JP2017228699A - Light-emitting diode device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting diode device in which occurrence of undesirable phenomena due to thermal cause can be suppressed.SOLUTION: A light-emitting diode device includes a light-emitting diode array including a submount substrate, and a large number of light-emitting diodes placed on the submount substrate, and capable of emitting light while lowering luminance gradually from a high luminance region toward the peripheral region, where each of the large number of light-emitting diodes includes an epitaxial semiconductor laminate on a support substrate, the support substrate is bonded to the submount substrate, and the average thickness of the support substrate of a light-emitting diode in the high luminance region is thinner than the average thickness of the support substrate of a light-emitting diode in a peripheral region separated from the high luminance region.SELECTED DRAWING: Figure 3-2

Description

  The present invention relates to a light emitting diode device and a method for manufacturing the same, and more particularly to a light emitting diode device suitable for illuminating the front using a plurality of light emitting diodes arranged in a planar light emitting region and a method for manufacturing the same.

  In recent years, in vehicle headlamps, attention has been paid to a technique (called ADB adaptive driving beam) that controls the light distribution shape in real time according to the situation ahead, that is, the presence or absence of an oncoming vehicle or a front vehicle and the position thereof. ing. According to this technology, for example, when an oncoming vehicle is detected while traveling with a light distribution shape for driving, that is, a high beam, only light directed to the area of the oncoming vehicle in real time is detected in the area irradiated to the headlamp. It becomes possible to reduce by. It is possible to always give the driver a field of view close to a high beam, while preventing the oncoming vehicle from giving glare.

  In addition, a headlight system (referred to as an AFS adaptive front-lighting system or the like) that adjusts the light distribution in the traveling direction in accordance with the steering angle of the steering wheel is being generalized. By moving the light distribution shape in the left-right direction according to the steering angle of the steering wheel, the field of view in the traveling direction can be expanded.

  Such a light distribution variable type headlamp system uses, for example, a light emitting diode device in which a large number of light emitting diodes (LED light emitting diodes) are arranged in an array, and each light emitting diode is turned on / off (on / off). In addition, it can be realized by controlling the input power (and hence the luminance) during conduction in real time.

  There has been proposed an illuminating device in which a large number of LED chips are arranged in a matrix on a support and have a wavelength conversion element and a scattering element that diffuses and scatters a beam on the LED chip (for example, Patent Document 1).

  The LED chip array includes a plurality of LED chip arrays arranged in a matrix and independently controllable for lighting, and a projection lens disposed on an optical path of light emitted from the LED chip array. There has been proposed a vehicle headlamp device configured to form a predetermined light distribution pattern ahead by controlling the pattern (for example, Patent Document 2). The outline of this proposal will be described below.

  FIG. 6A shows a side view of a main part of a vehicle headlamp in which a plurality of LEDs 212 are arranged in a matrix via a submount substrate 41 on a heat sink 211 having a heat dissipation mechanism, and a projection lens 210 is arranged in front. FIG.

  FIG. 6B is a front view of a state in which a plurality of LEDs 212 are arranged in a matrix. An optical system in which a light source including a plurality of LEDs (hereinafter sometimes referred to as “matrix LEDs”) arranged in a matrix is directed to the front of the vehicle and a projection lens is disposed in front of the light source. Project forward.

  The vehicle headlamp needs to form a luminance distribution in which the luminance is high at the center (light distribution center) and the luminance decreases toward the periphery. In the case of a vehicle headlamp using a semiconductor light emitting element array, it is possible to adjust the luminance by controlling the driving power of each semiconductor light emitting element and form a desired luminance distribution.

  The semiconductor light emitting element performs a light emitting operation and generates heat corresponding to driving power. In a vehicle headlamp, the luminance decreases and the heat generation amount decreases as it goes from the light distribution center to the periphery. The heat generated in each semiconductor light emitting element is transmitted to the support substrate, is transmitted outside in the support substrate, and is radiated to the heat radiating means.

Special table 2012-516044 gazette JP 2013-54849 A

  It is desirable to form a luminance distribution in which the illumination in front of the vehicle is high at the center and decreases toward the periphery. When a desired luminance distribution is formed by distributing the input power using the semiconductor white light emitting element array, the heat generation amount is also distributed according to the input power. Since heat generation and heat dissipation are not uniform in the array plane, a temperature distribution is formed in which the temperature gradually decreases from the high luminance region toward the peripheral region. When the temperature is increased, the physical properties of the constituent materials of the semiconductor light emitting device are changed, the luminous efficiency is lowered, and the reliability is lowered. Further, when the temperature difference between the high brightness area and the peripheral area in the array becomes large, the distortion becomes large, causing a decrease in reliability. It is desirable to suppress the occurrence of undesirable phenomena due to thermal causes.

  An object of the present invention is to provide a light emitting diode device capable of suppressing the occurrence of an undesirable phenomenon due to a thermal cause, and a method for manufacturing the same.

According to an embodiment of the present invention,
A light-emitting diode array including a sub-mount substrate and a plurality of light-emitting diodes disposed on the sub-mount substrate and capable of emitting light whose luminance gradually decreases from a high-luminance region toward a peripheral region;
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
There is provided a light emitting diode device including a light emitting diode device, wherein an average thickness of a support substrate of a light emitting diode in the high brightness region is thinner than an average thickness of a support substrate of a light emitting diode in a peripheral part of a peripheral region away from the high brightness region. The

  Note that a base substrate structure that is mounted while adjusting the relative positions of the plurality of light emitting elements is referred to as a submount substrate.

Also, according to an embodiment of the present invention,
A light emitting diode structure corresponding to a large number of light emitting diodes is formed on each of a plurality of growth substrates,
Bonding a support substrate above the light emitting diode structure of each of the growth substrates,
Removing each of the growth substrates;
Dividing each of the support substrates and the light emitting diode structure thereon into chips,
The chips are classified according to the thickness of the support substrate,
On the submount substrate, the high-luminance region is formed by arranging chips classified as having a thin support substrate,
On the submount substrate, in a region away from the high-luminance region, the peripheral region is formed by arranging chips classified into a thicker classification than the thin classification in the thickness of the support substrate.
A method of manufacturing a light emitting diode device is provided.

1A is a light distribution pattern within a desired field of view, FIG. 1B is a schematic plan view of a light emitting diode (LED) array used to form such a light distribution pattern, and FIG. 1C is a distribution with an ADB function and the like. It is a block diagram of a light variable type headlamp system. 2A to 2D are cross-sectional views schematically showing a manufacturing process of the semiconductor diode chip, and FIG. 2E is a cross-sectional view showing a state in which the semiconductor diode chips are arranged on the submount substrate. , as well as, 3A to 3E are diagrams showing a process of a method for manufacturing a vehicular lamp according to the first embodiment. 4A and 4B are plan views schematically showing the configuration of the light-emitting diode array according to the second embodiment. 5A, 5B, and 5C are plan views schematically showing the configuration of a light emitting diode array according to a modification. 6A and 6B are a side view of a main part of a vehicle headlamp and a plan view of a light-emitting diode array according to the prior art.

LP alignment pattern, LC light distribution center, BP luminance distribution,
BPh horizontal luminance distribution, BPv vertical luminance distribution, H horizontal axis,
V vertical axis, 1 submount substrate, 2 light emitting diode,
10 growth (sapphire) substrate, 11 GaN-based semiconductor buffer layer,
13 GaN-based semiconductor n-type layer, 14 GaN-based semiconductor active layer,
15 GaN-based semiconductor p-type layer, 17 electrode structure,
19 support (Si) substrate, 20 semiconductor diode chip,
C dividing line, 41 submount substrate, 42 adhesive layer,
28 Light Emitting Diode (LED) Array (Headlight), 100 Vehicle Headlight, 102 Light Distribution Control Unit, 104 Front Monitoring Unit,
108 vehicle-mounted camera, 110 radar, 112 vehicle speed sensor, 114 rudder angle sensor, 116 GPS navigation, 118 headlight switch,
120 driver, 200 headlight system, D light emitting diode,

  The description starts from the reference technology of the vehicle headlamp that the present inventors have studied. A light-emitting diode array using a GaN-based semiconductor is used as the light source, but this is not restrictive. In order to efficiently illuminate the field of view while suppressing waste of power, a large number of light emitting diode elements are distributed, and areas where high brightness is desired are illuminated brightly as needed, and high brightness is not required It is desirable to perform illumination having a luminance distribution by reducing the luminance in such a region.

  FIG. 1A is a schematic diagram showing an example of a light distribution pattern that is desired for a light beam emitted from a vehicle headlamp and that has a high luminance near the center and decreases in luminance toward the periphery. A high-luminance light distribution center LC is formed extending in the horizontal direction below the center of the light distribution pattern LP facing forward. In a vehicle headlamp, the light distribution pattern LP gradually decreases toward the periphery with the light distribution center LC generally extending in the horizontal direction as the maximum brightness in order to ensure the night view of the driver. A luminance distribution is desirable. In many cases, the driver of the vehicle drives the vehicle with the center of the visual field aligned with the light distribution center. The vicinity of the light distribution center LC may be referred to as a central portion.

  A luminance distribution BPh parallel to the horizontal (H) axis is shown above the light distribution pattern LP. The front road surface is set to the maximum brightness, and the brightness decreases as it moves left and right. A luminance distribution BPv parallel to the vertical (V) axis at the center of the horizontal axis is shown on the right side of the light distribution pattern LP. The road surface ahead is the light distribution center LC with the maximum luminance. The area below the light distribution center LC includes the road surface on the near side, and should be paid attention as necessary. For example, when there is a step on the road surface, it is preferable that the timing of crossing the step can be determined. Although the area below the light distribution center is reduced from the maximum brightness, the brightness sufficient to obtain information is maintained. When it goes upwards, the brightness decreases significantly. This is a target area that only needs to be recognized roughly, and energy is wasted when illuminated with high brightness.

  A semiconductor white light emitting element array can be used as a light source of a vehicle headlamp. A large number of semiconductor white light emitting elements are arranged in a matrix, and a desired luminance distribution is formed by adjusting the luminance of each semiconductor white light emitting element. The semiconductor white light emitting element has a yellow light emitting phosphor layer above the surface of a blue light emitting diode, for example, and has a function of emitting white light.

  Although not restrictive, for example, the GaN-based semiconductor light-emitting device disclosed in the column of the example of Japanese Patent Application Laid-Open No. 2014-232841, proposed by the present applicant, and disclosed in the column of the example of Japanese Patent Application No. 2014-237442. The GaN-based semiconductor light-emitting device, the GaN-based semiconductor light-emitting device disclosed in the Example section of Japanese Patent Application No. 2015-84612, the flip chip type device on the support substrate, and the like can be used.

  FIG. 1B is a schematic plan view showing a simplified example of a light emitting diode (LED) array 28 in which a large number of light emitting diodes (LEDs) 2 are arranged in a matrix on the submount substrate 1. Within the light emitting region, the light emitting diodes 2 having the same shape are arranged in a matrix to form an array 28. The submount substrate 1 desirably has a thermal expansion coefficient close to that of the light emitting diode. As the material, AlN or the like can be used. The light emitting diode 2 can be bonded to the submount substrate 1 using, for example, an AuSn adhesive amount.

  The LED array 28 has a configuration of, for example, about (4-8) rows x (25-60) columns. In the figure, the number of columns is simplified and shown by 6 rows × 12 columns. Six rows of segments A, B, C, D, E, and F are arranged in the vertical (V) direction. A light distribution center LC is formed in the segment E in the second row from the bottom, which is below the center. Here, horizontal and vertical mean the positional relationship for the orientation reflected when illuminated as a headlamp.

  It is desirable that the light distribution pattern of the vehicle headlamp achieves a luminance distribution as shown in FIG. 1A, in which the luminance is such that the center of the driver's visual field is the highest luminance and the luminance decreases toward the periphery. In order to form a luminance distribution as shown in FIG. 1A, the input power at the center is increased and the input power is reduced toward the periphery. In this way, the headlamp is designed to form a desired luminance distribution. In the case where both ends in the horizontal direction are related to the shoulder of the road, the luminance may be increased even in the peripheral portion, and a luminance distribution that meets the requirements is desired.

  The input power is determined by (voltage V) × (current J) × (time T). In the case of a semiconductor light emitting diode, the voltage is substantially fixed. The input power is controlled mainly by the product of current J and time T. For example, it can be performed by time control by duty control in pulse width modulation or frequency modulation with a constant current. Increasing the duty at the central portion can increase the input power, and decreasing the duty at the peripheral portion can decrease the input power. The chromaticity can also be adjusted by controlling the instantaneous current density. Even if the instantaneous current density is increased, the same power can be obtained if the time is reduced.

  FIG. 1C is a block diagram illustrating a schematic configuration of the headlamp system. The headlamp system 200 includes left and right vehicle headlamps 100, a light distribution control unit 102, a front monitoring unit 104, and the like. The vehicle headlamp 100 includes a light source including a matrix LED, a projection lens, and a lamp body that houses them.

  The front monitoring unit 104 to which various sensors such as the in-vehicle camera 108, the radar 110, and the vehicle speed sensor 112 are connected performs image processing on the imaging data acquired from the sensors, and the front vehicle (an oncoming vehicle or a preceding vehicle) or other road brightness. Objects and lane markings (lane marks) are detected, and data necessary for light distribution control, such as their attributes and positions, are calculated. The calculated data is transmitted to the light distribution control unit 102 and various in-vehicle devices via the in-vehicle LAN.

  The light distribution control unit 102 to which the vehicle speed sensor 112, the rudder angle sensor 114, the GPS navigation 116, the headlight switch 118, and the like are connected has the attribute of the road shining object (oncoming vehicle, leading vehicle) sent from the front monitoring unit 104. A light distribution pattern (luminance distribution) corresponding to the traveling scene is determined based on the vehicle (reflector, road illumination), its position (front and side) and the vehicle speed. The light distribution control unit 102 determines the control contents (lights on / off, input power, etc.) of each LED of the matrix LED necessary for realizing the light distribution pattern. The driver 120 converts the control amount information from the light distribution control unit 102 into instructions corresponding to the operation of the driving device and the light distribution control element and controls them.

  The vehicle headlamp needs to form a luminance distribution in which the luminance is high at the center (light distribution center) and the luminance decreases toward the periphery. In the case of a vehicle headlamp using a semiconductor light emitting element array, it is possible to adjust the luminance by controlling the driving power of each semiconductor light emitting element and form a desired luminance distribution.

  2A to 2D are cross-sectional views schematically showing a manufacturing process of a semiconductor diode chip. As shown in FIG. 2A, a semiconductor stack is epitaxially grown on the surface of a growth substrate 10 made of sapphire or the like. First, a GaN-based semiconductor buffer layer 11 is grown on the surface of the growth substrate 10, and a GaN-based semiconductor n-type layer 13, a GaN-based semiconductor active layer 14, and a GaN-based semiconductor p-type layer 15 are grown thereon. The active layer 14 is formed of, for example, a multiple quantum well structure formed by alternately growing a GaN layer as a barrier layer and an InGaN layer as a well layer.

  As shown in FIG. 2B, an electrode structure 17 is formed on the semiconductor epitaxial stack. For example, a p-side electrode including a reflective electrode such as an Ag layer is patterned on the surface of the GaN-based semiconductor p-type layer 15, and selected regions of the GaN-based semiconductor p-type layer 15 and the GaN-based semiconductor active layer 14 are etched. The GaN-based semiconductor n-type layer 13 is exposed to form an n-side electrode connected to the GaN-based semiconductor n-type layer 13.

  As shown in FIG. 2C, a support substrate 19 is attached on the electrode structure 17. For example, a necessary insulating structure is formed on the electrode structure 17, an adhesive layer such as AuSn is formed thereon, and an adhesive layer of the support substrate 19 such as a p-type Si plate formed with an adhesive layer such as AuSn is formed. Paste. The support substrate 19 is polished by chemical mechanical polishing (CMP) or the like to reduce the thickness.

  As shown in FIG. 2D, the growth substrate 10 is peeled off using laser lift-off or the like. The exposed GaN-based semiconductor buffer layer 11 is removed with hot water or the like. At this stage, a light emitting diode structure from which unnecessary portions are removed is obtained. At an appropriate timing, characteristics such as emission wavelength, emission output, forward voltage drop Vf and the like are measured. The semiconductor diode chip 20 is divided by dicing along the dividing line C or the like. By such a process, the semiconductor light emitting diode chip 20 is formed. The semiconductor diode chip 20 includes at least one semiconductor diode. For example, a light-emitting diode chip including a plurality of light-emitting diodes arranged in one column or in a plurality of columns and rows may be formed.

  FIG. 2E shows a state in which the light emitting diode chip 20 is bonded onto the submount substrate 41 with the support substrate 19 facing down through an adhesive layer 42. On the submount substrate 41, the light emitting diode chips 20 having the same characteristics such as light emission wavelength, light emission output, and forward voltage drop Vf are arranged to produce a semiconductor light emitting diode array.

  By the way, the semiconductor light-emitting diode chip 20 manufactured in this way often does not have uniform characteristics. Even when used under the same conditions, the amount of heat generated is different. The present inventors investigated the cause as follows.

  One of the causes is a difference in thickness of the support substrate 19. When the light emitting diode chip 20 emits light, heat is generated in the semiconductor layer, but the heat is transmitted to the submount substrate via the support substrate 19. In particular, when a heat sink is provided on the back surface of the submount substrate 41 as shown in FIG. 7A, such a heat dissipation path becomes conspicuous. The light emitting diode chip 20 varies in thickness of the support substrate depending on the manufacturing process. Assuming that the same amount of power is input to the elements having different thicknesses of the support substrate, the thinner the support substrate 19 is, the lower the thermal resistance, so that the heat transfer is faster.

  Another cause is the difference in Vf. The light emitting diode chip 20 varies in Vf depending on the manufacturing process. It is assumed that the light emitting diode chips 20 having different Vf are illuminated with the same luminance. That is, an equivalent current value is input. Since Vf is different, the voltage value is different and the input power is different even if the luminance is the same. Since the heat generation depends on the input power, the light emitting diode chip 20 having a high Vf also generates a large amount of heat.

  Due to the above two causes, the characteristics of the light-emitting diode chip 20 vary.

  A light-emitting diode that is at a high temperature tends to have low light emission efficiency and low reliability. In order to suppress the occurrence of undesired phenomena due to this thermal cause, semiconductor light-emitting diodes are also classified by heat characteristics, and light-emitting diodes with good heat characteristics should be used in high-luminance regions that can reach high temperatures. That's fine. For example, the characteristics with respect to heat are classified into 10 equal parts, and the high luminance region may be configured with a light emitting diode having the best characteristics with respect to heat.

In addition, the characteristic with respect to a heat | fever means that the calorie | heat amount produced as a result of the heat_generation | fever and heat radiation when light-emission is carried out with the same brightness | luminance is small. This can be confirmed by thermography, for example, and it can be determined that the heat resistance is better when the heat is smaller.
First Embodiment With reference to FIGS. 3A to 3E, a vehicle lamp and a method for manufacturing a light-emitting diode array, and a vehicle lamp and a light-emitting diode array according to a first embodiment will be described. First, an epitaxial stack for forming a light emitting diode is grown on a plurality of growth wafers formed of sapphire or the like by a process corresponding to FIG. 2A. An electrode structure is formed on the epitaxial layer by a process corresponding to FIGS. 2B and 2C, and a support substrate such as a Si substrate is bonded. The support substrate is appropriately polished and thinned.

  FIG. 3A shows a plurality of wafers in this state. The boundary of the chip to be divided is simulated. The thickness of the film structure on the growth substrate including the epitaxial stack and the support substrate is distributed from about 80 μm to about 120 μm. In the figure, a wafer having a thickness of 80 μm, a wafer having a thickness of 100 μm, and a wafer having a thickness of 120 μm are illustrated.

  The growth substrate is peeled by a process corresponding to FIG. 2D. From the formed light emitting diode structure, characteristics such as light emission wavelength, light emission output, and forward voltage drop Vf are measured. Vf varies even within the same wafer surface. Each light emitting diode chip 20 is divided along the dividing line. Measure the thickness of the support substrate.

As shown in FIG. 3B, semiconductor light emitting diode chips are classified according to characteristics such as emission wavelength.
The characteristic for heat can be determined by measuring the amount of heat when light is emitted with the same luminance. Thermography can be used as a measurement method. The measurement is preferably performed assuming the implementation status of the chip. When assumed as a light source for a vehicular lamp as shown in FIG. 6A, a measurement environment close to the situation of being arranged in a matrix on a heat sink is prepared. The amount of generated heat [T] is classified into 10 levels, P1 to P10. The smaller the amount of heat [T], the better is classified as P1 with better heat characteristics, and the closer to P10, the larger the amount of heat, and the chips with poor heat characteristics.
Instead of directly measuring the amount of heat, classification may be made approximately. As described above, the heat characteristic depends on the thickness of the support substrate and Vf. Characteristics with respect to heat can be approximately classified by the thickness [μm] × Vf [V] of the support substrate. For example, the value of the thickness [μm] × Vf [V] of the support substrate is classified into 10 steps Q1 to Q10. Smaller values are classified as Q1 with better heat characteristics, and chips closer to Q10 are classified as chips with poor heat characteristics.

Depending on the chip to be manufactured, the thickness of the support substrate or Vf may have a large degree of variation, and it may be sufficient to consider only one of them, and it is preferable that either of them be of the same rank. Therefore, approximate classification is also possible by classifying only either the support substrate thickness or Vf.
For example, the thickness is classified into about 10 steps R1 to R10. When the width of the thickness distribution is about 30 μm, for example, it is classified every 3 μm as R1 to R10. According to the thickness classification, LED chips included in one classification belong to a thickness width of 10 μm or less, more preferably a thickness width of 6 μm or less, and further preferably a thickness width of 3 μm or less.
Similarly, in the case of Vf, Vf is classified into 10 levels and is designated as S1 to S10.
The emission wavelength is also classified into several stages depending on the characteristics.
FIG. 3B shows classification according to the thickness of the support substrate and the emission wavelength characteristics. C11 to λ are emission wavelength characteristics.

  FIG. 3C shows a state in which a large number of LED chips are arranged in a matrix on the submount substrate 41. For example, LED chips are arranged in 60 rows and 50 columns. Here, it is preferable that the LED chip is adopted in the same classification in the above-mentioned classification with respect to the emission wavelength. In the figure, the number of columns is simplified. The LED chip in the middle lower part of 1 column and 2 rows is a chip having the maximum luminance. An extremely high brightness area is arranged around the area, and a first high brightness area B1 as a central portion is defined. A second high-luminance region B2 having the next highest luminance is defined around the first high-luminance region B1. The brightness of the peripheral part gradually decreases as the distance from the central part increases. For example, the relative luminance of the first high luminance region B1 is 100% to 80%, and the relative luminance of the second high luminance region B2 is 80% to 60%. In this case, for example, the relative luminance of the left and right lower ends B11 and B12 is about 20%, and the relative luminance of the left and right upper ends B13 and B14 is about 4%. Here, the brightness of each region is assumed to be normal. When used as a vehicular lamp, the luminance distribution changes depending on the driving situation, but the luminance distribution in a standard situation such as when driving on a straight road is assumed.

  FIG. 3D1 is a table showing the brightness and the rank of the thickness of the LED chip to be applied. The first high luminance region B1 has a relative luminance of 100% to 80%, and is formed by using LED chips of thickness ranks R1 and R2. Furthermore, it is more preferable that the LED chip of rank R1 is arranged at the center in the first high luminance region B1, and the LED chip of rank R2 is arranged around the LED chip. The second high-intensity region B2 has a relative luminance of 80% to 60%, and is formed by using LED chips of thickness ranks R3 and R4. Furthermore, it is more preferable that the LED chip of rank R3 is arranged in a region close to the center in the second high luminance region B2, and the LED chip of rank R4 is arranged around the LED chip. Thereafter, the thickness of the support substrate is sequentially assigned according to the luminance. In addition, the electric power supplied to the LED chip in the low luminance region is low, and usually excessive heating does not occur. In many cases, the LED chips having the thickness ranks R5 to R10 do not have to be selectively used depending on the luminance.

  The LED chips to be arranged are selected in accordance with the luminance in the same manner even when the rank is determined only by the amount of heat at the same luminance and the thickness of the support substrate × Vf, Vf. FIG. 3D2, FIG. 4D-3, and FIG. 4D-4 are tables when ranks are classified by only the characteristics with respect to directly measured heat, thickness × Vf, Vf.

  In the above rank classification, the number of divided ranks is prepared larger than the number of luminance areas, but these may be matched. Only three ranks may be assigned, and each of the three areas may be assigned. Furthermore, although ranks were divided at the same interval, the present invention is not limited to this. For example, in the case of thickness ranking, R1 and R2 may be ranked every 6 μm in the case of a 30 μm distribution, and the rest may be collectively set as R3.

  FIG. 3E is a cross-sectional view showing a state in which the LED chips are arranged on the submount substrate 41 via the adhesive layer 42. The case where it ranks according to the thickness of a support substrate is shown. The LED chip 20-0 having the smallest thickness of the support substrate is disposed in the maximum luminance region, and the LED chips 20-1 and 20-2 in which the thickness of the support substrate increases as the distance from the maximum luminance region is increased. . The outer LED chips 20-3 and 20-4 belong to the same thickness rank, and the thickness of the support substrate is thicker than the LED chip 20-2. The outer LED chip 20-5 has a thicker support substrate than the LED chip 20-4.

  The higher the brightness of the LED, the higher the electric power supplied and the greater the amount of heat generated. However, since the thickness of the support substrate of the heat radiating portion is thin, efficient heat dissipation can be performed. When an LED chip having a thick support substrate is used in the high luminance region, the occurrence of an undesirable phenomenon due to a thermal cause can be suppressed.

  Thereafter, at least the surface of the LED chip 20 is covered, and a sealing resin layer 22 including a phosphor such as yttrium aluminum garnet (YAG) is formed. Whitening can be achieved by receiving blue emission from the LED and emitting yellow fluorescence. Two or more kinds of phosphors can be used. A phosphor sheet or a phosphor plate can also be used.

Even in the case of ranking by only the amount of heat at the same luminance and the thickness of the supporting substrate × Vf, Vf, they are similarly arranged according to the luminance. Since a chip having a good heat characteristic or an approximation that can be approximated to the high luminance region (the amount of heat at the same luminance is small, or the thickness of the support substrate × Vf is small or Vf is small) is not preferable due to a thermal cause. The phenomenon can be suppressed. Then, as the distance from the high-luminance region is increased, a chip having inferior heat characteristics or that can be approximated in stages (the amount of heat at the same luminance is large, or the thickness of the support substrate × Vf is large or Vf is large) is arranged. . To leave the high brightness region means to move from the alignment center LC of the alignment pattern LP toward the peripheral portion.
In the present invention, in consideration of a difference in characteristics with respect to heat generated by the chip, the chip is disposed at a suitable position, so that an undesirable phenomenon due to heat can be suppressed without wasting the chip.

  In the case of the light-emitting diode array as shown in FIG. 1B, a chip having good or approximate heat characteristics with reference to a position near the center in the horizontal direction H and slightly lower than the center in the vertical direction V (the amount of heat at the same luminance is small, Or, the thickness of the supporting substrate × Vf is small, or the supporting substrate is thin, or Vf is small). In addition, as the distance from the reference position increases, a chip having inferior or close approximation to heat characteristics (large amount of heat at the same brightness, or large support substrate thickness × Vf, or thick support substrate, or large Vf) is disposed. Is done.

In the second embodiment or more, the case where one light emitting diode is arranged on one support substrate has been described. A plurality of light emitting diodes may be arranged on one supporting substrate. First, the case where the chip is arranged according to the thickness of the support substrate will be described. Considering the heat radiation surface, the thinner the support substrate, the more efficiently heat radiation is the same as in the first embodiment.

  FIG. 4A is a plan view showing an embodiment of a chip configuration in which a plurality of light emitting diodes are arranged in a line on a single support substrate. Six light emitting diodes DA to DF are formed on each of the stripe-shaped support substrates S1, S2, S3 to Si to constitute a chip. For example, after epitaxial growth and electrode formation are performed on the growth wafer shown in FIGS. 2A and 2B, the epitaxial layer is patterned to form one row of six light emitting diode structures. The supporting substrate bonding process shown in FIG. 2C is performed, the growth wafer is peeled off, and the supporting substrate is patterned in a chip shape each including six light emitting diodes.

  When a plurality of light emitting diodes are arranged on one chip, the strength of the support substrate is increased as necessary. For example, when six light emitting diodes are mounted in one row, the average thickness of the chip structure including the epitaxial stack, the wiring structure, and the support substrate is about 300 μm. In this case, the thickness distribution is, for example, 285 μm to 315 μm. Divide the distribution width into about 10 equal parts and classify by thickness.

  Support substrates U1 to Ui are arranged in one direction on the submount substrate 1. Six light-emitting diodes DA to DF are formed on each support substrate S, and a matrix-arranged light-emitting diode array with six columns is formed. Referring to the lower two rows in FIG. 3C, the luminance distribution is in the horizontal direction, and a thin support substrate is selected at the center as shown in FIG. 3D, and a thick support substrate is selected as it goes to the peripheral portion in the horizontal direction. Efficient heat dissipation can be achieved. According to the present embodiment, since the selection of the light emitting diode by the thickness of the support substrate is only in one direction, the manufacturing process can be simplified. In this embodiment, one row of light emitting diodes is arranged on one stripe-shaped support substrate, but it is also possible to arrange two or more rows of light emitting diodes.

  FIG. 4B shows each support substrate U1, U2,. . . The light emitting diodes DAA, DAB,... DFA, DFB in 2 columns and 6 rows are arranged above. If the areas of the supporting substrates belong to almost the same luminance area, efficient heat dissipation will be possible. Since the number of components is reduced, the manufacturing process can be simplified.

Although an embodiment has been described in which one row of light emitting diodes and two rows of light emitting diodes are arranged on one chip, the number of columns is not limited to one or two. It would be possible to arrange n rows and m columns of light emitting diodes on one chip.
Using a chip in which a plurality of light emitting diodes are arranged on the same supporting substrate, and using the completed light emitting diode array as a light source for a vehicle lamp, the supporting substrate of the chip including the light emitting diode that irradiates the alignment center LC is thin. The support substrate of the chip including the light emitting diode that irradiates in the peripheral direction in the horizontal direction H becomes thick.

In the above, the case where the chip arrangement is determined by the thickness of the support substrate has been described. In the second embodiment, as in the first embodiment, as in the case of thermography, the ranking is based on the amount of heat in the case of the same luminance, the thickness of the support substrate × It is also possible to perform ranking by Vf and ranking by Vf.
However, in the case of these rankings, it is not necessary to measure all the light emitting diodes on the same chip. When the light emitting diode array is arranged at the irradiation position including the alignment center LC, measurement and ranking may be performed with the light emitting diode that irradiates the alignment center.
In the case of the chip as shown in FIG. 4B, DEA and DEB (collectively DE) may irradiate the alignment center LC. Therefore, ranking can be performed based on the result of only DE at the time of ranking. Alternatively, ranking may be performed including the results of DD and DF in consideration of the vicinity of the orientation center.

  A chip (with a small amount of heat at the same brightness, or a thickness of the support substrate × Vf is small or Vf is small) where a light emitting diode with good heat characteristics (or can be estimated approximately) is located in the high luminance region Therefore, an undesirable phenomenon due to a thermal cause can be suppressed. And a chip where a light emitting diode whose characteristics against heat are gradually deteriorated as the distance from the high luminance region in the horizontal direction (the amount of heat at the same luminance is large, or the thickness x Vf of the support substrate is large or Vf is large) Is placed.

  When a light source for a vehicle lamp is used, the support substrate of the chip including the light emitting diode that irradiates the alignment center LC has a small amount of heat at the same luminance, or the thickness x Vf of the support substrate is small or Vf is small. The support substrate of the chip including the light emitting diode that performs irradiation in the peripheral direction with H has a large amount of heat at the same luminance, or the thickness of the support substrate × Vf is large, or Vf is large.

  5A, 5B, and 5C are plan views showing modifications.

  FIG. 5A shows a configuration in which the number of rows is reduced at the end of the matrix light emitting diode array, and the height of the light emitting region is reduced. Since there are few objects to be visually recognized on the upper side of the left and right ends in the illumination area of the headlamp, the demand for illumination is not high. If the illumination area on the upper side of the edge is reduced and the number of light emitting diodes is reduced, the number of components will be reduced, which will be effective for improving the yield.

  FIG. 5B shows a configuration in which light emitting diodes that are long in the vertical direction are arranged in the horizontal direction when, for example, it is desired to form a luminance distribution in the horizontal direction. The support substrate S and the light-emitting diodes D formed thereon are formed in a stripe shape, and the stripes are arranged in the width direction.

  FIG. 5C shows a case where light emitting diodes of different sizes are arranged on the stripe-shaped support substrate S. You may change the shape of the light emitting diode on each support substrate.

  According to the embodiment of the present invention, since the light emitting diode having a thin support substrate is disposed in the high luminance region, the generated heat can be efficiently radiated. It will be advantageous for yield improvement. A light emitting diode with a thick support substrate can be used in the periphery of the high luminance region. An increase in manufacturing costs can be suppressed.

  Although the embodiments have been described above, these do not limit the present invention. For example, the material of the support substrate is not limited to Si. A material having a thermal expansion coefficient close to that of the light-emitting diode structure and good thermal conductivity can be used. The adhesive layer can be formed of AuSn, AuSn paste, Ag paste, or the like. In some cases, non-conductive resin materials may be used. The light emitting diode (LED) may be a semiconductor laser. The semiconductor laser is also a diode. It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like are possible.

Claims (22)

A light-emitting diode array including a sub-mount substrate and a plurality of light-emitting diodes disposed on the sub-mount substrate and capable of emitting light whose luminance gradually decreases from a high-luminance region toward a peripheral region;
The light emitting diode device includes a light emitting diode array in which a heat amount value of the light emitting diode in the high brightness region is smaller than a heat amount value at the same brightness of the light emitting diodes in the peripheral area away from the high brightness region. A light-emitting diode array including a sub-mount substrate and a plurality of light-emitting diodes disposed on the sub-mount substrate and capable of emitting light whose luminance gradually decreases from a high-luminance region toward a peripheral region;
The light emitting diode device includes a light emitting diode array in which a value of Vf of the light emitting diodes in the high luminance region is smaller than a value of Vf of the light emitting diodes in the periphery of the peripheral region away from the high luminance region. A light-emitting diode array including a sub-mount substrate and a plurality of light-emitting diodes disposed on the sub-mount substrate and capable of emitting light whose luminance gradually decreases from a high-luminance region toward a peripheral region;
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
A light emitting diode device including a light emitting diode device, wherein an average thickness of a support substrate of light emitting diodes in the high brightness region is thinner than an average thickness of a support substrate of light emitting diodes in a peripheral area surrounding the peripheral region away from the high brightness region.   4. The light emitting diode device according to claim 3, wherein the light emitting diodes are arranged one by one on a single support substrate.   The light emitting diode device according to claim 3, wherein a plurality of the light emitting diodes are arranged on a single support substrate.   6. The light emitting diode device according to claim 5, wherein the plurality of light emitting diodes formed on the support substrate are arranged in a plurality of rows. A light-emitting diode array including a sub-mount substrate and a plurality of light-emitting diodes disposed on the sub-mount substrate and capable of emitting light whose luminance gradually decreases from a high-luminance region toward a peripheral region;
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
The average thickness x Vf of the support substrate of the light emitting diode in the high brightness region is smaller than the average thickness x Vf of the support substrate of the light emitting diode in the periphery of the peripheral region away from the high brightness region. Light emitting diode device. A light emitting diode array including a submount substrate and a plurality of light emitting diodes disposed on the submount substrate,
The light emitting diode device according to claim 1, wherein a value of heat quantity of the light emitting diodes arranged in the central part of the array is smaller than a value of heat quantity of the light emitting diodes arranged in the peripheral part of the array shape with the same luminance. A light emitting diode array including a submount substrate and a plurality of light emitting diodes disposed on the submount substrate,
The value of Vf of the said light emitting diode arrange | positioned at the center part of an array form is smaller than the value of Vf of the said light emitting diode arrange | positioned at the periphery part of an array form, The light emitting diode apparatus characterized by the above-mentioned. A light emitting diode array including a submount substrate and a plurality of light emitting diodes disposed on the submount substrate,
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
The average thickness value of the support substrate of the light emitting diodes disposed in the central portion of the array is smaller than the average thickness value of the support substrate of the light emitting diodes disposed in the peripheral portion of the array. A light emitting diode device. A light emitting diode array including a submount substrate and a plurality of light emitting diodes disposed on the submount substrate,
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
The value of the average thickness x Vf of the support substrate of the light emitting diodes arranged at the central portion of the array is larger than the value of the average thickness of the support substrate of the light emitting diodes arranged at the peripheral portion of the array × Vf. A light emitting diode device characterized by being small. A vehicle lamp having a light source and a lens,
A light emitting diode array in which the light source includes a plurality of light emitting diodes;
The vehicular lamp according to claim 1, wherein the light amount of the light emitting diode that irradiates the central portion of the alignment is smaller than that of the light emitting diode that irradiates the peripheral portion of the alignment. A vehicle lamp having a light source and a lens,
A light emitting diode array in which the light source includes a plurality of light emitting diodes;
The vehicular lamp characterized in that the value of Vf of the light emitting diode that irradiates the central portion of the alignment is smaller than that of the light emitting diode that irradiates the peripheral portion of the alignment. A vehicle lamp having a light source and a lens,
A light emitting diode array in which the light source includes a plurality of light emitting diodes;
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
The average thickness value of the support substrate of the light emitting diode that irradiates the alignment central portion is smaller than the average thickness value of the support substrate of the light emitting diode that irradiates the alignment peripheral portion. Light fixture. A vehicle lamp having a light source and a lens,
A light emitting diode array in which the light source includes a plurality of light emitting diodes;
Each of the plurality of light emitting diodes includes a semiconductor stack on a support substrate, and the support substrate is bonded to the submount substrate,
The value of the average thickness x Vf of the support substrate of the light emitting diode that irradiates the alignment central portion is smaller than the value of the average thickness x Vf of the support substrate of the light emitting diode that irradiates the alignment peripheral portion. A vehicular lamp. A light emitting diode structure corresponding to a large number of light emitting diodes is formed on each of a plurality of growth substrates,
Bonding a support substrate above the light emitting diode structure of each of the growth substrates,
Removing each of the growth substrates;
Dividing each of the support substrates and the light emitting diode structure thereon into chips,
The chips are classified according to the thickness of the support substrate,
On the submount substrate, the high-luminance region is formed by arranging chips classified as having a thin support substrate,
On the submount substrate, in a region away from the high-luminance region, the peripheral region is formed by arranging chips classified into a thicker classification than the thin classification in the thickness of the support substrate.
Manufacturing method of light emitting diode device.   The method of manufacturing a light emitting diode device according to claim 16, wherein one light emitting diode is disposed on each of the chips.   The method of manufacturing a light emitting diode device according to claim 16, wherein a plurality of light emitting diodes are arranged on the chip.     19. The method of manufacturing a light emitting diode device according to claim 18, wherein the plurality of light emitting diodes arranged on each chip are arranged in a plurality of rows. A light emitting diode structure corresponding to a large number of light emitting diodes is formed on each of a plurality of growth substrates,
Bonding a support substrate above the light emitting diode structure of each of the growth substrates,
Removing each of the growth substrates;
Dividing each of the support substrates and the light emitting diode structure thereon into chips,
The chips are classified by support substrate thickness x Vf,
On the submount substrate, a chip classified as having a small value of the thickness x Vf of the support substrate is arranged to form a high luminance region,
On the submount substrate, a peripheral region is formed by arranging chips classified as having a large thickness x Vf of the support substrate in a region away from the high luminance region.
Manufacturing method of light emitting diode device. Preparing a plurality of light emitting diodes;
The light emitting diodes are classified according to Vf, and on the submount substrate, light emitting diodes classified as having a small value of Vf are arranged to form a high luminance region,
A method for manufacturing a light-emitting diode device, wherein a peripheral region is formed by arranging light-emitting diodes classified as having a large Vf in a region away from the high-luminance region on the submount substrate. Preparing a plurality of light emitting diodes;
The light-emitting diodes are classified according to the amount of heat generated during light emission at the same luminance, and a high-luminance region is formed on the submount substrate by arranging light-emitting diodes classified as having a small value of heat generation during light emission at the same luminance.
A method of manufacturing a light emitting diode device, wherein a peripheral region is formed by arranging light emitting diodes classified as having a large amount of heat generated during light emission at the same luminance in a region away from the high luminance region on the submount substrate.

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