ELECTRONIC PRODUCTS

FIELD OF THE INVENTION The invention relates to quality inspection technology, particularly to quality prediction or quality control technology regarding electronic products.

BACKGROUND OF THE INVENTION

Commercially available electronic products are normally required to meet certain technical specifications to guarantee quality and performance. However, in a factory, not every product coming from the assembly line meets the technical specifications. A fault in a product could be due to imperfect design, variation in component performance, occasional mistakes in the assembly line, temperature fluctuation, and many other unpredictable factors. The costs of dealing with faulty products are usually high for both end users and product vendors. Therefore, it is the responsibility of the factories to identify and properly deal with faulty products before they come to the market. Nowadays, quality control in factories is becoming increasingly important, because any minor mistake in the assembly line of mass-production factories may lead to large numbers of faulty products.

Quality control is important, however, the cost of quality control is also very high. Therefore, a low-cost method of quality control or quality prediction is required.

SUMMARY OF THE INVENTION

The electronic products in the invention can be products for low voltage applications (eg. lower than 5V), or products operated from mains supply (eg. HOV or 220V), or products for high voltage applications (eg. power transmission systems). The electronic components thereof can be characterized by electrical characteristics or electromagnetic characteristics.

Generally, the performance of most electronic products varies with the environment, especially with temperature. For products manufactured in a factory environment which is different from the actual operational environment, it is required to emulate the operational environment to measure the performance of the product in question. The cost of quality control becomes higher, since it is not easy to emulate the real operational environment in a factory. A typical example is the compact halogen lamp. The temperature of a halogen lamp is very high during normal operation, and the ambient temperature of the circuits increases easily with the high temperature of the lamp body due to the compact structure thereof. The circuits could even be heated to temperatures in excess of 150°C after 3 hours of normal operation. Generally, the compact halogen lamp includes key components such as transformers and toroids. The performance of a compact halogen lamp changes significantly when the temperature increases over time. The reason for the change in performance of the compact halogen lamp is that the parameters of key components of the circuit, e.g. transistors, toroids, and transformers, vary with temperature. In addition, the compact halogen lamp can not be used any more when its possible lifetime is determined by means of a test. Thus, it is not realistic in factories to do the test for all compact halogen lamps in an operational environment.

After technical research and testing in practice for a long time, the applicant found that each electronic product contains some features which are, not explicitly, but intrinsically essential. These essential features always relate to the key components in the circuits, so these essential features are inherent, and reflect the fundamental properties of the product. The performance of a product may change with the environment (including temperature, etc.), but should always be determined by the essential features of that product. For example, the essential features of a compact halogen lamp may include the equivalent inductance of the transformer determined by the input signal at a specific frequency, the magnetic permeability of the toroid core, etc. So, the performance of the electronic product can be predicted by testing these essential features. Taking the compact halogen lamp as an example, it is convenient to measure the magnetic permeability of the toroid core and the equivalent inductance of the transformer determined by the input signal at a specific frequency in a non- operating state. However, to measure the performance in the operating state, for example, to measure the operating lifetime, is time-consuming and power-consuming. As a result, it is meaningful to measure these essential features of electronic products in a non-operating state, since the measurement is more convenient and cost-saving than that in the operating state. According to a first aspect of the present invention, there is provided a method of predicting the quality of electronic products, the method comprising the following steps: a. measuring the response of every key component of at least one key component in the assembly of said electronic product, under a pre-determined excitation input signal; b. determining a match parameter of said electronic product by comparing the measured response of the at least one key component with a pre-determined database, wherein the match parameter describes the predicted quality of said electronic product in the operating state.

According to a second aspect of the present invention, there is provided a quality-prediction system to predict the quality of electronic products, comprising: a device-inspection means configured to measure the response of every key component of at least one key component in the assembly of said electronic product, to a pre-determined excitation input signal; a comparing prediction means configured to determine a match parameter of said electronic product by comparing the response of the at least one key component with a pre-determined database, wherein the match parameter describes the predicted quality of said electronic product in the operating state.

Low-cost and high-efficiency quality prediction and quality control of electronic products can be achieved by applying the method and system of some embodiments of the present invention. The invention is especially practical for electronic products whose performance in a factory environment is significantly different from that in an actual operational environment. A detailed description of the invention will be given hereinbelow, based on the application in compact halogen lamps, and the invention also can be applied to other electronic products, such as compact fluorescent lamps (CFL), compact LED lamps, etc.

BRIEF DESCRIPTION OF THE DRAWINGS Hereinafter, the present invention will be further described with reference to the accompanying drawings, in which:

Fig. 1 is a detailed flowchart of a method of quality prediction for electronic products according to an embodiment of the invention;

Fig. 2 is a detailed flowchart of a method of quality prediction for electronic products according to an embodiment of the invention;

Fig. 3 is a detailed flowchart of a method of quality control for electronic products according to an embodiment of the invention;

Fig. 4 is a structure diagram of a quality predicting system for electronic products according to an embodiment of the invention;

Fig. 5 is a structure diagram of a quality predicting system for electronic products according to an embodiment of the invention;

The same or similar drawing reference signs mean the same or similar steps, features or devices (modules).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 is a detailed flowchart 100 of a method of quality prediction for electronic products according to an embodiment of the invention.

Fig. 4 is a structure diagram of a quality prediction system 400 for electronic products according to an embodiment of the invention. As shown in Fig.4, the quality prediction system 400 comprises a device inspection means 402, a comparing prediction means 426, and a memory 418.

The steps of flowchart 100 shown in Fig.l can be executed by the quality prediction system 400 shown in Fig.4. Generally, the quality prediction system can be integrated in the assembly line. Referring to Fig.l and Fig.4, the following part of the description will take the compact halogen lamp as an example to illustrate the flow 100.

In the assembly line, the quality of a compact halogen lamp is predicted by executing the flow 100.

The flow 100 starts with step SlOl. In step S 113, the response of every key component (two key components in the assembly of the compact halogen lamp), is measured under a pre-determined excitation input signal. Generally, the circuit of the compact halogen lamp comprises key components such as transformers and toroids. Alternatively, the key components tested in step S 113 include transformers and/or toroids. For transformers, the equivalent inductance determined by the input signal at a specific frequency is usually measured; for toroids, the magnetic permeability of the core is usually measured. In the assembly line, the process for measuring the response of key components of the compact halogen lamp costs little time. Generally, the process only takes a few seconds or even less time. The step can be executed by the device inspecting means 402. In step Sl 15, the response of the two key components is compared with a pre-determined database first, and then a match parameter of the compact halogen lamp is determined. The match parameter describes the predicted quality of the compact halogen lamp in the operating state. In this embodiment, step Sl 15 is executed by the comparing prediction means 426, and the pre-determined database is stored in the memory 418. Fig.l illustrates the content of the database in this embodiment, which shows the relationship between the different combinations of the detected response of the key components of the compact halogen lamp, which may be known as key characteristics (?), and the actual product quality in the operating state. FA and FB in Table 1 represent the response of two key components to the pre-determined excitation input signal, that is, the equivalent inductance of the transformer of the compact halogen lamp measured when the input signal is at a specific frequency and the magnetic permeability of the toroid core. In table 1, FAi to FA ₅ represent five different ranges of the equivalent inductance of the transformer of the compact halogen lamp determined by the input signal at a specific frequency. FBi to FB ₅ represent five different ranges of the magnetic permeability of the toroid core. According to different combinations of the responding range, Pn to P ₅₅ in table 1 symbolize the actual product quality of the 25 combinations of the compact halogen lamps respectively. For example, the product quality of combination FA ₂ and FB ₄ is P ₂₄ . In this embodiment, product quality is represented by the product life time, so P ₂₄ is usually expressed as a statistical time range or a statistical average value of time. More specifically, in this embodiment, the comparing prediction means 426 finds out the responding range of the equivalent inductance of the transformer of a compact halogen lamp determined by the input signal at a specific frequency and the magnetic permeability of the toroid core, based on the classification in the database. For example, the equivalent inductance of the transformer, determined by an input signal at a specific frequency, is found to belong to category FA ₃ , and the magnetic permeability of the toroid core is found to belong to category FBi first; and then the responding range of FA3 and FBI is compared with the database in memory 418 to get a match parameter P31 in accordance with the combination of FA ₃ and FBi. Consequently, the quality of the compact halogen lamp is predicted as P ₃₁ .

Table 1 the relationship between the responding-range-combination of key components of the

When step S 113 is executed, inspection of the key components of the compact halogen lamp can be done based on distributed key components, semi-finished products of the compact halogen lamp with assembled lamp holder and circuits, or finished products of the compact halogen lamp. The flow 100 in the embodiment can further comprise a step of assembling key components into the compact halogen lamp. The step can be executed by an assembly means (not shown in the Figure) included in the quality prediction system 400. As described above, the step can be executed before or after the step S 113. Preferably, in this embodiment, the state for inspecting the key components in step S 113 is different from the operating state of the compact halogen lamp. More specifically, the temperature of the lamp is high when the compact halogen lamp is in the operating state and the temperature of key components is also high (can be as high as 150°C). However, in step S113, the key component is inspected when the ambient temperature is typically equal to room temperature or the assembly line temperature, which is much lower than the temperature in the operating state.

According to a preferred embodiment of the invention, the quality prediction system 400 further comprises a display means (not shown in the Figure). The display means can display the compact halogen lamp quality, which is predicted by the comparing prediction means.

Fig. 2 is a detailed flowchart 200 of a method of quality prediction for electronic products according to an embodiment of the invention. Fig. 5 is a structure diagram of a quality prediction system 500 for electronic products according to an embodiment of the invention. As shown in Fig.5, the quality prediction system 500 comprises a device inspection means 502, a comparing prediction means 526, a grouping means 504, a quality inspection means 506, a database generation means 508, and a memory 518. The steps of the flowchart 200 shown in Fig.2 can be executed by the quality prediction system 500 shown in Fig.5. Generally, the quality prediction system 500 can be integrated in the assembly line. Referring to Fig.2 and Fig.5, in the following the compact halogen lamp serves as an example to illustrate the flow 200. The flow 200 starts from step S201. In step S203, the quality prediction system 500 measures the response of two key components, the transformer and the toroid, of at least one sample of a type of compact halogen lamp under a pre-determined excitation input signal by means of the device inspection means 502. For the transformer, the equivalent inductance determined by an input signal at a specific frequency is usually measured; for the toroid, the magnetic permeability of the core is usually measured.

In step 205, the grouping means 504 defines at least one range for the equivalent inductance of the compact halogen lamp transformer, which is determined by an input signal at a specific frequency, and at least one range for the magnetic permeability of the toroid core. Taking Table 1 as an example, the equivalent inductance of a type of compact halogen lamp transformer, which is determined by an input signal at a specific frequency, is classified into five ranges from FAi to FA ₅ , and the magnetic permeability of the toroid core is classified into five ranges from FBi to FB ₅ . This type of compact halogen lamps has been categorized into 25 groups, and each group corresponds to a range of the equivalent inductance of the compact halogen lamp transformer, which is determined by an input signal at a specific frequency, and a range of the magnetic permeability of the toroid core.

In step 207, the quality inspecting means 506 inspects the actual quality of these samples of compact halogen lamps in the operating state. For example, a simple method to test the compact halogen lamp lifetime is to record the length of time from the instant the samples are switched on to the time the samples burn out. The process may take anything from several hours to several months. Generally, an upper time limit should be set. If the upper limit is 1000 hours, the product lifetime records of the lamps still burning after 1000 hours should state 'exceeding 1000 hours'.

A sufficiently large number of samples of compact halogen lamps should be inspected in step S203 to S207 to ensure that at least one compact halogen lamp sample can be inspected in every combination of the response ranges of key components. Favourably, more than one compact halogen lamp is sampled in every combination of the response ranges of key components.

In step S209, a database is generated based on the mapping relationship between the product quality parameters and all 25 kinds of combinations of the key component response ranges. The content of the database could be illustrated by FIGl. Then, the database is stored in the memory 518. The step S209 can be executed by the database generation means 508.

Generally, the process from step S203 to step S209 is only executed once in the assembly line to generate the database needed. Then, in step S213, the response to a pre-determined excitation input signal is measured respectively for two key components in the assembly of compact halogen lamps. For the transformer, the equivalent inductance is usually measured when the input signal is at a specific frequency; for the toroid, the magnetic permeability of the core is usually measured. This step can still be executed by the device inspecting means 502. In step S215, the measured response of the two key components is compared with a pre-determined database stored in the memory 518 first, so as to determine a match parameter for the compact halogen lamp. The match parameter describes the predicted quality of the compact halogen lamp in the operating state. The step can be executed by the comparing prediction means 526. Generally, for every compact halogen lamp in the assembly line, the step S213 and the step S215 should be executed to predict the lamp's quality.

When executing step S207, all samples of compact halogen lamps are finished products. When executing step S203 and step S213, inspection of the key components of the compact halogen lamp can be done on distributed key components, semi-finished compact halogen lamps with assembled lamp holder and circuits, or finished compact halogen lamps. For samples of compact halogen lamps or for finished compact halogen lamps, a step of assembling the key component into the compact halogen lamp can be further included. As described above, the assembling step can be executed before step S203 and S213, or after step S203 and S213. According to another embodiment of the invention, the device inspection means 402 or 502 will test the response of three kinds of key components of compact halogen lamps, being either finished products or samples. The response of these three key components comprises but is not limited to the equivalent inductance of the transformer of the compact halogen lamp measured when the input signal is at a specific frequency, and the magnetic permeability of the toroid core.

Although the embodiments given above only describe examples of inspecting two or three kinds of key components of the compact halogen lamps, people skilled in the art can understand that, in other embodiments of the invention, it is feasible to inspect more kinds of key components of compact halogen lamps, to determine at least one range of parameters for the response of every key component in order to find a combination of responding ranges for all key components, and then predict the product quality corresponding to these combinations, respectively. Of course, in other embodiments of the invention, it is also feasible to inspect only one kind of key component of compact halogen lamps in the non-operating state, to find at least one range of parameters for the response of the key components, and then predict the product quality corresponding to these parameter ranges, respectively.

Fig. 3 is a detailed flowchart 300 of a method of quality prediction for electronic products according to an embodiment of the invention. In this embodiment, the flow 300 shown in Fig 3 can be partly executed by the prediction system 500 at least. The functions of steps S301 to S305 shown in Fig.3 are almost the same as the functions of steps S201 to S215 shown in Fig.2, and are executed by every means in the prediction system 500, respectively. In step S317, whether or not a compact halogen lamp is qualified, is determined by the product quality predicted in step S315. If a compact halogen lamp is qualified, step S319 is executed to go to the next station in the assembly line, for example, the packing station. If the compact halogen lamp is not qualified, step S329 is executed to remove the compact halogen lamp from the assembly line. Step S317, S319 and S329 can be executed by the predicting system 500 or other system in the assembly line.

According to another embodiment of the invention, the quality predicting system 500 is not completely installed in the assembly line. In the embodiment, the device inspecting means 502, the grouping means 504, the quality inspecting means 506, and the database generation means 508 can be set in a lab or research center; the quality prediction system 500 can further comprise another device inspection means 522 (not shown in the Figure), the device inspection means 522 and the comparing prediction means 526 can still be set in the assembly line; the memory 518 can be set in a network server. The samples of compact halogen lamps are tested in labs or research centers. The device inspection means 502 is applied to test two key components of at least one sample of one type of compact halogen lamps, that is, the transformer and the toroid. For the transformer, the equivalent inductance is measured when the input signal is at a specific frequency; for the toroid, the magnetic permeability of the core is measured. The grouping means 504 is applied to determine at least one range for the equivalent inductance, when the input signal is at a specific frequency, and for the magnetic permeability of the core. A combination is determined by one range of the equivalent inductance when the input signal is at a specific frequency and one range of the magnetic permeability of the core. The grouping means 504 is also applied to define all combinations of this type of compact halogen lamps. The quality inspection means 506 is applied to test the actual quality of these samples of the compact halogen lamps in the operating state. The database generation means 508 is applied to generate a database, based on the mapping relationship between the product quality parameters and all kinds of combinations for this type of compact halogen lamps. The data base will be stored in the memory 518 in the network server. In the assembly line, the key components of the compact halogen lamps will be inspected and the qualities of the key components will be predicted. The device inspection means 522 is applied to inspect the response of the two key components of every compact halogen lamp under different pre-determined excitation input signals, e.g. the equivalent inductance of transformers determined by an input signal at a specific frequency, and the magnetic permeability of the toroid core. The comparing prediction means 526 is applied to compare the response of the above two key components with the above pre-determined database stored in the network server, so as to determine a match parameter of every compact halogen lamp. The match parameter describes the predicted quality of the compact halogen lamp in the operating state. People skilled in the art can understand that the memory 518 in the embodiment can be replaced by floppy disks, compact disks or any other known storage medium.

Generally speaking, the circuit of an electronic product will exhibit oscillations of large amplitude and transmit oscillation signals in one or more bands when in the operating mode. An example of such a product is the compact halogen lamp. When the performance of the component of a compact halogen lamp sample in the circuit varies with the environment, such as the temperature, the frequencies of the transmitted oscillation signals also change subsequently. When the sample remains in a stable operating state, transmitted oscillation signals will be more stable. After having conducted technical research and practical experiments for a long time, the applicant found that there is a close relationship between the performance of the electronic products and the oscillation frequency of their circuits in the operating state. The electronic products include compact halogen lamps, compact fluorescent lamps, and compact light emitting diodes. As regards the above products, their circuit oscillation frequencies in the operating states are key indicators of the product quality. If the compact halogen lamp is taken as an example, on the whole, the life time of the compact halogen lamp increases with the oscillation frequency, and the lifetime of the compact halogen lamp decreases with decreasingoscillation frequency.

According to another embodiment of the invention, the circuit oscillation frequency of the compact halogen lamp in the operating state represents the product quality of the lamp. In this embodiment, the following method can be used to test the circuit oscillation frequency of the compact halogen lamp in the operating state: First, keeping the sample of a finished compact halogen lamp energized for a period of time to keep the lamp in the operating state, that is to say, to make the temperature of the lamp and the circuit stable (may reach or exceed 150 "C); then, detecting the oscillation signal having a larger or the largest amplitude that is transmitted by the finished compact halogen lamp, and the frequency of the detected oscillation signal is the oscillation frequency of the sample in the operating state. The means (quality inspecting means 506) to inspect the product quality of the finished compact halogen lamp samples in this embodiment should further include the following sub-means: a sub-means to provide power for the compact halogen lamp samples to make them work; and another sub-means to detect the oscillation signal of the compact halogen lamp samples. Table 2 shows the mapping relationship between the responding range combination of key components of the compact halogen lamp and the actual product quality.

As shown in table 2, the responses of the key components of compact halogen lamps include the equivalent inductance of the transformer when the input signal frequency is 50 kHz and the magnetic permeability of the toroid core. The equivalent inductance of the transformer when the input signal frequency is 5OkHz has been divided into 6 ranges according to the value of the equivalent inductance, and the magnetic permeability of the toroid core has been divided into 4 ranges according to the value of the magnetic permeability. The parameters of the response of the two key components (also known as key characteristics) in the table all correspond to a certain parameter range. People skilled in the art should understand that the responses of the key components herein are all characteristic parameters in the non-operating state . Thus, the magnetic permeability of the toroid core is the initial magnetic permeability, and the equivalent inductance of the transformer is the initial equivalent inductance. For example, the parameter 6 of the key characteristics 1 represents a relative magnetic permeability lower than 2.5k; the parameter 8 of the key characteristics 1 represents a relative magnetic permeability between 2.5k and 2.7k; the parameter 10 of the key characteristics 1 represents a relative magnetic permeability between 2.7k and 2.9k; the parameter 12 of the key characteristics 1 represents a relative magnetic permeability higher than 2.9k, etc. The parameter

7 4 7.6 of the key characteristics 2 represents an equivalent inductance higher than — mH; the

2π

5 7 parameter 6.0 of the key characteristics 2 represents an equivalent inductance between — mH

2π and — mH ; the parameter 5.3 of the key characteristics 2 represents an equivalent inductance

2π lower than — mH, etc. According to different combinations of the responding range of the key

2π components, this kind of compact halogen lamps has been divided into 24 combinations. Table 2 shows the product qualities corresponding to said 24 combinations of the compact halogen lamps, which is represented by the oscillation frequency of the circuit. The oscillation frequency can be considered as a frequency range whose center frequency is the data in the table. For example, the oscillation frequency bandwidth is 5% to 10% of the center frequency determined by the data in the table. Several embodiments of the invention have been described using compact halogen lamps by way of example. People skilled in the art can understand that the invention can also be applied to electronic products, such as compact fluorescent lamps (CFL), compact LED lamps, etc. Embodiments have been described hereinabove, but the invention is not limited to specific systems or equipment. Various modifications or alterations can be made by those skilled in the art without departing from the scope as defined by the appended claims.