical transmitter die 620, at least one photodetector. An optical receiver die 630 having 635, a light guide 640 formed by a transparent encapsulant, a light guide defining element 660, and a body 670 having an upper portion 671 and a lower portion 672. Optionally, a micro-optic element can be placed on the reflective surface 650 of the light guide defining element 660. The light guide 640 can have an upper portion 641 and a lower portion 642, similar to the optocoupler 400 shown in FIG.

  One difference between the optocoupler 600 and the optocoupler 400 shown in FIG. 4 is that both the optical transmitter die 620 and the optical receiver die 630 are attached to a common conductive pad 618. The optical transmitter die 620 can be attached to a common conductive pad 618 via three layers of material 625 consisting of an isolation layer sandwiched between two fixed layers. By attaching the optical transmitter die 620 and the optical receiver die 630 to a common pad 618, the distance traveled by the light emitted by the optical transmitter die 620 before reaching the optical receiver die 63 can be reduced. it can. Further, the light guide defining element 660 ensures that the light guide 640 is formed with a consistent (ie, uniform or constant) size and shape. Therefore, the efficiency of the light guide 640 shown in FIG. 6 can theoretically be higher than the embodiment shown in FIG.

  FIG. 7 illustrates one embodiment of an optocoupler 700 using a PCB. The optocoupler 700 includes a substrate 710, an optical transmitter die 720, an optical receiver die 730 having at least one optical detector 735, an optical guide 740 having a reflective surface 750, an optical guide defining element 760, and an opaque encapsulant 770. It has. The substrate 710 can be a PCB having a plurality of conductors 711, 712 disposed on both sides of the substrate 710. Unlike optocouplers 400, 500, and 600, the light guide defining element 760 of optocoupler 700 can be attached anywhere on substrate 710 by non-conductive epoxy 780, and only for conductors 711, 712. It is not limited. The light guide defining element 760 can optionally have one or more openings 765 for adding a liquid transparent encapsulant to the cavity of the light guide defining element 760. Optionally, more openings 761 can be formed in the light guide defining element 760 to act as air escape holes to prevent air from being trapped within the cavity.

  8A, 8B, and 8C are views of the light guide defining element 860 as seen from different perspectives. FIG. 8A is a perspective view of the light guide defining element 860. FIG. 8B is a cross-sectional view of the light guide defining element 860 along line 3-3 in FIG. 8A. FIG. 8C is a top view of the light guide defining element 860. The light guide defining element 860 can define a generally rectangular (rectangular) shape having a generally dome-shaped cavity 861. The light guide defining element 860 can define any shape suitable for attachment to the conductors 411, 412 (see FIG. 4) or the substrate 710 (see FIG. 7). Cavity 861 has any shape suitable for reflecting light from the optical transmitter die (720 in FIG. 7) to the optical receiver die (730 in FIG. 7) shown in FIGS. Can be defined. Optionally, the surface defining the cavity 861 can be a reflective material, or a semi-reflective material (a material that transmits part of the incident light and reflects part of it), or controls the distribution (or distribution) of light. It is possible to have a micro optical element for the purpose. There is typically one cavity 861 in the light guide defining element 860. However, in the case of a multi-channel optocoupler, there may be two or more cavities 861 as shown in FIG.

  FIG. 9 is a top view of one embodiment of a multi-channel optocoupler 900 without wire bonding and opaque encapsulant. The optocoupler 900 includes a plurality of conductors 911-916, a plurality of optical transmitter dies 920, 921, a plurality of optical receiver dies 930, 931, and a light guide defining element 960. The light guide defining element 960 includes a plurality of cavities 961, 962, each cavity defining a light guide 940, each cavity coupling an optical transmitter die 920, 921 and an optical receiver die 930, 931. doing. A first pair of optical transmitter die 920 and optical receiver die 930 can be disposed in or near the first cavity 961, and the first pair of optical transmitter die 921 and optical receiver die 931. Two pairs can be placed in or near the second cavity 962. In this configuration, crosstalk between the first pair of transmitter die 920 and receiver die 930 and the second pair of transmitter die 921 and receiver die 931 can be minimized.

  Furthermore, a light separation element 1068 shown in FIG. 10 can be used to optically separate the two cavities 960, 961. FIG. 10 is a top view 1000 of a light guide defining element 1060 having a plurality of cavities 1061, 1062. The light separating element 1068 can be a simple air gap (or space) defined within the body of the light guide defining element 1060, thereby allowing total light reflection. Alternatively, the light separating element 1068 is used to form a substantially opaque encapsulant (eg, the body 470 of the optocoupler 400 shown in FIG. 4) within the body of the light guide defining element 1060. Can be formed by filling with a material).

  In some situations, the optical transmitter dies 920, 921 and the optical receiver dies 930, 931 may not be separated into different cavities 961, 962, as shown in FIG. This is because the signal from the optical transmitter die 920 can be received by any one of the two receiver dies 930 and 931. In such a situation, only one cavity 960 can be used. This situation is illustrated in the embodiment shown in FIG. FIG. 11 shows a multi-channel optocoupler 1100 without wire bonding and opaque encapsulant. The multi-channel optocoupler 1100 includes a plurality of conductors 1111-1116, optical transmitter dies 1120 and 1121, optical receiver dies 1130 and 1131, an optical guide defining element 1160, and an optical guide 1140. As shown in FIG. 11, all optical transmitter dies 1120, 1121 and optical receiver dies 1130, 1131 can be encapsulated within a light guide 1140 in a single cavity 1161.

  To allow signals to be transmitted from any of the optical transmitter dies 1120, 1121 to any of the optical receiver dies 1130, 1131 of the nearby optocoupler 1100. If the optocoupler 1100 can be coupled to a nearby optocoupler 1100, the light guide defining element 1100 can be prevented from defining a dome shape as shown in FIG. In such circumstances, the light guide defining element 1260 may define a channel 1261 that may be an opening that terminates at both ends of the longitudinal axis, as shown in FIG. By aligning the channels 1261 of two adjacent optocouplers (not shown) so as to be coaxial, optical communication between two different optocouplers can be realized.

  FIG. 13 is a flowchart 1300 illustrating one possible manufacturing process for the optocoupler 400 shown in FIG. In step 1310, a plurality of conductors are provided. The plurality of conductors can be in the form of lead wires in a lead frame. In step 1320, an optical transmitter die and an optical receiver die can be attached to one or more conductors of the lead frame. For example, after the die attach epoxy material is applied to or attached to the back of the optical transmitter and receiver dies, the dies can be attached to appropriate portions of the lead frame. The method 1300 can then proceed to step 1330 where the optical transmitter die and the optical receiver die are wire bonded to respective conductors of the lead frame to establish an electrical connection. For example, the optical transmitter die can be connected to a first power source, while the optical receiver die can be connected to a second power source that is separated or isolated from the first power source.

  The method 1300 can then proceed to step 1340, where the light guide die and the light receiver die are positioned in or near the cavity of the light guide defining element. The defining element can be attached to a conductor of the lead frame or PCB substrate. In step 1350, a liquid transparent encapsulant is injected into the cavity of the light guide defining element to encapsulate the optical transmitter die and the optical receiver die. The transparent encapsulant can also encapsulate and protect all bonding wires that bond the dies to the conductor.

  The method 1300 can then proceed to step 1360 where the transparent encapsulant can be cured to a solid to form a light guide. Optionally, prior to step 1360, the adhesive tape (or the adhesive tape) is opposite the light guide defining element such that the light guide is surrounded by the light guide defining element and the adhesive tape (or adhesive tape). It can be attached to the lead frame side.

  The method 1300 can then proceed to step 1370, which begins with a first molding step and forms the lower portion of the body to encapsulate a portion of the conductor. Thereafter, another molding process is performed to form the upper portion of the body that encapsulates the light guide defining element, conductor and all dies (the dies are encapsulated following the light guide defining element and conductor). Can do. The upper and lower portions of the body can be formed in a different order, i.e., the upper portion can be formed first and then the lower portion. Finally, the method 1300 may proceed to step 1380 where the conductor may be cut from the lead frame and bent to form a particular package lead.

  With respect to FIG. 4, the size and shape of the light guide 440 may depend on the viscosity of the material used to make the light guide 440. However, if the liquid encapsulant is limited to only the upper portion 471 (ie, confined to the upper portion 471), a light guide 440 that is consistent in size and shape (ie, uniform and constant in size and shape) is produced. can do. By limiting the light guide 440 to only the upper portion 471 of the body 470, the amount of encapsulant required to make the light guide 440 is reduced. The volume of the light guide 440 is also significantly reduced. This allows a consistent light guide 440 to be made without using the light guide defining element 460. Furthermore, limiting the light guide 440 to only the upper portion 471 has another advantage. For example, the height of the optocoupler 400 can be reduced. Yet another advantage is that reliability can be increased. If the overall size of the light guide 440 is significantly reduced, the performance of the interlocking mechanism between the body 470 and the light guide 440 is improved. One means for limiting the light guide 440 to the upper portion 471 is to use the tape 590 shown in FIG. However, there are other means for confining the light guide 440 in the upper portion 471 of the body 470, as shown in the various embodiments described below.

  FIG. 14 illustrates one embodiment of an optocoupler 1400 that is similar to the optocoupler 400. Optocoupler 1400 does not have light guide defining element 460, but is at least different from optocoupler 400 shown in FIG. 4 in that it has a limiting element 1490 for limiting light guide 1440 to upper portion 1471 of body 1470. Is different. Optocoupler 1400 includes a plurality of conductors 1411, 1412, an optical transmitter die 1420, an optical receiver die 1430 having at least one optical detector 1435, an optical guide 1440, a limiting element 1490, and an upper portion 1471 and a lower portion 1472. A main body 1470 having In the embodiment shown in FIG. 14, two of the conductors 1411, 1412 extend to define conductive pads 1418, 1419 configured to receive an optical transmitter die 1420 and an optical receiver die 1430. Can do. However, in another embodiment, only one of the conductors 1411, 1412 may extend to define a conductive pad 1418 for receiving both the optical transmitter die 1420 and the optical receiver die 1430. it can.

  The limiting element 1490 is configured to reliably limit the light guide 1440 to the upper portion 1471 of the body 1470. The light transmission efficiency of the light guide 1440 is higher than that of the light guide 440 shown in FIG. This is because there is substantially no light loss due to the lower portion 442 of the light guide 440 shown in FIG. Further, the light guide 1440 may include a reflective surface 1450 for preventing light loss.

  The limiting element 1490 is an insulating tape (or dielectric tape) made from Mylar ™, polyimide, Melinex ™, or any other material similar to the tape 590 shown in FIG. be able to. The limiting element 1490 can be adhered to the conductors 1411, 1412 (with an adhesive or the like). Alternatively, the limiting element 1490 can be a pre-shaped (or preformed) surface plastic that is attached to the plurality of conductors 1411, 1412 using an epoxy material or adhesive. For example, the light guide 1440 can be added to the limiting element 1490 in the encapsulant before the liquid encapsulant for encapsulating the optical transmitter die 1420 and the optical receiver die 1430 is cured to a solid. As a result, conductive pads 1418 and 1419 configured to hold the optical transmitter die 1420 and the optical receiver die 1430 are sandwiched between the die 1420 and 1430 and the limiting element 1490, respectively. The size of the limiting element 1490 is typically larger than the light guide 1440. In some cases, the limiting element 1490 can be at least 50% larger than the light guide 1440.

  FIG. 15 illustrates a plurality of conductors 1511, 1512, an optical transmitter die 1520, an optical receiver die 1530 having at least one optical detector 1535, an optical guide 1540, a limiting element 1590, and an upper portion 1571 and a lower portion 1572. 1 illustrates one embodiment of an optocoupler 1500 comprising a body 1570 having The light guide 1540 can include a reflective surface 1550. Optical transmitter die 1520 and optical receiver die 1530 are attached to conductive pads 1518, 1519. Optocoupler 1500 differs at least from optocoupler 1400 in that limiting element 1590 is attached to a plurality of conductors 1511, 1512 via an epoxy layer 1595. Examples of epoxy 1595 include Tra-con F202 epoxy, Dymax OP-4-20632 epoxy, or any type of epoxy similar to them. The limiting element 1590 is an insulating tape (or dielectric tape) similar to the limiting element 1490 of the optocoupler 1400, or a polymer film, a molded plastic film, or any other material. be able to.

  16A and 16B illustrate a plurality of conductors 1611-1616, an optical transmitter die 1620, an optical receiver die 1630 having at least one optical detector 1635, an optical guide 1640 having a reflective surface 1650, a limiting element 1690, and One embodiment of an optocoupler 1600 comprising a body 1670 having an upper portion 1671 and a lower portion 1672 is shown. FIG. 16B is a perspective view of optocoupler 1600 without wire bonding and upper portion 1671 of body 1670. FIG. 16A is a cross-sectional view of optocoupler 1600 along line 4-4 shown in FIG. 16B. One of the conductors 1611-1616 (1611 in the figure) may extend to define a conductive pad 1618 configured to receive both the optical transmitter die 1620 and the optical receiver die 1630. . The conductive pad 1618 can be sandwiched between both the optical transmitter die 1620 and optical receiver die 1630 and the limiting element 1690; in another embodiment, the conductive pad 1618 is instead replaced by the die 1620. And one of 1630 and the limiting element 1690. As shown in FIGS. 16A and 16B, both the optical transmitter die 1620 and the optical receiver die 1630 are attached to a common conductive pad 1618, but the dies are attached differently from each other. ing. The optical transmitter die 1620 is attached to a common conductive pad 1618 via three material layers 1625 consisting of an isolation layer sandwiched between two fixed layers. The optical receiver die 1630 is attached directly (ie, directly) to the common conductive pad 1618. However, in another embodiment, this (attachment) configuration is interchangeable from one attachment configuration to the other (ie, the optical transmitter die 1620 is attached directly to a common conductive pad 1618 and the optical receiver The die 1630 can be attached to a common conductive pad 1618 via three layers of material 1625, or vice versa).

  Attaching the optical transmitter die 1620 and the optical receiver die 1630 to a common pad 1618 allows the optical transmitter die 1620 to be placed closer to the optical receiver die 1630. As a result, the light guide 1640 of the optocoupler 1600 can be made smaller than the optocouplers 1400 and 1500 shown in FIGS. 14 and 15, respectively. As the light guide becomes smaller like the light guide 1640, it becomes possible to make the size and shape consistent in mass production. Furthermore, a light guide 1640 with higher light transmission efficiency can be produced by a shorter distance (between the light transmitter die and the light receiver die).

  As shown in FIG. 16B, the limiting element 1690 can be larger than the light guide 1640 to accommodate the entire light guide 1640. In another embodiment, the limiting element 1690 can be larger than the light guide 1640. In consideration of reliability, the restriction element 1690 is typically enclosed within the body 1670 to securely connect the restriction element 1690 and the body 1670. Accordingly, the limiting element 1690 is typically smaller than the body 1670.

  FIG. 17 is a top view of one embodiment of a multi-channel optocoupler 1700 without wire bonding and the upper portion of the body. Optocoupler 1700 includes a plurality of conductors 1711-1716, a plurality of optical transmitter dies 1720, 1721, a plurality of optical receiver dies 1730, 1731, a plurality of limiting elements 1790, 1791, a plurality of light guides 1740, 1741, and an upper side. A body 1770 having a portion (not shown) and a lower portion 1772 is provided. Each of the limiting elements 1790, 1791 can be configured to accommodate each of the light guides 1740, 1741, respectively. In another embodiment, optocoupler 1700 may comprise a single limiting element 1790 configured to accommodate both light guides 1740, 1741.

  FIG. 18A is a top view of one embodiment of a multi-channel optocoupler 1800 without wire bonding and the upper portion of the body 1870. Optocoupler 1800 includes a plurality of conductors 1811-1816, a plurality of optical transmitter dies 1820, 1821, a plurality of optical receiver dies 1830, 1831, a limiting element 1890, a light guide 1840, and an upper portion (not shown) and a lower side. A body 1870 having a portion 1872 is provided. All optical transmitter dies 1820, 1821 and optical receiver dies 1830, 1831 are encapsulated within a single common light guide 1840. The light guide 1840 is formed on one limiting element 1890. Since a single light guide 1840 is used, light from any of the light transmitter dies 1820, 1821 can be received by any of the light receiver dies 1830, 1831.

  Although the limiting element 1890 is typically a thin flat rectangular object, the limiting element 1890 can define any shape, including inconsistent (ie, non-uniform) shapes. For example, the limiting element 1890 has a shape as shown in FIG. 18B and defines an inconsistent shape that cannot accommodate the light guide 1840. After the restrictive element 1890 is attached to the conductors 1811-1816, it combines with the conductors 1811-1816 to define a planar (flat surface) 1895, as shown in FIG. 18C. The flat surface 1895 can be configured to accommodate the light guide 1840 in the upper portion 1871 of the body 1870.

  Optocouplers 1400, 1500, 1600, 1700, and 1800 can be made using the method shown in FIG. 13, in which case the limiting elements 1490, 1590, 1690, 1790, before step 1320 or after step 1330, And 1890 mounting step can be optionally performed.

In the following, exemplary embodiments consisting of combinations of various constituents of the present invention are shown.
1. Packaging for optoelectronic devices,
A first optical transmitter die configured to emit light;
A first optical receiver die configured to receive a portion of the light emitted by the first optical transmitter die;
A plurality of conductors, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the plurality of conductors;
A limiting element, wherein the at least one of the plurality of conductors is sandwiched between one of the first optical transmitter die and the first optical receiver die and the limiting element. A limiting element attached to multiple conductors;
A first light guide formed on the limiting element;
An opaque encapsulant encapsulating the first light guide and the limiting element;
The first light guide is a substantially transparent encapsulant that encapsulates the first light transmitter die and the first light receiver die, and the first light guide is the first light guide. Packaging configured to transmit light from an optical transmitter die to the first optical receiver die.
2. The packaging of claim 1, wherein the limiting element is an insulating tape.
3. The packaging of claim 1, wherein the limiting element is bonded to the plurality of conductors.
4). The packaging of claim 1, wherein the limiting element is attached to the plurality of conductors with epoxy.
5. The packaging of claim 1, wherein the limiting element is substantially reflective.
6). The packaging of claim 1, wherein the limiting element is larger than the first light guide.
7). The packaging of claim 1, wherein the limiting element is coupled to a portion of the plurality of conductors to define a surface configured to receive the first light guide.
8). One of the first optical transmitter die and the first optical receiver die is directly attached to the at least one of the plurality of conductors, the first optical transmitter die and the first optical receiver The packaging of claim 1 wherein the other of the vessel dies is attached to at least one of the plurality of conductors through three layers of material comprising an isolation layer sandwiched between two fixed layers.
9. The packaging of claim 1 comprising a second optical transmitter die and a second optical receiver die.
10. The packaging of claim 9, wherein the second optical transmitter die and the second optical receiver die are encapsulated within the first light guide.
11. The packaging of claim 9, further comprising a second light guide encapsulating the second optical transmitter die and the second optical receiver die.
12 12. The packaging of item 11 above, wherein the first light guide and the second light guide are optically separated.
13. 12. The packaging of claim 11 comprising a second limiting element, wherein the second limiting element includes the plurality of conductors, the second light guide, the second optical transmitter die, and the second. The packaging according to the above item 11, which is provided so as to be sandwiched between two optical receiver dies.
14 The packaging of claim 1, wherein the first optical transmitter die and the first optical receiver die are each attached to two of the plurality of conductors.
15. The packaging of claim 1, wherein the packaging forms part of an optocoupler.
16. An optocoupler,
A first optical transmitter die configured to emit light, the first optical transmitter die configured to obtain power from a first external power source;
A first optical receiver die configured to receive light emitted by the first optical transmitter die, wherein the first optical receiver is configured to obtain power from a second external power source. A die,
A plurality of conductive leads, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the conductive leads. When,
A limiting element, said at least one of said plurality of conductive leads sandwiched between said limiting element and one of said first optical transmitter die and said first optical receiver die A limiting element attached to the
A light guide enclosing the first light transmitter die and the first light receiver die, the light guide formed on the limiting element;
An opaque encapsulant encapsulating the first light guide and the limiting element;
The first light guide is an optocoupler configured to transmit light from the first transmitter die to the first optical receiver die.
17. 17. The optocoupler according to item 16, wherein the limiting element is a dielectric film.
18. The optocoupler of claim 16, wherein the limiting element is substantially reflective.
19. One of the plurality of conductive leads defines a conductive pad, and one of the first optical transmitter die and the first optical receiver die is directly attached to the conductive pad; The other of the optical transmitter die and the first optical receiver die is attached to the conductive pad via three material layers consisting of an isolation layer sandwiched between two fixed layers. Optocoupler.
20. An optoelectronic device,
A first optical transmitter die configured to emit light;
A first optical receiver die configured to receive light emitted by the first optical transmitter die;
A plurality of conductive leads, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the plurality of conductive leads. Conductive leads,
A limiting element, wherein the at least one of the plurality of conductive leads is sandwiched between one of the first optical transmitter die and the first optical receiver die and the limiting element. A limiting element attached to the at least one of the plurality of conductive leads,
A first light guide formed on the limiting element;
An opaque encapsulant that encapsulates the first light guide and at least partially encapsulates the plurality of conductive leads and the restriction element;
The first light guide is a substantially transparent encapsulant that encapsulates the first light transmitter die and the first light receiver die, and the first light guide is the first light guide. An optoelectronic device configured to transmit light from an optical transmitter die to the second optical receiver die.

  While specific embodiments of the invention have been illustrated and described, the invention is not limited to the specific form or arrangement of parts or parts shown and described. Obviously, their illustration and description should not be interpreted narrowly. For example, the optical transmitter die 220 can be an LED, but the optical transmitter die can be a die incorporating an LED and circuitry, or a light source using future technology. Similarly, although optocouplers are described in all embodiments, those skilled in the art will appreciate packaging of any other optical device having at least an optical transmitter die and an optical receiver die encapsulated in a common light guide. It will be apparent that the present invention can be applied. The scope of the present invention is to be defined by the claims and their equivalents.

100 Optocouplers 111, 112 Conductor 120 Optical Transmitter Die 130 Optical Receiver Die 118, 119 Conductive Pad

Claims (20)

Packaging for optoelectronic devices (package structure),
A first optical transmitter die configured to emit light;
A first optical receiver die configured to receive a portion of the light emitted by the first optical transmitter die;
A plurality of conductors, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the plurality of conductors;
A limiting element, wherein the at least one of the plurality of conductors is sandwiched between one of the first optical transmitter die and the first optical receiver die and the limiting element. A limiting element attached to multiple conductors;
A first light guide formed on the limiting element;
An opaque encapsulant encapsulating the first light guide and the limiting element;
The first light guide is a substantially transparent encapsulant that encapsulates the first light transmitter die and the first light receiver die, and the first light guide is the first light guide. Packaging configured to transmit light from an optical transmitter die to the first optical receiver die.   The packaging of claim 1 wherein the limiting element is an insulating tape.   The packaging of claim 1, wherein the limiting element is adhered to the plurality of conductors.   The packaging of claim 1, wherein the limiting element is attached to the plurality of conductors with epoxy.   The packaging of claim 1, wherein the limiting element is substantially reflective.   The packaging of claim 1, wherein the limiting element is larger than the first light guide.   The packaging of claim 1, wherein the limiting element is coupled to a portion of the plurality of conductors to define a surface configured to receive the first light guide.   One of the first optical transmitter die and the first optical receiver die is directly attached to the at least one of the plurality of conductors, the first optical transmitter die and the first optical receiver The packaging of claim 1, wherein the other of the vessel die is attached to at least one of the plurality of conductors via three layers of material comprising an isolation layer sandwiched between two fixed layers.   The packaging of claim 1 comprising a second optical transmitter die and a second optical receiver die.   10. The packaging of claim 9, wherein the second optical transmitter die and the second optical receiver die are encapsulated within the first light guide.   10. The packaging of claim 9, further comprising a second light guide that encapsulates the second optical transmitter die and the second optical receiver die.   12. The packaging of claim 11, wherein the first light guide and the second light guide are optically separated.   12. The packaging of claim 11, comprising a second limiting element, wherein the second limiting element includes the plurality of conductors, the second light guide, the second optical transmitter die, and the second. 12. The packaging of claim 11, wherein the packaging is provided to be sandwiched between two optical receiver dies.   The packaging of claim 1, wherein the first optical transmitter die and the first optical receiver die are each attached to two of the plurality of conductors.   The packaging of claim 1, wherein the packaging forms part of an optocoupler. An optocoupler,
A first optical transmitter die configured to emit light, the first optical transmitter die configured to obtain power from a first external power source;
A first optical receiver die configured to receive light emitted by the first optical transmitter die, wherein the first optical receiver is configured to obtain power from a second external power source. A die,
A plurality of conductive leads, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the conductive leads. When,
A limiting element, said at least one of said plurality of conductive leads sandwiched between said limiting element and one of said first optical transmitter die and said first optical receiver die A limiting element attached to the
A light guide enclosing the first light transmitter die and the first light receiver die, the light guide formed on the limiting element;
An opaque encapsulant encapsulating the first light guide and the limiting element;
The first light guide is an optocoupler configured to transmit light from the first transmitter die to the first optical receiver die.   The optocoupler of claim 16, wherein the limiting element is a dielectric film.   The optocoupler of claim 16, wherein the limiting element is substantially reflective.   One of the plurality of conductive leads defines a conductive pad, and one of the first optical transmitter die and the first optical receiver die is directly attached to the conductive pad; 17. The other of the optical transmitter die and the first optical receiver die is attached to the conductive pad via three material layers consisting of an isolation layer sandwiched between two fixed layers. Optocoupler. An optoelectronic device,
A first optical transmitter die configured to emit light;
A first optical receiver die configured to receive light emitted by the first optical transmitter die;
A plurality of conductive leads, wherein the first optical transmitter die and the first optical receiver die are attached to at least one of the plurality of conductive leads. Conductive leads,
A limiting element, wherein the at least one of the plurality of conductive leads is sandwiched between one of the first optical transmitter die and the first optical receiver die and the limiting element. A limiting element attached to the at least one of the plurality of conductive leads,
A first light guide formed on the limiting element;
An opaque encapsulant that encapsulates the first light guide and at least partially encapsulates the plurality of conductive leads and the restriction element;
The first light guide is a substantially transparent encapsulant that encapsulates the first light transmitter die and the first light receiver die, and the first light guide is the first light guide. An optoelectronic device configured to transmit light from an optical transmitter die to the second optical receiver die.

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