JP2003214982A - Light receiving device inspection device, its adjusting method, and noise measuring method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light receiving device inspection device capable of providing a product at a low cost, an adjustment method of the same, and a noise measuring method using the same by easily forming a precise light source intensity in the product inspection process of a light receiving device to improve calibration level in the inspection process, thereby improving the yield, and also providing a means capable of easily confirming electromagnetic noise resistance level. <P>SOLUTION: This light receiving device inspection device is a device for inspecting whether the light receiving distance of the light receiving device arranged opposite to measuring light sources 11 and 12 for repeatedly outputting pulse wave light of a prescribed period with a fixed space is a prescribed distance or more. This device comprises a judgment means for measuring the pulse width of the measuring light sources 11 and 12 received by the light receiving device and judging whether the pulse width is a set value or more or not. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting an inspection device for a light receiving device capable of measuring a reception distance characteristic, an inspection device for a light receiving device, and a noise measuring method using the inspection device for the light receiving device.

[0002]

2. Description of the Related Art Conventionally, a device which receives signal light and outputs an output waveform has been widely used on the light receiving side of a remote control device such as a TV, a VTR, an audio system, and a remote control light receiving unit, remote control photo IC, remote control. It is widely used as the name of sensor, remote control light receiving element, etc.

As a characteristic of these devices, terminals are generally Vcc (power supply voltage), Vo (output terminal), GND.
Since it is a 3-terminal output and Vo is a TTL output, it can be easily coupled to the IC circuit in the subsequent stage.

In recent years, an infrared ray receiving / emitting element of the IrDA (infrared data communication standard) system for a mobile phone has come to be used, and its application field as a light receiving device is expanding.

The most important characteristic in using these light receiving devices is the reception distance characteristic, and the distance range in which communication is possible between the transmitting side and the light receiving device is important.

The reception distance characteristic is closely related to the light emission intensity on the transmitting side, and by increasing the device having a high light emission intensity or the current value, the signal light to the receiving device also becomes strong and the maximum reception distance is extended. However, for evaluation and inspection, a standard light source is created and the emission intensity of the standard light source is specified in order to keep the conditions constant.

An example of a method for inspecting the light receiving distance of the remote controller will be described below.

As a method for producing a standard light source, as shown in FIG. 7, P for signal light is used at a constant distance of about 20 cm by using a reference PD (photodiode) of a standard receiver.
It is specified by the peak voltage value of D. For example, the emission intensity is regulated by adjusting the output on the standard light source side so that the output value of the PD becomes 50 mVp-p.

In the inspection using the remote control light receiving device, the above-mentioned reception distance characteristics are important. Regarding the maximum reception distance (8 to 20 m), intermediate distance (3 to 7 m), and short distance characteristics (10 to 20 cm) in the inspection. We are inspecting each. Furthermore, rank classification according to the maximum reception distance required for each type of usage is also implemented. For example, 20m or more, 15m
As described above, the light receiving devices of 10 m or more are classified.

The intensity on the light source side of the inspector for each remote control reception distance is evaluated by observing the light receiving device with the standard light source as a reference, and the light receiving device is evaluated at a reception distance of 20 m for a sample of 15 m.
Samples of 10 m are selected, set in an inspector, and the light source power is adjusted so that the samples are non-defective and inspected. When the distance sample to be inspected cannot be obtained, a sample in which the lens surface of the light receiving device is partially deleted is created to determine the light source intensity of the inspector. Therefore, it is necessary to create reception samples for each distance.

Further, the remote controller modulates the sub-carrier in the transmission waveform, and the sub-carrier is different depending on the user and the set used. Therefore, in the light receiving unit, the center frequency corresponding to the sub-carrier is matched. P. It has a built-in F (band pass filter). Therefore, a range sample is required for each type of product having different inspection reception distances and different center frequencies.

Further, not only the emission intensity on the transmitting side, but also the maximum receiving distance greatly differs due to the difference in the format of the transmitting side, the difference in the reference signal pulse width value, and the difference in the reference of the reading pulse width value of the receiving side microcomputer.

On the other hand, the light receiving device has a use environment of, for example, T.
In the case of V, since it is installed near a noise source such as a cathode ray tube, high electromagnetic noise resistance is required. A metal shield case has been added to the light-receiving device to improve the electromagnetic noise resistance. For a set with a high electromagnetic noise level, the light-receiving window is meshed and the back side of the device is also covered with metal. There is also. Since the metal case is generally provided with a positioning pin on the set side, there are various kinds of metal cases. Therefore, it is very difficult to perform an automated inspection for various metal cases having different shapes, and it is common to perform the characteristic inspection before adding the metal case. As a result, the light-receiving device before the addition of the metal case generally has low electromagnetic noise resistance, and if the electromagnetic noise level of the inspection environment is large, the yield is reduced. Therefore, it is important to check the inspection environment, and when equipment movement or changes in the surrounding environment occur, a great deal of effort is put into checking yield transitions and EMC (electromagnetic environment compatibility) evaluation, and conducting survey analysis.

Regarding measurement of the operating distance range of the remote control light receiving element, a plurality of remote control light emitting elements are arranged at a fixed distance from the light emitting source as shown in, for example, Japanese Patent Laid-Open No. 11-51811, and the light of the light emitting source is emitted. By controlling and transmitting the output set value, the operable set value range of the remote control light receiving element is confirmed, and the remote control light receiving element of the remote control light receiving element is converted by conversion based on the correlation characteristics between the set value and the operating distance obtained by actual measurement in advance. Since the operating distance range is determined, the space for the measurement system can be made much smaller than before, and it is possible to measure multiple remote control light-receiving elements side by side, making it possible to reduce the number of measurement steps. It is said that it can greatly contribute to the reduction. In the measurement method, it is shown that the set value of the light output is substantially changed to a wider range by disposing the filter for adjusting the light output between the remote control light receiving element and the light emitting source for measurement.

[0015]

However, in the inspection of the light receiving device, the reception distance characteristic inspection and the rank classification are necessary, but the yield is greatly affected.
Therefore, in order to increase the rank collection rate, it is necessary to accurately generate the light intensity corresponding to the light emission distance, but there is a problem that it takes a lot of time to create a sample for each distance.

Further, in the measuring method disclosed in Japanese Patent Laid-Open No. 11-51811, due to the difference in the format of the transmitting side, the difference in the reference signal pulse width value, and the difference in the reference of the reading pulse width value of the receiving side microcomputer, Since the maximum receiving distance and the operating distance range are greatly different, reference samples for each format, each reference signal pulse width value, and each reading pulse width value of the receiving side microcomputer are required, which requires a great deal of labor.

In order to solve these problems, there is a demand for an inexpensive inspection device for a light-receiving device that accurately determines the light source intensity.

On the other hand, when it is attempted to generate a light source intensity from a short distance to a long distance by using a single LED as a light source, for example, if a light amount corresponding to a standard light source of 20 m is used as a reference, a current flowing through the LED at a short distance is several tens. Since it is necessary to use ampere, deterioration of the LED is a concern, and stable inspection cannot be performed. Further, if the filter is mechanically changed, the control system becomes complicated, the time for replacing the filter is required, and the inspection time becomes long. Therefore, there is also a demand for a stable light source that can freely output light corresponding to a short distance to a long distance.

Further, the inspection environment has a great influence on the yield, but in recent years, due to the shortening of the product cycle, equipment replacement and the like frequently occur, and the surrounding environment is apt to change. There is also a problem that a great deal of labor is required for evaluation of environmental compatibility.

Therefore, according to the present invention, in the product inspection process of the light receiving device, an accurate light source intensity is easily created, and the yield is improved by improving the calibration level in the inspection process, and at the same time, it is easy to confirm the electromagnetic noise resistance level. It is an object of the present invention to provide an inspection device for a light-receiving device, an adjustment method therefor, and a noise measurement method using the same, which provide various means and finally provide a product at low cost.

[0021]

In an inspection device for a light receiving device of the present invention, a pulse width value output from a standard light source is measured by the light receiving device, and a light receiving distance by the light receiving device is calculated from this pulse width value. Is. According to the present invention, it is not necessary to prepare a plurality of samples for each distance as a measurement light source, and an inspection device for a light receiving device capable of performing measurement with a single measurement light source can be obtained.

Further, in the adjusting method of the inspection device for the light receiving device of the present invention, the current is adjusted in accordance with the relationship between the previously measured reception distance and the pulse width value to obtain a predetermined pulse width value. According to the present invention, it is possible to easily and quickly adjust the measurement light sources having different performances.

Further, the light-receiving device inspection apparatus of the present invention is provided with a changeover switch for changing the emission intensity by changing the number of measurement light sources to be simultaneously output among the plurality of measurement light sources. According to the present invention, it is possible to obtain a light receiving device inspection apparatus capable of performing detailed light source output and adjustment from a long distance to a short distance.

Further, in the noise measuring method using the light receiving device inspecting apparatus of the present invention, the standard deviation of the pulse width value is calculated and compared with the standard deviation to evaluate the noise level at the measuring place. To do. According to the present invention, it is possible to obtain a noise measuring method using an inspection device for a light-receiving device, which enables simple and easy measurement.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a light receiving device of a light receiving device which is arranged to face a measuring light source which repeatedly outputs light of a pulse wave having a predetermined period, with a constant interval. An apparatus for inspecting whether a distance is a predetermined distance or more has a determination means for measuring a pulse width of the measurement light source received by the light receiving device and determining whether the pulse width is a set value or more. The light-receiving device is inspected, and the light-receiving distance can be obtained by measuring the pulse width value from a predetermined distance.

According to a second aspect of the present invention, a plurality of the light sources for measurement are provided, and the plurality of light sources for measurement are provided with the number of the light sources for measurement that simultaneously output the light of the pulse wave. The inspection apparatus for a light receiving device according to claim 1, further comprising a changeover switch for changing the emission intensity. Change the number of light sources for measurement to create a light amount equivalent to a long distance, and increase the number of light sources for measurement to create a light amount equivalent to a short distance. It has the effect of making the amount appropriate.

According to a third aspect of the present invention, the pulse width value for each reception distance of the light receiving device is measured in advance with respect to a standard light source that repeatedly outputs the light of the pulse wave having a predetermined period, and the received light is received. An inspection device provided with a measurement light source by setting a predetermined distance with respect to the device is adjusted, and a current supplied to the measurement light source is adjusted to set a predetermined pulse width value corresponding to the reception distance. It is a characteristic method for adjusting an inspection apparatus for a light receiving device, and has an effect of accurately and quickly adjusting measurement light sources having different performances.

According to a fourth aspect of the present invention, there is provided a method for measuring ambient noise using an inspection device for a light-receiving device equipped with a measuring light source for repeatedly outputting light of a pulse wave having a predetermined period. The pulse width value of the light receiving device with respect to the light source for measurement is measured many times in advance at a place where the noise level is a predetermined value or less, and a standard deviation serving as a reference is derived, and the inspection device is set at a predetermined measurement place. An inspection apparatus for a light-receiving device, characterized by deriving a standard deviation for measuring and comparing a large number of pulse waves of light output from the device, and evaluating a noise level at the measurement location from the difference in the magnitude of the standard deviation. This is a noise measurement method that uses a pulse width that differs from a predetermined pulse width due to the effect of noise. It has the effect of being able to value.

FIG. 1 shows an embodiment of the present invention.
4 to FIG.

(Embodiment 1) FIG. 1 is an explanatory view of an inspection apparatus for a light receiving device according to an embodiment of the present invention. In FIG. 1, an inspection apparatus 10 includes light emitting diodes 11 and 12 which are examples of a plurality of measurement light sources which are provided on a substrate 13 and which can repeatedly output light of a pulse wave having a predetermined cycle, and light emitting diodes which are received by a light receiving device. It has a determination means (not shown) that measures the pulse widths of 11 and 12 and determines whether or not the pulse width is equal to or larger than a set value.

Further, the inspection device 10 changes the number of light sources for measurement which simultaneously outputs the light of the pulse wave among the plurality of light emitting diodes 11 and 12 to 1 and 8 to change the emission intensity, which is not shown. And a switch. That is,
The inspection device 10 can generate a light source power corresponding to a predetermined reaching distance by changing the number of the light emitting diodes 11 and 12 and the amount of current flowing through the light emitting diodes 11 and 12 while keeping the distance to the sample constant. it can.

For example, a light source power equivalent to several cm to 25 m can be produced by turning on one light emitting diode 11, and eight light emitting diodes 12 arranged in a circle around the light emitting diode 11 can be used. By turning on the light source, a light source power equivalent to 10 cm to several tens of meters can be produced. In particular, even when a light source power equivalent to 10 cm is produced, the current flowing through the light emitting diode 12 can be several hundred mA, and the load on the light emitting diode 12 can be significantly reduced.

Next, the amount of current flowing through the light emitting diodes 11 and 12 is adjusted.

First, a sample capable of outputting a pulse width equal to or larger than the reception distance whose reception distance characteristic is desired to be inspected is prepared, and the characteristics of the light reception distance and the pulse width value are actually measured using a standard light source. At this time, the pulse width value is the number of times that statistical value analysis is possible, for example, hundreds to 10,000 times of measurements are performed, and the average value
Calculate maximum, minimum and standard deviation. In recent years, measuring instruments such as time interval analyzers and long memory type oscilloscopes that evaluate accurate time have been developed, and it is possible to easily measure several hundred to 10,000 pulses and to display statistical values. Therefore, it is easy to evaluate using a measuring instrument. Similar results can be obtained by adding a pulse statistical value processing function to the inspection tester side.

FIG. 2 is an explanatory diagram in which the transmission signal and the light receiving signal on the far distance side are measured and displayed on the same screen, and FIG. 3 is the illustration where the transmission signal and the light receiving signal on the near distance side are measured and displayed on the same screen. FIG. 4 is a graph showing the relationship between the light receiving distance of the light receiving device and the pulse width value.

2 and 3, the transmission signal and the reception signal which are rectangular waves are displayed in the upper and lower rows, respectively. The transmission signal has a High side as an output, and the reception signal has a Low side as an output.

As shown in FIG. 2, the pulse width value t of the transmission signal
In contrast to 1, the pulse width value t2 of the light receiving signal on the far side is smaller. On the other hand, as shown in FIG. 3, the pulse width value t3 of the transmission signal is different from the pulse width value t of the light receiving signal on the short distance side.
4 is getting bigger.

Further, as shown in FIG. 4, generally, in the light receiving device, the pulse width value of the output varies depending on the light receiving distance,
The average pulse width value tends to decrease as the distance increases.

Here, since the average pulse width value for each light receiving distance is determined, when setting the light receiving distance of the inspection device 10,
This can be easily performed by adjusting the current to match the pulse width value corresponding to the light receiving distance. Further, by collecting data of the reception pulse width for each distance at intervals of several tens of cm, it becomes possible to create a light source intensity for each fine distance. Furthermore, once the standard light source is used for pricing, different light sources with different center frequencies have the same light source intensity, and therefore different samples are not required. further,
A pulse statistical value processing function may be added to the inspection tester side, or an external measuring instrument may be prepared for evaluation.

Next, a method of inspecting the light receiving device using the inspection apparatus 10 will be described.

First, the light emitting diode 1 is manufactured by the above procedure.
The pulse width value of each receiving distance of the light receiving device for 1 and 12 is measured in advance. And the light emitting diode 1
A light receiving device to be measured by setting a predetermined distance with respect to 1 and 12 is installed. This distance is arbitrary, but is set to 20 cm, for example.

Then, the pulse width value output from the light emitting diodes 11 and 12 is measured by this light receiving device, and the light receiving distance by the light receiving device is calculated from this pulse width value.

In this way, since the light-receiving ability of the light-receiving device can be quantified and specified, not only the yield can be improved, but also the characteristic variation due to the manufacturing place and the timing of the same product can be converted into data and accumulated. It is possible to quickly grasp fluctuations in quality.

(Embodiment 2) Next, a noise measuring method using a light receiving device inspection apparatus will be described.

FIG. 5 is a graph showing the distribution of many pulse width values when there is no electromagnetic noise, and FIG. 6 is a graph showing the distribution of many pulse width values when there is electromagnetic noise.

As shown in FIG. 5, the measured pulse width value is within a certain range of variation. The magnitude of the range of variation is determined corresponding to the magnitude of the standard deviation calculated from the measurement data, for example.

The inspection device 10 is used for measuring the noise.

First, the pulse width value of the light receiving device for the light emitting diodes 11 and 12 is measured many times in advance at a place where the noise level is a predetermined value or less, and the range of variation is derived and the reference is obtained as shown in FIG. The standard deviation is calculated.

Then, a large number of pulse waves output from the inspection device are measured at a predetermined measurement location where the noise level is desired to be measured, and the standard deviation is calculated.

As shown in FIG. 6, when the influence of electromagnetic noise appears, the pulse width value output from the light receiving device has a distribution different from the regular pulse width distribution, so that the actual inspection environment By evaluating the sample with
The noise level can be easily evaluated. Compared with the distance-pulse width characteristic at a place where the noise level is equal to or lower than a predetermined value, the jitter characteristic of the pulse width value of the light receiving device in a noise environment fluctuates, and thus the standard deviation becomes large. In this way, the influence of the noise level can be easily known by comparing with the standard deviation serving as the reference.

Note that the relationship between the noise level and the standard deviation, or the relationship between the noise level and the number of pulse width values outside the range of variation may be obtained in advance by experiments.

Similarly to the above, with respect to the light source intensity of the IrDA device, it is possible to evaluate the distance-pulse width value characteristic on the light receiving side of the IrDA device and generate the light source intensity by a similar method. Also, the effect of noise level can be easily evaluated.

[0053]

As described above, in the light receiving device inspection apparatus of the present invention, since the light receiving distance by the light receiving device is calculated from the pulse width value, it is not necessary to prepare a plurality of samples for each distance as the measurement light source. An inspection apparatus for a light-receiving device that can perform measurement with a single light source for measurement is obtained, and the accuracy of inspection can be improved.

If a changeover switch for changing the number of light sources that emit light at the same time is provided, the number of light sources is reduced to generate weak light corresponding to a long distance, and the number of light sources is increased to increase a strong light corresponding to a short distance. Since light is generated, the amount of current flowing through the measurement light source can be made appropriate and the life of the inspection device can be extended.

In the method for adjusting the inspection device for the light receiving device of the present invention, the current is adjusted to set the pulse width value according to the receiving distance, so that the measuring light sources having different performances can be adjusted accurately and quickly, and the inspection can be performed. The accuracy of can be improved.

In the noise measuring method using the light receiving device inspection apparatus of the present invention, the fact that the pulse width fluctuates due to noise is utilized, and the standard deviation obtained by counting the pulse width values is simply compared with the reference value. Therefore, the noise level can be easily evaluated without the EMC evaluation equipment.

As described above, in the product inspection process of the light receiving device, it is possible to easily produce an accurate light source intensity and improve the calibration level in the inspection process to improve the yield and also to confirm the electromagnetic noise resistance level. It becomes possible to provide an easy means and finally provide an inexpensive product.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an inspection device for a light receiving device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram in which a transmission signal and a light receiving signal on the far side are measured and displayed on the same screen.

FIG. 3 is an explanatory diagram in which a transmission signal and a light receiving signal on the short distance side are measured and displayed on the same screen.

FIG. 4 is a graph showing a relationship between a light receiving distance of a light receiving device and a pulse width value.

FIG. 5 is a graph showing the distribution of many pulse width values in the absence of electromagnetic noise.

FIG. 6 is a graph showing the distribution of many pulse width values in the presence of electromagnetic noise.

FIG. 7 is an explanatory diagram of an inspection method of a light receiving device according to a conventional example.

[Explanation of symbols]

11,12 Light emitting diode (light source for measurement) 13 board

Claims (4)

[Claims] 1. An apparatus for inspecting whether a light receiving distance of a light receiving device, which is arranged to face a measurement light source that repeatedly outputs light of a pulse wave having a predetermined cycle with a constant interval, is a predetermined distance or more, An inspection apparatus for a light-receiving device, comprising: a determination unit that measures a pulse width of the measurement light source received by the light-receiving device and determines whether or not the pulse width is equal to or larger than a set value. 2. A plurality of measuring light sources are provided, and a changeover switch for changing the emission intensity by changing the number of the measuring light sources that simultaneously output the light of the pulse wave to the plurality of measuring light sources. The light receiving device inspection apparatus according to claim 1, further comprising: 3. A pulse width value for each receiving distance of a light receiving device is measured in advance for a standard light source that repeatedly outputs a pulsed wave light of a predetermined cycle, and a predetermined distance is set for the light receiving device. An inspection device equipped with a measurement light source is installed, and a current supplied to the measurement light source is adjusted to set a predetermined pulse width value corresponding to the reception distance. Method. 4. A method of measuring ambient noise using an inspection device for a light-receiving device equipped with a light source for measurement that repeatedly outputs light of a pulse wave having a predetermined cycle, the pulse of the light-receiving device with respect to the light source for measurement. Width value,
A large number of pulse waves of the light output from the inspection device are measured at a predetermined measurement location by measuring a large number of times in advance at a noise level of a predetermined value or less and deriving a standard deviation as a reference. A noise measuring method using an inspection apparatus for a light-receiving device, which comprises deriving a standard deviation to be compared, and evaluating a noise level at the measurement location from a difference in magnitude of the standard deviation.