Wavelength measuring apparatus and wavelength measurement method

Abstract

To provide a wavelength measuring apparatus and a wavelength measurement method capable of efficiently and highly accurately measuring representative wavelength of a large number of LED chips.SOLUTION: The wavelength measuring apparatus comprises: means 3 for spectroscopically splitting light emitted by exciting a plurality of light-emitting element chips 101; and means 5 having a plurality of pixels 51 receiving light by dividing it into a plurality of areas, the light emitted from each emission surface of each light-emitting element chip and spectroscopically split; means 6 for obtaining, on the basis of light reception result, measurement data for each wavelength for each area sized corresponding to pixels on the surface of a measurement target; means 6 for classifying, from among pieces of data of a pixel group of the area including measurement data of the plurality of light-emitting element chips, each pixel by brightness at a first prescribed wavelength and performing image processing with the prescribed brightness level as a threshold, thereby separating the measurement data for each light-emitting element chip; and means 6 for calculating, for each separated light-emitting element chip 101, representative wavelength from measurement data at each wavelength for a plurality of areas in the light emission surface.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a wavelength measurement device and a wavelength measurement method for measuring the representative wavelengths of light-emitting element chips, such as a plurality of LED chips, included in an object to be measured. [Background technology]

[0002] For example, the emitted color of LEDs used in backlights for television displays and other devices must be strictly controlled, as variations in color can cause image quality degradation such as uneven color on the display. For this reason, a process known as binning has traditionally been carried out, in which the wavelength of each LED chip is measured and sorted by color.

[0003] As a method for measuring the wavelength of LED chips in such binning, Non-Patent Document 1 discloses measuring the LED chips individually one by one using a spot spectrometer. [Prior art documents] [Patent documents]

[0004] [Non-Patent Document 1] Otsuka Electronics Co., Ltd. Home Page Example of use: "LED manufacturing process LED color classification (LE series)" URL: https: / / www.otsukael.jp / appcase / detail / caseid / 116 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique described in Non-Patent Document 1, which uses a spot spectrometer to measure the representative wavelength of each LED chip individually, has the following problems.

[0006] In other words, the smaller the size of the LED chip, such as a micro LED chip with a side length of 100 μm or less, the greater the number of LED chips that need to be measured, and doing this for each chip is time-consuming and inefficient.

[0007] Furthermore, when measurements are performed on a wafer, if the size of the LED chip becomes small, multiple LED chips will be included in the measurement area of ​​the spot spectrometer, making it impossible to perform highly accurate measurements.

[0008] The present invention has been made in consideration of the above technical background, and aims to provide a wavelength measurement device and a wavelength measurement method that can measure the representative wavelengths of multiple LED chips efficiently and with high accuracy. [Means for solving the problem]

[0009] The above object can be achieved by the following means. (1) a spectroscopic means for spectroscopically separating light emitted by a plurality of light-emitting element chips included in the object to be measured upon excitation; a light receiving means having a plurality of pixels that receives light emitted from each light emitting surface of the plurality of light emitting element chips and dispersed by the dispersing means; an acquisition means for acquiring measurement data for each wavelength for each area having a size corresponding to the pixel on a surface of a measurement object including the plurality of light-emitting surfaces based on a light receiving result by the light-receiving means; a separating means for separating the measurement data acquired by the acquiring means for each of the light-emitting element chips by dividing each pixel into levels according to brightness at a first predetermined wavelength among data of a pixel group in an area including measurement data of a plurality of light-emitting element chips, and performing image processing using a predetermined brightness level as a threshold; a calculation means for calculating a representative wavelength from measurement data for each wavelength for a plurality of regions in a light-emitting surface of each light-emitting element chip separated by the separation means; A wavelength measuring device comprising: (2) The wavelength measuring device according to the preceding paragraph (1), wherein the calculation means averages the measurement data of a region in the light-emitting surface where the maximum value is obtained for a second predetermined wavelength and one or more regions adjacent to that region, and calculates a representative wavelength from the averaged measurement data for each wavelength. (3) A wavelength measuring device as described in the preceding paragraph (2), wherein at least one of the first and second predetermined wavelengths is either the wavelength having the maximum brightness among the data of a pixel group in an appropriate area that includes measurement data of multiple light-emitting element chips, the wavelength having the maximum brightness among the measurement data in a data area for one light-emitting element chip, or the design wavelength of the light-emitting element chip. (4) the light receiving means is an area sensor; The wavelength measurement device according to any one of the preceding paragraphs (1) to (3), wherein each pixel in one pixel row of the area sensor corresponds to a plurality of regions in a one-dimensional direction of the object to be measured, and each pixel in the other pixel row perpendicular to the one pixel row receives light emitted from the plurality of regions in the one-dimensional direction and dispersed. (5) A moving means is provided for relatively moving at least one of the measurement object and the wavelength measurement device in the direction of the other pixel row, The wavelength measurement device according to the preceding paragraph (4), wherein the area sensor receives dispersed light from each area in a two-dimensional direction of the object to be measured by performing measurement while moving at least one of the object to be measured or the wavelength measurement device using the moving means. (6) The wavelength measuring device according to any one of (1) to (5) above, wherein the representative wavelength is an emission peak wavelength. (7) The wavelength measuring device according to any one of (1) to (5) above, wherein the representative wavelength is a centroid wavelength. (8) The wavelength measurement device according to any one of (1) to (5) above, wherein the representative wavelength is a center wavelength. (9) The wavelength measurement device according to any one of (1) to (8) above, wherein the light-emitting element chip is an LED chip. (10) The wavelength measurement device according to any one of (1) to (9) above, further comprising a light source unit that excites the plurality of light-emitting element chips to emit light. (11) a spectroscopic step of spectroscopically separating light emitted by a plurality of light-emitting element chips included in the object to be measured, using a spectroscopic means; a light receiving step of receiving light emitted from each light emitting surface of the plurality of light emitting element chips and dispersed by the dispersing step; an acquiring step of acquiring measurement data for each wavelength for each region having a size corresponding to the pixel on a surface of the measurement object including the plurality of light-emitting surfaces based on a light receiving result from the light receiving step; a separating step of separating the measurement data acquired in the acquiring step for each of the light-emitting element chips by dividing each pixel into levels according to brightness at a first predetermined wavelength among data of a pixel group in an area including measurement data of a plurality of light-emitting element chips, and performing image processing using a predetermined brightness level as a threshold; a calculation step of calculating a representative wavelength from measurement data for each wavelength for a plurality of regions in a light-emitting surface for each light-emitting element chip separated by the separation step; A wavelength measurement method comprising: (12) A wavelength measurement method according to the preceding paragraph (11), wherein the calculation step averages the measurement data of a region in the light-emitting surface where the maximum value is obtained for a second predetermined wavelength and one or more regions adjacent to that region, and calculates a representative wavelength from the averaged measurement data for each wavelength. (13) A wavelength measurement method as described in the preceding paragraph (12), wherein at least one of the first and second predetermined wavelengths is either the wavelength having the maximum brightness among the data of a pixel group in an appropriate area that includes measurement data of multiple light-emitting element chips, the wavelength having the maximum brightness among the measurement data in a data area for one light-emitting element chip, or the design wavelength of the light-emitting element chip. (14) The light receiving means is an area sensor, The wavelength measurement method according to any one of the preceding items (11) to (13), wherein one pixel row of the area sensor receives light from each region in a one-dimensional direction of the object to be measured, and another pixel row orthogonal to the one pixel row receives dispersed light corresponding to each region in the one-dimensional direction. (15) A moving step of relatively moving at least one of the area sensor and the object to be measured in a direction of the other pixel row, The wavelength measurement method according to the preceding paragraph (14), wherein the movement of at least one of the area sensor and the object to be measured by the moving step causes the area sensor to receive light from each area in a two-dimensional direction of the object to be measured. (16) The wavelength measuring method according to any one of (11) to (15) above, wherein the representative wavelength is an emission peak wavelength. (17) The wavelength measurement method according to any one of (11) to (15) above, wherein the representative wavelength is a centroid wavelength. (18) The wavelength measurement method according to any one of (11) to (15) above, wherein the representative wavelength is a center wavelength. (19) The wavelength measurement method according to any one of (11) to (18) above, wherein the light-emitting element chip is an LED chip. [Effects of the Invention]

[0010] According to the inventions described in the preceding paragraphs (1) and (11), a plurality of light-emitting element chips included in the object to be measured are excited to emit light, and the light emitted from the light-emitting surface of each light-emitting element chip and dispersed by the spectroscopic means is received by a plurality of pixels of the light-receiving means. Based on the light-receiving results, measurement data for each wavelength is acquired for each region of a size corresponding to the pixel on the surface of the object to be measured, which includes a plurality of light-emitting surfaces. Of the data of pixel groups in the region including the measurement data of the plurality of light-emitting element chips, each pixel is classified by brightness level at a first predetermined wavelength, and image processing is performed using the predetermined brightness level as a threshold value. The acquired measurement data is separated for each light-emitting element chip, and a representative wavelength is calculated from the measurement data for each wavelength for a plurality of regions in the light-emitting surface of each separated light-emitting element chip.

[0011] In this way, the representative wavelength for each light-emitting element chip is calculated using measurement data obtained when multiple light-emitting element chips are excited and emit light at the same time, which shortens the measurement time and improves measurement efficiency compared to measuring the representative wavelength of each light-emitting element chip individually using a spot spectrometer. Moreover, since the representative wavelength is calculated from measurement data for multiple regions within the light-emitting surface of the light-emitting element chip, it is possible to eliminate variation and obtain highly accurate measurement results.

[0012] According to the inventions described in the preceding paragraphs (2) and (12), the measurement data of the area within the light-emitting surface where the maximum value was obtained for the second predetermined wavelength and the measurement data of one or more areas adjacent to that area are averaged, and the representative wavelength is calculated from the averaged measurement data for each wavelength, so that a highly accurate representative wavelength can be easily obtained.

[0013] According to the inventions described in the preceding paragraphs (3) and (13), the area in which the maximum value is obtained for either the wavelength with the greatest brightness among the data of a pixel group in an appropriate area that includes the measurement data of multiple light-emitting element chips, the wavelength with the greatest brightness among the measurement data of a data area for one light-emitting element chip, or the design wavelength of the light-emitting element chip, and the measurement data of one or more areas adjacent to that area are averaged.

[0014] According to the inventions described in the preceding paragraphs (4) and (14), one pixel row of the area sensor can receive light from each area in a one-dimensional direction of the object to be measured, and the other pixel row perpendicular to the one pixel row can receive dispersed light corresponding to each area in the one-dimensional direction.

[0015] According to the inventions described in the preceding paragraphs (5) and (15), by moving at least one of the object to be measured or the wavelength measurement device, the area sensor can receive dispersed light from each area in the two-dimensional direction of the object to be measured.

[0016] According to the inventions described in the preceding paragraphs (6) and (16), the emission peak wavelength can be measured as the representative wavelength.

[0017] According to the inventions described in the preceding paragraphs (7) and (17), the centroid wavelength can be measured as the representative wavelength.

[0018] According to the inventions described in the preceding paragraphs (8) and (18), the central wavelength can be measured as the representative wavelength.

[0019] According to the inventions described in the preceding paragraphs (9) and (19), the representative wavelength of each LED chip can be calculated using measurement data obtained when multiple LED chips are excited and emit light at the same time.

[0020] According to the invention described in the preceding paragraph (10), the light source section can excite the plurality of light-emitting element chips to emit light. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a block diagram showing a configuration of a wavelength measurement device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a specific configuration of a part of the wavelength measurement device of FIG. [Figure 3] 10 is a diagram for explaining the relationship between the size of a plurality of LED chips on a measurement object and the size of pixels of a light receiving means. FIG. [Figure 4] 10 is a diagram showing a schematic representation of the light receiving state at each pixel when light of an arbitrary wavelength is received by the light receiving means from the surface of the object to be measured. [Figure 5] (A) is a diagram showing the state in which the measurement data for each pixel is separated for each light-emitting element chip, (B) is a diagram for explaining the method for calculating the representative wavelength, and (C) is an enlarged view of (B). [Figure 6] This is a spectrum graph in which the average values ​​of nine pixels for each wavelength are plotted for the data areas of multiple light-emitting element chips. [Figure 7] 10 is a spectrum graph in which the value of one pixel for each wavelength is plotted for the data areas of a plurality of light-emitting element chips. [Figure 8]The average values ​​of nine pixels were calculated for each wavelength for the data area of ​​one light-emitting element chip, and the graph shows the average values ​​and a fitting curve based on them. [Figure 9] 10A and 10B are diagrams for explaining a measurement method for a measurement object having a wide measurement range. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] 1 is a block diagram showing the configuration of a wavelength measurement device according to one embodiment of the present invention. In this embodiment, the light-emitting element chips are LED chips, and the measurement object 100 is a wafer on which a plurality of LED chips are formed.

[0024] The wavelength measurement device shown in FIG. 1 includes an excitation light source 1, an objective lens 2 with a variable magnification, a spectroscopic unit 3, an imaging lens 4, an area sensor 5 which is a two-dimensional image sensor such as a CCD sensor, a calculation unit 6, and a measurement result display unit 7 which is such as a liquid crystal display device.

[0025] The excitation light source 1 irradiates the plurality of LED chips on the measurement object 100 with excitation light, thereby exciting the plurality of LED chips to emit light.

[0026] The spectroscopic unit 3 separates the light from each LED chip that has passed through the objective lens 2 into wavelengths, and the imaging lens 4 forms an image of the light of each wavelength separated by the spectroscopic unit 3 onto the area sensor 5. In this embodiment, the light is separated into wavelengths at a wavelength pitch of 5 nm.

[0027] The area sensor 5 corresponds to a light receiving unit and includes a plurality of pixels 51 arranged vertically and horizontally as shown in FIG. 2. The horizontal direction of the area sensor 5 (Y direction in FIG. 2) refers to the horizontal direction in physical space, and each pixel 51 in the horizontal direction corresponds to a horizontal region of the measurement object. On the other hand, the vertical direction of the area sensor 5 (Z direction in FIG. 2) corresponds to the brightness (luminance) of each wavelength of light. In other words, each pixel 51 in the horizontal pixel row corresponds to a plurality of regions in the one-dimensional direction of the measurement object 100, and light emitted from each region and resolved into wavelengths is received by each pixel 51 in the vertical pixel row. Therefore, in order to perform spectroscopic measurement of each region in the two-dimensional direction (plane) of the measurement object 100, it is necessary to move the measurement object 100 in the Z direction in FIG. 2. Alternatively, instead of moving the measurement object 100, the wavelength measurement device may be moved in the Z direction in Fig. 2, or both the measurement object 100 and the wavelength measurement device may be moved with a speed difference, in short, at least one of the measurement object 100 and the wavelength measurement device may be moved relative to the other in the Z direction in Fig. 2. In this embodiment, the measurement object 100 is moved, and as shown in Fig. 1, a moving device 300 is provided that can move a table 200 on which the measurement object 100 is placed in the Z direction.

[0028] In addition, a technology for dividing the plane of the object to be measured 100 as described above into regions of a size corresponding to each pixel 51 of the area sensor 5, and dispersing the light from each region and receiving it at each pixel 51 of the area sensor 5 is well known, for example, as a hyperspectral camera.

[0029] The measurement data, which is an electrical signal output from each pixel 51 of the area sensor 5, is converted into a digital signal as needed through a current-voltage (IV) conversion circuit and an analog-digital (AD) conversion circuit (not shown), and sent to the calculation unit 6. Using the measurement data sent to it, the calculation unit 6 calculates the representative wavelength for each of the multiple LED chips on the measurement object using a CPU or the like. The method for calculating the representative wavelength will be described in detail later.

[0030] The measurement result display unit 7 displays the results of the calculation performed by the calculation unit 6. The calculation unit 6 may also convert the measurement data output from the area sensor 5 into a digital signal.

[0031] The calculation unit 6 may be a dedicated device or may be configured with a personal computer. Furthermore, the measurement data output from the area sensor 5 and processed into a digital signal may be sent to the calculation unit 6 via a network. In this case, even if the calculation unit 6 is located in a place distant from the measurement location, it is possible to measure the representative wavelength of the LED chip.

[0032] Next, a method for measuring the representative wavelength of each LED chip on a wafer, which is the measurement object 100, using the wavelength measurement device shown in FIG. 1 will be described.

[0033] 3 is a diagram for explaining the relationship between the size of the multiple LED chips 101 on the measurement object 100 and the size of the pixels 51 of the area sensor 5. The horizontal axis of the fine grid in FIG. 3 is the spatial Y direction in FIG. 2, and the vertical axis is the spatial Z direction generated by scanning the LED chip 101 in the wavelength Z direction. The size of one grid is the measurement area, and corresponds to the size of the pixel 51.

[0034] The LED chips 101 are displayed as rectangles and are arranged vertically and horizontally on the measurement object 100. The rectangular area is the light-emitting surface of each LED chip 101.

[0035] The arrangement pitch of the LED chips 101, the pitch of the pixels 51 of the area sensor 5, the magnification of the objective lens 2, etc. are set so that data can be acquired by multiple pixels 51 for the light-emitting surface of one LED chip 101, that is, so that light emitted from multiple areas on the light-emitting surface of one LED chip 101, each having a size corresponding to the pixel 51, can be received by the corresponding multiple pixels 51. In this embodiment, the arrangement pitch is set so that light from the light-emitting surface of one LED chip 101 can be divided into 3 × 3 = 9 or more pixels and received.

[0036] Next, excitation light is irradiated from excitation light source 1 onto measurement object 100 placed on table 200, and light emitted from multiple LED chips 101 on measurement object 100 is received by each pixel 51 of area sensor 5 while table 200 is moved in the Z direction of FIG. 2 by movement device 300. The light emitted from LED chip 101 is dispersed into predetermined wavelengths by spectroscopic unit 3, and the dispersed light of each wavelength is received by each pixel 51. The value (brightness value) of each pixel 51 that receives the light is sent to calculation unit 6 as measurement data and stored in a memory (not shown) within calculation unit 6. Furthermore, since measurement is performed while moving measurement object 100 on table 200 in the Z direction of FIG. 2 by movement device 300, measurement data for each dispersed wavelength is obtained for each area corresponding to a pixel in a two-dimensional direction of measurement object 100, in other words, within a plane.

[0037] Based on the measurement data thus obtained, the calculation unit 6 calculates the representative wavelength of each LED chip 101 .

[0038] FIG. 4 is a schematic diagram showing the light reception state at each pixel 51 when the area sensor 5 receives light of an arbitrary wavelength from the surface of the measurement object 100, for example, light of wavelength λ having the maximum brightness among data from a pixel group in an appropriate area that includes measurement data from multiple LED chips 101. The horizontal direction in FIG. 4 corresponds to the spatial Y direction in FIG. 2, and the vertical direction corresponds to spatial Z-direction data obtained by scanning the LED chip 101 in the Z direction. The black frame 8 in FIG. 4 indicates the area corresponding to the light-emitting surface of one LED chip 101. It is also shown that the darkened area 9 is bright and the brightness decreases toward the periphery.

[0039] Next, the measurement data received by each pixel 51 of the area sensor 5 is separated for each LED chip 10. This separation can be performed, for example, as follows. That is, the wavelength λ at which the maximum brightness is obtained is determined from the data of a pixel group in an appropriate area that includes the measurement data of multiple LED chips 101. Next, at wavelength λ, each pixel 51 is classified by brightness level, and image processing is performed using a certain brightness level as a threshold, thereby separating the data for each LED chip 101. Figure 5(A) shows the state in which the measurement data for each pixel 51 has been separated for each LED chip 101. In Figure 5(A), the data has been separated into nine data areas 10a to 10i, indicated by black frames.

[0040] Next, a pixel of interest that has the maximum brightness (luminance value) is identified from the measurement data for each separated LED chip 101. For example, as shown in Fig. 5(B), if the maximum value is obtained at pixel 51a in the measurement data of a data area (e.g., data area 10b) for one LED chip 101 at a certain wavelength, this pixel 51a is identified as the pixel of interest.

[0041] Here, the wavelength is a wavelength used only to find the separated brightness level or the pixel of interest, and examples thereof include, as described above, the wavelength having the maximum brightness among the data of a pixel group in an appropriate area that includes the measurement data of multiple LED chips 101, or the wavelength having the maximum brightness among the measurement data in a data area for one LED chip, or the design wavelength of the light-emitting element chip, etc.

[0042] After the target pixel 51a is identified, the value of the target pixel 51a and the values ​​of one or more pixels surrounding the target pixel 51a are averaged to obtain the spectrum data for that wavelength (brightness data at that wavelength). In the example of Fig. 5(B), as shown enlarged in Fig. 5(C), the values ​​of a total of nine pixels 51, including the target pixel 51a and eight pixels 51b to 51i surrounding the target pixel 51a, are averaged.

[0043] In this way, by averaging the data of a plurality of pixels including the pixel of interest 51a, it is possible to obtain the effect of reducing measurement noise. This point will be explained below.

[0044] That is, the emission wavelength is an important factor that determines the characteristics of a self-emitting element. Self-emitting elements are mainly divided into LEDs and OLEDs (Organic Light Emitting Diodes). Compared to OLEDs, LEDs have a relatively uniform emission wavelength at any point on their light-emitting surface, in principle. Therefore, in the case of LEDs, it is possible to measure the representative wavelength of the LED at any point on its light-emitting surface, and averaging the data obtained by dividing the area can reduce measurement noise. However, the light-emitting element chip is not limited to the LED chip 101, and can also be an OLED.

[0045] The reason for averaging the pixels surrounding the target pixel 51a is to fit the wavelength measurement area of ​​the LED chip 101 within the light-emitting surface, and a value that is less affected by variation can be obtained with a relatively small amount of data. Specifically, by using the values ​​of the nine surrounding pixels including the target pixel 51a that shows the maximum brightness, a value that is sufficiently less affected by variation can be obtained.

[0046] In principle, LEDs have a relatively uniform emission wavelength anywhere on the light-emitting surface compared to OLEDs for the following reasons.

[0047] That is, the emission wavelength of an LED is determined by the energy band gap (Eg) of the compound semiconductor material, and is expressed by the following formula:

[0048] λ(nm)=1240 / Eg(eV) For example, GaAs (gallium arsenide) has an Eg of 1.4 eV (at a temperature of 300 K), resulting in an emission wavelength λ of 885 nm. Because Eg is determined by the composition of the compound semiconductor materials that make up the LED, variations in material composition can be a factor in variations in emission wavelength. On the other hand, because OLEDs share the same basic principles as LEDs, variations in material composition can also be a factor in variations in emission wavelength. Furthermore, because OLEDs have a relatively broad emission spectrum, the use of a microcavity structure sharpens the spectrum and improves color purity. Because the microcavity structure utilizes the optical resonance effect between the upper and lower electrodes of the organic light-emitting layer, variations in the film thickness of the organic light-emitting layer can be a factor in variations in emission wavelength.

[0049] In other words, LEDs have fewer factors of variation than OLEDs, so there is less variation in the emission wavelength within the light-emitting surface of the chip.

[0050] FIG. 6 is a spectrum graph plotting the average values ​​of nine pixels for each wavelength for four data regions (10b, 10d, 10f, and 10h) among the data regions 10a to 10i of the multiple LED chips 101 shown in FIG. 5(A). Meanwhile, FIG. 7 is a spectrum graph plotting the values ​​of only the target pixel 51a for each wavelength for the same four data regions (10b, 10d, 10f, and 10h). In both graphs, the horizontal axis represents wavelength and the vertical axis represents brightness. Comparing the two graphs, it can be seen that the spectral shape of the value of only the target pixel 51a shown in FIG. 7 is more distorted.

[0051] The luminance values ​​of the pixel of interest 51a and its surrounding pixels 51b to 51i are averaged for each wavelength as described above, and the representative wavelength is determined from the average value of each wavelength. Specifically, as shown in Figure 8, a fitting curve is determined using Gaussian fitting or the like based on the average values ​​of each wavelength, and the wavelength of the peak value of the fitting curve is determined as the representative wavelength. Note that if the wavelength pitch is small, the wavelength with the largest average value among the average values ​​of each wavelength may be determined as the representative wavelength without fitting.

[0052] In this way, the representative wavelength is calculated from the measurement data for all LED chips 101 in the measurement object 100. In this embodiment, the calculated representative wavelength is the emission peak wavelength, but it may also be the centroid wavelength, central wavelength, etc. The centroid wavelength is a weighted average of wavelengths, with the emission spectrum as the weight. In other words, the centroid wavelength is the value obtained by integrating the product of each wavelength and the light intensity of that wavelength over the entire range of emission wavelengths, divided by the value obtained by integrating the light intensity over the entire range of emission wavelengths. Furthermore, the central wavelength is the average of the two half-maximum wavelengths that are 3 dB below the maximum amplitude on either side of the peak wavelength.

[0053] Next, the measurement repeatability of the representative wavelength calculated as described above is compared between the case where it is calculated from the average value of nine pixels including the pixel of interest 51a for each wavelength and the case where it is calculated from the value of only the pixel of interest 51a. The LED chip 101 was measured ten times, and a process was performed to calculate the average value of nine pixels for each wavelength for one data area of ​​the LED chip 101. The representative wavelengths calculated from the peak positions of the fitting curves obtained in each measurement are shown in Table 1(A). Furthermore, the process was performed to calculate the value of only the pixel of interest 51a for each wavelength, and the representative wavelengths calculated from the peak positions of the fitting curves obtained in each measurement are shown in Table 1(B).

[0054] [Table 1]

[0055] In Table 1, "maximum value" refers to the maximum value of the fitting curve, and "peak position" refers to the peak wavelength at the maximum value of the fitting curve, i.e., the representative wavelength. In the method of calculating the representative wavelength by focusing on only one pixel in Table 1(B), the difference (△) between the maximum (max) and minimum (min) representative wavelength was 1.15, the standard deviation using the STDEV function was 0.42, and the average value (ave) was 626.83. In contrast, in the method of calculating the representative wavelength from the average value of nine pixels in Table 1(A), the difference (△) between the maximum (max) and minimum (min) representative wavelength was 0.39, the standard deviation using the STDEV function was 0.14, and the average value (ave) was 626.67, showing little variation, less than approximately 0.5 nm at 3σ.

[0056] If the measurement range of the measurement object 100 is wider than the single measurement area 11 shown by the rectangle in Fig. 9 and measurement of the entire measurement range cannot be completed in one measurement, the representative wavelength of each LED chip 101 in the measurement area 11 can be measured, and then the measurement area 11 can be moved to the next measurement location by moving at least one of the measurement object 100 or the measurement device, and measurement can be performed there, and this process can be repeated in sequence. In Fig. 9, the movement direction of the measurement area 11 is indicated by solid arrows and dashed arrows, and the measurement area 11 is moved from left to right and from top to bottom in that order.

[0057] As described above, in this embodiment, the multiple LED chips 101 included in the measurement object 100 are excited and emit light at the same time, and the light emitted from the light-emitting surface of each LED chip 101 and dispersed by the spectroscopic unit 3 is received in multiple regions by the multiple pixels 51 of the area sensor 5. The measurement data obtained based on the light-reception results is separated for each LED chip 101, and a representative wavelength is calculated for each separated LED chip 101 from the measurement data for each wavelength for multiple regions in the light-emitting surface.

[0058] In this way, the representative wavelength is calculated for each LED chip 101 using measurement data when multiple LED chips 101 are excited and emit light at the same time, which shortens measurement time and improves measurement efficiency compared to measuring the representative wavelength of each LED chip 101 individually using a spot spectrometer. Moreover, the measurement data for the area within the light-emitting surface of the LED chip 101 where the maximum value is obtained and the measurement data for one or more areas adjacent to that area are averaged, and the representative wavelength is calculated from the averaged measurement data for each wavelength, which eliminates variation and makes it easy to obtain a highly accurate representative wavelength.

[0059] This application claims priority from Japanese Patent Application No. 2020-186652, filed on November 9, 2020, the disclosure of which is incorporated herein by reference in its entirety. [Industrial Applicability]

[0060] The present invention can be used as a wavelength measurement device for measuring the respective representative wavelengths of light-emitting element chips, such as a plurality of LED chips, included in an object to be measured. [Explanation of symbols]

[0061] 1. Excitation light source 2 objective lenses 3 Spectroscopic section 4 Imaging lenses 5 Area Sensor 51 pixels 51a Pixel of interest 51b~51i Surrounding pixels 6 Arithmetic section 7 Measurement result display section 10a~10i data area 100 Measurement object 101 Light emitting element chip (LED chip) 200 tables 300 Mobile Device

Claims

1. a spectroscopic means for spectroscopically separating light emitted by a plurality of light-emitting element chips included in the object to be measured upon excitation; a light receiving means having a plurality of pixels that receives light emitted from each light emitting surface of the plurality of light emitting element chips and dispersed by the dispersing means; an acquisition means for acquiring measurement data for each wavelength for each region having a size corresponding to the pixel on a surface of a measurement object including a plurality of the light-emitting surfaces based on a light receiving result by the light receiving means; a separating means for separating the measurement data acquired by the acquiring means for each of the light-emitting element chips by dividing each pixel into levels according to brightness at a first predetermined wavelength among data of a pixel group in an area including measurement data of a plurality of light-emitting element chips, and performing image processing using a predetermined brightness level as a threshold value; a calculation means for calculating a representative wavelength from measurement data for each wavelength for a plurality of regions in a light-emitting surface of each light-emitting element chip separated by the separation means; A wavelength measuring device comprising:

2. 2. The wavelength measurement device according to claim 1, wherein the calculation means averages the measurement data of a region within the light-emitting surface where the maximum value is obtained for a second predetermined wavelength and one or more regions adjacent to that region, and calculates a representative wavelength from the averaged measurement data for each wavelength.

3. 3. The wavelength measuring device according to claim 2, wherein at least one of the first and second predetermined wavelengths is a wavelength having the maximum brightness among data of a pixel group in an appropriate area including measurement data of a plurality of light-emitting element chips, a wavelength having the maximum brightness among measurement data in a data area for one light-emitting element chip, or a design wavelength of the light-emitting element chip.

4. the light receiving means is an area sensor, 4. The wavelength measurement device according to claim 1, wherein each pixel in one pixel row of the area sensor corresponds to a plurality of regions in a one-dimensional direction of the object to be measured, and each pixel in the other pixel row perpendicular to the one pixel row receives light emitted from the plurality of regions in the one-dimensional direction and dispersed.

5. a moving means for relatively moving at least one of the measurement object and the wavelength measurement device in a direction toward the other pixel row, 5. The wavelength measurement device according to claim 4, wherein the measurement is performed while moving at least one of the object to be measured or the wavelength measurement device using the moving means, thereby causing the area sensor to receive dispersed light from each area in a two-dimensional direction of the object to be measured.

6. 6. The wavelength measuring device according to claim 1, wherein the representative wavelength is an emission peak wavelength.

7. 6. The wavelength measurement device according to claim 1, wherein the representative wavelength is a centroid wavelength.

8. 6. The wavelength measurement device according to claim 1, wherein the representative wavelength is a central wavelength.

9. 9. The wavelength measurement device according to claim 1, wherein the light emitting element chip is an LED chip.

10. 10. The wavelength measurement device according to claim 1, further comprising a light source unit that excites the plurality of light-emitting element chips to emit light.

11. a spectroscopic step of spectroscopically separating light emitted by a plurality of light-emitting element chips included in the object to be measured using a spectroscopic means; a light receiving step of receiving light emitted from each light emitting surface of the plurality of light emitting element chips and dispersed by the dispersing step; an acquiring step of acquiring measurement data for each wavelength for each region having a size corresponding to the pixel on a surface of the measurement object including the plurality of light-emitting surfaces based on a light receiving result from the light receiving step; a separating step of separating the measurement data acquired in the acquiring step for each of the light-emitting element chips by dividing each pixel into levels according to brightness at a first predetermined wavelength among data of a pixel group in an area including measurement data of a plurality of light-emitting element chips, and performing image processing using a predetermined brightness level as a threshold; a calculation step of calculating a representative wavelength from measurement data for each wavelength for a plurality of regions in a light-emitting surface for each light-emitting element chip separated by the separation step; A wavelength measurement method comprising:

12. 12. The wavelength measurement method according to claim 11, wherein the calculation step averages the measurement data of a region in the light-emitting surface where the maximum value is obtained for a second predetermined wavelength and one or more regions adjacent to that region, and calculates a representative wavelength from the averaged measurement data for each wavelength.

13. 13. The wavelength measurement method according to claim 12, wherein at least one of the first and second predetermined wavelengths is a wavelength having the maximum brightness among data of a pixel group in an appropriate area including measurement data of a plurality of light-emitting element chips, a wavelength having the maximum brightness among measurement data in a data area for one light-emitting element chip, or a design wavelength of the light-emitting element chip.

14. the light receiving means is an area sensor, 14. The wavelength measurement method according to claim 11, wherein one pixel row of the area sensor receives light from each region in a one-dimensional direction of the object to be measured, and another pixel row perpendicular to the one pixel row receives dispersed light corresponding to each region in the one-dimensional direction.

15. a moving step of relatively moving at least one of the area sensor and the object to be measured in a direction of the other pixel row, The wavelength measurement method according to claim 14, wherein the movement of at least one of the area sensor and the object to be measured in the moving step causes the area sensor to receive light from each area in a two-dimensional direction of the object to be measured.

16. The wavelength measurement method according to any one of claims 11 to 15, wherein the representative wavelength is an emission peak wavelength.

17. The wavelength measurement method according to any one of claims 11 to 15, wherein the representative wavelength is a centroid wavelength.

18. The wavelength measurement method according to any one of claims 11 to 15, wherein the representative wavelength is a central wavelength.

19. The wavelength measurement method according to any one of claims 11 to 18, wherein the light emitting element chip is an LED chip.

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