Optical coupler CTR adjusting method

Abstract

The invention provides an optocoupler CTR adjusting method, in a silica gel dispensing link in an optocoupler manufacturing process, silica gel and color paste in a set proportion are mixed and stirred, then IR chip coating is carried out, the color paste does not affect light transmittance, the dispensing amount is adjusted through a dispensing machine so as to control the silica gel height H, and the height H of the silica gel is adjusted through the dispensing machine so as to adjust the CTR of the optocoupler. Therefore, the purpose of adjusting the CTR of the optocoupler is achieved. According to the method, the original mode is kept in other links, and on the premise that the range of IR and PT chips does not need to be changed, the chip range is unified, prepared materials are single, and production management and control are facilitated.

Description

Technical Field

[0001] The invention relates to an optical coupler CTR adjustment method and belongs to the technical field of optical coupler manufacturing. Background Art

[0002] CTR is an important parameter of optocoupler products, usually expressed as the DC current transfer ratio IC / IF, that is, the percentage of the ratio of the DC output current IC to the DC input current IF when the output voltage remains constant. Since there are many factors that affect CTR, such as the luminous power of the IR chip, the HFE of the photosensitive triode PT chip, the comparison distance between the IR and PT chips, the transmittance of the inner sealing white glue and the transmittance of the inner coating silicone, etc., when producing optocoupler products, how to switch between different CTR levels and how to ensure the output qualification rate have always been the difficulties that the industry pays attention to.

[0003] At present, there are two common methods for adjusting CTR: one is to match CTR by selecting IR or PT chips with different parameters; the other is to change the comparison distance between IR and PT chips by adjusting the die-bonding position of IR or PT chips to achieve CTR matching. However, both methods have some defects. The first method requires increasing the number of chips, which brings management difficulties to the production of reserve chip materials and production lines, and may also affect important parameters of optocouplers such as withstand voltage and switching time (rise time Tr, fall time Tf, turn-on time Ton, turn-off time Toff). The second method is complicated to operate, has high requirements for equipment accuracy and production line monitoring, and is prone to increase in defective rates.

[0004] CN117374148A discloses a method for adjusting the CTR of an optocoupler, in which the IR chip is coated after being mixed with a set proportion of white paste. Since the white paste is used to block light, the more white paste is added, the less light is transmitted and the lower the CTR is. Therefore, the CTR can only be reduced but not increased, and the mixing ratio of the silicone and the white paste cannot be precisely controlled.

[0005] Therefore, it is necessary to design a new method, especially one that can improve CTR, so that the process of adjusting the optocoupler CTR can be simple to control, easy to operate, and easy to manage, without affecting the important parameters of the optocoupler such as withstand voltage and switching time. Summary of the invention

[0006] The purpose of the present invention is to provide a method for adjusting the CTR of an optocoupler. The method achieves the purpose of adjusting the CTR by mixing and stirring silicone and color paste in a set ratio in the silicone dispensing process during the manufacture of the optocoupler and then coating the IR chip. The silicone height H is controlled by adjusting the dispensing amount through a glue dispensing machine.

[0007] The technical solution of the present invention is as follows:

[0008] A method for adjusting the CTR of an optical coupler is disclosed. In the process of manufacturing an optical coupler, the silicone is mixed with a color paste of a set ratio and then coated with an IR chip. The color paste does not affect the transmittance, and the amount of glue dispensed is adjusted by a glue dispenser to control the height H of the silicone, thereby achieving the purpose of adjusting the CTR of the optical coupler.

[0009] Preferably, when the electrical ranges of the IR chip and the PT chip are fixed, after the silica gel and the color paste are mixed in a certain ratio, by changing the height H of the silica gel coated on the IR chip, the CTR range of the optical coupler will change accordingly.

[0010] Preferably, in the step of applying the silicone, the silicone and color paste are evenly mixed in proportion by vacuum stirring, and then the IR chip is coated, and the amount of glue applied is adjusted by the glue dispensing machine to control the silicone height H, thereby achieving the purpose of adjusting the CTR of the optocoupler.

[0011] Preferably, the color paste is a red color paste. Since the red color paste does not affect the transmittance, the red color is only used for color marking, which can easily identify whether silicone is applied. The mass ratio of the red color paste to the silicone is controlled at 0.1 to 1.0:100.

[0012] The beneficial effects of the present invention are:

[0013] 1. The present invention achieves the adjustment of CTR by mixing and stirring silica gel and a set proportion of red paste in the silica gel dispensing process when manufacturing the optocoupler, and then coating the IR chip, and adjusting the dispensing amount by the dispensing machine to control the silica gel height H. The other links remain the same, and there is no need to change the range of IR and PT chips, so that the chip range is unified, the material preparation is single, and it is conducive to production control.

[0014] 2. Since the dispensing machine has high precision and a large adjustable range of dispensing height, it is easy to adjust the range of the optocoupler CTR and the output is stable.

[0015] 3. The method of the present invention has no influence on the important parameters of the optocoupler, such as withstand voltage and switching time (rise time Tr, fall time Tf, on time Ton, off time Toff), thus ensuring the stable performance of the optocoupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of an optocoupler CTR adjustment method provided in an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of glue dispensing height according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] Example:

[0020] like Figure 1 FIG. 1 is a flow chart of a method for adjusting the CTR of an optical coupler provided by an embodiment of the present invention; the method can adjust the CTR parameters of the optical coupler by adjusting the height of the silicone gel without changing the chip parameters or the internal structure position. The method is used in the process of manufacturing an optical coupler.

[0021] like Figure 2 As shown, when manufacturing the optocoupler, in the silicone dispensing process, silicone and red paste are mixed and stirred in proportion to coat the IR chip, and the silicone height H is controlled by adjusting the dispensing amount through the glue dispensing machine to achieve the purpose of adjusting CTR.

[0022]

[0023] Table 1

[0024] From the experimental data in Table 1, it can be obtained that as the dispensing height increases, the average CTR also increases. Under the premise that other parameters remain unchanged, such as the IR and PT chip ranges, the chip range is unified, and the adjustment of the optocoupler CTR range is easy to achieve and the output is stable.

[0025] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for adjusting the CTR of an optical coupler, characterized in that: In the process of making optocouplers, the IR chip is coated after mixing silicone with a color paste of a set ratio. The color paste does not affect the transmittance, and the amount of glue is adjusted by the glue dispensing machine to control the height H of the silicone, thereby achieving the purpose of adjusting the CTR of the optocoupler.

2. The optical coupler CTR adjustment method according to claim 1, characterized in that: When the electrical ranges of the IR chip and the PT chip are fixed, after the silica gel and the color paste are mixed in a certain ratio, the CTR range of the optical coupler will change accordingly by changing the height H of the silica gel coated on the IR chip.

3. The optical coupler CTR adjustment method according to claim 1 or 2, characterized in that: In the silicone dispensing process, the silicone and color paste are evenly mixed in proportion through vacuum stirring, and then the IR chip is coated. The dispensing amount is adjusted by the dispensing machine to control the silicone height H, so as to achieve the purpose of adjusting the CTR of the optocoupler.

4. A method for adjusting the optical coupler CTR according to claim 1 or 2, characterized in that: The color paste is a red color paste, and the mixing mass ratio is 0.1-1.0:100.

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