The present disclosure relates to the field of optocouplers.
An optocoupler includes at least one light-emitting chip optically coupled to at least one light-sensing chip via an optical transmission medium. These designs allow for the transfer of information from a circuit containing a light-emitting chip to another circuit containing a light-sensing chip. A high degree of electrical isolation is maintained between the two circuits, since the information passing through the isolative gap is in the form of light, thereby the transmission is unidirectional. For example, a light-sensing chip does not change the operation of a circuit containing a light-emitting chip. This feature is paramount importance since, for example, the transmitter will be driven at a low voltage using a microprocessor or logic gate while an output light-sensing chip can be part of a high voltage direct current (DC) load circuit or alternating current (AC) load circuit. In addition, an optical isolation also prevents an input circuit from being damaged by an output circuit with higher energy.
Embodiments of the present disclosure provide an optocoupler. The technical solutions are as follows:
According to first aspect of the present disclosure, an optocoupler is provided. The optocoupler includes:
at least one light-emitting chip disposed at a first connective region for emitting at least one invisible light;
at least one light-sensing chip disposed at a second connective region for receiving the at least one invisible light;
an isolative structure disposed between the at least one light-emitting chip and the at least one light-sensing chip for isolating an electric field;
a first encapsulant covering the at least one light-emitting chip, the at least one light-sensing chip, the first connective region, the second connective region and the isolative structure;
a second encapsulant covering the first encapsulant; and
a substrate having a recess, wherein the first connective region and the second connective region are disposed within the substrate and have conductive characteristic, the at least one light-emitting chip is disposed within the recess and electrically connected with the first connective region being a signal input terminal, the at least one light-sensing chip is disposed within the recess and electrically connected with the second connective region being a signal output terminal, and the first encapsulant and the second encapsulant are disposed within the recess.
According to a first implementation form of the first aspect, the isolative structure includes at least one convex portion and/or at least one concave portion disposed on the recess, wherein a height of the at least one convex portion is not greater than one-half of a height of the first encapsulant and a height of the at least one concave portion is not greater than one-half of a thickness of the substrate.
According to a second implementation form of the first aspect, the recess comprises a bottom surface and a side surface provided with a reflective layer, wherein the side surface surrounds the bottom surface, and the at least one light-emitting chip and the at least one light-sensing chip are disposed at the bottom surface.
According to a third implementation form of the first aspect, wherein the first encapsulant is formed of a highly transparent material comprising polyimide (PI) or silicone; the second encapsulant is formed of a reflective material comprising Epoxy; a material of the substrate is a non-metal material comprising a silicon substrate or a glass substrate; the at least one light-emitting chip comprises an Infrared Light-emitting Diode (LED), a gallium nitride (GaN) base LED, an aluminum gallium arsenide (AlGaAs) LED or a gallium arsenide phosphide (GaAsP) LED; and the at least one light-sensing chip comprises a photo diode, a photo transistor, a photo darlington transistor, a photo tryristor, a photo bidirectional thyristor, or a photo integrated circuit.
According to a fourth implementation form of the first aspect, when the isolative structure includes the at least one convex portion and the at least one concave portion, the at least one convex portion is adjacent to the at least one concave portion.
According to a fifth implementation form of the first aspect, wherein cross-sectional shapes of the at least one convex portion and the at least one concave portion are triangles, quadrangles, or polygons.
According to a sixth implementation form of the first aspect, when the isolative structure includes the at least one convex portion and the at least one concave portion, the at least one convex portion is at least one secondary convex portion disposed within the at least one concave portion.
According to second aspect of the present disclosure, an optocoupler is provided. The optocoupler includes:
at least one light-emitting chip disposed at a first connective region for emitting at least one invisible light;
at least one light-sensing chip disposed at a second connective region for receiving the at least one invisible light;
an isolative structure disposed between the at least one light-emitting chip and the at least one light-sensing chip for isolating an electric field, wherein the isolative structure includes a connective portion and an isolative portion, and wherein the isolative structure is connected to the first connective region and the second connective region via the connective portion in such a way that the isolative portion disposed at the connective portion is located between the light-emitting chip and the light-sensing chip;
a first encapsulant covering the at least one light-emitting chip, the at least one light-sensing chip, the first connective region, the second connective region and the isolative structure; and
a second encapsulant covering the first encapsulant.
According to a first implementation form of the second aspect, the connective portion is made of an adhesive material, and the isolative portion is made of a transparent isolative material comprising polyimide.
According to a second implementation form of the second aspect, the isolative portion is perpendicularly disposed at the connective portion, and a perpendicular height of the isolative portion extending from the connective portion is not greater than a thickness of the first encapsulant, and the isolative portion is a cube or a cone.
According to a third implementation form of the second aspect, the isolative portion is obliquely disposed at the connective portion.
According to a fourth implementation form of the second aspect, the connective portion further comprises a first connective portion and a second connective portion, wherein the isolative portion is disposed between the first connective portion and the second connective portion in advance, wherein the first connective portion and the second connective portion are respectively connected to the first connective region and the second connective region in such a way that the isolative portion is located between the light-emitting chip and the light-sensing chip, and wherein the first connective portion, the second connective portion and the isolative portion are integrally molded in sequence.
According to a fifth implementation form of the second aspect, the first encapsulant covers the first connective portion, the light-emitting chip, the second connective portion, the light-sensing chip and the isolative structure to form an elliptical structure, wherein the light-emitting chip and the light-sensing chip are respectively disposed at two focuses of the elliptical structure of the first encapsulant.
According to a sixth implementation form of the second aspect, the optocoupler further includes a third encapsulant made of a light-transparent material for covering one of the light-emitting chip or the light-sensing chip, so that the oblique isolative portion is disposed at the third encapsulant simultaneously, wherein the first encapsulant covers the third encapsulant.
According to a seventh implementation form of the second aspect, the isolative portion formed in advance is a V-shaped structure, and perpendicular to the first connective portion and the second connective portion.
To make the technical solutions in the embodiments of the present disclosure clearer, the accompanying drawings for illustrating the embodiments of the present disclosure are briefly described below. Apparently, the accompanying drawings are only some embodiments of the present disclosure, and persons of ordinary skill in the art may derive other drawings from such accompanying drawings without creative efforts.
To make the objectives, technical solutions, and advantages of the present disclosure clearer, the embodiments of the present disclosure will be described below in further detail with reference to the accompanying drawings.
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However, the technical problem of the above optocoupler is that the closer the distance between two metal conductive frames is or the larger the overlap area of two metal conductive frames is, the larger the capacitance value is and the lower the common mode rejection ratio (CMRR) is, thereby electrical properties of the optocoupler are affected and can not meet application requirements.
Moreover, because the optocoupler is an element that converts an electrical signal into an optical signal by a light-emitting chip, and receives the optical signal and subsequently converts the received optical signal back to an electrical signal by a light-sensing chip, such conversion is a security mechanism ensuring the electrical isolation of an input terminal and an output terminal. However, in an integrated circuit chip, there is another factor that will affect the security mechanism, which is a common mode transient mechanism. The creation of this mechanism is as follows: because if there is a drastic voltage change between an input and an output, for the chip at the output terminal, opening of the chip may lead to an occurrence of an output due to the drastic voltage change. Therefore, in the integrated circuit type optocoupler element, measurement to such parameter of common mode transient suppression (CMRI) is conducted. How to enhance the CMRI becomes technical problem to be solved by the skilled person.
The above relevant technics is merely relevant information of the present invention, rather than the necessary prior art technics.
In order to solve the above problem, the present disclosure provides an optocoupler having an isolative structure. The electrical isolation is improved by increasing a creepage distance (Creepage Distance) and an isolative distance (Clearance), wherein the creepage distance refers to the shortest distance from an electrical signal input terminal (a light-emitting chip) to an electrical signal output terminal (a light-sensing chip) along a surface of an isolative material, wherein the isolative distance refers to the shortest distance from the input terminal to the output terminal in the air.
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at least one light-emitting chip 30 disposed at a first connective region (31a, 31b) for emitting at least one invisible light;
at least one light-sensing chip 40 disposed at a second connective region (41a, 41b) for receiving the at least one invisible light;
an isolative structure disposed between the at least one light-emitting chip 30 and the at least one light-sensing chip 40 for isolating an electric field;
a first encapsulant 350 covering the at least one light-emitting chip 30, the at least one light-sensing chip 40, the first connective region (31a, 31b), the second connective region (41a, 41b) and the isolative structure;
a second encapsulant 360 covering the first encapsulant 350; and
a substrate 310 having a recess 320;
wherein the first connective region (31a, 31b) and the second connective region (41a, 41b) are disposed within the substrate 310 and having conductive characteristic, the at least one light-emitting chip 30 is disposed within the recess 320 and electrically connected with the first connective region (31a, 31b) being a signal input terminal, the at least one light-sensing chip is disposed within the recess 320 and electrically connected with the second connective region (41a, 41b) being a signal output terminal, and the first encapsulant 350 and the second encapsulant 360 are disposed within the recess 320.
Specifically, the recess 320 of the substrate 310 includes a bottom surface and a side surface, wherein the side surface surrounds the bottom surface, and the at least one light-emitting chip 30 and the at least one light-sensing chip 40 are disposed at the bottom surface. The material of the substrate may be a non-metal material and includes a silicon substrate or a glass substrate. The first encapsulant 350 fully covers the at least one light-emitting chip 30 and the at least one light-sensing chip 40, and fills a portion of the recess 320, and has high light transmittance, thereby increasing the light coupling efficiency of the optocoupler 300, and has a function of protecting the at least one light-emitting chip 30 and the at least one light-sensing chip 40. For example, a material of the first encapsulant 350 can be polyimide (PI) or silicone. The second encapsulant 360 fills the entire recess 320 and surrounds the first encapsulant 350. In an embodiment of the present disclosure, a material of the second encapsulant 360 is different from the material of the first encapsulant 350. For example, the material of the second encapsulant 360 includes epoxy, which has characteristics of, for example, high light reflectivity, water blocking property, gas barrier property, isolative property, mechanical strength, and etc. The at least one light-emitting chip 30 includes an infrared light-emitting diode (LED), a gallium nitride (GaN) base LED, an aluminum gallium arsenide (AlGaAs) LED or a gallium arsenide phosphide (GaAsP) LED; and the at least one light-sensing chip 40 includes a photo diode, a photo transistor, a photo darlington transistor, a photo tryristor, a photo bidirectional thyristor, or a photo integrated circuit.
In the present embodiment, the creepage distance between the light-emitting chip and the light-sensing chip is improved by providing the isolative structure between at least one light-emitting chip and at least one light-sensing chip, so as to improve the conductive and electrical isolative function. Meanwhile, the problem of the high capacitance value and the low common-mode rejection ratio of the existing optocoupler due to the overlap of the metal conductive frames is solved by providing the light-emitting chip and the light-sensing chip within the recess 320 of a non-metal substrate, thereby enabling the optocoupler to have the characteristics of simplified process, high optical coupling efficiency and high CMRR.
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at least one light-emitting chip 111 disposed at a first connective region 110 for emitting at least one invisible light;
at least one light-sensing chip 121 disposed at a second connective region 120 for receiving the at least one invisible light;
an isolative structure disposed between the at least one light-emitting chip 111 and the at least one light-sensing chip 121 for isolating an electric field, wherein the isolative structure includes a connective portion 132 and an isolative portion 131, and wherein the isolative structure is connected to the first connective region 110 and the second connective region 120 via the connective portion 132, so that the isolative portion 131 disposed at the connective portion 132 is located between the light-emitting chip 111 and the light-sensing chip 121;
a first encapsulant 140 covering the at least one light-emitting chip 111, the at least one light-sensing chip 121, the first connective region 110, the second connective region 120 and the isolative structure; and
a second encapsulant 150 covering the first encapsulant 140.
Specifically, the first connective region 110 can be a first conductive frame and the second connective region 120 can be a second conductive frame. An elliptical structure is formed with the first encapsulant 140 covering the first connective region 110, the light-emitting chip 111, the second connective region 120, the light-sensing chip 121, and the isolative structure, wherein the light-emitting chip 111 and the light-sensing chip 121 are respectively disposed at two focuses of the elliptical structure of the first encapsulant 140. The first encapsulant 140 fully covers the at least one light-emitting chip 112 and the at least one light-sensing chip 122, and has high light transmittance, thereby increasing the light coupling efficiency of the optocoupler 1800, and has a function of protecting the at least one light-emitting chip 112 and the at least one light-sensing chip 122. For example, a material of the first encapsulant 140 can be polyimide (PI) or silicone. The second encapsulant 150 surrounds the first encapsulant 140 and the material of the second encapsulant 150 can be a black encapsulant or a white encapsulant. In an embodiment of the present disclosure, a material of the second encapsulant 150 is different from the material of the first encapsulant 140. For example, the material of the second encapsulant 150 includes epoxy, which has characteristics of, for example, high light reflectivity, water blocking property, gas barrier property, isolative property and mechanical strength, etc. The at least one light-emitting chip 112 includes an infrared light-emitting diode (LED), a gallium nitride (GaN) base LED, an aluminum gallium arsenide (AlGaAs) LED or a gallium arsenide phosphide (GaAsP) LED; and the at least one light-sensing chip 122 includes a photo diode, a photo transistor, a photo darlington transistor, a photo tryristor, a photo bidirectional thyristor, or a photo integrated circuit.
In the present embodiment, a material of the isolative structure is a semi-transmissive material, a mirror material, a selective wavelength mirror optical material, a thermally-sensitive material including vanadium dioxide, or a transparent isolative material including polyimide. In another preferred embodiment, the isolative structure can be of a multi-layer structure including a variety of combinations of the above materials.
Optionally, the isolative portion 131 is perpendicularly disposed at the connective portion 132, and a perpendicular height of the isolative portion 131 extending from the connective portion 132 is not greater than a thickness of the first encapsulant 140.
Optionally, the connective portion 132 is further made of an adhesive material, and the isolative portion 131 is made of a transparent isolative material including polyimide.
Optionally, the connective portion 132 further includes a first connective portion 132a and a second connective portion 132b, wherein the isolative portion 131 is disposed between the first connective portion 132a and the second connective portion 132b in advance, wherein the first connective portion 132a and the second connective portion 132b are respectively connected to the first connective region 110 and the second connective region 120 in such a way that the isolative portion 131 is located between the light-emitting chip 111 and the light-sensing chip 121, and wherein the first connective portion 132a, the second connective portion 132b and the isolative portion 131 are integrally molded in sequence.
In the present embodiment, the electric filed effect from both of the input terminal and the output terminal can be isolated by providing the isolative structure between the at least one light-emitting chip 111 and the at least one light-sensing chip 121. Meanwhile, the protruded isolative structure can effectively assist the encapsulant in forming an ellipse. By taking advantage of the characteristics of the ellipse that a light is emitted from one elliptical focus and converges to another elliptical focus after reflection, the characteristics of the component can be improved.
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The foregoing descriptions are merely exemplary embodiments of the present disclosure, but not intended to limit the present disclosure. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present disclosure should fall within the protection scope of the present disclosure.
The present disclosure claims priority to U.S. Provisional Patent Application No. 62/488,052 filed Apr. 20, 2017 by Kuo-Chun Chiang et al. and entitled “Optical Device”, which is incorporated herein by reference as if reproduced in their entirety.
Number | Date | Country | |
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62488052 | Apr 2017 | US |