An infrared receiver

Abstract

This invention discloses an infrared receiver, comprising a photodiode chip, a transistor chip, a resistor, a chip carrier, and a package. The photodiode chip, transistor chip, and resistor are fixed on the top of the chip carrier, and the package surrounds the top of the chip carrier. The bottom of the chip carrier extends out of the package and is provided with a control pin, a collector pin, and an emitter pin. The photodiode chip and the transistor chip are electrically connected. The resistor is connected across the two electrodes of the photodiode chip, and the transistor chip is electrically connected to the control pin, the collector pin, and the emitter pin, respectively. This infrared receiver retains the characteristics of photodiodes, such as a large detection angle, fast response speed, and low temperature drift, while also enabling signal amplification, facilitating control, having short interconnections between components, strong anti-interference capability, and a high signal-to-noise ratio.

Description

Technical Field

[0001] This invention relates to the field of photosensitive electronic components, and more particularly to an infrared receiver. Background Technology

[0002] Infrared photodiodes are widely used as infrared detection units due to their large receiving angle, high response speed, and low temperature. However, when a photodiode detects a signal, it generates a current signal with a small amplitude. Therefore, the current signal needs to be converted into a voltage signal and amplified before it can be provided to the control system.

[0003] Taking the infrared detection unit of an infrared touch screen as an example, the infrared detection unit consists of a photodiode, a transistor, and an amplifier. The photodiode receives the infrared emission signal and generates a weak current signal, which is amplified by the transistor and then flows through a resistor to be converted into a primary voltage signal. The amplifier then amplifies the signal to a sufficient amplitude and sends it to the MCU and other control systems.

[0004] In existing solutions, the photodiode, transistor, and amplifier are independent devices or circuits, and their electrical connections are achieved through traces on a printed circuit board (PCB). Figure 1 As shown, components such as photodiode 1, transistor 3, operational amplifier 5, first resistor 2, and second resistor 4 are electrically connected through PCB traces. The traces are long and susceptible to interference, resulting in a low signal-to-noise ratio. Summary of the Invention

[0005] To address the issues of susceptibility to interference and low signal-to-noise ratio in existing solutions, this invention provides an infrared receiver that retains the advantages of photodiodes, such as a large detection angle, fast response speed, and low temperature drift, while incorporating a transistor to amplify the signal and facilitate the host computer's control over turning the infrared receiver on and off. Furthermore, the component encapsulation results in shorter interconnections between components, stronger anti-interference capabilities, and a higher signal-to-noise ratio.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] An infrared receiver includes a photodiode chip, a transistor chip, and a resistor, as well as a chip carrier and a package. The photodiode chip, transistor chip, and resistor are fixed on the top of the chip carrier. The package surrounds the top of the chip carrier. The bottom of the chip carrier extends out of the package and is provided with a control pin, a collector pin, and an emitter pin. The photodiode chip and the transistor chip are electrically connected. The resistor is connected across the two electrodes of the photodiode chip. The transistor chip is electrically connected to the control pin, the collector pin, and the emitter pin, respectively.

[0008] As one of the preferred embodiments of the present invention, the top of the chip carrier is provided with a PD base island for mounting a photodiode chip, a TR base island for mounting a transistor chip, and a bonding base island.

[0009] As one of the preferred embodiments of the present invention, the photodiode chip is fixed to the PD base island by die bonding adhesive; the transistor chip is fixed to the TR base island by die bonding adhesive.

[0010] As one of the preferred embodiments of the present invention, the resistor is bonded and fixed to the chip carrier by resistive adhesive, and the electrical connection between the resistor and the chip carrier is achieved by resistive adhesive, wherein the resistive adhesive is solder paste or silver paste.

[0011] As one of the preferred embodiments of the present invention, the photodiode chip is a PIN photodiode, and the substrate type can be N-type or P-type;

[0012] As one of the preferred embodiments of the present invention, the back electrode of the transistor chip is the collector, and the front side is provided with a collector and a base, which is an NPN type transistor chip or a PNP type transistor chip; when the transistor chip is an NPN type transistor chip, the cathode N of the photodiode chip is connected to the control pin, and the anode P is connected to the base of the transistor chip; when the transistor chip is a PNP type transistor chip, the anode P of the photodiode chip is connected to the control pin, and the cathode N is connected to the base of the transistor chip;

[0013] As one of the preferred embodiments of the present invention, the chip carrier is a substrate, and the top surface of the substrate is also provided with a resistor base island for mounting resistors. The bonding base island includes an A bonding base island and a B bonding base island. A control pin, a collector pin and an emitter pin are provided on one side of the bottom of the substrate.

[0014] As one of the preferred embodiments of the present invention, the chip carrier is a lead frame, the bonding base island includes a C-bonding base island and a D-bonding base island, the PD base island extends outside the package body to become a control pin, the TR base island extends outside the package body to become a collector pin, and the C-bonding base island extends outside the package body to become an emitter pin.

[0015] As one of the preferred embodiments of the present invention, the surface of the transistor chip is coated with black glue.

[0016] As one of the preferred embodiments of the present invention, the encapsulation body is a hemispherical convex lens structure made of resin, which can transmit infrared light and block visible light.

[0017] As one of the preferred embodiments of the present invention, it is used in a gesture detection system, an infrared switch system, a pedestrian access system, and an infrared touch screen tube detection system.

[0018] Compared with the prior art, the beneficial effects of this invention are:

[0019] (1) It retains the characteristics of photodiodes, such as large detection angle, fast response speed and low temperature drift, and adds a transistor to amplify the current signal generated by the photodiode, thereby increasing the output amplitude and improving the signal-to-noise ratio.

[0020] (2) It provides three external pins: the collector C of the transistor, the emitter E of the transistor, and the control pin connected to the base B of the transistor. It can be easily connected to external circuits to realize current-voltage conversion and turn the infrared receiving module on and off.

[0021] (3) The components are encapsulated in a package and the electrical connection is made by bonding wire, which shortens the connection between components and improves the anti-interference ability and signal-to-noise ratio. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the device connection of an existing infrared receiving module.

[0023] Figure 2 This is a schematic diagram of the infrared receiver packaging structure described in Example 1.

[0024] Figure 3 This is the equivalent circuit diagram of the infrared receiver described in Example 1.

[0025] Figure 4 This is a schematic diagram of the infrared receiver packaging structure described in Embodiment 2.

[0026] Figure 5 This is the equivalent circuit diagram of the infrared receiver described in Example 2;

[0027] In the diagram: 1-Photodiode; 2-Resistor; 3-Transistor; 4-Operational Amplifier; 5-PCB Board; 6-Photodiode Chip; 7-Transistor Chip; 8-Substrate; 9-Copper Foil Wire; 10-Bonding Wire; 11-Die Glue; 12-PD Base Island; 13-TR Base Island; 14-Package; 15-A-Bonding Base Island; 16-Bonding Base Island; 17-Collector Pin; 18-Emitter Pin; 19-Control Pin; 20-Black Glue; 21-Resistor Adhesive; 22-Resistor Base Island; 23-Lead Frame; 24-C-Bonding Base Island; 25-D-Bonding Base Island. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0029] Example 1

[0030] like Figure 2 and Figure 3 As shown, this embodiment provides an infrared receiver, which includes a photodiode chip 6, a transistor chip 7, and a resistor 2, as well as a substrate 8 and a package 14. The package 14 surrounds the top of the substrate 8 and encapsulates the photodiode chip 6, the transistor chip 7, and the resistor 2 located on the top of the substrate 8 together. The bottom of the substrate 8 is located outside the package 14. One side of the bottom of the substrate 8 is provided with three external pins: a control pin 19, a collector pin 17, and an emitter pin 18. The photodiode chip 6 and the transistor chip 7 are electrically connected. The resistor 2 is connected across the two electrodes of the photodiode chip 6. The transistor chip 7 is electrically connected to the control pin 19, the collector pin 17, and the emitter pin 18, respectively.

[0031] The substrate 8 is covered with copper foil lines 9, which are configured together with bonding lines 10 to realize the connection between the photodiode chip 6, the transistor chip 7, the resistor 2 and the three external pins, namely the control pin 19, the collector pin 17 and the emitter pin 18, and to form the three external pins, namely the control pin 19, the collector pin 17 and the emitter pin 18.

[0032] The copper foil line 9 is configured according to the connection requirements as follows: PD base island 12 for mounting photodiodes, TR base island 13 for mounting transistor chips, resistor base island 22 for mounting resistors, and A bonding base island 15 and B bonding base island 16 for bonding.

[0033] In this embodiment, the photodiode chip used is a P-substrate PIN photodiode chip or an N-substrate PIN photodiode chip; the transistor chip is an NPN transistor chip or a PNP transistor chip. The types of photodiode chips and transistor chips can be randomly combined, only requiring corresponding configuration of electrical connections. When the transistor chip is an NPN transistor chip, the cathode N of the photodiode chip is connected to the control pin, and the anode P is connected to the base of the transistor chip. When the transistor chip is a PNP transistor chip, the anode P of the photodiode chip is connected to the control pin, and the cathode N is connected to the base of the transistor chip.

[0034] The electrical connection method in this embodiment is described below using an N-substrate photodiode and an NPN transistor as examples:

[0035] Photodiode chip 6 is an N-substrate PIN photodiode with a cathode N as the back electrode and an anode P as the front electrode; transistor chip 7 is an NPN transistor with a collector C as the back electrode and two electrode points, a base B and an emitter E, on the front.

[0036] The photodiode chip 6 is mounted and fixed on the PD base island 12 via die bonding 11; the back electrode N of the photodiode chip 6 is connected to the PD base island 12 via the die bonding 11 and is connected to the control pin 19 via copper foil wire 9; the front electrode P of the photodiode chip 6 is connected to the A bonding base island 15 via bonding wire 10; the transistor chip 7 is mounted and fixed on the TR base island 13 via the die bonding 11; the back collector C of the transistor chip 7 is connected to the TR base island 13 via the die bonding 11 and is connected to the collector pin 17 via copper foil wire 9; the base B of the transistor chip 7 is connected to the A bonding base island 15 via bonding wire 10; the emitter E of the transistor chip 7 is connected to the B bonding base island 16 via bonding wire 10 and is connected to the emitter pin 18 via copper foil wire 9;

[0037] The resistor 2 is mounted and fixed on the resistor base island 22 by the resistor adhesive 21. One end of the resistor 2 is connected to the A bonding base island 15, the front electrode P of the photodiode chip 6, and the base B of the transistor chip 7 through the copper foil wire 9. The other end is connected to the PD base island 12, the back electrode N of the photodiode chip 6, and the control pin 19 through the copper foil wire 9.

[0038] The substrate adhesive 11 is a conductive adhesive, and the resistor bonding adhesive 21 is solder paste. After reflow soldering, a reliable connection is formed between the resistor 2 and the resistor base island 22.

[0039] The bonding wire 10 is preferably a gold wire, which can improve product reliability.

[0040] The transistor chip 7 is covered with black adhesive 20 to reduce the influence of light on the transistor chip;

[0041] The encapsulation body 14 is formed by curing an infrared-transmitting and visible-light-blocking resin to receive infrared rays and remove interfering light. The encapsulation body 14 has a hemispherical convex lens structure to better converge the incident infrared signal, thereby improving the detection rate of the product.

[0042] In Example 1, the photodiode chip 6, transistor chip 7, resistor 2, bonding wire 10, mounting adhesive 11, resistive adhesive 21, and black adhesive 20 are encapsulated on the substrate 8 to form a patch infrared receiver that can be applied to gesture detection systems, infrared switch systems, pedestrian access systems, or infrared touch screen transistor detection systems. This shortens the wiring between components, improves anti-interference capability and signal-to-noise ratio, and has control pins for easy on / off operation.

[0043] Example 2

[0044] like Figure 4 and Figure 5 As shown, in this embodiment, a lead frame 23 is used as the chip carrier. The photodiode chip 6, the transistor chip 7, and the resistor 2 are fixed on the top of the lead frame 23. The top of the lead frame 23 is also fixed with a PD base island 12 for mounting the photodiode, a TR base island 13 for mounting the transistor chip, a C-bonding base island 24 for bonding, and a D-bonding base island 25. The package 14 surrounds the top of the lead frame 23, sealing the chip, base island, and bonding wires together. The PD base island 12 extends outside the package 14 to become the control pin 19, the TR base island 13 extends outside the package 14 to become the collector pin 17, and the C-bonding base island 24 extends outside the package 14 to become the emitter pin 18.

[0045] In this embodiment, the photodiode chip can be a P-substrate type photodiode chip or an N-substrate type photodiode chip; the transistor chip can be an NPN type transistor chip or a PNP type transistor chip. The types of photodiode chips and transistor chips can be randomly combined, only requiring corresponding configuration of electrical connections. When the transistor chip is an NPN type transistor chip, the cathode N of the photodiode chip is connected to the control pin, and the anode P is connected to the base of the transistor chip. When the transistor chip is a PNP type transistor chip, the anode P of the photodiode chip is connected to the control pin, and the cathode N is connected to the base of the transistor chip.

[0046] The electrical connection method in this embodiment is described below using a P-substrate photodiode and a PNP transistor as examples:

[0047] The photodiode chip 6 is a P-substrate type photodiode with the back electrode being the anode P and the front electrode being the cathode N;

[0048] The transistor chip 7 is a PNP type transistor with a collector C on the back and two electrode points, a base B and an emitter E, on the front.

[0049] The photodiode chip 6 is mounted and fixed on the PD base island 12 by the die adhesive 11; the anode P of the photodiode chip is connected to the PD base island 12 by the die adhesive 11, and the cathode N of the photodiode chip is connected to the D bonding base island 25 by the bonding wire 10.

[0050] The transistor chip 7 is mounted and fixed on the TR base island 13 by the die adhesive 11. The back collector C of the transistor chip 7 is connected to the TR base island 13 by the die adhesive 11. The base B of the transistor chip 7 is connected to the D bonding base island 25 by the bonding wire 10. The emitter E of the transistor chip 7 is connected to the C bonding base island 24 by the bonding wire 10.

[0051] The resistor 2 is mounted and fixed on the D bonding base island 25 at one end via the resistive adhesive 21, and mounted and fixed on the PD base island 12 at the other end; one end of the resistor 2 is connected to the PD base island 12 and the back electrode P of the photodiode chip 6; the other end is connected to the front electrode N of the photodiode chip 6 and the base B of the transistor chip 7 via the bonding wire 10.

[0052] The substrate adhesive 11 is a conductive adhesive; the resistor bonding adhesive 21 is solder paste, which, after reflow soldering, forms a reliable connection between the resistor 2 and the resistor base island 22.

[0053] The bonding wire 10 is preferably a gold wire, which can improve product reliability.

[0054] The transistor chip 7 is covered with black adhesive 20 to reduce the influence of light on the transistor chip.

[0055] The encapsulation body 14 is formed by curing an infrared-transmitting and visible-light-blocking resin to receive infrared rays and remove interfering light. The encapsulation body 14 has a hemispherical convex lens structure to better converge the incident infrared signal, thereby improving the detection rate of the product.

[0056] In Example 2, the photodiode chip 6, transistor chip 7, resistor 2, bonding wire 10, die adhesive 11, resistor adhesive 21, black glue 20, lead frame 23, etc., are encapsulated together in the package 14 to form another surface-mount infrared receiving module that can be applied to gesture detection systems, infrared switch systems, pedestrian access systems, or infrared touch screen diode detection systems. This shortens the wiring between components, improves anti-interference capability and signal-to-noise ratio, and has control pins for easy on / off operation.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An infrared receiver, comprising a photodiode chip, a transistor chip, and a resistor, characterized in that, It also includes a chip carrier and a package. The photodiode chip, the transistor chip and the resistor are fixed on the top of the chip carrier. The package surrounds the top of the chip carrier. The bottom of the chip carrier extends out of the package and is provided with a control pin, a collector pin and an emitter pin. The photodiode chip and the transistor chip are electrically connected. The resistor is connected across the two electrodes of the photodiode chip. The transistor chip is electrically connected to the control pin, the collector pin and the emitter pin respectively. The photodiode chip is a PIN photodiode, and the substrate can be N-type or P-type. The back electrode of the transistor chip is the collector, and the front electrode is the emitter and the base. The transistor is a PNP or NPN type transistor chip. The anode P of the photodiode chip is connected to the control pin, and the cathode N is connected to the base of the transistor chip. The surface of the transistor chip is covered with black glue; the package is a convex lens structure with a hemispherical shape, made of resin, which can transmit infrared light and block visible light. The photodiode chip, transistor chip, and resistor are connected by bonding wires; The top of the chip carrier is equipped with a PD base island for mounting photodiode chips, a TR base island for mounting transistor chips, and a bonding base island; The photodiode chip is fixed to the PD base island by die bonding adhesive; the transistor chip is fixed to the TR base island by die bonding adhesive; the resistor is bonded and fixed to the chip carrier by resistive adhesive, and the electrical connection with the chip carrier is achieved by resistive adhesive; the resistive adhesive is solder paste or silver paste. The chip carrier is a lead frame, and the bonding base islands include C-bonding base islands and D-bonding base islands. The PD base island extends outside the package body to become a control pin, the TR base island extends outside the package body to become a collector pin, and the C-bonding base island extends outside the package body to become an emitter pin.

2. The infrared receiver according to claim 1, characterized in that, The chip carrier is a substrate, and the top surface of the substrate is also provided with a resistor base island for mounting resistors. The bonding base island includes an A bonding base island and a B bonding base island. The bottom side of the substrate is provided with a control pin, a collector pin and an emitter pin.

3. The infrared receiver according to claim 1, characterized in that, Used in gesture detection systems, infrared switch systems, pedestrian access control systems, and infrared touch screen tube detection systems.

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