WO2023286657A1

WO2023286657A1 - Wavelength measurement device and wavelength measurement method

Info

Publication number: WO2023286657A1
Application number: PCT/JP2022/026693
Authority: WO
Inventors: 亮大木; 祐亮平尾; 明小坂
Original assignee: コニカミノルタ株式会社
Priority date: 2021-07-16
Filing date: 2022-07-05
Publication date: 2023-01-19
Also published as: CN117651850A; KR20240027128A; JPWO2023286657A1

Abstract

The present invention comprises a light-splitting means (3) that splits light emitted from an excited LED chip (101), a light-receiving means (5) that has a plurality of pixels (51) that receive each wavelength of the light split by the light-splitting means (3), a plurality of readout means (52), (54), (55), (513) that correspond to each of the plurality of pixels (51) and read out signals from each of the pixels, and a computation means (6) that computes a representative wavelength for the LED chip (101) on the basis of the signals read out by a portion of the readout means from among the plurality of readout means.

Description

Wavelength measuring device and wavelength measuring method

The present invention relates to a wavelength measuring device and wavelength measuring method for measuring a representative wavelength of an LED (light emitting diode) chip.

For example, backlight LEDs used in displays such as televisions have their emission colors strictly controlled, as variations in color can cause deterioration in image quality, such as color unevenness on the display. For this reason, a so-called binning process, in which the wavelength of each LED chip is measured and classified by color, has been conventionally performed.

However, when the size of the LED chip becomes smaller, for example, a micro LED chip with a side of 100 μm or less, it becomes necessary to measure a huge number of LED chips, resulting in a longer wavelength measurement time, which in turn lengthens the binning process. (Binning time) becomes longer. Therefore, shortening of the wavelength measurement time is required from the standpoint of manufacturing efficiency and cost.

Wavelength measurement of an LED chip involves splitting the light emitted from the LED chip into different wavelengths, receiving the split light of each wavelength with a plurality of pixels of the light receiving sensor, and reading out the signal from each pixel that received the light. performed by Conventionally, signal readout is performed for pixels of all spectrally separated wavelengths, so the time required for signal readout increases, and it is difficult to shorten the wavelength measurement time.

In addition, in Patent Document 1, a CCD (Charge Coupled Device) detector including a plurality of light receiving elements arranged two-dimensionally, an optical system for dispersing incident light and irradiating it on the CCD detector, and the plurality of light receiving elements An optical spectrum measuring apparatus is disclosed that includes a limiting section that limits irradiation of light from the optical system to at least one of some rows of each row and some columns of each column of elements.

According to this optical spectrum measurement device, at least one of the number of rows and columns irradiated with light can be reduced. It is said that the time required for the charge acquisition process can be shortened.

JP 2018-128326 A

However, in the technique described in Patent Document 1, charges are not accumulated in the light receiving elements whose light irradiation is restricted by the restricting portion. is done. Therefore, even if the technique described in Patent Document 1 is applied to the wavelength measurement of an LED chip, there is a limit to shortening the readout time, and thus there is a limit to shortening the wavelength measurement time.

In addition, there was also the problem that the configuration was complicated because a physical restriction section was required to restrict the irradiation of light.

The present invention has been made in view of such a technical background, and provides a wavelength measurement device that does not require a physical restriction unit for restricting light irradiation and that can shorten the measurement time of the representative wavelength of an LED chip. An object is to provide an apparatus and a wavelength measurement method.

The above object is achieved by the following means.
(1) spectroscopy means for spectroscopy the light emitted by the excited LED chip;
a light-receiving means having a plurality of pixels for receiving the light separated by the spectroscopic means for each wavelength;
a plurality of reading means corresponding to each of the plurality of pixels and reading a signal from each pixel;
computing means for computing a representative wavelength of the LED chip based on a signal read by some of the plurality of reading means;
Wavelength measurement device with
(2) The wavelength measuring apparatus according to (1) above, wherein the partial readout means forms one readout means group, and there are a plurality of readout means groups.
(3) Prior to the main measurement, the computing means acquires the spectrum information of the LED chip based on the signals read by all the reading means, and from the acquired spectrum information, a part of the readout of the signal in the main measurement 3. The wavelength measuring device according to the preceding

item

1 or 2, wherein the means is set.
(4) The computing means acquires the spectrum information of the LED chip based on the signals read by all the reading means prior to the main measurement, and from the acquired spectrum information, the read means group for reading out the signals in the main measurement. The wavelength measuring device according to the preceding item 2 to be selected.
(5) the light receiving means is an area sensor;
Each pixel in one pixel row of the area sensor receives light from a plurality of regions within the light emitting surface of the LED chip, and each pixel in the other pixel row orthogonal to the one pixel row receives light from each of the regions. 5. The wavelength measuring device according to any one of the preceding items 1 to 4, which receives the light emitted from and dispersed by each wavelength.
(6) The wavelength measuring device according to the preceding item 5, wherein the computing means averages signals from a plurality of regions within the light emitting surface of the LED chip.
(7) The wavelength measuring device according to

item

5 or 6 above, wherein the area sensor is moved in a direction orthogonal to the one pixel row to receive light from a two-dimensional region within the light emitting surface of the LED chip. .
(8) Light is received from a two-dimensional region within the light emitting surface of the LED chip by moving the LED chip in a direction perpendicular to the row region within the light emitting surface of the LED chip corresponding to the one pixel row. 8. The wavelength measuring device according to any one of 5 to 7 above.
(9) The wavelength measuring device according to any one of the preceding items 1 to 8, wherein the representative wavelength is at least one of an emission peak wavelength, a centroid wavelength, and a central wavelength.
(10) The wavelength measuring device according to any one of the preceding items 1 to 9, comprising a light source section that excites the LED chip to emit light.
(11) The wavelength measuring device according to any one of the preceding items 1 to 10, wherein the light receiving means and the reading means are composed of CMOS sensors.
(12) a spectroscopic step of spectroscopically dispersing the light emitted by the excited LED chip with spectroscopic means;
a light-receiving step of receiving the light split by the splitting step by a plurality of pixels for each wavelength;
a reading step of reading out the signals by some reading means among a plurality of reading means corresponding to the plurality of pixels and reading signals from the respective pixels;
a computing step of computing a representative wavelength of the LED chip based on the signal read out by the reading step;
Wavelength measurement method including.
(13) The wavelength measurement method according to (12) above, wherein the part of the readout means forms one readout means group, and there are a plurality of readout means groups.
(14) In the calculation step, prior to the main measurement, the spectrum information of the LED chip is obtained based on the signals read by all the reading means, and from the obtained spectrum information, the signal in the main measurement is read out. 14. The wavelength measurement method according to the preceding item 12 or 13, wherein the means is set.
(15) In the calculating step, prior to the main measurement, the spectrum information of the LED chip is obtained based on the signals read by all the reading means, and from the obtained spectrum information, a reading means group for reading the signal in the main measurement 14. The wavelength measurement method according to 13 above.
(16) the light receiving means is an area sensor;
Each pixel in one pixel row of the area sensor receives light from a plurality of regions within the light emitting surface of the LED chip, and each pixel in the other pixel row orthogonal to the one pixel row receives light from each of the regions. 16. The wavelength measuring method according to any one of the preceding items 12 to 15, wherein the light emitted from and dispersed is received for each wavelength.
(17) The wavelength measuring method according to (16) above, wherein in the computing step, signals from a plurality of regions within a light emitting surface of the LED chip are averaged.
(18) The wavelength measurement method according to item 16 or 17, wherein the area sensor is moved in a direction orthogonal to the one pixel row to receive light from a two-dimensional area within the light emitting surface of the LED chip. .
(19) Light is received from a two-dimensional region within the light emitting surface of the LED chip by moving the LED chip in a direction orthogonal to the row region within the light emitting surface of the LED chip corresponding to the one pixel row. 19. The wavelength measurement method according to any one of 16 to 18 above.
(20) The wavelength measuring method according to any one of (12) to (19) above, wherein the representative wavelength is at least one of an emission peak wavelength, a centroid wavelength, and a center wavelength.
(21) The wavelength measuring method according to any one of the preceding items 12 to 20, wherein the light receiving means and the reading means are composed of CMOS sensors.

According to the inventions described in the preceding paragraphs (1) and (12), the light emitted by the excited LED chip is separated by the spectroscopic means and received for each wavelength by the light receiving means having a plurality of pixels. Among a plurality of readout means for reading out signals from the respective pixels, some of the readout means read the signals of the pixels. Then, the representative wavelength of the LED chip is calculated by the calculating means based on the read signal.

In this way, since only the signals from some of the pixels are read out by some of the readout means, it is not necessary to read out the signals of all the pixels, and the readout time can be shortened accordingly, and the wavelength measurement time can be shortened. Moreover, no physical limiting portion for limiting light reception is required, and the configuration is not complicated.

Especially in this invention, the emission colors of the LED chip are red (R), green (G), and blue (B), and the wavelength range required for measuring each representative wavelength is generally limited. No signal acquisition is required. For example, when measuring an LED chip for red color, it is sufficient to acquire signals in the 550 to 700 nm region. Therefore, there is no problem even if the signal from the pixel is read out by restricting the wavelength region, and the advantage of shortening the wavelength measurement time due to the shortening of the readout time can be enjoyed.

In addition, since the LED chip is excited by the excitation light and emits light, it is necessary to eliminate the influence of the excitation light. There is also an effect that can be done.

According to the inventions described in the preceding items (2) and (13), some of the reading means form one reading means group, and there are a plurality of reading means groups. can read out signals in the respective limited wavelength regions.

According to the inventions described in the preceding items (3) and (14), prior to the main measurement, the computing means acquires the spectral information of the LED chip based on the signals read by all the reading means, and from the acquired spectral information , it is possible to accurately set a part of reading means for reading signals in the main measurement.

According to the inventions described in the preceding paragraphs (4) and (15), prior to the main measurement, the computing means acquires the spectral information of the LED chip based on the signals read by all the reading means, and from the acquired spectral information , the reading means group for reading the signal in the main measurement can be selected with high accuracy.

According to the inventions described in the preceding items (5) and (16), each pixel in one pixel row of the area sensor receives light from a plurality of regions in the light emitting surface of the LED chip, Each pixel in the other orthogonal pixel row receives the light emitted from each region and separated for each wavelength, thereby separating the light from the plurality of regions within the light emitting surface of the LED chip for each wavelength. can receive light.

According to the above inventions (6) and (17), the computing means averages the signals from a plurality of regions within the light emitting surface of the LED chip, so that the setting of the reading means for reading the signals is performed with high accuracy. be able to.

According to the inventions described in the preceding items (7) and (18), by moving the area sensor in a direction perpendicular to one pixel row, light is received from a two-dimensional area within the light emitting surface of the LED chip. be able to.

According to the inventions described in the preceding items (8) and (19), by moving the LED chip in a direction perpendicular to the row region in the light emitting surface of the LED chip corresponding to one pixel row, the light emitting surface of the LED chip It can receive light from a two-dimensional region within.

According to the inventions described in the preceding paragraphs (9) and (20), at least one of the emission peak wavelength, the centroid wavelength, and the central wavelength can be obtained as the representative wavelength.

According to the invention described in the preceding item (10), the light source section can excite the LED chip to emit light.

According to the above inventions (11) and (21), the light receiving means and the reading means are composed of CMOS sensors. Readout can be realized.

1 is a block diagram showing the configuration of a wavelength measuring device according to one embodiment of the present invention; FIG. FIG. 2 is a perspective view showing a specific configuration of part of the wavelength measurement device of FIG. 1; It is a circuit diagram which shows the structural example of a CMOS sensor. FIG. 4 is an explanatory diagram for setting a wavelength readout range; FIG. 4 is a diagram for explaining the relationship between a plurality of LED chips on the object to be measured and the pixel size of the light receiving means; It is a figure for demonstrating the determination example of the wavelength read-out range in this measurement. FIG. 10 is a diagram for explaining another example of determination of the wavelength readout range in the main measurement; (A), (B), and (C) are explanatory diagrams for setting the reading unit group. Among the light received from the surface of the object to be measured, the light of any wavelength, for example, the wavelength with the maximum brightness among the data of the pixel group in the appropriate area containing the measurement data of a plurality of LED chips FIG. 4 is a diagram schematically showing only the data of λ extracted; (A) is a diagram showing a state in which measurement data for each pixel is separated for each LED chip, (B) is a diagram for explaining a method of calculating a representative wavelength, and (C) is an enlarged view of (B). . It is a spectrum graph obtained by plotting average values of nine pixels for each wavelength for data regions of a plurality of LED chips. 4 is a spectrum graph plotting the value of one pixel for each wavelength for data regions of a plurality of LED chips; It is the graph which calculated the average value of 9 pixels for every wavelength about the data area|region of one LED chip, and drew the average value and the fitting curve based on it. It is a figure for demonstrating the measuring method about the measuring object with a wide measuring range.

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a wavelength measuring device according to one embodiment of the present invention. In this embodiment, a case where the measurement object 100 is a wafer on which a plurality of LED chips are formed will be described.

The wavelength measurement device shown in FIG. 6 and a measurement result display unit 7 configured by a liquid crystal display device or the like.

The light source 1 for excitation irradiates a plurality of LED chips on the measurement object 100 with excitation light to excite the plurality of LED chips to emit light.

The spectroscopic section 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 section 3 on the area sensor 5 . In this embodiment, the light is split into respective wavelengths at a wavelength pitch of 5 nm.

The area sensor 5 corresponds to light receiving means, and includes a plurality of pixels 51 arranged vertically and horizontally as shown in FIG. The horizontal direction of the area sensor 5 (space X direction in FIG. 2) means the horizontal direction of the physical space, and each horizontal pixel 51 corresponds to the horizontal region of the measurement object 100 . On the other hand, the vertical direction of the area sensor 5 (wavelength Z direction in FIG. 2) corresponds to the wavelength of light. That is, each pixel 51 in the pixel row in the spatial X direction corresponds to a plurality of regions (row regions) 100a in the one-dimensional direction of the object 100 to be measured. Light incident on the slit 31 of the unit 3 and wavelength-decomposed by the spectroscopic unit 3 is received by each pixel 51 of the pixel array in the wavelength Z direction. Therefore, in order to perform spectroscopic measurement on each region in the two-dimensional direction (plane) of the measurement object 100, the measurement object 100 is moved (scanned) in the Z1 direction orthogonal to the row region 100a in the one-dimensional direction. There is a need. Alternatively, instead of moving the measurement object 100, the wavelength measurement device including the area sensor 5 may be moved in the wavelength Z direction orthogonal to the space X direction in FIG. may be moved with a speed difference, in short, at least one of the measurement object 100 and the wavelength measurement device should be moved relative to the other.

Each time the measurement object 100 is relatively moved, the row regions 100a of the measurement object 100 are switched, and a plurality of frames of spectral data are obtained with the spectral data of each row region 100a as one frame, and accumulated as a spectral data cube. To go. In this embodiment, the measurement object 100 (LED chip 101) is to be moved, and as shown in FIG. ing.

The plane of the measurement object 100 as described above is divided into regions each having a size corresponding to each pixel 51 of the area sensor 5 , and the light from each region is spectrally separated by each pixel 51 of the area sensor 5 . A technique for obtaining spectral data by receiving light and repeating this while moving at least one of the measurement object 100 and the wavelength measurement device relative to the other is called a push bloom method, and can be used, for example, as a hyperspectral camera. It is publicly known.

In this embodiment, the area sensor 5 is a sensor that has a plurality of readout units that read out signals from respective pixels and that can designate a readout range, and uses, for example, a CMOS sensor. The area sensor is hereinafter also referred to as a CMOS sensor. A configuration example of the CMOS sensor 5 is schematically shown in FIG.

In the CMOS sensor 5 shown in FIG. 3, each pixel 51 includes a light receiving element 511 such as a photodiode, an amplifier 512 that converts and amplifies the charge accumulated by the light receiving element 511 into a voltage, and a pixel selection switch 513. I have. A pixel selection switch 513 of each pixel 51 is connected to a corresponding vertical signal line 52 among a plurality of vertical signal lines 52 arranged for each column of pixels 51 . Also, the vertical signal line 52 is connected to the horizontal signal line 55 via the CDS circuit 53 and the column selection switch 54 .

Therefore, the pixel selection switch 513 of the pixel 51 from which the signal is to be read is turned on to connect the light receiving element 511 and the vertical signal line 52, and the vertical signal line 52 is connected to the horizontal signal line 55 by turning on the column selection switch 54. , the signal of the selected pixel 51 can be read out through the vertical signal line 52 and the horizontal signal line 55 . That is, the pixel selection switch 513 of each pixel 51, the vertical signal line 52 common to the plurality of pixels 51, the horizontal signal line 55, the column selection switch 54, and the like form a signal readout portion of each pixel 51, and the signal readout is performed. A signal of an arbitrary pixel 51 can be read out by controlling the unit.

Therefore, as shown in FIG. 4, a readout range W2 is set from the entire readout area W1 in the wavelength Z direction of the area sensor 5, and the readout portions of the plurality of pixels 51 existing within the set readout range W2 are determined. By setting them as one readout unit group, it is possible to read out only the signals of the wavelengths in the specified range W2 among the wavelengths spectroscopically separated by the spectroscopic unit 3 .

Measured data, which are signals output from the plurality of pixels 51 of the area sensor 5 with a designated readout range, are converted to digital data through a current/voltage (IV) conversion circuit and an analog/digital (AD) conversion circuit (not shown) as necessary. It is converted into a signal and sent to the calculation unit 6 . Using the sent measurement data, the computing unit 6 computes the representative wavelength for each of the plurality of LED chips on the object to be measured by the CPU or the like. The details of the method of calculating the representative wavelength will be described later.

The measurement result display unit 7 displays the calculation result by the calculation unit 6. Note that the calculation unit 6 may convert the measurement data output from the area sensor 5 into a digital signal.

The computing unit 6 may be a dedicated device, or may be configured by a personal computer. Moreover, 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, the representative wavelength of the LED chip can be measured even if the computing unit 6 is located away from the measurement location.

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

FIG. 5 is a diagram for explaining the relationship between the plurality of LED chips 101 on the measurement object 100 and the size of the pixels 51 of the area sensor 5. FIG. The horizontal axis of the fine grid in FIG. 5 is the spatial X direction, and the vertical axis is the spatial Y direction produced 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 .

The LED chips 101 are displayed as rectangles and arranged vertically and horizontally on the measurement object 100 . Also, the rectangular area becomes the light emitting surface of each LED chip 101 as it is.

The light emitted from a plurality of regions of a size corresponding to the pixels 51 on the light emitting surface of one LED chip 101 is obtained so that data can be obtained with a plurality of pixels 51 for the light emitting surface of one LED chip 101. , are set based on the array pitch of the LED chips 101, the pitch of the pixels 51 of the area sensor 5, the magnification of the objective lens 2, and the like so that the corresponding pixels 51 can receive the light. In this embodiment, the light from the light emitting surface of one LED chip 101 is divided into pixels of 3×3=9 pixels or more and set so that they can receive the light.

Next, before performing the main measurement, pre-measurement is performed to determine the readout range in the wavelength Z direction, in other words, the wavelength region to be readout.

First, signals for one line in the spatial X direction, that is, measurement data for one frame are read from pixels corresponding to all wavelength ranges (380 to 780 nm) (all pixels in the wavelength Z direction in FIGS. 2 and 4). The read measurement data for one frame is spectrum data (brightness data at each wavelength) with a wavelength pitch of 5 nm.

Next, the wavelength λ0 of the pixel 51 having the maximum brightness is determined from the data of the pixel group of the suitable partial area containing the plurality of LED chips 101 . Note that λ0 may be the average of the wavelengths of a plurality of pixels 51 with the highest brightness, instead of the wavelength of the pixel 51 having the highest brightness. Averaging the wavelengths increases the accuracy of the wavelength λ0.

A preset range of, for example, ±75 nm centered on the wavelength λ0 thus determined is taken as the readout range, that is, the wavelength range in the main measurement (hereinafter also referred to as the main measurement wavelength range). As an example, as shown in FIG. 6, when the determined wavelength λ0 is 626.0 nm, 551 nm to 701 nm, which is 626.0±75 nm, is determined as the main measurement wavelength range. Note that ±75 nm may be other values. By determining the main measurement wavelength range, a readout unit group consisting of a part of the readout units that perform readout among all the readout units of the pixels 51 of the area sensor 5 is set.

As another method of determining the main measurement wavelength range by pre-measurement, there is a method of selecting from a plurality of main measurement wavelength ranges prepared in advance based on the determined value of the wavelength λ0. For example, as shown in FIG. 7, when the LED chip 101 is blue, 390 to 540 nm (center wavelength: 465 nm) is preset as the main measurement wavelength range WB, and when the LED chip 101 is green, 465 to 540 nm is set as the main measurement wavelength range WG. 615 nm (central wavelength: 540 nm) is preset, and in the case of red, 550 to 700 nm (central wavelength: 625 nm) is preset as the main measurement wavelength range WR.

If the value of wavelength λ0 is close to 465 nm, the main measurement wavelength range WB of 390 to 540 nm set for blue is selected, and if the value of wavelength λ0 is close to 540 nm, 465 to 615 nm set for green is selected. is selected, and if the value of the wavelength λ0 is close to 625 nm, the main measurement wavelength range WR of 550 to 700 nm set for red is selected. A reading unit group for reading out the pixels 51 is set by selecting the main measurement wavelength range. For example, when the main measurement wavelength range WR is determined, as shown in FIG. When the wavelength range WG is determined, as shown in FIG. 8B, a reading unit group 50G for reading the measurement data of the plurality of pixels 51 corresponding to the main measurement wavelength range WG is set, and the main measurement wavelength range WB is set. , a reading unit group 50B for reading the measurement data of the plurality of pixels 51 corresponding to the main measurement wavelength range WB is set as shown in FIG. 8(C). In this manner, different readout unit groups are set from among the plurality of

readout unit groups

50R, 50G, and 50B according to the main measurement wavelength range.

Further, as still another method for determining the main measurement wavelength range, when the emission color of the LED chip 101 is known in advance, it is possible to set in advance for each of blue, green, and red similar to the above without performing pre-measurement. Alternatively, the main measurement wavelength ranges WB, WG, and WR may be selected. Also in this case, among the

readout unit groups

50R, 50G, and 50B, the

readout unit groups

50B, 50G, and 50R corresponding to the main measurement wavelength ranges WB, WG, and WR are set.

After determining the main measurement wavelength range in this way and setting the reading unit group corresponding to the plurality of pixels 51 from which signals are to be read, the main measurement is performed as follows.

That is, the excitation light source 1 irradiates the measurement object 100 placed on the table 200 with excitation light, and while the table 200 is moved by the moving device 300, the LED chips 101 on the measurement object 100 emit light. Each pixel 51 of the area sensor 5 receives the emitted light. Light emitted from the LED chip 101 is separated into predetermined wavelengths by the spectroscopic section 3 , and the separated light of each wavelength is received by each pixel 51 . The table 200 is moved after reading out the main measurement wavelength range for one frame of measurement data. If exposure has been completed, the table 200 may be moved during readout or the like.

Of all the pixels 51 that have received light, readout of measurement data from the pixels 51 is performed only in the readout unit group set corresponding to the main measurement wavelength range determined in the pre-measurement.

The read measurement data is sent to the computing unit 6 and stored in a memory (not shown) within the computing unit 6 . The measurement is performed while moving the measurement object 100 on the table 200 by the moving device 300, and one frame of measurement data is obtained each time it moves (each time it scans). Then, multiple frames of measurement data are obtained for the planar area. In addition, in each frame, the measurement data is read out only for the pixels 51 corresponding to the readout section group, and the measurement data for the wavelengths within the main measurement wavelength range among the spectrally separated wavelengths is obtained.

Based on the measurement data thus obtained, the calculation unit 6 obtains the representative wavelength of each LED chip 101 by calculation.

FIG. 9 shows the light of an arbitrary wavelength among the light received from the surface of the measurement object 100, for example, the data of the pixel group in the appropriate area containing the measurement data of the plurality of LED chips 101, the maximum Only the data of the wavelength λ with the brightness of λ are extracted and schematically shown. A black frame 8 shown in FIG. 9 indicates a region corresponding to the light emitting surface of one LED chip 101 . In addition, it is shown that the darkened region 9 has high brightness, and the brightness decreases toward the periphery.

Next, the measurement data received by each pixel 51 of the area sensor 5 is separated for each LED chip 10 . This separation may be performed, for example, as follows. That is, the wavelength λ with the maximum brightness is obtained from the data of the pixel group in the appropriate area including the measurement data of the plurality of LED chips 101 . Next, with respect to the wavelength λ, each pixel 51 is divided into levels according to brightness, and image processing is performed using a certain brightness level as a threshold value, thereby separating each LED chip 101 . FIG. 10A shows a state in which measurement data for each pixel 51 is separated for each LED chip 101 . In FIG. 10A, it is separated into nine data areas 10a to 10i indicated by black frames.

Next, for the separated measurement data for each LED chip 101, the pixel of interest with the maximum brightness (luminance value) is specified. For example, as shown in FIG. 10B, in the measurement data of the data area (for example, data area 10b) for one LED chip 101, if the maximum value at a certain wavelength is obtained at a target pixel 51a, this pixel 51a is It is specified as a pixel of interest. Here, a certain wavelength is a wavelength used only for finding a separate brightness level or a pixel of interest. Among them, the wavelength with the maximum brightness, the wavelength with the maximum brightness in the measurement data of the data area for one LED chip, the design wavelength of the LED chip, and the like can be mentioned.

After specifying the pixel of interest 51a, the value of the pixel of interest 51a and the value of a certain wavelength obtained from one or a plurality of pixels surrounding the pixel of interest 51a are averaged to obtain spectral data of that wavelength (brightness at that wavelength). data). In the example of FIG. 10B, as shown in FIG. is becoming

By averaging the data of a plurality of pixels including the pixel of interest 51a in this way, it is possible to obtain the effect of reducing measurement noise.

The reason why the pixels to be averaged are the pixels around the target pixel 51a is that the wavelength measurement region of the LED chip 101 is contained within the light emitting surface. value can be obtained. Specifically, by using the values of nine surrounding pixels including the target pixel 51a showing the maximum brightness, it is possible to obtain a value that is sufficiently less affected by variations.

FIG. 11 shows four

data areas

10b, 10d, 10f, and 10h among the data areas 10a to 10i of the plurality of LED chips 101 shown in FIG. is a spectral graph plotting average values of pixels of . On the other hand, FIG. 12 is a spectral graph plotting the values of only the pixel of interest 51a obtained for each wavelength in four

data areas

10b, 10d, 10f, and 10h. In both graphs, the horizontal axis represents wavelength and the vertical axis represents brightness. Comparing both graphs, it can be seen that the value of only the target pixel 51a shown in FIG. 12 has the shape of the spectrum distorted.

The brightness values of the target pixel 51a and the surrounding pixels 51b to 51i are averaged for each wavelength as described above, and the representative wavelength is obtained from the obtained average value of each wavelength. Specifically, as shown in FIG. 13, a fitting curve is obtained by Gaussian fitting or the like based on the average value of each wavelength, and the wavelength of the peak value of the fitting curve is taken as the representative wavelength. If the wavelength pitch is small, the wavelength with the largest average value among the average values of the wavelengths may be used as the representative wavelength without fitting.

In this way, for all the LED chips 101 of the measurement object 100, the representative wavelength is calculated from the measurement data. Although the representative wavelength calculated in this embodiment is the emission peak wavelength, it may be the centroid wavelength, the central wavelength, or the like. The centroid wavelength is a weighted average of wavelengths weighted by the emission spectrum. In other words, the centroid wavelength is a value obtained by integrating the product of each wavelength and the light intensity of that wavelength over the entire emission wavelength and dividing the value by integrating the light intensity over the entire emission wavelength. The central wavelength is the average value of two half-value wavelengths that are 3 dB lower than the maximum amplitude on both sides of the peak wavelength.

As described above, in the present embodiment, instead of reading the signals of all the pixels 51 corresponding to the wavelengths in the entire spectroscopic range, the main measurement wavelength range for reading is determined, and the determined main measurement wavelength Signals are read out by a reading unit group composed of reading units of a part of the pixels 51 set corresponding to the range. Therefore, it is not necessary to read out the signals of all the pixels, so that the readout time can be shortened, the wavelength measurement time can be shortened, and the binning time can be shortened. Moreover, since a physical limiting section for limiting the light reception of the pixels 51 that are not read is not required, the configuration is not complicated.

In particular, the emission colors of the LED chip 101 are red (R), green (G), and blue (B), and the wavelength range required to measure each representative wavelength is generally limited. is unnecessary, there is no problem even if the signal from the pixel 51 is read out by limiting the wavelength region, and the advantage of shortening the wavelength measurement time due to the shortening of the readout time can be enjoyed.

Incidentally, when the integration time of the CMOS sensor 5 is 1 ms and the measurement wavelength range is 400 nm in the entire visible region, the frame rate indicating the number of frames that can be read out per second is about 520 FPS. The frame rate can be improved to around 920 FPS when the range is limited to 150 nm, and the readout time can be shortened.

In addition, since the LED chip 101 is excited by the excitation light and emits light, it is necessary to eliminate the influence of the excitation light. There are also possible effects.

This application claims priority from Japanese Patent Application No. 2021-118071 filed on July 16, 2021, the disclosure of which is incorporated herein by reference. .

The present invention can be used to measure the representative wavelength of LED chips.

1 light source for excitation 2 objective lens 3 spectroscopic section 4 imaging lens 5 area sensor (light receiving means)
51 pixel 511 light receiving element 512 amplifier 513 pixel selection switch 52 vertical signal line 54 column selection switch 55 horizontal signal line 6 calculation section 7 measurement result display section 10a to 10i data area 100 measurement object 100a column area 101 LED chip (LED chip)
200 Table 300 Mobile device WB, WG, WR Wavelength range in

actual measurement

50B, 50G, 50R Readout unit group

Claims

spectroscopic means for spectroscopically dispersing the light emitted by the excited LED chip;
a light-receiving means having a plurality of pixels for receiving the light separated by the spectroscopic means for each wavelength;
a plurality of reading means corresponding to each of the plurality of pixels and reading a signal from each pixel;
computing means for computing a representative wavelength of the LED chip based on a signal read by some of the plurality of reading means;
Wavelength measurement device with
The wavelength measuring device according to claim 1, wherein the partial readout means form one readout means group, and there are a plurality of readout means groups.
Prior to the main measurement, the computing means acquires the spectral information of the LED chip based on the signals read by all the reading means, and from the acquired spectral information, sets a part of the reading means for reading the signal in the main measurement. The wavelength measuring device according to claim 1 or 2.
Prior to the main measurement, the computing means acquires the spectral information of the LED chip based on the signals read by all the reading means, and selects a reading means group for reading the signals in the main measurement from the acquired spectral information. Item 3. The wavelength measuring device according to item 2.
The light receiving means is an area sensor,
Each pixel in one pixel row of the area sensor receives light from a plurality of regions within the light emitting surface of the LED chip, and each pixel in the other pixel row orthogonal to the one pixel row receives light from each of the regions. 5. The wavelength measurement device according to claim 1, wherein the light emitted from and dispersed by the wavelength is received by each wavelength.
The wavelength measuring device according to claim 5, wherein the computing means averages signals from a plurality of regions within the light emitting surface of the LED chip.
The wavelength measurement device according to claim 5 or 6, wherein light from a two-dimensional area within the light emitting surface of the LED chip is received by moving the area sensor in a direction orthogonal to the one pixel row.
6. Light from a two-dimensional area within the light emitting surface of the LED chip is received by moving the LED chip in a direction orthogonal to a row region within the light emitting surface of the LED chip corresponding to the one pixel row. 8. The wavelength measuring device according to any one of 1 to 7.
The wavelength measuring device according to any one of claims 1 to 8, wherein the representative wavelength is at least one of an emission peak wavelength, a centroid wavelength, and a central wavelength.
The wavelength measuring device according to any one of claims 1 to 9, comprising a light source section that excites the LED chip to emit light.
The wavelength measuring device according to any one of claims 1 to 10, wherein the light receiving means and reading means are composed of CMOS sensors.
a spectroscopic step of spectroscopically dispersing the light emitted by the excited LED chip with spectroscopic means;
a light-receiving step of receiving the light split by the splitting step by a plurality of pixels for each wavelength;
a reading step of reading out the signals by some reading means among a plurality of reading means corresponding to the plurality of pixels and reading signals from the respective pixels;
a computing step of computing a representative wavelength of the LED chip based on the signal read out by the reading step;
Wavelength measurement method including.
The wavelength measurement method according to claim 12, wherein the partial reading means form one reading means group, and there are a plurality of reading means groups.
In the calculation step, prior to the main measurement, spectral information of the LED chip is obtained based on the signals read by all the reading means, and from the obtained spectral information, a part of the reading means for reading the signal in the main measurement is set. 14. The wavelength measurement method according to claim 12 or 13.
In the calculating step, prior to the main measurement, spectral information of the LED chip is obtained based on the signals read by all the reading means, and from the obtained spectral information, a reading means group for reading the signals in the main measurement is selected. Item 14. The wavelength measurement method according to Item 13.
The light receiving means is an area sensor,
Each pixel in one pixel row of the area sensor receives light from a plurality of regions within the light emitting surface of the LED chip, and each pixel in the other pixel row orthogonal to the one pixel row receives light from each of the regions. 16. The wavelength measuring method according to any one of claims 12 to 15, wherein the light emitted from and dispersed is received for each wavelength.
17. The wavelength measuring method according to claim 16, wherein in said calculating step, signals from a plurality of regions within a light emitting surface of said LED chip are averaged.
The wavelength measurement method according to claim 16 or 17, wherein light from a two-dimensional area within the light emitting surface of the LED chip is received by moving the area sensor in a direction orthogonal to the one pixel row.
16. Light from a two-dimensional area within the light emitting surface of the LED chip is received by moving the LED chip in a direction orthogonal to the row area within the light emitting surface of the LED chip corresponding to the one pixel row. 19. The wavelength measurement method according to any one of 18.
The wavelength measurement method according to any one of claims 12 to 19, wherein the representative wavelength is at least one of an emission peak wavelength, a centroid wavelength, and a central wavelength.
The wavelength measuring method according to any one of claims 12 to 20, wherein said light receiving means and reading means are composed of CMOS sensors.