JP2013174546A - Light emission-inspecting device and light emission-inspecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emission-inspecting device which, even when a light source is formed by arranging light emitting elements having a biased radiation intensity distribution or chromaticity distribution in an array, can perform evaluation and inspection by averaging a light emission state of the whole array-shaped light source in a short tact time regardless of a relative position between light receiving means and a light emitting element.SOLUTION: Emitted light from a light source 102 comprising a plurality of LED packages 101 is passed through a first diffuser plate 103 and led to a second diffuser plate 104, and emitted light from the second diffuser plate 104 is received by a light receiving part 105. The optical properties of the light source 102 are inspected by inspection means 120 on the basis of output from the light receiving part 105.

Description

  The present invention relates to a light emission inspection apparatus and a light emission device capable of quickly measuring light emission characteristics of a light source composed of light emitting elements such as LEDs (Light Emitting Diodes), regardless of differences in light distribution characteristics for each wavelength caused by a package. It relates to the inspection method.

  In recent years, as the necessity of LEDs has been recognized as a part of energy-saving lighting and television backlights, the demand for low-cost LEDs has also increased greatly.

  Manufacturers that produce LED packages and modules that combine the LED packages need to measure the optical characteristics of each light emitting device package as part of the final inspection. Examples of measurement items include luminance and chromaticity.

  As disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2008-76126), a conventional LED light emission inspection apparatus takes in a total luminous flux emitted from an LED element into an integrating sphere, and takes the total luminous flux from the LED element. Measurement is performed by diffusing and reflecting a plurality of times inside the integrating sphere to guide light that has been made uniform in a predetermined space to the same intensity to a light receiver such as a photodiode. This is the integrating sphere method.

  Further, as disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2009-150791), a plurality of light receivers are installed around the light receiving element at intervals, and all light emitted from the LEDs of the light emitting element is emitted. There is also a luminescence inspection apparatus that measures a light beam by taking it in many light receiving surfaces. This is the on-axis inspection method.

  However, in the conventional integrating sphere method disclosed in Patent Document 1, in order to capture light emitted from the LED element without omission during light emission measurement, the LED element is moved horizontally together with the element holding portion, and then the LED element is moved to the element. The element holding part and the measurement main body part are raised together with the holding part and integrated so that light does not leak to form an integrating sphere.

  In this way, there is a need for a vertical mechanism for vertically driving the element holding portion that accommodates the LED element inside the integrating sphere, and the vertical driving after the horizontal driving causes an increase in inspection tact. Not suitable for. In addition, when trying to inspect a module in which a large number of LED elements are arranged, if the element becomes large, it is necessary to increase the size of the inspection apparatus, which causes a problem in cost increase and versatility of the apparatus.

  Further, in the conventional on-axis measurement method disclosed in Patent Document 2, a plurality of light receivers are installed to enlarge the light receiving surface, so here too, let's inspect a module in which a large number of LED elements are arranged. As a result, the increase in the size and cost of the inspection apparatus is also a problem. In addition, performance variations of a plurality of light receivers (in the case of Patent Document 2, photodiodes PD1 to PD9) and software for converting received light into an electrical signal become complicated.

  Therefore, in order to have both the advantage of the integrating sphere method of using a reflection diffusing member for averaging and the advantage of the on-axis inspection method of having a short inspection tact, the emitted light from the LED element is transmitted and diffused. A method of measuring with a light receiver has been proposed. As disclosed in Patent Document 3 (Japanese Patent Laid-Open No. 2005-283217), this light emission inspection apparatus does not directly receive light emitted by a light receiver in order to capture light emitted from LED elements on an average. Instead, the emitted light is once applied to a single diffuser plate to be diffused, and the diffused light is measured. By doing so, the number of light receivers can be reduced as compared with the on-axis inspection method, and the tact time is shorter than that of the integrating sphere method.

JP 2008-76126 A JP 2009-150791 A JP 2005-283217 A

  However, in the system in which one diffusion plate disclosed in Patent Document 3 is arranged, when inspecting a module in which a large number of LED elements packaged by sealing with a phosphor resin are inspected, a short time is required. There is a problem with the tact inspection. This is described below.

  Consider LED elements having a plurality of wavelength peaks such as blue and yellow or blue, green and red among LED elements. For example, a pseudo white LED can be considered. A schematic diagram of this LED package is shown in FIG.

  In order to manufacture such an element, a single-color LED chip 1011 such as blue is die-bonded and wire-bonded on a substrate 1012 so that a current can be applied, and then a resin 1013 kneaded with a fine particle phosphor is used. Sealing is generally performed.

  Therefore, when a pseudo white LED having two wavelength peaks of blue and yellow is taken as an example, the light emitted from the LED element is emitted from the LED chip 1011 in blue and the phosphor resin 1013 in yellow. Considering the radiant intensity distribution, the blue component has many components that have traveled straight from the original LED 1011. Therefore, the intensity is highest directly above the chip, and the intensity decreases as the radiation angle increases. Moreover, since yellow light is fluorescence, it radiates | emits uniformly irrespective of an angle, and becomes uniform irrespective of the radiation angle. In FIG. 11, the radiant intensity distribution 1014 of the blue component and the radiant intensity distribution 1015 of the yellow component are shown superimposed on the module. As described above, the LED package of the type in which the phosphor 1013 is excited with the LED chip 1011 having a monochromatic wavelength often has a chromaticity distribution depending on the radiation angle.

  Consider a case where LED packages having such a chromaticity distribution are arranged in a one-dimensional or two-dimensional array to form a single light source and light emission is measured by an on-axis inspection method. A schematic diagram of the luminescence measurement system is shown in FIG. This includes a light source 1102 in which LED packages 1101a and 1101b are arranged in an array and a light receiving unit 1105 placed in a direction in which light from the light source 1102 is emitted. The observation area 1106 of the received light is limited by the viewing angle.

  At this time, with respect to the light incident on the light receiving unit 1105, the blue component increases in the LED package 1101a immediately below the light receiving unit 1105, whereas the yellow component increases in the LED package 1101b far from the light receiving unit 1105. I understand. In addition, since the distance between the two LED packages 1101a and 1101b is different from the light receiving unit 1105, the intensity of light incident on the light receiving unit 1105 is changed, and as a result, the ratio of the signal intensity of each package in the entire signal (hereinafter referred to as the light intensity) , Contribution rate) will be different. In this case, only the LED package 1101a immediately below the light receiving unit and the LED package in the vicinity thereof are evaluated, and the ratio of the chromaticity component incident on the light receiving unit 1105 differs depending on the LED package, so that uniform evaluation cannot be performed.

  On the other hand, as shown in FIG. 13, consider a case where a diffusion plate 1103 is arranged between the light source 1102 and the light receiving unit 1105. In this case, in the case of the LED package 1101 a arranged immediately below the light receiving unit 1105, both the blue component and the yellow component are diffused by the diffusion plate 1103 and then reach the light receiving unit 1105. Therefore, variation in chromaticity components included in the signal can be suppressed as compared with the case where the diffusion plate 1103 is not provided.

  However, in the LED package 1101b arranged away from directly below the light receiving unit 1105, the optical path length of the diffused light is longer than that in the LED package 1101a directly below the light receiving unit, and thus the signal intensity is weak. Moreover, it is difficult for the light intensity distribution to be Lambertian distribution by the diffusion plate 1103, and the ratio of the blue component is often high immediately above the chip. Therefore, even when a single diffusion plate 1103 is added, no significant improvement can be expected for the above problem.

  In order to solve this, even if the distance between the light receiving unit 1105 and the diffusion plate 1103 is increased, the number of the light receiving units 1105 is increased, or the number of the light receiving units 1105 is small, the relative position with the light source 1102 can be changed. Although it is conceivable to measure a plurality of locations using an apparatus, this causes problems such as an increase in the size and cost of the apparatus and a longer inspection tact.

  Accordingly, an object of the present invention is to provide a light source in which light emitting elements having a biased radiation intensity distribution or chromaticity distribution are arranged in an array, regardless of the relative positions of the light receiving means and the light emitting elements. An object of the present invention is to provide a light emission inspection apparatus and a light emission inspection method capable of evaluating and inspecting the light emission state of the entire light source in an average with a short tact time.

In order to solve the above problems, the light emission inspection apparatus of the present invention is:
A light receiving means for receiving emitted light from a light source including a plurality of light emitting elements arranged on a plane;
A light diffusing means disposed on an optical path between the light source and the light receiving means;
Optical means disposed on an optical path between the light source and the light diffusing means;
Inspection means for inspecting the optical characteristics of the light source based on the output from the light receiving means.

  Here, the optical characteristics of the light source are, for example, luminance and chromaticity.

  According to the light emission inspection apparatus of the present invention, since the light receiving means, the light diffusing means, and the optical means are provided, even if the light emitting element has a radiation intensity distribution or a radiation chromaticity distribution, the light receiving means receives light. In the received light signal, the contribution ratio of each of the plurality of light emitting elements can be made constant. Thereby, it is possible to suppress variations in intensity and chromaticity due to a difference in relative position between the light receiving means and each light emitting element.

  Since the optical characteristics of the light source are inspected based on the output from the light receiving means, the output from the light receiving means in which variations in intensity and chromaticity are suppressed is used, so that the light emission state of the entire light source can be reduced to a short tact time. Can be evaluated and tested on average.

Moreover, in the luminescence inspection apparatus of one embodiment,
The light receiving means includes an optical fiber,
The distance L1 between the light receiving means and the light diffusing means is
NA is the numerical aperture of the optical fiber included in the light receiving means,
The outer dimension width of the observation area by the light receiving means is D,
D / (2 tan (sin ⁻¹ (NA)) ≦ L1
Meet.

According to the light emission inspection apparatus of this embodiment, the distance L1 satisfies D / (2 tan (sin ⁻¹ (NA)) ≦ L1. Therefore, the entire observation region can be covered using an optical fiber.

Moreover, in the luminescence inspection apparatus of one embodiment,
The light receiving means includes a lens,
The distance L1 between the light receiving means and the light diffusing means is
The angle of view in the lens included in the light receiving means is θ,
The outer dimension width of the observation area by the light receiving means is D,
D / (2 tan (θ / 2)) ≦ L1
Meet.

  According to the light emission inspection apparatus of this embodiment, the distance L1 satisfies D / (2 tan (θ / 2)) ≦ L1, so that the entire observation region can be covered using a lens.

  In one embodiment, the optical means includes a light transmission diffusion member.

  According to the light emission inspection apparatus of this embodiment, since the optical means includes the light transmission diffusion member, it is possible to perform evaluation with a simple configuration and little measurement variation.

In the luminescence inspection method of one embodiment,
A step of guiding outgoing light from a light source including a plurality of light emitting elements arranged on a plane to light diffusing means through optical means;
Receiving at least a part of the emitted light from the light diffusing means by the light receiving means;
And a step of inspecting the optical characteristics of the light source by the inspection means based on the output from the light receiving means.

  According to the light emission inspection method of this embodiment, the emitted light from the light source is guided to the light diffusing means through the optical means, and the emitted light from the light diffusing means is received by the light receiving means. Even if there is a chromaticity distribution, the contribution ratio of each of the plurality of light emitting elements can be made constant in the received light signal of the emitted light received by the light receiving means. Thereby, it is possible to suppress variations in intensity and chromaticity due to a difference in relative position between the light receiving means and each light emitting element.

  Then, since the optical characteristic of the light source is inspected by the inspection means based on the output from the light receiving means, the output from the light receiving means in which variations in intensity and chromaticity are suppressed is used, and the light emission state of the entire light source is determined. Can be evaluated and tested on average with short tact times.

  According to the light emission inspection apparatus of the present invention, since the light receiving means, the light diffusing means, the optical means, and the inspection means are provided, light emitting elements having a biased radiation intensity distribution or chromaticity distribution are arranged in an array. Even if the light sources are arranged side by side, the light emission state of the entire array light source can be averaged and evaluated in a short tact time regardless of the relative position between the light receiving means and the light emitting element.

  According to the light emission inspection method of the present invention, the emitted light from the light source is guided to the light diffusing means through the optical means, and the emitted light from the light diffusing means is received by the light receiving means. Even if a light source with distributed light sources is arranged in an array, the light emission state of the entire array light source is averaged and evaluated in a short tact time regardless of the relative position between the light receiving means and the light emitting element. be able to.

It is a schematic diagram which shows the light emission inspection apparatus of 1st Embodiment of this invention. It is a schematic diagram of the measurement system to which the luminescence inspection apparatus of the present invention is applied. It is a schematic diagram of the measurement system to which the luminescence inspection apparatus of the present invention is applied. It is a measurement result by the light emission test | inspection apparatus of this invention. It is a graph which shows the experimental result regarding intensity ratio. It is a graph which shows the experimental result regarding a contribution rate. It is a graph which shows the experimental result regarding chromaticity. It is a graph which shows the experimental result regarding chromaticity. It is a schematic diagram which shows the light emission test | inspection apparatus of 2nd Embodiment of this invention. It is a schematic diagram which shows the light emission inspection apparatus of 3rd Embodiment of this invention. It is a schematic diagram which shows the light emission inspection apparatus of 4th Embodiment of this invention. It is a schematic diagram which shows another light-shielding member. It is a schematic diagram which shows the light intensity distribution of the LED package sealed with fluorescent substance resin. It is a schematic diagram which shows the state which test | inspects an LED package array by an axial inspection system. It is a schematic diagram which shows the state which installed one diffusion plate.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a schematic diagram showing a light emission inspection apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the light emission inspection apparatus includes a first diffusion plate 103 as an optical unit, a second diffusion plate 104 as a light diffusion unit, a light receiving unit 105 as a light reception unit, and an inspection unit 120. Prepare. The 1st diffuser plate 103, the 2nd diffuser plate 104, and the light-receiving part 105 are arrange | positioned in order from the light source 102 side.

  The light source 102 includes an LED package 101 as a plurality of light emitting elements arranged on a plane. There are n (n ≧ 2) LED packages 101, which are arranged one-dimensionally or two-dimensionally (arrayed). The LED package 101 includes a package 101a positioned directly below the light receiving unit 105 and a package 101b positioned at the end.

  The light receiving unit 105 includes a photoelectric conversion element, receives light emitted from the light source 102, and converts it into an electrical signal.

  The second diffusion plate 104 is disposed on the optical path between the light source 102 and the light receiving unit 105.

  The first diffusion plate 103 is disposed on the optical path between the light source 102 and the second diffusion plate 104. The optical means may be a light transmissive diffusing member such as a prism or a lens other than the first diffusing plate 103.

  The inspection unit 120 inspects the optical characteristics of the light source 102 based on the electrical signal output from the light receiving unit 105. The optical characteristics of the light source 102 are, for example, luminance and chromaticity.

  The emitted light from the LED package 101 is diffused twice by the first diffusion plate 103 and the second diffusion plate 104 before reaching the light receiving unit 105 directly above. For this reason, the intensity distribution becomes more uniform.

  Further, even if there is a chromaticity distribution represented by the blue component diffused light 111a and the yellow component diffused light 111b in the surface of the first diffuser plate 103, the first diffuser plate 103 and the second diffuser plate 104 are used. Are separated from each other, the two colors of diffused light 111a and 111b are mixed in the second diffusion plate 104. The blue component diffused light 111a is indicated by a solid line in the figure, and the yellow component diffused light 111b is indicated by a dotted line in the figure. The mixed light is emitted as diffused light 112 and reaches the light receiving unit 105. For this reason, the chromaticity distribution is also reduced. The light receiving unit 105 detects light in the observation region 106.

  The first diffusion plate 103 not only diffuses the light from the LED package directly under and near the light receiving unit 105 to reduce the contribution rate, but also receives the light in the LED package separated from the light receiving unit 105. The light is guided to the unit 105. Thus, it has a function of increasing the contribution rate. As a result, the contribution rate and chromaticity distribution of each LED element in the signal incident on the light receiving unit 105 are further averaged.

  Next, [Example] to which the light emission inspection apparatus having the above configuration is applied will be described.

  As shown in FIG. 2, the light source 202 uses an LED module in which pseudo white LED packages 201 are linearly arranged. In this package 201, a blue LED chip die-bonded and wire-bonded on a base material is sealed with a silicone resin in which a green phosphor and a red phosphor are kneaded. The length in the longitudinal direction of the module to be measured is 170 mm. The peak wavelength λ of the blue LED is 455 nm, and the applied current is set to 30 mA. The package 201 includes a package 211a positioned immediately below the light receiving unit 210 and a package 211b positioned at the end.

  A transmission diffusion plate (Sumitex Opal manufactured by Sumitomo Chemical Co., Ltd.) is used for the diffusion plate 204 as an optical means. The size of the diffusion plate 204 is 200 mm × 250 mm × t2 mm. The same diffusion plate is also used for the diffusion plate 205 as the light diffusion means.

  A quartz fiber 208 and a spectroscope 209 are used in the light receiving unit 210 as the light receiving means. The core diameter of the quartz fiber 208 is 600 μm, NA = 0.22, and the receptacle 207 is connected to the tip. The detected wavelength region of the spectroscope 209 is 200 to 1100 nm, and a sufficient region for measuring the spectrum of the current light source is secured. The spectroscope 209 is driven by a computer.

  Note that a camera may be used as the light receiving unit 210. In this case, the quartz fiber can be replaced with a lens, and the spectroscope can be replaced with a detector such as a CCD (Charge Coupled Device).

  Then, the light source 202 is fixed on the XY stage 203, and the diffusion plate 204, the diffusion plate 205, and the receptacle 207 are installed in order on the light emitting surface side of the light source 202. The total length of the light source 202 in the longitudinal direction is approximately 170 mm, and a configuration in which this is inspected by the two light receiving units 210 is considered. Here, although two light receiving parts are set, the number of light receiving parts is arbitrary, and the width D of the observation region 206 changes according to the number of light receiving parts.

  The distances L1, L2, and L3 between the members 204, 205, and 210 will be described.

  From NA = 0.22 of the quartz fiber 208, the viewing angle θ of the observation region 206 can be calculated as follows. The viewing angle θ corresponds to the viewing angle when the light receiving unit 210 is a camera, and can be expressed by a similar expression.

NA = sin (θ / 2)
By transforming this equation,
θ / 2 = sin −1 (NA) = sin −1 (0.22) = 12.7 °
And, as the width D of the observation area 206, as described above, when the module total length 170mm is observed with two measuring heads,
D ≧ 170/2 = 85.5 Formula (1)
It must be.

  From FIG. 2, the width D of the observation region 206 and the distance L1 between the receptacle 207 and the diffusion plate 205 are related by the following relational expression.

D / 2 = L1 × tan (θ / 2) (2)
From equation (1) and equation (2), for distance L1, L1 ≧ 85.5 / (2 × tan (θ / 2))
≧ 85.5 / (2 × tan12.7)
≧ 189.6 Formula (3)
It becomes.

  In this embodiment, L1 = 200 mm. At this time, since the width D of the observation region 206 is D = 2 × L1 × tan 12.7 = 90 mm, the observation region 206 can be covered from Equation (1).

  The distance L2 between the diffusion plate 204 and the diffusion plate 205 is set to 100 mm. The reason is described below.

Of the light emitted from the LED package 201, a component that is Lambert-distributed from the point immediately above the LED package on the diffusion plate 204 as a base point is considered.
At this time, it is assumed that the receptacle 207 is directly above the center of the observation region 206. FIG. 3 is a diagram obtained by adding depth to FIG. As shown in FIG. 2 and FIG. 3, a point immediately above the central LED package 211a in the diffuser plate 204 is a point 211a ′, and a point just above the end LED package 211b is a point 211b ′.

  Then, it is assumed that the emitted light from the LED packages 211a and 211b has a Lambertian distribution at the points 211a ′ and 211b ′, and the portions incident on the observation region 206 are 214a and 214b in the respective radiated light distributions, respectively. . At this time, since the emitted light has a Lambertian distribution, the radiation intensity distribution has no angular dependence. Therefore, the ratio of the emitted light from each LED package contributing to the entire signal (hereinafter referred to as the contribution ratio) varies depending on the ratio of the sizes of the radiation distributions 214a and 214b.

  At this time, the solid angles of the conical light intensity distribution entering the observation region 206 from the points 211a 'and 211b' are θ1 and θ2, respectively. Further, when the light intensity distribution is cut on the plane passing through the receptacle 207 and the points 211a 'and 211b', the spread angles of the light intensity distribution on the cut surface 215 are φ1 and φ2, respectively. At this time, φ1 and φ2, and θ1 and θ2 are expressed by the following equations, respectively.

φ1 = 2 tan ⁻¹ (D / (2L2))
φ2 = 2 tan ⁻¹ (D / (L2))
θ1 = 2π (1-cos ((φ1) / 2))
θ2 = 2π (1-cos ((φ2) / 2))
FIG. 4 shows the solid angle ratio (θ1 / θ2) and the result of calculating the contribution rate based on the ratio based on these equations. At this time, by setting L2 / D ≧ 1, the intensity ratio (214a / 214b) of the radiated light distributions 214a and 214b is 85% or more and the contribution rate difference (214a-214b) is 5%. It can be regarded as a contribution rate of a degree.

  As described above, by setting L2 ≧ D for the observation region width D and the distance L2, even when the position of the light emitting element incident on the diffusion plate 204 is away from the receptacle 207, the diffused light is sufficiently absorbed. It becomes possible to enter the diffusion plate 205.

  In addition, as shown in FIG. 2, the distance L3 between the diffusion plate 204 and the light source 202 is set to 30 mm. The reason is described below.

  When the pitch P between the packages is calculated, since the total length of the module is 170 mm and the number of packages is n ′ and n ′ = 19, P = 170 / n ′ = 9 mm. From Equation (1), since D = 85.5 mm, P / D = 9.5. Accordingly, nine LED packages 201 are included in the measurement region.

  Here, it is assumed that the radiant intensity patterns from the respective packages are Lambert-distributed starting from the center of the package. In this case, regarding the parameters when the L2 is calculated earlier, if the width D of the observation region is replaced with 2P and L2 is replaced with L3, the distance from one LED package to the adjacent LED packages on each side, each in the total 2P The contribution rate of the LED package can be obtained.

  Therefore, according to the same calculation as before, if L3 / (2P) ≧ 1, light from each LED package can be incident on the diffusion plate 204 so as to sufficiently overlap. In this [Example], L3 = 30 mm was set. Accordingly, light having an emission angle of 45 ° or less can reach the diffuser plate 204 so as to overlap by six LED packages.

  Next, [Experiment] using the luminescence inspection apparatus shown in FIG. 2 will be described.

  As shown in FIG. 2, only one of a plurality of LED packages 201 on the light source 202 is turned on in order to evaluate a change in contribution ratio and chromaticity due to a relative position between the receptacle 207 and the light source 202 in the light receiving unit 210. Then, as indicated by the arrow 212 in the figure, the spectrum was measured while changing the position in the arrangement direction of the LED package 201.

  As described above, there are four positions of the LED package 201 from the position of the LED package 211a immediately below the receptacle 207, based on the fact that the light receiving unit 210 measures an area corresponding to nine of the LED packages 201 at a time. While moving to the position of the adjacent package 211b, measurement was performed by lighting only one LED package 201 in a total of five locations. The chromaticity was determined from the acquired spectrum and the relative luminous efficiency coefficient, and the contribution rate was determined from the peak intensity ratio. The measurement conditions of the spectroscope 209 are an integration time of 500 ms and an average number of 10 times, and it has been confirmed that a sufficient signal intensity with little variation for each measurement is obtained.

  [Experimental results] will be described.

  The experimental results of [Experiment] are shown in FIGS. 5A to 5C. As shown in FIG. 5A, by adding a diffusing plate 204 as an optical means, the intensity ratio change amount at each position from the package 211a immediately below the receptacle to the four adjacent packages 211b is increased from 80% to 26%. Can be reduced.

  5A to 5C, the case where one diffusion plate as the light diffusion means is provided is indicated by a rhombus, one diffusion plate as the light diffusion means is provided, and one diffusion plate as the optical means is provided. The case where a sheet is provided is indicated by a rectangle. The module position indicates the position of the package 201, the module position “0” indicates the position of the package 211a immediately below the receptacle, and the module position “4” indicates the position of the four adjacent packages 211b. .

  Furthermore, as shown in FIG. 5B, the variation in the contribution rate was also reduced. At this time, a case where it is assumed that all nine LED packages have the same contribution rate (contribution rate A = 11%) is indicated by a dotted line graph 213 in FIG. 5B. In contrast to the contribution rate (dotted line graph 213) having the same contribution rate, in the case of a single diffusion plate, the average value is −0.5 A to +1.0 A (%), whereas the optical means As a result, a variation of ± 0.15 A (%) is obtained.

  Further, as shown in FIG. 5C, the chromaticity change amount is reduced by half from +0.004 to +0.002 when only one diffusion plate is provided and when two diffusion plates are provided. doing. This is an effect due to the fact that a wide area can be measured more uniformly with respect to the radiation chromaticity distribution of each LED package 201.

  Thus, by adding the diffusion plate 204 as an optical means, it was possible to bring the respective contribution ratios of the LED modules arranged in one dimension close to the average.

  Next, in order to confirm the effect that the contribution ratio can be averaged, the chromaticity measurement variation is estimated with the following contents.

  This means that, as shown in FIG. 2, the chromaticity of only one package 201 out of nine LED packages 201 measured at one time by one light receiving unit 210 is 0.010 higher. Assuming a difference in the measured value according to the package position. This is because, even when the chromaticity variation between the LED packages is the same at the time of inspection, the measured value of chromaticity is expected to be different depending on the positional relationship of the packages where the chromaticity varies.

  Assume that 8 out of 9 packages in the measurement region have a spectrum with a specific chromaticity, and for a specific package, the spectrum with chromaticity y shifted by 10/1000 is assumed. Using the contribution rate derived in the previous experiment, we derived the weighted average with other packages.

  The calculation results are shown in FIG. In the case of only one diffusion plate, the module position where the chromaticity y is shifted is changed from the position 211a immediately below the light receiving portion receptacle to the four adjacent package positions 211b, so that the measured value of chromaticity is 0.9 / There is a deviation of about 1000. In general, the resolution required for classifying the light sources and determining good or bad is generally considered to be 1/1000. Therefore, considering that the chromaticity measurement value variation due to other variation factors such as the module position accuracy and the repeat measurement accuracy is superimposed on this, the 0.9 / 1000 measurement variation is considered insufficient.

  On the other hand, when two diffusion plates are combined, the chromaticity measurement value variation is reduced to 0.3 / 1000 and 1/3, and the present invention provides sufficient measurement value resolution for ranking. can get. Therefore, the average evaluation of the LED package array can be performed collectively in a state where the measurement variation is small.

  In the measurement system used this time, the measurement time was set to 500 ms. On the other hand, if it is intended to measure each pocket individually, it takes 4.5 s because it is 9 packages. In order to shorten the tact time, shortening one measurement time is not preferable from the viewpoint of measurement variation. Since this difference in tact time becomes more prominent as the number of packages increases, this method, which can be averaged and collectively measured, is advantageous for shortening tact time.

  According to the light emission inspection apparatus having the above configuration, since the light receiving unit as the light receiving unit, the first diffusion plate as the optical unit, and the second diffusion plate as the light diffusion unit are provided, the LED package (light emitting element) Even if there is a radiation intensity distribution or a radiation chromaticity distribution, the contribution ratio of each of the plurality of light emitting elements can be made constant in the light receiving signal of the outgoing light received by the light receiving means. Thereby, it is possible to suppress variations in intensity and chromaticity due to a difference in relative position between the light receiving means and each light emitting element.

  Then, since the optical characteristic of the light source is inspected by the inspection means based on the output from the light receiving means, the output from the light receiving means in which variations in intensity and chromaticity are suppressed is used, and the light emission state of the entire light source is determined. Can be evaluated and tested on average with short tact times.

When the light receiving means includes an optical fiber, the distance L1 between the light receiving means and the light diffusing means satisfies D / (2tan (sin ⁻¹ (NA)) ≦ L1. The entire area can be covered.

  Further, when the light receiving means includes a lens, the distance L1 between the light receiving means and the light diffusing means satisfies D / (2 tan (θ / 2)) ≦ L1. Can be covered.

  In addition, since the optical means includes the light transmission diffusion member, it is possible to perform evaluation with a simple configuration and little measurement variation.

  Further, the distance L2 between the optical means and the light diffusing means satisfies L2 ≧ D, where D is the outer dimension width of the observation region by the light receiving means, so that when a light fiber is used as the light receiving means, the light emitting element At least half of the amount of emitted light from each of the light beams can be incident on the light receiving means. Thereby, evaluation with less variation can be performed.

  Further, the distance L3 between the light source and the optical means satisfies L3 ≧ 2P, where P is the arrangement pitch of the light emitting elements, so that light from adjacent light emitting elements is superimposed and incident on the optical means. be able to. Thereby, evaluation with less variation can be performed.

  Further, according to the light emission inspection method having the above configuration, the emitted light from the light source is guided to the light diffusing means through the optical means, and the emitted light from the light diffusing means is received by the light receiving means. Even if there is a radiation chromaticity distribution, the contribution ratio of each of the plurality of light emitting elements can be made constant in the light receiving signal of the emitted light received by the light receiving means. Thereby, it is possible to suppress variations in intensity and chromaticity due to a difference in relative position between the light receiving means and each light emitting element.

  Then, since the optical characteristic of the light source is inspected by the inspection means based on the output from the light receiving means, the output from the light receiving means in which variations in intensity and chromaticity are suppressed is used, and the light emission state of the entire light source is determined. Can be evaluated and tested on average with short tact times.

(Second Embodiment)
FIG. 7 is a longitudinal sectional view showing a light emission inspection apparatus according to the second embodiment of the present invention. The differences from the first embodiment will be described. In the second embodiment, the configuration of the optical means is different. In the second embodiment, the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 7, a lens array 103A is used as an optical means instead of the first diffusion plate 103 of the first embodiment (FIG. 1). The lens array 103 </ b> A guides light from the LED package 101 b at a position away from directly below the light receiving unit 105 to the light receiving unit 105.

  The lens array 103 </ b> A has a lens corresponding to each LED package 101, spreads the light from the LED package 101, and irradiates the second diffusion plate 104. At this time, each lens of the lens array 103A is formed so that the energy density of each spot on the second diffuser plate 104 matches. As a result, the light from each LED package 101 can be evaluated regardless of the relative position and distance from the light receiving unit 105.

  Further, since the diffused light 112 is measured through the second diffusing plate 104, the position of the light receiving unit 105 can be set lower than the case where it directly enters the light receiving unit 105. Therefore, the apparatus can be made compact.

  In addition, since the uniform diffused light 112 is measured, measurement variations due to the positional accuracy of the light receiving unit 105 can be reduced.

(Third embodiment)
FIG. 8 is a longitudinal sectional view showing a light emission inspection apparatus according to a third embodiment of the present invention. The differences from the first embodiment will be described. In the third embodiment, the configuration of the optical means is different. In the third embodiment, the same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and thus description thereof is omitted.

  As shown in FIG. 8, an optical unit 113 is used as an optical means instead of the first diffusion plate 103 of the first embodiment (FIG. 1). The optical unit 113 includes an aperture 113a and a diffusion plate 113b.

  The aperture 113a and the diffusion plate 113b are arranged corresponding to the position of each LED module 101. By adjusting the aperture ratio of the aperture 113a, it is possible to cut out a specific portion or adjust the intensity in the radiation intensity distribution of the diffused light from the second diffusion plate 104.

  Even if the light emitted from each LED package 101 is received by the second diffusion plate 104 at different distances 114, the optical unit 113 is set and arranged so that the light emitted from each LED package 101 has the same energy density. As a result, the contribution ratio and chromaticity distribution can be made uniform more easily than the lens.

(Fourth embodiment)
FIG. 9 is a longitudinal sectional view showing a light emission inspection apparatus according to a fourth embodiment of the present invention. The difference from the first embodiment will be described. In the fourth embodiment, a light shielding member is added. In the fourth embodiment, the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 9, a light shielding member 107 is provided so that light from a region other than the observation region 106 of the light receiving unit 105 does not propagate to the light receiving unit 105.

  The light shielding member 107 is formed in an umbrella shape and covers the periphery of the light receiving unit 105. The light shielding member 107 prevents light resulting from the environment from the periphery of the apparatus or light reflected by the constituent members of the apparatus from entering the light receiving unit 105 as stray light. Thereby, the signal / noise ratio can be improved and the measurement accuracy can be increased.

  Further, the light shielding member 107 not only shields light from other than the observation region 106 of the light receiving unit 105 but also has a function of a reflecting plate, and captures light that is originally diffused and cannot enter the light receiving unit 105. Is possible. Thereby, measurement with higher accuracy becomes possible.

  Further, as shown in FIG. 10, instead of the umbrella-shaped light shielding member 107, an aperture-shaped light shielding member 107A may be arranged on the optical path. This enables light shielding with a simpler configuration.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the feature points of the first to fourth embodiments may be variously combined. The optical means may be a prism, a diffraction grating, or the like in addition to the diffusion plate and the lens.

101 LED package (light emitting device)
101a LED package (directly under the light receiving means) 101b LED package (at the end) 102 Light source 103 First diffuser plate (optical means)
103A Lens array (optical means)
104 Second diffusion plate (light diffusion means)
105 Light receiving part (light receiving means)
107, 107A Light shielding member 112 Diffused light 113 Optical unit (optical means)
113a Aperture 113b Diffusion plate 120 Inspection means 201 LED package (light emitting element)
202 Light source 204 Diffuser (optical means)
205 Diffuser (light diffusion means)
210 Light receiving part (light receiving means)

Claims (5)

A light receiving means for receiving emitted light from a light source including a plurality of light emitting elements arranged on a plane;
A light diffusing means disposed on an optical path between the light source and the light receiving means;
Optical means disposed on an optical path between the light source and the light diffusing means;
A light emission inspection apparatus comprising: inspection means for inspecting optical characteristics of the light source based on an output from the light receiving means. The luminescence inspection apparatus according to claim 1,
The light receiving means includes an optical fiber,
The distance L1 between the light receiving means and the light diffusing means is
NA is the numerical aperture of the optical fiber included in the light receiving means,
The outer dimension width of the observation area by the light receiving means is D,
D / (2 tan (sin ⁻¹ (NA)) ≦ L1
A light emission inspection device characterized by satisfying In the luminescence inspection apparatus according to claim 1 or 2,
The light receiving means includes a lens,
The distance L1 between the light receiving means and the light diffusing means is
The angle of view in the lens included in the light receiving means is θ,
The outer dimension width of the observation area by the light receiving means is D,
D / (2 tan (θ / 2)) ≦ L1
A light emission inspection device characterized by satisfying In the luminescence inspection apparatus according to any one of claims 1 to 3,
The light emitting inspection apparatus, wherein the optical means includes a light transmission diffusion member. A step of guiding outgoing light from a light source including a plurality of light emitting elements arranged on a plane to light diffusing means through optical means;
Receiving at least a part of the emitted light from the light diffusing means by the light receiving means;
And a step of inspecting an optical characteristic of the light source by an inspection unit based on an output from the light receiving unit.

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