KR20240027128A - Wavelength measurement device and wavelength measurement method - Google Patents

Abstract

A spectroscopic means (3) for splitting the light emitted by being excited by the LED chip (101), and a light receiving means (5) having a plurality of pixels (51) for receiving the light split by the spectroscopic means (3) for each wavelength. , a plurality of readout means (52, 54, 55, 513) corresponding to each of the plurality of pixels (51) and reading and outputting signals from each pixel, and among the plurality of readout means, some readout output means. It is provided with calculation means 6 that calculates the representative wavelength of the LED chip 101 based on the signal read and output by the means.

Description

Wavelength measurement device and wavelength measurement method

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

For example, the emission color of LEDs for backlights used in displays such as televisions is strictly managed because color variations cause deterioration in image quality such as color unevenness of the display. For this reason, a process called binning, which measures the wavelength of each LED chip and classifies it by color, has been performed conventionally.

However, when the size of the LED chip becomes smaller, such as a micro LED chip with a side of 100 ㎛ or less, measurement of a vast number of LED chips is required, which increases the wavelength measurement time and further increases the time of the binning process. (Binning time) becomes longer. For this reason, there is a need to shorten the wavelength measurement time in terms of manufacturing efficiency and cost.

Measurement of the wavelength of an LED chip is carried out by splitting the light emitted from the LED chip for each wavelength, receiving the splitted light at each wavelength at a plurality of pixels of the light receiving sensor, and reading and outputting the signal from each pixel. do. Conventionally, signal readout was performed for pixels of all spectralized wavelengths, so the time required for signal readout became long, making it difficult to shorten the wavelength measurement time.

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

According to this optical spectrum measurement device, at least one of the number of rows and the number of columns to which light is irradiated can be reduced, so compared to a configuration in which the irradiation destination of light is not limited, the time required for the acquisition process of the charge generated in each light receiving element is reduced. It is said that can be shortened.

Japanese Patent Publication No. 2018-128326

However, in the technology described in Patent Document 1, charges are not accumulated in the light-receiving elements whose irradiation of light is limited by the limiting portion, so although they can be read and discarded at high speed, the charge reading and output itself is performed even for these light-receiving elements. . For this reason, even if the technology described in Patent Document 1 was applied to measuring the wavelength of an LED chip, there was a limit to shortening the read-out time, and for this reason, there was a limit to shortening the wavelength measurement time.

In addition, since a physical limiter that limits the irradiation of light is required, there is also a problem that the configuration becomes more complicated.

This invention was made in consideration of the above technical background, and aims to provide a wavelength measurement device and a wavelength measurement method that do not require a physical limiter that limits the irradiation of light and can shorten the measurement time of the representative wavelength of an LED chip. The purpose.

The above objective is achieved by the following means.

(1) a spectroscopic means for speculating the light emitted by being excited by the LED chip,

a light receiving means having a plurality of pixels for each wavelength to receive the light split by the spectroscopic means;

a plurality of reading and output means corresponding to each of the plurality of pixels and reading and outputting a signal from each pixel;

A wavelength measuring device comprising calculation means for calculating a representative wavelength of the LED chip based on signals read and output by some of the readout means among the plurality of readout means.

(2) The wavelength measuring device according to the preceding paragraph 1, wherein some of the reading/output means form one reading/output means group, and a plurality of reading/output means groups exist.

(3) The calculation means acquires spectrum information of the LED chip based on the signals read and output by all readout means prior to the main measurement, and reads and outputs signals in the main measurement from the acquired spectrum information. The wavelength measuring device according to the preceding paragraph 1 or 2, which sets the reading output means.

(4) Before the main measurement, the calculating means acquires spectrum information of the LED chip based on the signals read and output by all readout means, and reads and outputs signals in the main measurement from the acquired spectrum information. The wavelength measuring device according to the preceding paragraph 2, which selects the output means group.

(5) The light receiving means is an area sensor,

Each pixel of one pixel column of the area sensor receives light from a plurality of regions in the light emitting surface of the LED chip, and each pixel of the other pixel column orthogonal to the one pixel column emits light from each of the regions. The wavelength measuring device according to any one of the preceding paragraphs 1 to 4, which receives the divided light for each wavelength.

(6) The wavelength measuring device according to the preceding paragraph 5, wherein the calculating means averages signals from a plurality of areas within the light emitting surface of the LED chip.

(7) The wavelength measuring device according to the preceding paragraph 5 or 6, which receives light from a two-dimensional area within the light emitting surface of the LED chip by moving the area sensor in a direction orthogonal to the one pixel column.

(8) Of the preceding clauses 5 to 7, receiving light from a two-dimensional area within the light-emitting surface of the LED chip by moving the LED chip in a direction perpendicular to the thermal region within the light-emitting surface of the LED chip corresponding to the one pixel row. The wavelength measuring device described in any one.

(9) The wavelength measuring device according to any one of the preceding paragraphs 1 to 8, wherein the representative wavelength is at least one of an emission peak wavelength, a center of gravity wavelength, and a center wavelength.

(10) The wavelength measuring device according to any one of the preceding paragraphs 1 to 9, comprising a light source unit that excites the LED chip to emit light.

(11) The wavelength measuring device according to any one of the preceding paragraphs 1 to 10, wherein the light receiving means and the reading output means are constituted by a CMOS sensor.

(12) a spectroscopic step for dispersing the light emitted by being excited by the LED chip using a spectroscopic means;

a light receiving step for receiving the light split by the spectral step at a plurality of pixels for each wavelength;

a read-out step for reading and outputting the signal by some read-out means among the plurality of read-out means corresponding to each of the plurality of pixels and reading and outputting the signal from each pixel;

A wavelength measurement method comprising a calculation step for calculating a representative wavelength of the LED chip based on the signal read and output by the read output step.

(13) The wavelength measurement method according to the preceding paragraph 12, wherein some of the reading/output means form one reading/output means group, and a plurality of reading/output means groups exist.

(14) In the calculation step, prior to the main measurement, the spectrum information of the LED chip is acquired based on the signals read and output by all readout means, and the part that reads and outputs the signal in the main measurement from the acquired spectrum information. The wavelength measurement method according to paragraph 12 or 13 of the preceding paragraph, which sets the reading output means.

(15) In the calculation step, prior to the main measurement, the spectrum information of the LED chip is acquired based on the signals read and output by all readout means, and from the acquired spectrum information, the signal is read and output in the main measurement. The wavelength measurement method described in paragraph 13 of the preceding paragraph for selecting the output means group.

(16) The light receiving means is an area sensor,

Each pixel of one pixel column of the area sensor receives light from a plurality of regions in the light emitting surface of the LED chip, and each pixel of the other pixel column orthogonal to the one pixel column emits light from each of the regions. The wavelength measurement method according to any one of the preceding paragraphs 12 to 15, wherein the divided light is received for each wavelength.

(17) The wavelength measurement method according to item 16, wherein in the calculation step, signals from a plurality of regions within the light emitting surface of the LED chip are averaged.

(18) The wavelength measurement method according to the preceding paragraph 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 column.

(19) Of the preceding clauses 16 to 18, receiving light from a two-dimensional area within the light-emitting surface of the LED chip by moving the LED chip in a direction orthogonal to the thermal region within the light-emitting surface of the LED chip corresponding to the one pixel row. The wavelength measurement method described in any one.

(20) The wavelength measurement method according to any one of the preceding paragraphs 12 to 19, wherein the representative wavelength is at least one of an emission peak wavelength, a center of gravity wavelength, and a center wavelength.

(21) The wavelength measurement method according to any one of the preceding paragraphs 12 to 20, wherein the light receiving means and the reading output means are constituted by a CMOS sensor.

According to the invention described in the preceding paragraph (1) and (12), the light emitted by being excited by the LED chip is split by a spectroscopic means and received for each wavelength by a light receiving means having a plurality of pixels. Among the plurality of reading and output means corresponding to each of the plurality of pixels and reading and outputting the signal from each pixel, the signal of the pixel is read and output by some of the reading and output means. Then, based on the read-output signal, the representative wavelength of the LED chip is calculated by the calculation means.

In this way, since only signals from some pixels are read and output by some readout means, there is no need to read out signals from all pixels, and the readout time can be shortened accordingly, thereby shortening the wavelength measurement time. You can. In addition, a physical limiter for limiting light reception is unnecessary and the configuration is not complicated.

In particular, in this invention, the emission colors of the LED chip are red (R), green (G), and blue (B), and the wavelength range required for measurement of each representative wavelength is generally limited, and acquisition of signals in the radio wave field in the visible region is not necessary. do. For example, when measuring an R-color LED chip, only signals in the 550 to 700 nm region need to be acquired. In this regard, there is no problem in reading and outputting signals from pixels by limiting the wavelength range, and the advantage of shortening the wavelength measurement time by shortening the read-out time can be enjoyed.

In addition, since the LED chip is excited by excitation light and emits light, it is necessary to exclude the influence of the excitation light. Limiting the wavelength range in which measurement data is read and output has the effect of eliminating the influence of the excitation light as much as possible.

According to the invention described in the preceding paragraph (2) and (13), some of the readout means form one readout means group, and there are a plurality of readout means groups, so that for different color LED chips, a plurality of readout means groups are formed. Each group of reading and output means can read and output signals in a limited wavelength range.

According to the invention described in the preceding paragraph (3) and (14), the calculating means acquires the spectrum information of the LED chip based on the signals read and output by all the reading output means prior to the main measurement, and calculates the spectrum information of the LED chip from the acquired spectrum information. In measurement, some readout means for reading and outputting signals can be set with good precision.

According to the invention described in the preceding paragraph (4) and (15), the calculation means acquires the spectrum information of the LED chip based on the signals read and output by all the readout means prior to the main measurement, and calculates the spectrum information of the LED chip from the acquired spectrum information. In measurement, a group of readout means that reads and outputs signals can be selected with good precision.

According to the invention described in the preceding paragraph (5) and (16), each pixel of one pixel column of the area sensor receives light from a plurality of areas within the light emitting surface of the LED chip, and the other pixel orthogonal to one pixel column Each pixel in a row receives the light emitted and split from each region for each wavelength, so that light from a plurality of regions within the light emitting surface of the LED chip can be split for each wavelength and received at the pixel.

According to the invention described in the preceding paragraph (6) and (17), the calculating means averages signals from a plurality of areas within the light emitting surface of the LED chip, so that the reading and output means for reading and outputting the signal can be set with good precision. can do.

According to the invention described in the preceding paragraph (7) and (18), light from a two-dimensional area within the light emitting surface of the LED chip can be received by moving the area sensor in a direction orthogonal to one pixel column.

According to the invention described in the preceding paragraph (8) and (19), by moving the LED chip in a direction perpendicular to the column region in the light-emitting surface of the LED chip corresponding to one pixel column, can receive light.

According to the invention described in the preceding paragraph (9) and (20), at least one of the emission peak wavelength, the center of gravity wavelength, and the center wavelength can be determined as the representative wavelength.

According to the invention described in the preceding paragraph (10), the LED chip can be excited by the light source unit to emit light.

According to the invention described in the preceding clauses (11) and (21), the light receiving means and the read output means are constituted by a CMOS sensor, so that the CMOS sensor transmits signals from some of the pixels by some of the read output means. Read output can be realized.

1 is a block diagram showing the configuration of a wavelength measuring device according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a specific configuration of a part of the wavelength measuring device of FIG. 1.
Figure 3 is a circuit diagram showing a configuration example of a CMOS sensor.
Figure 4 is an explanatory diagram for setting the wavelength readout output range.
FIG. 5 is a diagram for explaining the relationship between a plurality of LED chips on a measurement object and the size of a pixel of a light receiving means.
Figure 6 is a diagram for explaining an example of determination of the wavelength readout output range in this measurement.
Figure 7 is a diagram for explaining another example of determination of the wavelength readout output range in this measurement.
Figure 8 (A) (B) (C) is an explanatory diagram of the setting of the read output unit group.
Figure 9 shows data of wavelength λ with the maximum brightness among the light received from the surface of the measurement object, light of an arbitrary wavelength, for example, data of a pixel group of an appropriate area containing measurement data of a plurality of LED chips. This is a diagram schematically showing only the extraction.
FIG. 10 (A) is a diagram showing the state in which measurement data from each pixel is separated for each LED chip, FIG. 10 (B) is a diagram for explaining a method of calculating a representative wavelength, and FIG. 10 (C) is FIG. 10 (B) is an enlarged view.
Figure 11 is a spectrum graph plotting the average value of 9 pixels for each wavelength in the data area of a plurality of LED chips.
Fig. 12 is a spectrum graph plotting the value of one pixel for each wavelength in the data areas of a plurality of LED chips.
Figure 13 is a graph in which the average value of 9 pixels for each wavelength is calculated for the data area of one LED chip, and the average value and a fitting curve based on it are drawn.
Figure 14 is a diagram for explaining a measurement method for a measurement object with a wide measurement range.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention will be described based on the drawings.

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

The wavelength measuring device shown in FIG. 1 includes a light source 1 for excitation, an objective lens 2 with changeable magnification, a spectroscope 3, an imaging lens 4, and an area sensor that is a two-dimensional imaging device. (5), a calculation unit (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 excitation light to a plurality of LED chips on the measurement object 100 to excite the plurality of LED chips and cause them to emit light.

The spectrometer 3 splits the light from each LED chip that has passed through the objective lens 2 into wavelengths, and the imaging lens 4 divides the light of each wavelength split by the spectrometer 3 into an area sensor ( 5) Form an image at . In this embodiment, it is configured to split light into each wavelength at a wavelength pitch of 5 nm.

The area sensor 5 corresponds to a light receiving means and includes a plurality of pixels 51 arranged vertically and horizontally as shown in FIG. 2 . The horizontal direction of the area sensor 5 (space On the other hand, the vertical direction of the area sensor 5 (wavelength Z direction in FIG. 2) corresponds to the wavelength of light. In short, each pixel 51 of the pixel column in the spatial The light that passes through 2), enters the slit 31 of the spectrometer 3, and is wavelength-resolved in the spectrometer 3 is received by each pixel 51 of the pixel column in the wavelength Z direction. Therefore, in order to perform spectral measurement on each area of the measurement object 100 in the two-dimensional direction (plane), the measurement object 100 is moved (scanned) in the Z1 direction orthogonal to the thermal region 100a in the one-dimensional direction. It needs to be implemented. Alternatively, instead of moving the measurement object 100, the wavelength measuring device including the area sensor 5 may be moved in the wavelength Z direction orthogonal to the spatial X direction in FIG. 2, or the measurement object 100 and the wavelength Both measuring devices may be moved with a speed difference, and the point is to move at least one of the measurement object 100 and the wavelength measuring device relative to the other.

Each time it is relatively moved, the thermal area 100a of the measurement object 100 is switched, and multiple frames of spectral data are obtained with one frame of spectral data for each thermal area 100a, and the spectral data is obtained. It accumulates as a data cube. In this embodiment, the measurement object 100 (LED chip 101) is moved, and as shown in FIG. 1, a moving device capable of moving the table 200 on which the measurement object 100 is mounted ( 300) is provided.

In addition, the plane of the measurement object 100 as described above is divided into each region with a size corresponding to each pixel 51 of the area sensor 5, and the light from each region is split to form the area sensor 5. The technology for obtaining spectral data by receiving light at each pixel 51 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 pushbroom method, and is, for example, a hyper It is known as a spectrum camera, etc.

In this embodiment, the area sensor 5 is a sensor that has a plurality of read output units that read and output signals from each pixel and can specify a read output range. For example, a CMOS sensor is used. Hereinafter, the area sensor is also referred to as a CMOS sensor. An example of the configuration of the CMOS sensor 5 is schematically shown in FIG. 3.

In the CMOS sensor 5 shown in FIG. 3, each pixel 51 includes a light-receiving element 511 made of a photodiode or the like, and converts and amplifies the charge accumulated by the light-receiving element 511 into a voltage. It is provided with an amplifier 512 that operates and a pixel selection switch 513. The pixel selection switch 513 of each pixel 51 is connected to a corresponding vertical signal line 52 among the plurality of vertical signal lines 52 arranged for each pixel 51 in a column. Additionally, the vertical signal line 52 is connected to the horizontal signal line 55 via the CDS circuit 53 and the column selection switch 54.

Accordingly, the pixel selection switch 513 of the pixel 51 from which a signal is to be read and output is turned on, the light receiving element 511 and the vertical signal line 52 are connected, and the vertical signal line 52 is connected to the column selection switch 54. ) is turned on to connect to the horizontal signal line 55, so that the signal for the selected pixel 51 can be read and output via the vertical signal line 52 and the horizontal signal line 55. In short, each pixel 51 is selected by the pixel selection switch 513 of each pixel 51, the vertical signal line 52, the horizontal signal line 55, and the column selection switch 54 common to the plurality of pixels 51. A signal reading and output section is formed, and by controlling the signal reading and output section, the signal of an arbitrary pixel 51 can be read and output.

For this reason, as shown in FIG. 4, the read output range W2 is set among the entire read output area W1 in the wavelength Z direction in the area sensor 5, and the read output range W2 that exists within the set read output range W2 is set. By setting the read output units of the plurality of pixels 51 as one group of read output units, it is possible to read and output only signals for wavelengths in the specified range W2 among the wavelengths split by the spectrometer 3.

The measurement data, which is a signal output from a plurality of pixels 51 of the area sensor 5 with a specified read output range, is converted to a current/voltage (IV) conversion circuit (not shown) or an analog/digital (AD) conversion circuit as needed. It is converted into a digital signal and sent to the calculation unit 6. The calculation unit 6 uses the transmitted measurement data to calculate a representative wavelength for each of a plurality of LED chips on the measurement object using a CPU or the like. Details of the calculation method of the representative wavelength will be described later.

The measurement result display unit 7 displays the calculation results by the calculation unit 6. Additionally, the measurement data output from the area sensor 5 may be converted into a digital signal by the calculation unit 6.

The calculation unit 6 may be a dedicated device or may be configured by a personal computer. Additionally, 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 calculation unit 6 is located in a location 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 measuring 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 pixel 51 of the area sensor 5. The horizontal axis of the fine grid in FIG. 5 is the spatial X direction, and the vertical axis is the spatial Y direction created 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 in a rectangular shape and are arranged vertically and horizontally on the measurement object 100. Additionally, the rectangular area becomes the light-emitting surface of each LED chip 101.

In order to be able to acquire data from a plurality of pixels 51 on the light emitting surface of one LED chip 101, in other words, a plurality of pixels 51 in size corresponding to the light emitting surface of one LED chip 101 are used. The array pitch of the LED chip 101, the pitch of the pixels 51 of the area sensor 5, and the objective lens 2 so that the light emitted from the area can be received by the plurality of pixels 51 corresponding to each other. ) is set based on the magnification, etc. In this embodiment, it is set so that light from the light emitting surface of one LED chip 101 can be received by dividing it into 3 × 3 = 9 pixels or more.

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

First, the signal for one line in the spatial . The measured data for one frame that is read and output is spectral spectrum data (brightness data at each wavelength) with a wavelength pitch of 5 nm.

Next, the wavelength λ0 of the pixel 51 with maximum brightness is determined from the data of the pixel group of an appropriate partial area including the plurality of LED chips 101. Additionally, even if it is not the wavelength of the pixel 51 with the maximum brightness, the average of the wavelengths of a plurality of pixels 51 with different brightnesses may be set to λ0. By averaging the wavelengths, the precision of the wavelength λ0 increases.

Centering on the wavelength λ0 determined in this way, a preset range of, for example, ±75 nm is set as the reading output range, in other words, 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 measurement wavelength range. Additionally, ±75 nm may be a value other than that. By determining the measurement wavelength range, a read output unit group consisting of some read output units that perform read output among the read output units of all pixels 51 of the area sensor 5 is set.

Another method of determining the main measurement wavelength range by pre-measurement includes a method of selecting based on the determined value of the wavelength λ0 from a plurality of previously prepared main measurement wavelength ranges. 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 it is green, the main measurement wavelength range (WB) is set in advance. 465 to 615 nm (center wavelength: 540 nm) is preset as the measurement wavelength range (WG), and in the case of red, 550 to 700 nm (center wavelength: 625 nm) is preset as the measurement wavelength range (WR). It is done.

Then, 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, set for green. Select the main measurement wavelength range (WG) of 465 to 615 nm, and if the value of wavelength λ0 is close to 625 nm, select the main measurement wavelength range (WR) of 550 to 700 nm set for red. . By selecting this measurement wavelength range, a group of readout output units that perform readout output of the pixel 51 are set. For example, when the main measurement wavelength range (WR) is determined, as shown in FIG. 8 (A), a read output that reads and outputs measurement data of a plurality of pixels 51 corresponding to the main measurement wavelength range (WR) When the subgroup 50R is set and the main measurement wavelength range (WG) is determined, as shown in FIG. 8(B), measurement data of a plurality of pixels 51 corresponding to the main measurement wavelength range (WG) are When the reading output section group 50G for reading and outputting is set and the main measurement wavelength range (WB) is determined, as shown in FIG. 8(C), a plurality of pixels 51 corresponding to the main measurement wavelength range (WB) ) A read output unit group 50B is set to read and output the measurement data. In this way, among the plurality of read output unit groups 50R, 50G, and 50B, different read output unit groups are set according to the main measurement wavelength range.

In addition, as another method of determining the measurement wavelength range, if the emission color of the LED chip 101 is already known in advance, pre-measurement is not performed, but the pattern preset for each of blue, green, and red as above is used. You may select the measurement wavelength range (WB, WG, WR). In this case as well, among the read output section groups 50R, 50G, 50B, the read output section groups 50B, 50G, 50R corresponding to the main measurement wavelength ranges (WB, WG, WR) are set.

In this way, after determining the main measurement wavelength range and setting the readout output section group corresponding to the plurality of pixels 51 that read and output the signal, the main measurement is performed as follows.

That is, excitation light is irradiated from the excitation light source 1 to the measurement object 100 placed on the table 200, and the table 200 is moved by the moving device 300, while the measurement object 100 is moved. The light emitted from the plurality of LED chips 101 is received by each pixel 51 of the area sensor 5. The light emitted from the LED chip 101 is split into predetermined wavelengths by the spectrometer 3, and the split light of each wavelength is received by each pixel 51. The movement of the table 200 is performed after reading and outputting the measurement wavelength range for one frame of measurement data. When exposure has been completed, the table 200 may be moved, such as during read output.

Among all the pixels 51 that received light, measurement data is read and output from the pixels 51 only in the group of readout output units set to correspond to the main measurement wavelength range determined by pre-measurement.

The read-out measurement data is sent to the calculation unit 6 and stored in a memory not shown in the calculation unit 6. The measurement is performed while moving the measurement object 100 on the table 200 using the moving device 300, and since one frame of measurement data is obtained each time it moves (each time it is scanned), the measurement object 100 Multiple frames of measurement data are obtained in a two-dimensional direction, in other words, in a flat area. Additionally, in each frame, measurement data is read out only for the pixels 51 corresponding to the readout output unit group, and measurement data for wavelengths within the main measurement wavelength range among the spectralized wavelengths are obtained.

Based on the measurement data obtained in this way, the calculation unit 6 calculates the representative wavelength of each LED chip 101.

FIG. 9 shows the maximum light of any wavelength among the light received from the surface of the measurement object 100, for example, among the data of the pixel group of an appropriate area containing the measurement data of the plurality of LED chips 101. It is schematically expressed by extracting only the data of wavelength λ with brightness. The black frame 8 shown in FIG. 9 represents an area corresponding to the light emitting surface of one LED chip 101. In addition, the area (9) shown in bold has strong brightness, and it is shown that the brightness becomes weaker as it approaches the periphery.

Next, the measurement data received from 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 having the maximum brightness is determined from the data of the pixel group of an appropriate area containing the measurement data of the plurality of LED chips 101. Next, at the wavelength λ, each pixel 51 is classified into levels based on brightness, and image processing is performed using a certain brightness level as a threshold to separate each pixel 51 for each LED chip 101. FIG. 10(A) shows the state in which the measurement data for each pixel 51 is separated for each LED chip 101. In Fig. 10(A), it is divided into nine data areas 10a to 10i indicated by black frames.

Next, with respect to the measurement data for each separated LED chip 101, the pixel of interest that obtained the maximum brightness (luminance value) is specified. For example, as shown in FIG. 10(B), in the measurement data of the data area (e.g., data area 10b) for one LED chip 101, the maximum value at a certain wavelength is observed in pixel 51a. ), this pixel 51a is specified as the pixel of interest. Here, a certain wavelength is a wavelength used only to find a separate brightness level or a pixel of interest, and for example, as described above, data of a group of pixels in an appropriate area containing measurement data of a plurality of LED chips 101. Examples include the wavelength with the maximum brightness, the wavelength with the maximum brightness among the measurement data in the data area for one LED chip, and the design wavelength of the LED chip.

After specifying the pixel of interest 51a, the value of the pixel of interest 51a and the wavelength values obtained from one or more pixels around the pixel of interest 51a are averaged to obtain spectral data for that wavelength (at that wavelength). brightness data). In the example of Fig. 10(B), as enlarged and shown in Fig. 10(C), there are 8 pixels 51b to 51i surrounding the pixel 51a of interest and a total of 9 pixels 51 of the pixel 51a of interest. ) is averaging the values.

By averaging the data of a plurality of pixels including the pixel of interest 51a in this way, the effect of reducing measurement noise can be obtained.

In addition, the reason that the pixels to be averaged are pixels around the pixel of interest 51a is to make the measurement area of the wavelength of the LED chip 101 fit within the light emitting surface, and with a relatively small number of data, the influence of deviation is not affected. Small values can be obtained. Specifically, by using the values of the surrounding 9 pixels including the pixel of interest (51a) showing maximum brightness, a value with sufficiently small influence of variation can be obtained.

FIG. 11 shows the respective wavelengths for four data areas (10b, 10d, 10f, 10h) among the data areas (10a to 10i) of the plurality of LED chips 101 shown in FIG. 10(A). This is a spectrum graph plotting the average value of each 9 pixels. Meanwhile, FIG. 12 is a spectrum graph plotting the value of only the pixel of interest 51a obtained for each wavelength in the four data areas 10b, 10d, 10f, and 10h. The horizontal axis of all graphs represents wavelength, and the vertical axis represents brightness. Comparing both graphs, it can be seen that the spectral shape of the value of only the pixel of interest 51a shown in FIG. 12 is broken.

The luminance values of the pixel of interest (51a) and the pixels (51b to 51i) surrounding it as described above are averaged for each wavelength, and a representative wavelength is determined from the average value of each wavelength. Specifically, as shown in Figure 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 set as the representative wavelength. Additionally, in cases such as when the wavelength pitch is small, fitting may not be performed and the wavelength with the largest average value among the average values of each wavelength may be used as the representative wavelength.

In this way, representative wavelengths are calculated from the measurement data for all LED chips 101 of the measurement object 100. The representative wavelength calculated in this embodiment is the emission peak wavelength, but it may also be the center of gravity wavelength or the center wavelength. The center of gravity wavelength is a weighted average of wavelengths with the emission spectrum as the weight. In other words, the center of gravity wavelength refers to the value obtained by dividing the product of each wavelength and the intensity of light at that wavelength integrated over the entire emission wavelength by the value integrated over the entire emission wavelength. Additionally, the center wavelength refers to the average value of two half-maximum wavelengths that are 3 dB lower than the maximum amplitude on both sides of the peak wavelength.

As described above, in this embodiment, the signals of all pixels 51 corresponding to all the spectralized wavelength ranges are not read, but the main measurement wavelength range for which read output is performed is determined, and the main measurement wavelength range for which read output is performed is determined. The signal is read and output by a correspondingly set reading unit group comprised of the reading units of some of the pixels 51. For this reason, there is no need to read and output signals from all pixels, and the read-out time can be shortened accordingly, the wavelength measurement time can be shortened, and the binning time can be shortened. Moreover, since a physical limiting part for limiting the light reception of the pixel 51 that is not being read is unnecessary, the configuration does not become complicated.

In particular, the emission colors of the LED chip 101 are red (R), green (G), and blue (B), and the wavelength range required for measurement of each representative wavelength is generally limited, and signal acquisition of all wavelengths in the visible range is limited. Since it is not necessary, there is no problem in reading and outputting the signal from the pixel 51 by limiting the wavelength range, and the advantage of shortening the wavelength measurement time by shortening the read-out time can be enjoyed.

In addition, when the integration time of the CMOS sensor 5 is 1 ms and the measurement wavelength range is 400 nm across the visible range, the frame rate, which represents the number of frames that can be read and output per second, is about 520 FPS. , the frame rate when the wavelength measurement range is limited to 150 nm can be improved to about 920 FPS, and the readout time can be shortened.

In addition, since the LED chip 101 is excited by excitation light and emits light, it is necessary to exclude the influence of the excitation light. By limiting the wavelength range in which measurement data is read and output, the effect of the excitation light can be excluded as much as possible. There is also.

This application accompanies the priority claim of Japanese Patent Application No. 2021-118071 filed on July 16, 2021, and the disclosure content constitutes a part of the present application as is.

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

1: Light source for excitation
2: Objective lens
3: Spectrometer
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 unit
7: Measurement result display section
10a ∼ 10i: data area
100: Measurement object
100a: thermal area
101: LED chip (LED chip)
200: table
300: moving device
WB, WG, WR: Wavelength range in this measurement
50B, 50G, 50R: Reading output unit group

Claims (21)

A spectroscopic means for speculating the light emitted by being excited by the LED chip,
a light receiving means having a plurality of pixels for each wavelength to receive the light split by the spectroscopic means;
a plurality of reading and output means corresponding to each of the plurality of pixels and reading and outputting a signal from each pixel;
A wavelength measuring device comprising calculation means for calculating a representative wavelength of the LED chip based on signals read and output by some of the readout means among the plurality of readout means. According to claim 1,
A wavelength measuring device in which some of the reading/output means form one reading/output means group, and a plurality of reading/output means groups exist. The method of claim 1 or 2,
The calculating means acquires spectrum information of the LED chip based on signals read and output by all readout means prior to the main measurement, and reads and outputs a portion of signals from the acquired spectrum information in the main measurement. Wavelength measuring device for setting means. According to claim 2,
The calculation means is a group of readout means that acquires spectrum information of the LED chip based on signals read and output by all readout means prior to the main measurement, and reads and outputs signals in the main measurement from the acquired spectrum information. Select a wavelength measuring device. The method according to any one of claims 1 to 4,
The light receiving means is an area sensor,
Each pixel of one pixel column of the area sensor receives light from a plurality of regions in the light emitting surface of the LED chip, and each pixel of the other pixel column orthogonal to the one pixel column emits light from each of the regions. A wavelength measuring device that receives splitted light for each wavelength. According to claim 5,
A wavelength measuring device in which the calculating means averages signals from a plurality of areas within the light emitting surface of the LED chip. The method of claim 5 or 6,
A wavelength measuring device that receives light from a two-dimensional area within the light emitting surface of the LED chip by moving the area sensor in a direction orthogonal to the one pixel column. According to any one of claims 5 to 7,
A wavelength measuring device that receives light from a two-dimensional area within the light-emitting surface of an LED chip by moving the LED chip in a direction orthogonal to a thermal region within the light-emitting surface of the LED chip corresponding to the one pixel row. The method according to any one of claims 1 to 8,
A wavelength measuring device wherein the representative wavelength is at least one of an emission peak wavelength, a center of gravity wavelength, and a center wavelength. The method according to any one of claims 1 to 9,
A wavelength measuring device comprising a light source unit that excites the LED chip to emit light. The method according to any one of claims 1 to 10,
A wavelength measuring device in which the light receiving means and the reading output means are comprised of a CMOS sensor. A spectroscopic step that specifies the light emitted by being excited by the LED chip using a spectroscopic means,
a light receiving step for receiving the light split by the spectral step at a plurality of pixels for each wavelength;
a read-out step for reading and outputting the signal by some read-out means among the plurality of read-out means corresponding to each of the plurality of pixels and reading and outputting the signal from each pixel;
A wavelength measurement method comprising a calculation step for calculating a representative wavelength of the LED chip based on the signal read and output by the read output step. According to claim 12,
A wavelength measurement method in which some of the reading/output means form one reading/output means group, and a plurality of reading/output means groups exist. The method of claim 12 or 13,
In the calculation step, prior to the main measurement, the spectrum information of the LED chip is acquired based on the signals read and output by all readout means, and from the acquired spectrum information, a part of the signal is read and output in the main measurement. Method of measuring wavelength to establish means. According to claim 13,
In the calculation step, a group of readout means acquires spectrum information of the LED chip based on signals read and output by all readout means prior to the main measurement, and reads and outputs signals in the main measurement from the acquired spectrum information. Which wavelength measurement method to choose. The method according to any one of claims 12 to 15,
The light receiving means is an area sensor,
Each pixel of one pixel column of the area sensor receives light from a plurality of regions in the light emitting surface of the LED chip, and each pixel of the other pixel column orthogonal to the one pixel column emits light from each of the regions. A wavelength measurement method that receives divided light at each wavelength. According to claim 16,
A wavelength measurement method in which, in the calculation step, signals from a plurality of areas within the light emitting surface of the LED chip are averaged. The method of claim 16 or 17,
A wavelength measurement method in which light is received from a two-dimensional area within the light emitting surface of the LED chip by moving the area sensor in a direction orthogonal to the one pixel column. The method according to any one of claims 16 to 18,
A wavelength measurement method that receives light from a two-dimensional area within the light-emitting surface of an LED chip by moving the LED chip in a direction orthogonal to a thermal region within the light-emitting surface of the LED chip corresponding to the one pixel row. The method according to any one of claims 12 to 19,
A wavelength measurement method wherein the representative wavelength is at least one of an emission peak wavelength, a center of gravity wavelength, and a center wavelength. The method according to any one of claims 12 to 20,
A wavelength measurement method in which the light receiving means and the reading output means are comprised of a CMOS sensor.