JP2002195882A - Luminous body inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminous body inspection device having excellent practicability in an inspection process for LEDs, etc., a low misinformation rate, and stable inspection quality. SOLUTION: This luminous body inspection device for LEDs comprises an LED sensor unit 2 for detecting light emitted from inspected LEDs 31A and 31B to determine the state of light emission and a tester controller 1 for final determination. The sensor unit 2 determines the state of light emission of the luminous bodies based on the ratio of a plurality of luminance values obtained from light filters 22A and 22B and on a preset threshold for determination. The light filters 22A and 22B have filter characteristics corresponding to the different colors of the emitted light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting inspection apparatus for inspecting the light emitting state of a light emitting body composed of a light emitting diode.

[0002]

2. Description of the Related Art Conventionally, in electronic equipment such as a personal computer, a light-emitting element represented by a light-emitting diode (LED) has been used as various indicators such as a power supply display and a status display. In a manufacturing process of an electronic device, an LED inspection process is included in various inspection processes.

In the LED inspection process, various inspection methods such as an inspection method visually inspected by an operator, an automatic inspection method using image recognition processing, and the like have been implemented, developed, and proposed. In recent years, development of a dedicated inspection apparatus using a computer and having excellent inspection efficiency and practicality has been promoted.

[0004] Specifically, there has been proposed an inspection apparatus comprising a detection unit using a color CCD camera or the like for emitting light when the LED emits light, and an inspection / determination unit using a computer (for example). See JP-A-11-201868). This inspection apparatus is a method of determining the quality of an LED to be inspected by comparing a light emission color detected by a detection unit with a preset reference display color.

[0005]

In the conventional LED inspection method, the visual inspection method based on the visual inspection of an operator depends on the skill and skill of the operator, so that stable inspection quality (inspection accuracy) is ensured. It is difficult. In addition, in the automatic inspection method using image recognition processing, a long time is required for image processing, and a false information rate (occurrence rate of erroneous inspection results) increases due to the dependence on the accuracy of image comparison data.
There are many problems for practical use.

Further, since the above-described inspection apparatus is a determination method based on the absolute value of the reference display color, if the luminous intensity varies greatly for each LED to be inspected, the accuracy of the LED quality determination result decreases. As a result, there is a problem that a false information rate increases.

An object of the present invention is to provide a luminous body inspection apparatus which is excellent in practicality in an inspection process of an LED or the like and has a low false alarm rate and a stable inspection quality.

[0008]

The present invention uses a plurality of optical filters having filter characteristics (characteristics transmitting light of an effective wavelength) corresponding to different emission colors of a light-emitting body (for example, an LED) to be inspected. The present invention also relates to a luminous body inspection device that inspects a luminous state (good or bad) of a luminous body based on a ratio of a plurality of luminance values obtained by each optical filter and a preset determination threshold.

More specifically, the inspection apparatus of the present invention has means for emitting light from a luminous body to be inspected, and a plurality of optical filters having filter characteristics corresponding to different luminous colors of the luminous body. Sensor means for detecting a plurality of luminance values corresponding to the effective wavelength of light transmitted through each of the optical filters in response to light emission; and a ratio of the plurality of luminance values detected by the sensor means and a judgment prepared in advance. Inspection means for inspecting the light emitting state of the illuminant to be inspected using the threshold value.

[0010] With the inspection apparatus having such a configuration, a stable and efficient inspection process can be realized because the inspection apparatus is an automatic inspection method that is not affected by the skill or skill of the operator. Further, since no image recognition processing or the like is used, high-speed inspection processing is possible. Furthermore, even when the luminous intensity of the luminous body to be inspected varies, the inspection method refers to the ratio of luminance values other than the determination threshold value that is an absolute value. Pass / fail judgment can be realized.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an LED inspection apparatus related to the present embodiment, and FIG. 3 is a block diagram showing a configuration of an LED sensor unit of the embodiment.

[0013] (Configuration of LED inspection apparatus) inspection apparatus of the embodiment, as shown in FIG. 1, the tester controller 1 roughly, and a LED sensor unit 2. The tester controller 1 controls the entire inspection apparatus, controls the activation of a test program, and executes a previously prepared automatic test routine, as described later, and executes final LED pass / fail determination. I do. LED
The sensor unit 2 receives the light emitted from the LEDs to be inspected (here, the two LEDs 31A and 31B having different emission colors), and executes a luminance value detection process and a emission color determination process ( See FIG. 3).

In the embodiment, the LED 3 to be inspected is
1A and 31B are mounted on a printed circuit board (PCB) 3 used for a personal computer together with a CPU 30 of the computer. CPU30, for example connected to the tester controller 12 via the printer interface 4, to start the test program stored in advance in response to a command from the tester controller 12. The CPU 30 controls the power supply circuit 32 to emit light from one or both of the LEDs 31A and 31B to be inspected by executing the test program. LED3
1A and 31B have different emission colors.
Assume an ED and a green LED.

(LED Sensor Unit) The LED sensor unit 2 is activated when power is supplied in cooperation with the tester controller 1 and has a function of automatically recognizing the light emission of the LEDs 31A and 31B. The LED sensor unit 2 is roughly divided into a one-chip microcomputer (to be referred to as an MPU hereinafter) 20, which will be described later, and a plurality of optical filters 2 having different optical filter characteristics (characteristics for transmitting light of an effective wavelength).
1A and 21B and photo ICs 22A and 22B.

The optical filter 21A corresponds to the LED 31A and has a filter characteristic of transmitting the red light. On the other hand, the optical filter 21B corresponds to the LED 31B and has a filter characteristic of transmitting the green light. Photo IC22
A and 22B correspond to the optical filters 21A and 21B, respectively, have a photodiode and an amplifier, and output a detection current corresponding to the detected luminance value. Each of these detection currents is converted into a voltage value by voltage conversion circuits 23A and 23B having resistance and sent to the MPU 20.

The MPU 20 is connected to the tester controller 1 via the serial data line 5. MPU20
Has an A / D converter 26 as shown in FIG.
The luminance values converted into voltage values are input from the voltage conversion circuits 23A and 23B, which are input side circuits, and are converted into digital values. The voltage conversion circuits 23A and 23B are connected to the photo IC 22 via the connector 25 and the flexible cable 24.
A, 22B.

Further, the MPU 20 has a computing unit 28 for executing a luminance value detecting process and a luminescent color determining process, which will be described later.
Memory (RAM) 2 for storing various processing results
7 and an I / O port 29 connected to the serial data line 52 for inputting and outputting data and commands.

FIG. 7 is a view showing the structure of the LED sensor unit 2 described above. FIG. 1A is a plan view, and FIG. 1B is a side view.

(LED inspection operation) FIGS. 2, 4 and 5
The LED inspection operation of the embodiment will be described with reference to the flowcharts of FIG. First, the schematic operation will be described with reference to the flowchart of FIG.

When the power of the tester controller 1 is turned on, the test program of the tester controller 1 is started to start the LED inspection operation (step S1). Accordingly, the power supply of the LED sensor unit 2 is turned on (Step S20 in FIG. 5).

Further, the LEDs 31A and 31B to be inspected are
When the power is turned on to the PCB 3 on which the
0 indicates an operable state (step S2). Then, in response to a command from the tester controller 1, the CPU 3
0 LED test program starts (step S
3). Here, the CPU 30 includes the tester controller 1
The configuration may be such that the LED test program is downloaded from.

The tester controller 1 executes an automatic test routine included in the control program, transmits various commands to the LED sensor unit 2,
The data and status are received from the D sensor unit 2 (Step S4). And the tester controller 1
Based on the determination result from the LED sensor unit 2, a final inspection, that is, a pass / fail determination of whether or not the LEDs 31A and 31B to be inspected operate normally (step S).
5). If the final inspection result is not normal, the tester controller 1 executes a predetermined process (step S5).
NO).

As shown in FIG. 4, the tester controller 1 executes an automatic test routine to confirm that the LEDs 31A and 31B to be inspected are turned off, and transmits an offset value acquisition command to the LED sensor unit 2. (Steps S10 and S11). The offset value is a compensation value of the luminance value obtained by the detection processing in the LED sensor unit 2.

Next, the tester controller 1
02 to the LED 31 to be inspected.
A and 31B are turned on (light emission) (step S12).
Here, the tester controller 1 includes the LEDs 31A and 31A.
B may emit light, or both may emit light at the same time. The tester controller 1 transmits an initialization command to the LED sensor unit 2 to execute a self-diagnosis test described later (step S1).
3). Thereafter, the tester controller 1 receives the LED sensor status (state of the unit 2) and the LED light emission status (determination result) from the LED sensor unit 2 (Steps S14 and S15). Then, the tester controller 1 compares the reception result with an expected value prepared in advance, and executes a final LED pass / fail determination process based on the comparison result (steps S16 and S17).

(Operation of LED Sensor Unit 2) LED
As described above, the power of the sensor unit 2 is turned on in conjunction with the power on of the tester controller 1 (step S20). Following the reset operation immediately after the power is turned on, the MPU 20 executes a self-diagnosis test process in accordance with an initialization command from the tester controller 1 (Step S21). When an error is detected in the self-diagnosis test, the MPU 20 shifts to a predetermined error processing routine (YES in step S22).

When the self-diagnosis test is completed normally, the MPU 20 outputs the luminance value associated with the emission of the LEDs 31A and 31B via the photo ICs 22A and 22B, the voltage conversion circuits 23A and 23B, and the A / D converter 26. Is read for the set number of times (steps S23 and S24). M
The PU 20 compensates by subtracting the offset value received from the tester controller 1 from the read luminance value, and determines the light emitting state of the LEDs 31A and 31B to be inspected (ON when the LED is normally lit; Is turned off) (steps S25 and S2).
6). The MPU 20 stores the determination result in a predetermined area of the RAM 27 (Step S27). Then, in response to receiving a command from the test controller 1, the MPU 20
Is the LED that is the status of unit 2 and the judgment result
The light emission status is transmitted to the tester controller 1 via the I / O port 29 and the serial data line 5 (YES in step S28, S29).

(Judgment Method) FIG. 6 shows that the MPU 20 determines whether the LEDs 31A and 31B to be inspected emit light (ON or OF).
It is a conceptual diagram for demonstrating the determination method at the time of determining F).

In FIG. 6, the luminescent color (for example, red) of LED 31A is luminescent color 1, and the luminescent color of LED 31B (for example, green) is luminescent color 2.

V11 and V12 mean the light emission of the LED 31A, that is, the luminance value (digital value of the voltage conversion value) of the light for the emission color 1. That is, V11 is the luminance value of the light transmitted through the optical filter 21A having the filter characteristic corresponding to the emission color 1. V12 is the luminance value of the light transmitted through the optical filter 21B having the filter characteristic corresponding to the emission color 2.

On the other hand, V21 and V22 mean the light emission value of the LED 31B, that is, the luminance value (digital value of the voltage conversion value) for the light emission color 2. That is, V21 is the luminance value of the light transmitted through the optical filter 21B having the filter characteristic corresponding to the emission color 2. V22 is a luminance value of light transmitted through the optical filter 21A having a filter characteristic corresponding to the emission color 1.

Further, V31 and V32 are LED 31A and L
Simultaneous light emission of the ED 31B, that is, light luminance value (digital value of voltage conversion value) for light emission colors 1 and 2. That is, V31 is the luminance value of the light transmitted through the optical filter 21A having the filter characteristic corresponding to the emission color 1. Also,
V32 is a luminance value of light transmitted through the optical filter 21B having a filter characteristic corresponding to the emission color 2.

The MPU 20, as shown in FIG.
Determination threshold values Vmin, Vt stored in the ROM 100 in advance
1, Vt2 and Vt3 (Vmax) are read and used for the judgment processing. Here, the tester controller 1 sends the judgment threshold Vmi
n, Vt1, Vt2, Vt3 (Vmax) may be downloaded to the EEPROM 100.

The MPU 20 calculates the ratio "V11 / V12" of the luminance values V11 and V12 of the light transmitted through the respective optical filters 21A and 21B due to the light emission of the LED 31A (light emission color 1).
Then, this ratio is equal to the determination threshold values Vt2, Vt3 shown in FIG.
If (Vt2 <V11 / V12 <Vt3) is within the range of (Vmax), the MPU 20 turns on the luminescent color 1, that is, the LED 31A.
It is determined that the light emission status is ON. Similarly, the ratio “V21 / V22” of the luminance values V22 and V21 of the light transmitted through the optical filters 21A and 21B due to the light emission of the LED 31B (light emission color 2) is calculated. Then, this ratio is within the range of the determination thresholds Vmin and Vt1 shown in FIG. 6 (Vmin <V21
If / V22 <Vt1), the MPU 20 determines that the emission color 2 is turned on, that is, the emission status of the LED 31B is ON.

Further, each of the optical filters 21A, 21A associated with the simultaneous light emission (emission color 1, 2) of the LED 31A and the LED 31B.
The ratio “V31 / V” of the luminance values V31 and V32 of the light transmitted through 1B
32 ”is calculated. This ratio is equal to the determination threshold V shown in FIG.
If it is within the range of t1 and Vt2 (Vt1 <V31 / V32 <Vt2), the MPU 20 turns on the emission colors 1 and 2 simultaneously, that is, LE
It is determined that the simultaneous light emission status of D31A and LED 31B is ON.

When each ratio is equal to or less than Vmin or equal to or more than Vt3 (Vmax), the MPU 20 determines that the unit 2 is abnormal, and notifies the tester controller 1 as the status of the unit 2.

As described above, the inspection apparatus of the embodiment can execute the LED inspection almost automatically when the tester controller 1 and the PCB 3 are turned on. further,
The inspection apparatus uses a plurality of optical filters having filter characteristics (characteristics transmitting light of an effective wavelength) corresponding to different emission colors, and is set in advance to a ratio of a plurality of luminance values obtained by each optical filter. The light emitting state (good or bad) of the light emitting body is determined based on the determination threshold. Therefore, since the determination method refers to not only the determination threshold value that is an absolute value but also the ratio of a plurality of luminance values, it is possible to reduce the false alarm rate even when the luminosity of the LED to be inspected varies. Become. In addition, since data processing that requires a long time such as image processing is not required, relatively high-speed LED inspection processing can be realized.

In this embodiment, the inspection target is LE
Although D is assumed, the present invention can be applied to another type of luminous body inspection device.

[0039]

As described above in detail, according to the present invention, an automatic inspection method is not affected by the skill and skill of an operator, so that a stable and efficient inspection process can be realized. Further, since no image recognition processing or the like is used, high-speed inspection processing is possible. Furthermore, even when the luminous intensity of the luminous body to be inspected varies, the inspection method refers to the ratio of luminance values other than the determination threshold value that is an absolute value. Pass / fail judgment can be realized. Therefore, it is possible to provide a luminous body inspection apparatus which is excellent in practicality and has a low false alarm rate and a stable inspection quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an LED inspection device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a schematic operation of the LED inspection apparatus according to the embodiment;

FIG. 3 is an exemplary block diagram showing the configuration of the LED sensor unit of the embodiment.

FIG. 4 is a flowchart for explaining the operation of the tester controller according to the embodiment;

FIG. 5 is a flowchart for explaining the operation of the LED sensor unit according to the embodiment;

FIG. 6 is an exemplary view for explaining a judgment method of the LED inspection apparatus according to the embodiment.

FIG. 7 is an exemplary view showing the structure of an LED sensor unit according to the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tester controller 2 ... LED sensor unit 3 ... Printed circuit board (PCB) 4 ... Printer interface 5 ... Serial data line 20 ... MPU 21A, 21B ... Optical filter 22A, 22B ... Photo IC 23A, 23B ... Voltage conversion circuit 26 ... A / D converter 30 ... CPU 31A, 31B ... LED

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G020 AA08 DA05 DA13 DA31 DA34 DA63 2G065 AA02 AB28 BA09 BB26 BC03 BC13 BC14 BC16 BC19 BC28 BC33 BC35 BD01 2G086 EE03 5F041 AA46 EE22

Claims (5)

[Claims] A light source for emitting light to be inspected; and a plurality of optical filters having filter characteristics corresponding to different emission colors of the light emitter. Sensor means for detecting a plurality of brightness values according to the effective wavelength of the transmitted light, and the inspection using a ratio of the plurality of brightness values detected by the sensor means and a threshold for determination prepared in advance. A luminous body inspection device, comprising: inspection means for inspecting a luminous state of a target luminous body. 2. The sensor unit includes: a photoelectric conversion unit that converts light output from each of the optical filters into a luminance voltage value; and an A / D conversion unit that converts the luminance voltage value into a digital value. The luminous body inspection device according to claim 1, wherein: 3. The first inspection unit calculates the ratio of the luminance value, and determines the emission color of the illuminant from the ratio of the luminance value and the determination threshold. 2. A second inspection means for comparing a judgment result of said inspection means with an expected value prepared in advance and executing a final inspection on a light emitting state of said luminous body. Luminous body inspection equipment. 4. The light-emitting body is a display light-emitting diode member, and is mounted on a printed circuit board together with control means for executing light-emission control of the display light-emitting diode member in accordance with an instruction from the inspection means. The luminous body inspection device according to claim 1, wherein 5. A tester controller for executing control for inspecting a light emitting state of a light emitting diode member to be inspected, and controlling light emission of the light emitting diode member in response to an instruction from the tester controller. A printed circuit board on which a control unit to be executed is mounted, and a plurality of optical filters having filter characteristics corresponding to different emission colors of the luminous bodies, and each of the optical filters is transmitted according to the luminescence of the luminous bodies. Sensor means for detecting a plurality of brightness values corresponding to the effective wavelength of light, and in response to an instruction from the tester controller, calculates a ratio of the plurality of brightness values detected by the sensor means, and calculates the brightness value. And an automatic test routine for determining the emission color of the illuminant from the ratio of Luminous body inspection apparatus characterized by comprising a sensor unit to be sent to the tester controller.