US20180261647A1 - Display device and epitaxial wafer - Google Patents
Display device and epitaxial wafer Download PDFInfo
- Publication number
- US20180261647A1 US20180261647A1 US15/496,880 US201715496880A US2018261647A1 US 20180261647 A1 US20180261647 A1 US 20180261647A1 US 201715496880 A US201715496880 A US 201715496880A US 2018261647 A1 US2018261647 A1 US 2018261647A1
- Authority
- US
- United States
- Prior art keywords
- sub pixel
- pixel unit
- peak wavelength
- measured
- luminous area
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000000758 substrate Substances 0.000 claims abstract description 39
- 238000005259 measurement Methods 0.000 claims abstract description 25
- 238000005424 photoluminescence Methods 0.000 claims abstract description 25
- 235000012431 wafers Nutrition 0.000 description 34
- 101100365087 Arabidopsis thaliana SCRA gene Proteins 0.000 description 26
- 238000004519 manufacturing process Methods 0.000 description 17
- 238000000034 method Methods 0.000 description 10
- 239000008186 active pharmaceutical agent Substances 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 238000000059 patterning Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 238000000407 epitaxy Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 150000002830 nitrogen compounds Chemical class 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
- H01L27/153—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars
- H01L27/156—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars two-dimensional arrays
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/20—Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
- H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
- H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
- H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
- H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/08—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
- H10K59/35—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels
- H10K59/352—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels the areas of the RGB subpixels being different
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/30—Devices specially adapted for multicolour light emission
- H10K59/35—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels
- H10K59/353—Devices specially adapted for multicolour light emission comprising red-green-blue [RGB] subpixels characterised by the geometrical arrangement of the RGB subpixels
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/0257—Doping during depositing
- H01L21/02573—Conductivity type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/14—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/20—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
- H01L33/22—Roughened surfaces, e.g. at the interface between epitaxial layers
Definitions
- the disclosure relates to a display device and an epitaxial wafer, more particularly to a display device displaying images via light emitting diodes (LEDs), and a LED epitaxial wafer.
- LEDs light emitting diodes
- LEDs characterized by high energy conversion efficient, small in size and long-life have widely been applied to various electronic products.
- LEDs are used for indictors or lighting, or are used in a display device for display images.
- a LED has an illumination layer and at least two types of semiconductor layers, so manufacturers can produce different color LEDs by adjusting the material of the illumination layer and the materials of the semiconductor layers.
- the semiconductor layers in various regions of the same wafer may have different epitaxial qualities during an epitaxy process.
- the uneven quality of epitaxy may cause the occurrence of deviation to the peak wavelengths of light emitted by LEDs that are driven. That is, a certain batch of LEDs, initially expected to emit the same color light, have a difference in color of light therebetween due to their uneven epitaxial qualities; the difference in color of light is even sensible to human's eyes.
- micro LEDs are formed by the same epitaxial wafer in a chip manufacturing process and then transferred to a substrate having driving circuits therein by the mass transfer technology. In other words, there is no chance to additionally classify LEDs during the manufacturing process. Therefore, when these LEDs with different epitaxial qualities are disposed in the same display device, the image quality of the display device will be affected, and the yield rate of production will also decrease.
- the disclosure provides a display device.
- the display device includes a display substrate, a first sub pixel unit and a second sub pixel unit.
- the first sub pixel unit is located on the display substrate and has a first luminous area.
- the second sub pixel unit is located on the display substrate and has a second luminous area.
- the first sub pixel unit and the second sub pixel unit belong to the same color type.
- the first sub pixel unit and the second sub pixel unit are formed from the epitaxial wafer and then transferred to the display substrate.
- the first luminous area and the second luminous area are related to a photoluminescence (PL) measurement result of the epitaxial wafer.
- PL photoluminescence
- the disclosure provides an epitaxial wafer.
- the epitaxial wafer includes an epitaxial substrate and an epitaxial structure on the epitaxial substrate.
- the epitaxial structure includes a first sub epitaxial structure and a second sub epitaxial structure.
- the first sub epitaxial structure has a first luminous area
- the second sub epitaxial structure has a second luminous area.
- the first sub epitaxial structure and the second sub epitaxial structure belong to the same color type.
- the sizes of the first and second luminous areas are related to a photoluminescence measurement result of the epitaxial structure of the epitaxial wafer.
- FIG. 1A is a top view of a display device according to an embodiment of the disclosure.
- FIG. 1B is a top view of an epitaxial wafer according to an embodiment of the disclosure.
- FIG. 2A is a schematic diagram of the photoluminescence measurement result of the epitaxial wafer according to an embodiment of the disclosure.
- FIG. 2B is a schematic diagram of a comparison of the photoluminescence measurement results of sub pixel units and an epitaxial wafer according to an embodiment of the disclosure.
- FIG. 1A is a top view of a display device according to an embodiment of the disclosure.
- a display device 1 includes a display substrate DS and a plurality of pixel units.
- the plurality of pixel units is disposed on the display substrate DS.
- 25 pixel units are shown in FIG. 1 and are arranged in an array.
- the following description will exemplify the pixel units P 1 , P 2 , P 3 , P 4 and P 5 of the 25 pixel units.
- the number of pixel units and the arrangement of the pixel units are not limited to what the figures show.
- the pixel unit P 1 includes sub pixel units SP 1 , SP 2 and SP 3 .
- the sub pixel units SP 1 , SP 2 and SP 3 respectively emit light of different colors.
- the sub pixel units SP 1 , SP 2 and SP 3 belong to different color types, respectively.
- the sub pixel unit SP 1 emits red light
- the sub pixel unit SP 2 emits green light
- the sub pixel unit SP 3 emits blue light.
- the correlation among sub pixel units SP 4 , SP 5 and SP 6 in the pixel unit P 2 is similar to that among the sub pixel units SP 1 , SP 2 and SP 3 .
- the sub pixel unit SP 4 and the sub pixel unit SP 1 belong to the same color type
- the sub pixel unit SP 5 and the sub pixel unit SP 2 belong to the same color type
- the sub pixel unit SP 6 and the sub pixel unit SP 3 belong to the same color type.
- Different sub pixel units of the same color type are classified into a first sub pixel unit and a second sub pixel unit.
- the sub pixel unit SP 1 is defined as a first sub pixel unit
- the sub pixel unit SP 4 is defined as a second sub pixel unit.
- FIG. 1B is a top view of an epitaxial wafer according to an embodiment of the disclosure.
- an epitaxial wafer W includes an epitaxial substrate ES and an epitaxial structure E formed on the epitaxial substrate ES.
- the epitaxial structure E contains one or more materials of ⁇ - ⁇ group or one or more ⁇ - ⁇ nitrogen compound materials.
- the thickness of the epitaxial structure E is not larger than 6 ⁇ m but is usually larger than 1 ⁇ m, because the thickness being too thick or too thin will affect the production yield of the follow-up manufacturing process.
- the epitaxial substrate ES is a sapphire substrate, silicon substrate or a GaN substrate.
- the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 are formed by directly transferring LED chips to the display substrate DS in the display device 1 after the LED chips are formed from sub epitaxial structures EP 2 , EP 5 , EP 8 , EP 11 and EP 14 , defined in the epitaxial structure E of the epitaxial wafer W in a chip manufacturing process; or, the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 are formed by transferring LED chips from a provisional substrate (not shown in drawings) to the display substrate DS in the display device 1 after the LED chips are formed from the sub epitaxial structures EP 2 , EP 5 , EP 8 , EP 11 and EP 14 , defined in the epitaxial structure E of the epitaxial wafer W in a chip manufacturing process, and then is transferred to the provisional substrate (not shown in drawings).
- the display device 1 may provide better display quality and visual experience to viewers.
- the display device 1 includes pixel units P 1 ⁇ P 5 , and each pixel unit includes at least one red sub pixel unit, at least one blue sub pixel unit, and at least one green sub pixel unit.
- each pixel unit includes at least one red sub pixel unit, at least one blue sub pixel unit, and at least one green sub pixel unit.
- multiple red sub epitaxial structures are formed on a first epitaxial wafer
- multiple green sub epitaxial structures are formed on a second epitaxial wafer
- multiple blue sub epitaxial structures are formed on a third epitaxial wafer
- LED chips are respectively formed from the sub epitaxial structures on the first, second and third epitaxial wafers in a chip manufacturing process and then are directly or indirectly transferred to the display substrate for forming the sub pixel units of the display device.
- these sub pixel units can further be connected to a driving circuit on the display substrate.
- a driving circuit on the display substrate For the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 , their relative position before they are formed from the epitaxial wafer W, is substantially the same as the relative position of the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 on the display substrate DS.
- the relative position of the sub epitaxial structures EP 2 , EP 5 , EP 8 , EP 11 and EP 14 , before being used to form the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 on the epitaxial wafer W, is substantially the same as the relative position of the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 on the display substrate DS.
- sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 correspond to the sub epitaxial structures EP 2 , EP 5 , EP 8 , EP 11 and EP 14 , the following exemplary description will mainly focus on the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 .
- each sub pixel unit SP 2 , SP 5 , SP 8 , SP 11 and SP 14 has a maximum width ranging from 1 to 100 ⁇ m, and preferably ranging from 3 to 30 ⁇ m.
- the scale of each of the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 is a micrometer scale. Therefore, the display device may have a better display resolution.
- the driving current density of each of the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 on the micrometer scale falls in a preferable range between 0.001 A/cm 2 and 5 A/cm 2 in a low current operation. That is, the sub pixel units SP 2 , SP 5 , SP 8 , SP 11 and SP 14 may have better efficiency under low driving current density.
- the measurement result of one or more relevant test items can be timely provided according to the epitaxial wafer, and compensation and calibration can also be timely performed.
- the aforementioned photoluminescence measurement result is obtained by measuring the initial light emission result of each part of the epitaxial substrate of the epitaxial wafer in a photoluminescence measurement process before the sizes of the sub epitaxial structures are defined on the epitaxial structure.
- the photoluminescence measurement result includes the information about the measured peak wavelength distribution.
- the photoluminescence measurement result includes the information about a measured luminous intensity distribution.
- a photoluminescence measurement result includes information about a measured luminous efficiency distribution.
- the measured peak wavelength distribution indicates the peak wavelength of light emitted by each region that is excited on the epitaxial structure of the epitaxial wafer. Since the epitaxial quality of a sub epitaxial structure is related to the location of the sub epitaxial structure in the epitaxial structure, the user can use the correlation to initially judge how each variable in the manufacturing process affects the peak wavelength of light emitted by each sub pixel unit.
- Said photoluminescence measurement result is obtained by, for example, measuring the epitaxial structure of the epitaxial wafer based on a standard area that is set as a unit area, and the manufacturer can, according to the photoluminescence measurement result and the standard area, define a standard peak wavelength range for a reference basis. That is, theoretically, the peak wavelength of light emitted by a sub epitaxial structure having the standard area should fall within the standard peak wavelength range.
- the measured peak wavelength distribution can also be used together with the standard peak wavelength range and a reference luminous area to define various regions in the epitaxial structure of the wafer for compensation and calibration.
- this region When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is larger than the upper limitation of the standard peak wavelength range, this region will be defined as a positive deviation region. When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is shorter than the lower limitation of the standard peak wavelength range, this region will be defined as a negative deviation region. When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is not shorter than the lower limitation of the standard peak wavelength range and not larger than the upper limitation of the standard peak wavelength range, this region will be defined as a non-deviation region.
- the luminous area corresponding to a sub epitaxial structure in a positive deviation region, the luminous area corresponding to a sub epitaxial structure in a non-deviation region, and the luminous area corresponding to a sub epitaxial structure in a negative deviation region are substantially equal to each other.
- the peak wavelength of light emitted by the sub pixel unit corresponding to the positive deviation region is longer than the peak wavelength of light emitted by the sub pixel unit corresponding to the non-deviation region
- the peak wavelength of light emitted by the sub pixel unit corresponding to the negative deviation region is shorter than the peak wavelength of light emitted by the sub pixel unit corresponding to the non-deviation region.
- the difference in peak wavelength will become larger if the driving current has a low driving current density.
- the luminous area corresponding to the sub pixel unit in the positive deviation region is defined to be smaller than the standard area
- the luminous area corresponding to the sub pixel unit in the non-deviation region is defined to be substantially equal to the standard area
- the luminous area corresponding to the sub pixel unit in the negative deviation region is defined to be larger than the standard area.
- the aforementioned standard peak wavelength range can further be narrowed to become a standard peak wavelength.
- a region corresponding to a measured wavelength longer than the standard peak wavelength is defined as a positive deviation region
- a region corresponding to a measured wavelength substantially equal to the standard peak wavelength is defined as a non-deviation region
- a region corresponding to a measured wavelength shorter than the standard peak wavelength is defined as a negative deviation region.
- FIG. 2A is a schematic diagram of the photoluminescence measurement result of the epitaxial wafer according to an embodiment of the disclosure
- FIG. 2B is a schematic diagram of a comparison of the photoluminescence measurement results of sub pixel units and an epitaxial wafer according to an embodiment of the disclosure.
- FIG. 2A illustrates the measured peak wavelength distribution in the photoluminescence measurement result.
- Each closed curve in FIG. 2A represents a wavelength, and a region between every two closed curves corresponds to a wavelength range.
- the regions R 1 ⁇ R 5 in FIG. 2A respectively correspond to different wavelength ranges.
- the measured luminous intensity distribution or luminous efficiency distribution in the photoluminescence measurement result can be used to produce relevant diagrams or tables, and the disclosure does not intend to limit the use of parameters.
- the measured wavelength corresponding to the region R 1 is not longer than the upper limitation of the standard peak wavelength range and is not shorter than the lower limitation of the standard peak wavelength range, so the region R 1 can be considered as the aforementioned non-deviation region.
- the measured wavelength corresponding to the region R 2 is longer than the upper limitation of the standard peak wavelength range, so the region R 2 can be considered as the aforementioned positive deviation region.
- the measured wavelength corresponding to the region R 3 is not longer than the upper limitation of the standard peak wavelength range and is not shorter than the lower limitation of the standard peak wavelength range, so the region R 3 can be considered as the aforementioned non-deviation region.
- the measured wavelength corresponding to the region R 4 is shorter than the lower limitation of the standard peak wavelength range, so the region R 4 can be considered as the aforementioned negative deviation region.
- the measured wavelength corresponding to the region R 5 is shorter than the lower limitation of the standard peak wavelength range, so the region R 5 can be considered as the aforementioned negative deviation region. Since the measured wavelength corresponding to the region R 5 is shorter than the measured wavelength corresponding to the region R 4 , the measured wavelength corresponding to the region R 5 deviates from the standard peak wavelength range more than the measured wavelength corresponding to the region R 4 .
- FIG. 2B is a schematic comparison diagram obtained by superimposing a part of the sub pixel units in FIG. 1A on the measured wavelength distribution in FIG. 2A for exemplarily illustrating the correlation between the sizes of luminous areas of sub pixel units and the regions R 1 ⁇ R 5 .
- the sub pixel unit SP 2 of the pixel unit P 1 formed from the sub epitaxial structure EP 2 corresponds to the region R 1 of the epitaxial wafer W.
- the region R 1 is a non-deviation region.
- the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm; the measured peak wavelength corresponding to the sub pixel unit SP 2 is 535 nm and falls within the standard peak wavelength range. That is, when the luminous area of the sub pixel unit SP 2 is defined as a standard area, the sub pixel unit SP 2 is driven by a current to emit light whose peak wavelength is within a tolerant range, and does not need to additionally adjust the luminous area of the sub pixel unit SP 2 . Therefore, the luminous area of the sub pixel unit SP 2 is defined to be substantially equal to the standard area. Similarly, the luminous area of the sub pixel unit SP 8 of the pixel unit P 3 is defined to be substantially equal to the standard area.
- the sub pixel unit SP 5 of the pixel unit P 2 corresponds to the region R 2 of the epitaxial wafer W.
- the region R 2 is a positive deviation region.
- the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm.
- the measured peak wavelength corresponding to the sub pixel unit SP 5 is, for example, 537 nm and is larger than the upper limitation of the standard peak wavelength range.
- the luminous area of the sub pixel unit SP 5 is defined as a standard area
- the sub pixel unit SP 5 is driven by a current to emit light whose peak wavelength exceeds the upper limitation of the tolerant range, so that it is necessary to additionally adjust the luminous area of the sub pixel unit SP 5 . Therefore, the luminous area of the sub pixel unit SP 5 is defined to be smaller than the standard area.
- the luminous area of the sub pixel unit SP 5 corresponding to a high deviation region is smaller than the luminous area of the sub pixel unit SP 2 corresponding to a non-deviation region.
- the luminous area of the sub pixel unit SP 5 is 90% of the luminous area of the sub pixel unit SP 2 . Therefore, the peak wavelength of light emitted by the sub pixel unit SP 5 may almost fall within the standard peak wavelength range.
- the sub pixel unit SP 11 of the pixel unit P 4 corresponds to the region R 4 of the epitaxial wafer W.
- the region R 4 is a negative deviation region.
- the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm.
- the measured peak wavelength corresponding to the sub pixel unit SP 11 is, for example, 533 nm that is shorter than the lower limitation of the standard peak wavelength range.
- the luminous area of the sub pixel unit SP 11 is defined as a standard area
- the sub pixel unit SP 11 is driven by a current to emit light with a peak wavelength shorter than the lower limitation of the tolerant range, so that it is necessary to additionally adjust the luminous area of the sub pixel unit SP 11 . Therefore, the luminous area of the sub pixel unit SP 11 is defined to be larger than the standard area. That is, the luminous area of the sub pixel unit SP 11 is larger than the luminous area of the sub pixel unit SP 2 .
- the luminous area of the sub pixel unit SP 11 corresponding to a negative deviation region is larger than the luminous area of the sub pixel unit SP 2 corresponding to a non-deviation region.
- the luminous area of the sub pixel unit SP 11 is 110% of the luminous area of the sub pixel unit SP 2 . In this way, the peak wavelength of light emitted by the sub pixel unit SP 11 may almost fall within the standard peak wavelength range.
- the luminous area of the sub pixel unit SP 14 is defined to be larger than a standard area.
- the measured peak wavelength corresponding to the sub pixel unit SP 14 is, for example, 531 nm and is shorter than the measured peak wavelength corresponding to the sub pixel unit SP 11 . That is, when the luminous area of the sub pixel unit SP 14 is defined as a standard area, the sub pixel unit SP 14 is driven by a current to emit light with a peak wavelength that deviates from the lower limitation of the tolerant range more than the peak wavelength of light emitted by the sub pixel unit SP 11 .
- the luminous area of the sub pixel unit SP 14 is defined to be larger than not only the standard area but also the luminous area of the sub pixel unit SP 11 . Therefore, the peak wavelength of light emitted by the sub pixel unit SP 14 may almost fall within the standard peak wavelength range.
- the luminous area of the sub pixel unit is defined as a standard area.
- the luminous area of the sub pixel unit is defined to be smaller than the standard area.
- the luminous area of the sub pixel unit is defined to be larger than the standard area.
- the degree of deviation of the measured peak wavelength from the standard peak wavelength range affects the degree of adjustment in the luminous area of each sub pixel unit.
- the peak wavelength of light emitted by each sub pixel unit driven by a current is properly calibrated, so that each sub pixel unit that is driven can emit light with a peak wavelength falling within the standard peak wavelength range.
- the luminous area can be properly calibrated according to the measured luminous intensity distribution or the luminous efficiency distribution in the photoluminescence measurement result.
- the measured intensity distribution or luminous efficiency corresponding to a sub pixel unit is in the standard intensity distribution or luminous efficiency range
- the luminous area of this sub pixel unit is defined as a standard area.
- the luminous area of this sub pixel unit is defined to be smaller than the standard area.
- the luminous area of this sub pixel unit is defined to be larger than the standard area.
- the degree of deviation of the measured intensity distribution or luminous efficiency from the standard intensity distribution or luminous efficiency range decides the degree of adjustment in luminous area for each sub pixel unit.
- the luminous intensity of light emitted by each sub pixel unit driven by a current may be properly calibrated, so that the luminous intensity of light emitted by each sub pixel unit that is driven may fall in the standard intensity distribution or luminous efficiency range.
- the sub pixel units of the same color type in the display device 1 can emit respective light having a difference in peak wavelength therebetween, which is not larger than 2 nm.
- the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm, i.e. 535 nm ⁇ 1 nm. Therefore, the screen of the display device 1 may become more uniform and harmonious.
- the exemplary description is based on green sub pixel units, and however, in practice, the luminous areas of red sub pixel units and blue sub pixel units can be adjusted by the foregoing method. Therefore, the sub pixel units of the same color type in the display device may have a substantially identical peak wavelength of emitted light, luminous intensity or luminous efficiency.
- the sub pixel units of the same color type in the display device may have a substantially identical peak wavelength of emitted light, luminous intensity or luminous efficiency.
- all luminous areas of the green sub pixel units may not be the same
- all luminous areas of the red sub pixel units may not be the same
- all luminous areas of the blue sub pixel units may not be the same.
- the increase rate or decrease rates of the luminous areas of the sub pixel units of each color type can be adjusted according to particular requirements by one of ordinary skill in the art, and thus, they may be different.
- the manufacturer can define a patterning process according to the photoluminescence measurement result, and define various luminous areas for sub epitaxial structures in the epitaxial structure in the patterning process, form sub pixel units having different luminous areas from the sub epitaxial structures in a chip manufacturing process, and then transfer the sub pixel units to a display substrate by mass transfer technology.
- the luminous areas of all sub pixel units of the same color type are substantially and properly equalized, so that the manufacturing process can be simplified.
- the manufacturer can define one universal patterning process or different universal patterning processes using one or more past photoluminescence measurement results, so as to get a balance between the manufacturing cost and the yield rate of production.
- the above exemplary description is based on a color type of sub pixel units, but one of ordinary skill in the art can simultaneously and respectively adjust luminous areas for more than one color type of sub pixel units in view of the disclosure.
- the disclosure provides a display device and an epitaxial structure.
- the display device includes a first sub pixel unit and a second sub pixel unit, and the luminous areas of the first and second sub pixel units are related to the photoluminescence measurement result of a related epitaxial substrate in an epitaxial process. Therefore, the first and second sub pixel units formed based from the same epitaxial wafer may substantially have the same color of emitted light when the peak wavelength of light emitted by the first sub pixel unit and the peak wavelength of light emitted by the second sub pixel unit are appropriately calibrated.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
Disclosed are an epitaxial wafer and a display device that includes a display substrate, a first sub pixel unit and a second sub pixel unit. The first sub pixel unit is disposed on the display substrate and has a first light emitting area. The second sub pixel unit is disposed on the display substrate and has a second light emitting area. The first sub pixel unit and the second sub pixel unit belong to same color type. The first sub pixel unit and the second sub pixel unit are formed from an epitaxial structure on the epitaxial wafer. The first sub pixel unit and the second sub pixel unit are formed and transferred to the display substrate from the epitaxial wafer. The first light emitting area and the second light emitting area are related to at least the photoluminescence measurement result of the epitaxial wafer.
Description
- This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 106107605 filed in Taiwan, R.O.C. on Mar. 8, 2017, the entire contents of which are hereby incorporated by reference.
- The disclosure relates to a display device and an epitaxial wafer, more particularly to a display device displaying images via light emitting diodes (LEDs), and a LED epitaxial wafer.
- LEDs characterized by high energy conversion efficient, small in size and long-life have widely been applied to various electronic products. Usually, LEDs are used for indictors or lighting, or are used in a display device for display images. In brief, a LED has an illumination layer and at least two types of semiconductor layers, so manufacturers can produce different color LEDs by adjusting the material of the illumination layer and the materials of the semiconductor layers.
- However, the semiconductor layers in various regions of the same wafer may have different epitaxial qualities during an epitaxy process. The uneven quality of epitaxy may cause the occurrence of deviation to the peak wavelengths of light emitted by LEDs that are driven. That is, a certain batch of LEDs, initially expected to emit the same color light, have a difference in color of light therebetween due to their uneven epitaxial qualities; the difference in color of light is even sensible to human's eyes.
- Moreover, the microminiaturization of LEDs is very expectative in the next generation of semiconductor technology. The existing technology has been able to shrink LEDs down to a micrometer scale. However, since the sizes of LEDs are getting smaller, it becomes a very key factor to various LEDs whether the epitaxial quality of various LEDs is even or not. For some manufacturing processes of display panels, micro LEDs are formed by the same epitaxial wafer in a chip manufacturing process and then transferred to a substrate having driving circuits therein by the mass transfer technology. In other words, there is no chance to additionally classify LEDs during the manufacturing process. Therefore, when these LEDs with different epitaxial qualities are disposed in the same display device, the image quality of the display device will be affected, and the yield rate of production will also decrease.
- According to one or more embodiments, the disclosure provides a display device. The display device includes a display substrate, a first sub pixel unit and a second sub pixel unit. The first sub pixel unit is located on the display substrate and has a first luminous area. The second sub pixel unit is located on the display substrate and has a second luminous area. The first sub pixel unit and the second sub pixel unit belong to the same color type. The first sub pixel unit and the second sub pixel unit are formed from the epitaxial wafer and then transferred to the display substrate. The first luminous area and the second luminous area are related to a photoluminescence (PL) measurement result of the epitaxial wafer.
- According to one or more embodiments, the disclosure provides an epitaxial wafer. The epitaxial wafer includes an epitaxial substrate and an epitaxial structure on the epitaxial substrate. The epitaxial structure includes a first sub epitaxial structure and a second sub epitaxial structure. The first sub epitaxial structure has a first luminous area, and the second sub epitaxial structure has a second luminous area. The first sub epitaxial structure and the second sub epitaxial structure belong to the same color type. The sizes of the first and second luminous areas are related to a photoluminescence measurement result of the epitaxial structure of the epitaxial wafer.
- The present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present disclosure and wherein:
-
FIG. 1A is a top view of a display device according to an embodiment of the disclosure; -
FIG. 1B is a top view of an epitaxial wafer according to an embodiment of the disclosure; -
FIG. 2A is a schematic diagram of the photoluminescence measurement result of the epitaxial wafer according to an embodiment of the disclosure; and -
FIG. 2B is a schematic diagram of a comparison of the photoluminescence measurement results of sub pixel units and an epitaxial wafer according to an embodiment of the disclosure. - In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings.
- Please refer to
FIG. 1A .FIG. 1A is a top view of a display device according to an embodiment of the disclosure. As shown inFIG. 1A , adisplay device 1 includes a display substrate DS and a plurality of pixel units. The plurality of pixel units is disposed on the display substrate DS. For a concise description, only 25 pixel units are shown inFIG. 1 and are arranged in an array. The following description will exemplify the pixel units P1, P2, P3, P4 and P5 of the 25 pixel units. However, the number of pixel units and the arrangement of the pixel units are not limited to what the figures show. - In the case of the pixel unit P1, the pixel unit P1 includes sub pixel units SP1, SP2 and SP3. For example, the sub pixel units SP1, SP2 and SP3 respectively emit light of different colors. In another aspect, the sub pixel units SP1, SP2 and SP3 belong to different color types, respectively. In an embodiment, the sub pixel unit SP1 emits red light, the sub pixel unit SP2 emits green light, and the sub pixel unit SP3 emits blue light. For other pixel units, the correlation among sub pixel units SP4, SP5 and SP6 in the pixel unit P2 is similar to that among the sub pixel units SP1, SP2 and SP3. That is, the sub pixel unit SP4 and the sub pixel unit SP1 belong to the same color type, the sub pixel unit SP5 and the sub pixel unit SP2 belong to the same color type, and the sub pixel unit SP6 and the sub pixel unit SP3 belong to the same color type. The related detail will not be repeatedly described hereafter. Different sub pixel units of the same color type are classified into a first sub pixel unit and a second sub pixel unit. For example, the sub pixel unit SP1 is defined as a first sub pixel unit, and the sub pixel unit SP4 is defined as a second sub pixel unit.
- In a particular example, the aforementioned sub pixel units of the same color type is formed from the epitaxial structure of the same epitaxial wafer and then is transferred to the display substrate DS. Please further refer to
FIG. 1B .FIG. 1B is a top view of an epitaxial wafer according to an embodiment of the disclosure. As shown inFIG. 1B , an epitaxial wafer W includes an epitaxial substrate ES and an epitaxial structure E formed on the epitaxial substrate ES. The epitaxial structure E contains one or more materials of □-□ group or one or more □-□ nitrogen compound materials. Preferably, the thickness of the epitaxial structure E is not larger than 6 μm but is usually larger than 1 μm, because the thickness being too thick or too thin will affect the production yield of the follow-up manufacturing process. For example, the epitaxial substrate ES is a sapphire substrate, silicon substrate or a GaN substrate. - The sub pixel units SP2, SP5, SP8, SP11 and SP14 are formed by directly transferring LED chips to the display substrate DS in the
display device 1 after the LED chips are formed from sub epitaxial structures EP2, EP5, EP8, EP11 and EP14, defined in the epitaxial structure E of the epitaxial wafer W in a chip manufacturing process; or, the sub pixel units SP2, SP5, SP8, SP11 and SP14 are formed by transferring LED chips from a provisional substrate (not shown in drawings) to the display substrate DS in thedisplay device 1 after the LED chips are formed from the sub epitaxial structures EP2, EP5, EP8, EP11 and EP14, defined in the epitaxial structure E of the epitaxial wafer W in a chip manufacturing process, and then is transferred to the provisional substrate (not shown in drawings). By transferring such sub pixel units of different color types to the display substrate DS, various pixel units are initially defined. Note that, in the same direction, the sub pixel units of the same color type in every two adjacent pixel units substantially have the same pitch therebetween on the display substrate DS. For example, the pitch between the sub pixel units SP2 and SP5 is substantially equal to the pitch between the sub pixel units SP2 and SP14 in the same direction. Therefore, thedisplay device 1 may provide better display quality and visual experience to viewers. - In this embodiment, the
display device 1 includes pixel units P1˜P5, and each pixel unit includes at least one red sub pixel unit, at least one blue sub pixel unit, and at least one green sub pixel unit. In a detailed example, multiple red sub epitaxial structures are formed on a first epitaxial wafer, multiple green sub epitaxial structures are formed on a second epitaxial wafer, and multiple blue sub epitaxial structures are formed on a third epitaxial wafer; and then, LED chips are respectively formed from the sub epitaxial structures on the first, second and third epitaxial wafers in a chip manufacturing process and then are directly or indirectly transferred to the display substrate for forming the sub pixel units of the display device. After that, these sub pixel units can further be connected to a driving circuit on the display substrate. For the sub pixel units SP2, SP5, SP8, SP11 and SP14, their relative position before they are formed from the epitaxial wafer W, is substantially the same as the relative position of the sub pixel units SP2, SP5, SP8, SP11 and SP14 on the display substrate DS. In other words, the relative position of the sub epitaxial structures EP2, EP5, EP8, EP11 and EP14, before being used to form the sub pixel units SP2, SP5, SP8, SP11 and SP14 on the epitaxial wafer W, is substantially the same as the relative position of the sub pixel units SP2, SP5, SP8, SP11 and SP14 on the display substrate DS. In brief, the sub pixel units SP2, SP5, SP8, SP11 and SP14 correspond to the sub epitaxial structures EP2, EP5, EP8, EP11 and EP14, the following exemplary description will mainly focus on the sub pixel units SP2, SP5, SP8, SP11 and SP14. - As described above, an example based on the sub pixel units SP2 and SP5 is taken as follows. The sub pixel unit SP2 has a first luminous area, and the sub pixel unit SP5 has a second luminous area. The sizes of the first and second luminous areas are related to a photoluminescence measurement result of the epitaxial substrate in an epitaxial process. In this and the following embodiments, each sub pixel unit is exemplarily defined to be rectangle-shaped, but other shapes, such as a circular shape, may be contemplated in this or some embodiments. In this case, each of the sub pixel units SP2, SP5, SP8, SP11 and SP14 has a maximum width ranging from 1 to 100 μm, and preferably ranging from 3 to 30 μm. That is, the scale of each of the sub pixel units SP2, SP5, SP8, SP11 and SP14 is a micrometer scale. Therefore, the display device may have a better display resolution. Note that the driving current density of each of the sub pixel units SP2, SP5, SP8, SP11 and SP14 on the micrometer scale falls in a preferable range between 0.001 A/cm2 and 5 A/cm2 in a low current operation. That is, the sub pixel units SP2, SP5, SP8, SP11 and SP14 may have better efficiency under low driving current density.
- During the manufacturing process of sub epitaxial structures, the measurement result of one or more relevant test items can be timely provided according to the epitaxial wafer, and compensation and calibration can also be timely performed. For example, the aforementioned photoluminescence measurement result is obtained by measuring the initial light emission result of each part of the epitaxial substrate of the epitaxial wafer in a photoluminescence measurement process before the sizes of the sub epitaxial structures are defined on the epitaxial structure. In an embodiment, the photoluminescence measurement result includes the information about the measured peak wavelength distribution. In another embodiment, the photoluminescence measurement result includes the information about a measured luminous intensity distribution. In yet another embodiment, a photoluminescence measurement result includes information about a measured luminous efficiency distribution. More particularly, the measured peak wavelength distribution, in an example in this embodiment, indicates the peak wavelength of light emitted by each region that is excited on the epitaxial structure of the epitaxial wafer. Since the epitaxial quality of a sub epitaxial structure is related to the location of the sub epitaxial structure in the epitaxial structure, the user can use the correlation to initially judge how each variable in the manufacturing process affects the peak wavelength of light emitted by each sub pixel unit.
- Said photoluminescence measurement result is obtained by, for example, measuring the epitaxial structure of the epitaxial wafer based on a standard area that is set as a unit area, and the manufacturer can, according to the photoluminescence measurement result and the standard area, define a standard peak wavelength range for a reference basis. That is, theoretically, the peak wavelength of light emitted by a sub epitaxial structure having the standard area should fall within the standard peak wavelength range. In an embodiment, the measured peak wavelength distribution can also be used together with the standard peak wavelength range and a reference luminous area to define various regions in the epitaxial structure of the wafer for compensation and calibration. When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is larger than the upper limitation of the standard peak wavelength range, this region will be defined as a positive deviation region. When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is shorter than the lower limitation of the standard peak wavelength range, this region will be defined as a negative deviation region. When the measured peak wavelength corresponding to a measured position in a certain region of the epitaxial structure is not shorter than the lower limitation of the standard peak wavelength range and not larger than the upper limitation of the standard peak wavelength range, this region will be defined as a non-deviation region.
- The definitions and amounts of the aforementioned positive deviation region, negative deviation region and non-deviation region or whether to additionally define other regions, can be freely set according to particular requirements in view of the disclosure by one of ordinary skill in the art, and are not limited to the disclosure.
- In another aspect, assume that the luminous area corresponding to a sub epitaxial structure in a positive deviation region, the luminous area corresponding to a sub epitaxial structure in a non-deviation region, and the luminous area corresponding to a sub epitaxial structure in a negative deviation region are substantially equal to each other. When the same driving current is applied to sub pixel units respectively corresponding to a positive deviation region, a non-deviation region and a negative deviation region among the sub pixel units formed from transferring sub epitaxial structures formed in a chip manufacturing process to a display substrate, the peak wavelength of light emitted by the sub pixel unit corresponding to the positive deviation region is longer than the peak wavelength of light emitted by the sub pixel unit corresponding to the non-deviation region, and the peak wavelength of light emitted by the sub pixel unit corresponding to the negative deviation region is shorter than the peak wavelength of light emitted by the sub pixel unit corresponding to the non-deviation region. The difference in peak wavelength will become larger if the driving current has a low driving current density.
- To deal with this situation, in an embodiment, the luminous area corresponding to the sub pixel unit in the positive deviation region is defined to be smaller than the standard area, the luminous area corresponding to the sub pixel unit in the non-deviation region is defined to be substantially equal to the standard area, and the luminous area corresponding to the sub pixel unit in the negative deviation region is defined to be larger than the standard area. In practice, the aforementioned standard peak wavelength range can further be narrowed to become a standard peak wavelength. In this condition, a region corresponding to a measured wavelength longer than the standard peak wavelength is defined as a positive deviation region, a region corresponding to a measured wavelength substantially equal to the standard peak wavelength is defined as a non-deviation region, and a region corresponding to a measured wavelength shorter than the standard peak wavelength is defined as a negative deviation region.
- Next, please refer to
FIG. 2A andFIG. 2B .FIG. 2A is a schematic diagram of the photoluminescence measurement result of the epitaxial wafer according to an embodiment of the disclosure, andFIG. 2B is a schematic diagram of a comparison of the photoluminescence measurement results of sub pixel units and an epitaxial wafer according to an embodiment of the disclosure. Concretely,FIG. 2A illustrates the measured peak wavelength distribution in the photoluminescence measurement result. Each closed curve inFIG. 2A represents a wavelength, and a region between every two closed curves corresponds to a wavelength range. In other words, the regions R1˜R5 inFIG. 2A respectively correspond to different wavelength ranges. In practice, the measured luminous intensity distribution or luminous efficiency distribution in the photoluminescence measurement result can be used to produce relevant diagrams or tables, and the disclosure does not intend to limit the use of parameters. - In the embodiment shown in
FIG. 2A , the measured wavelength corresponding to the region R1 is not longer than the upper limitation of the standard peak wavelength range and is not shorter than the lower limitation of the standard peak wavelength range, so the region R1 can be considered as the aforementioned non-deviation region. The measured wavelength corresponding to the region R2 is longer than the upper limitation of the standard peak wavelength range, so the region R2 can be considered as the aforementioned positive deviation region. The measured wavelength corresponding to the region R3 is not longer than the upper limitation of the standard peak wavelength range and is not shorter than the lower limitation of the standard peak wavelength range, so the region R3 can be considered as the aforementioned non-deviation region. The measured wavelength corresponding to the region R4 is shorter than the lower limitation of the standard peak wavelength range, so the region R4 can be considered as the aforementioned negative deviation region. The measured wavelength corresponding to the region R5 is shorter than the lower limitation of the standard peak wavelength range, so the region R5 can be considered as the aforementioned negative deviation region. Since the measured wavelength corresponding to the region R5 is shorter than the measured wavelength corresponding to the region R4, the measured wavelength corresponding to the region R5 deviates from the standard peak wavelength range more than the measured wavelength corresponding to the region R4. -
FIG. 2B is a schematic comparison diagram obtained by superimposing a part of the sub pixel units inFIG. 1A on the measured wavelength distribution inFIG. 2A for exemplarily illustrating the correlation between the sizes of luminous areas of sub pixel units and the regions R1˜R5. As shown inFIG. 1A toFIG. 2B , the sub pixel unit SP2 of the pixel unit P1 formed from the sub epitaxial structure EP2 corresponds to the region R1 of the epitaxial wafer W. As described above, the region R1 is a non-deviation region. In a particular example based on the color type that is green light, the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm; the measured peak wavelength corresponding to the sub pixel unit SP2 is 535 nm and falls within the standard peak wavelength range. That is, when the luminous area of the sub pixel unit SP2 is defined as a standard area, the sub pixel unit SP2 is driven by a current to emit light whose peak wavelength is within a tolerant range, and does not need to additionally adjust the luminous area of the sub pixel unit SP2. Therefore, the luminous area of the sub pixel unit SP2 is defined to be substantially equal to the standard area. Similarly, the luminous area of the sub pixel unit SP8 of the pixel unit P3 is defined to be substantially equal to the standard area. - On the other hand, the sub pixel unit SP5 of the pixel unit P2 corresponds to the region R2 of the epitaxial wafer W. As described above, the region R2 is a positive deviation region. In a particular example, the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm. In this condition, the measured peak wavelength corresponding to the sub pixel unit SP5 is, for example, 537 nm and is larger than the upper limitation of the standard peak wavelength range. That is, when the luminous area of the sub pixel unit SP5 is defined as a standard area, the sub pixel unit SP5 is driven by a current to emit light whose peak wavelength exceeds the upper limitation of the tolerant range, so that it is necessary to additionally adjust the luminous area of the sub pixel unit SP5. Therefore, the luminous area of the sub pixel unit SP5 is defined to be smaller than the standard area. In another aspect, the luminous area of the sub pixel unit SP5 corresponding to a high deviation region is smaller than the luminous area of the sub pixel unit SP2 corresponding to a non-deviation region. For example, the luminous area of the sub pixel unit SP5 is 90% of the luminous area of the sub pixel unit SP2. Therefore, the peak wavelength of light emitted by the sub pixel unit SP5 may almost fall within the standard peak wavelength range.
- The sub pixel unit SP11 of the pixel unit P4 corresponds to the region R4 of the epitaxial wafer W. As described above, the region R4 is a negative deviation region. In a particular example, the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm. In this condition, the measured peak wavelength corresponding to the sub pixel unit SP11 is, for example, 533 nm that is shorter than the lower limitation of the standard peak wavelength range. That is, when the luminous area of the sub pixel unit SP11 is defined as a standard area, the sub pixel unit SP11 is driven by a current to emit light with a peak wavelength shorter than the lower limitation of the tolerant range, so that it is necessary to additionally adjust the luminous area of the sub pixel unit SP11. Therefore, the luminous area of the sub pixel unit SP11 is defined to be larger than the standard area. That is, the luminous area of the sub pixel unit SP11 is larger than the luminous area of the sub pixel unit SP2. In another aspect, the luminous area of the sub pixel unit SP11 corresponding to a negative deviation region is larger than the luminous area of the sub pixel unit SP2 corresponding to a non-deviation region. For example, the luminous area of the sub pixel unit SP11 is 110% of the luminous area of the sub pixel unit SP2. In this way, the peak wavelength of light emitted by the sub pixel unit SP11 may almost fall within the standard peak wavelength range.
- Similar to the sub pixel unit SP11, the luminous area of the sub pixel unit SP14 is defined to be larger than a standard area. In this embodiment, the measured peak wavelength corresponding to the sub pixel unit SP14 is, for example, 531 nm and is shorter than the measured peak wavelength corresponding to the sub pixel unit SP11. That is, when the luminous area of the sub pixel unit SP14 is defined as a standard area, the sub pixel unit SP14 is driven by a current to emit light with a peak wavelength that deviates from the lower limitation of the tolerant range more than the peak wavelength of light emitted by the sub pixel unit SP11. Therefore, the luminous area of the sub pixel unit SP14 is defined to be larger than not only the standard area but also the luminous area of the sub pixel unit SP11. Therefore, the peak wavelength of light emitted by the sub pixel unit SP14 may almost fall within the standard peak wavelength range.
- Briefly, when the measured peak wavelength corresponding to a sub pixel unit falls within a standard peak wavelength range, the luminous area of the sub pixel unit is defined as a standard area. When the measured peak wavelength corresponding to a sub pixel unit is larger than a standard peak wavelength range, the luminous area of the sub pixel unit is defined to be smaller than the standard area. When the measured peak wavelength corresponding to a sub pixel unit is shorter than a standard peak wavelength range, the luminous area of the sub pixel unit is defined to be larger than the standard area. The degree of deviation of the measured peak wavelength from the standard peak wavelength range affects the degree of adjustment in the luminous area of each sub pixel unit. By adjusting the luminous area of each sub pixel unit, the peak wavelength of light emitted by each sub pixel unit driven by a current is properly calibrated, so that each sub pixel unit that is driven can emit light with a peak wavelength falling within the standard peak wavelength range. In another embodiment, the luminous area can be properly calibrated according to the measured luminous intensity distribution or the luminous efficiency distribution in the photoluminescence measurement result. When the measured intensity distribution or luminous efficiency corresponding to a sub pixel unit is in the standard intensity distribution or luminous efficiency range, the luminous area of this sub pixel unit is defined as a standard area. When the measured intensity distribution or luminous efficiency corresponding to a sub pixel unit is larger than the standard intensity distribution or luminous efficiency range, the luminous area of this sub pixel unit is defined to be smaller than the standard area. When the measured intensity distribution or luminous efficiency corresponding to a sub pixel unit is smaller than the standard intensity distribution or luminous efficiency range, the luminous area of this sub pixel unit is defined to be larger than the standard area. The degree of deviation of the measured intensity distribution or luminous efficiency from the standard intensity distribution or luminous efficiency range decides the degree of adjustment in luminous area for each sub pixel unit. By adjusting the luminous area of each sub pixel unit, the luminous intensity of light emitted by each sub pixel unit driven by a current may be properly calibrated, so that the luminous intensity of light emitted by each sub pixel unit that is driven may fall in the standard intensity distribution or luminous efficiency range.
- In an embodiment, the sub pixel units of the same color type in the
display device 1 can emit respective light having a difference in peak wavelength therebetween, which is not larger than 2 nm. As described in the aforementioned example, the standard peak wavelength range is not larger than 536 nm and not shorter than 534 nm, i.e. 535 nm±1 nm. Therefore, the screen of thedisplay device 1 may become more uniform and harmonious. - Moreover, the exemplary description is based on green sub pixel units, and however, in practice, the luminous areas of red sub pixel units and blue sub pixel units can be adjusted by the foregoing method. Therefore, the sub pixel units of the same color type in the display device may have a substantially identical peak wavelength of emitted light, luminous intensity or luminous efficiency. In other words, as shown in
FIG. 1A , for the display device experiencing calibration or manufacturing as described above, all luminous areas of the green sub pixel units may not be the same, all luminous areas of the red sub pixel units may not be the same, and all luminous areas of the blue sub pixel units may not be the same. The increase rate or decrease rates of the luminous areas of the sub pixel units of each color type can be adjusted according to particular requirements by one of ordinary skill in the art, and thus, they may be different. - As described above, in practice, the manufacturer can define a patterning process according to the photoluminescence measurement result, and define various luminous areas for sub epitaxial structures in the epitaxial structure in the patterning process, form sub pixel units having different luminous areas from the sub epitaxial structures in a chip manufacturing process, and then transfer the sub pixel units to a display substrate by mass transfer technology. Or, through such a defined patterning process, the luminous areas of all sub pixel units of the same color type are substantially and properly equalized, so that the manufacturing process can be simplified. Or, the manufacturer can define one universal patterning process or different universal patterning processes using one or more past photoluminescence measurement results, so as to get a balance between the manufacturing cost and the yield rate of production. The above exemplary description is based on a color type of sub pixel units, but one of ordinary skill in the art can simultaneously and respectively adjust luminous areas for more than one color type of sub pixel units in view of the disclosure.
- According to the above embodiments, the disclosure provides a display device and an epitaxial structure. In an exemplary embodiment, the display device includes a first sub pixel unit and a second sub pixel unit, and the luminous areas of the first and second sub pixel units are related to the photoluminescence measurement result of a related epitaxial substrate in an epitaxial process. Therefore, the first and second sub pixel units formed based from the same epitaxial wafer may substantially have the same color of emitted light when the peak wavelength of light emitted by the first sub pixel unit and the peak wavelength of light emitted by the second sub pixel unit are appropriately calibrated.
Claims (14)
1. A display device, comprising:
a display substrate; and
a plurality of pixel units, comprising:
a first pixel unit located on the display substrate and comprising a first sub pixel unit having a first luminous area; and
a second pixel unit located on the display substrate and comprising a second sub pixel unit having a second luminous area,
wherein the first sub pixel unit and the second sub pixel unit belong to the same color type;
the first sub pixel unit and the second sub pixel unit are formed from a same epitaxial wafer and then transferred to the display substrate; and
the first luminous area and the second luminous area are different and are related to a photoluminescence measurement result of the epitaxial wafer.
2. The display device according to claim 1 , wherein the photoluminescence measurement result comprises a measured peak wavelength distribution; there is a plurality of measured positions on the epitaxial wafer; the first sub pixel unit, before being formed from the epitaxial wafer, corresponds to one measured position among the plurality of measured positions; the second sub pixel unit, before being formed from the epitaxial wafer, corresponds to another measured position among the plurality of measured positions; the measured peak wavelength distribution indicates a plurality of measured peak wavelengths respectively related to the plurality of measured positions; the first luminous area of the first sub pixel unit is related to the measured peak wavelength of the measured position corresponding to the first sub pixel unit; and the second luminous area of the second sub pixel unit is related to the measured peak wavelength of the measured position corresponding to the second sub pixel unit.
3. The display device according to claim 2 , wherein, when the measured peak wavelength corresponding to the first sub pixel unit is larger than an upper limitation of a reference wavelength range, the first luminous area of the first sub pixel unit is determined as smaller than a standard area; and when the measured peak wavelength corresponding to the first sub pixel unit is shorter than a lower limitation of the reference wavelength range, the first luminous area of the first sub pixel unit is determined as larger than the standard area; and when the measured peak wavelength corresponding to the second sub pixel unit is larger than an upper limitation of a reference wavelength range, the second luminous area of the second sub pixel unit is determined as smaller than a standard area; and when the measured peak wavelength corresponding to the second sub pixel unit is shorter than a lower limitation of the reference wavelength range, the second luminous area of the second sub pixel unit is determined as larger than the standard area.
4. The display device according to claim 3 , wherein the first sub pixel unit is controlled by a driving current to generate first emitted light, the second sub pixel unit is controlled by the driving current to generate second emitted light, and a difference between the peak wavelength of the first emitted light and the peak wavelength of the second emitted light is less than a first predetermined threshold.
5. The display device according to claim 4 , wherein the first predetermined threshold is not larger than 2 nm.
6. The display device according to claim 4 , wherein a current density of the first sub pixel unit and a current density of the second sub pixel unit range from 0.001 A/cm2 to 5 A/cm2.
7. (canceled)
8. The display device according to claim 1 , wherein each of the plurality of pixel units comprises at least three different color types of sub pixel units; and in the same direction, every two adjacent sub pixel units of the same color, among the pixel units, have a substantially same distance therebetween.
9. The display device according to claim 1 , wherein a relative location of the first and second sub pixel units before being formed from the epitaxial wafer is substantially equal to a relative location of the first and second sub pixel units on the display substrate.
10. (canceled)
11. (canceled)
12. (canceled)
13. The display device according to claim 1 , wherein the photoluminescence measurement result of the epitaxial wafer comprises a standard peak wavelength range, the measured peak wavelength of the first sub pixel unit is in the standard peak wavelength range, and the measured peak wavelength of the second sub pixel unit exceeds the standard peak wavelength range.
14. The display device according to claim 13 , wherein when the measured peak wavelength of the second sub pixel unit is larger than measured peak wavelengths in the standard peak wavelength range, the luminous area of the second sub pixel unit is smaller than the luminous area of the first sub pixel unit; and when the measured peak wavelength of the second sub pixel unit is less than the measured peak wavelengths in the standard peak wavelength range, the luminous area of the second sub pixel unit is larger than the luminous area of the first sub pixel unit.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/230,629 US10580825B2 (en) | 2017-03-08 | 2018-12-21 | Method of manufacturing display device Including Photoluminescence measurement |
US16/455,631 US10784238B2 (en) | 2017-03-08 | 2019-06-27 | Display device including sub-pixel units of the same color type and different luminous areas |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
TW106107605 | 2017-03-08 | ||
TW106107605A TWI621277B (en) | 2017-03-08 | 2017-03-08 | Display device and epitaxial wafer |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/230,629 Division US10580825B2 (en) | 2017-03-08 | 2018-12-21 | Method of manufacturing display device Including Photoluminescence measurement |
US16/455,631 Continuation-In-Part US10784238B2 (en) | 2017-03-08 | 2019-06-27 | Display device including sub-pixel units of the same color type and different luminous areas |
Publications (1)
Publication Number | Publication Date |
---|---|
US20180261647A1 true US20180261647A1 (en) | 2018-09-13 |
Family
ID=62639913
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/496,880 Abandoned US20180261647A1 (en) | 2017-03-08 | 2017-04-25 | Display device and epitaxial wafer |
US16/230,629 Active US10580825B2 (en) | 2017-03-08 | 2018-12-21 | Method of manufacturing display device Including Photoluminescence measurement |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/230,629 Active US10580825B2 (en) | 2017-03-08 | 2018-12-21 | Method of manufacturing display device Including Photoluminescence measurement |
Country Status (2)
Country | Link |
---|---|
US (2) | US20180261647A1 (en) |
TW (1) | TWI621277B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10354981B2 (en) * | 2016-12-02 | 2019-07-16 | PlayNitride Inc. | Display and repair method thereof |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020090183A1 (en) * | 2018-11-02 | 2020-05-07 | 株式会社ジャパンディスプレイ | Display device |
CN110289295B (en) * | 2019-06-27 | 2021-11-23 | 昆山国显光电有限公司 | Display panel and display device |
CN116097458A (en) * | 2020-09-22 | 2023-05-09 | 苏州晶湛半导体有限公司 | Full-color LED epitaxial structure |
WO2022120580A1 (en) * | 2020-12-08 | 2022-06-16 | 重庆康佳光电技术研究院有限公司 | Display module and manufacturing method therefor, and electronic device |
CN115336015A (en) * | 2021-03-11 | 2022-11-11 | 京东方科技集团股份有限公司 | Display substrate and display device |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150187991A1 (en) * | 2013-12-27 | 2015-07-02 | LuxVue Technology Corporation | Led with internally confined current injection area |
US20170133439A1 (en) * | 2008-10-01 | 2017-05-11 | Universal Display Corporation | Novel oled display architecture |
US20170236807A1 (en) * | 2014-10-28 | 2017-08-17 | The Regents Of The University Of California | Iii-v micro-led arrays and methods for preparing the same |
US20170278906A1 (en) * | 2016-03-28 | 2017-09-28 | Samsung Display Co., Ltd. | Organic light-emitting display apparatus |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI480660B (en) * | 2012-12-25 | 2015-04-11 | Au Optronics Corp | Display device |
KR102124043B1 (en) * | 2013-07-25 | 2020-06-18 | 삼성디스플레이 주식회사 | Pixel array structure and display device employing the same |
TWI563490B (en) * | 2015-12-04 | 2016-12-21 | Ind Tech Res Inst | Display pixel and display panel |
CN108956550A (en) * | 2018-06-12 | 2018-12-07 | 华灿光电(浙江)有限公司 | A kind of method and apparatus of photoluminescence spectra processing |
-
2017
- 2017-03-08 TW TW106107605A patent/TWI621277B/en active
- 2017-04-25 US US15/496,880 patent/US20180261647A1/en not_active Abandoned
-
2018
- 2018-12-21 US US16/230,629 patent/US10580825B2/en active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170133439A1 (en) * | 2008-10-01 | 2017-05-11 | Universal Display Corporation | Novel oled display architecture |
US20150187991A1 (en) * | 2013-12-27 | 2015-07-02 | LuxVue Technology Corporation | Led with internally confined current injection area |
US20170236807A1 (en) * | 2014-10-28 | 2017-08-17 | The Regents Of The University Of California | Iii-v micro-led arrays and methods for preparing the same |
US20170278906A1 (en) * | 2016-03-28 | 2017-09-28 | Samsung Display Co., Ltd. | Organic light-emitting display apparatus |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10354981B2 (en) * | 2016-12-02 | 2019-07-16 | PlayNitride Inc. | Display and repair method thereof |
US10476043B2 (en) * | 2016-12-02 | 2019-11-12 | PlayNitride Inc. | Repair method |
Also Published As
Publication number | Publication date |
---|---|
TWI621277B (en) | 2018-04-11 |
US10580825B2 (en) | 2020-03-03 |
US20190115390A1 (en) | 2019-04-18 |
TW201834261A (en) | 2018-09-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10580825B2 (en) | Method of manufacturing display device Including Photoluminescence measurement | |
US11270985B2 (en) | Solid state lighting device with different illumination parameters at different regions of an emitter array | |
US20200203319A1 (en) | Mass transfer method for micro light emitting diode and light emitting panel module using thereof | |
US8674379B2 (en) | Light-emitting device package and method of manufacturing the same | |
US20120326627A1 (en) | Systems and methods for controlling white light | |
WO2018152865A1 (en) | Micro light emitting diode display panel, and manufacturing method | |
US8354665B2 (en) | Semiconductor light-emitting devices for generating arbitrary color | |
US20210057396A1 (en) | Led display screen and manufacturing method therefor | |
US11901480B2 (en) | Method of manufacturing a light-emitting device | |
US20160155894A1 (en) | Light-emitting device and manufacturing method thereof | |
TWI805564B (en) | Chip transferring method and the apparatus thereof | |
US11264531B2 (en) | LED transfer device and micro LED transferring method using the same | |
KR102661676B1 (en) | Method of fabricating display device | |
CN104466027A (en) | Microcavity structure of organic light-emitting display and organic light-emitting display | |
CN108336206B (en) | Method for manufacturing light-emitting diode display | |
US9048172B2 (en) | Method of manufacturing white light emitting device (LED) and apparatus measuring phosphor film | |
US10784238B2 (en) | Display device including sub-pixel units of the same color type and different luminous areas | |
KR102244667B1 (en) | Method to manufacture Micro-LED pixel package and Micro-LED pixel package by this | |
CN113410368B (en) | Mixed-woven packaging method for high-uniformity integrated LED display module chip | |
JP2013511146A (en) | Light emitting diode repair method and apparatus using quantum dot coating | |
US20230178681A1 (en) | Method for manufacturing display device | |
KR20230049033A (en) | Optoelectronic product and manufacture method thereof | |
TW202316679A (en) | Optoelectronic product and manufacture method thereof | |
KR102182015B1 (en) | Method for evaluating a luminance of a light source and lighting apparatus | |
KR20230150975A (en) | Transfer system, transfer positioning device, and transfer method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: PLAYNITRIDE INC., TAIWAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:LAI, YU-HUNG;REEL/FRAME:042141/0954 Effective date: 20170413 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: FINAL REJECTION MAILED |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |