JP2008262993A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase contrast of display by reducing crosstalk between adjacent LED elements. <P>SOLUTION: The display device 21 comprises a substrate 61 which allows light of a predetermined wavelength region to pass through it and a plurality of LED elements 41R, 41G, and 41B disposed two-dimensionally on the substrate 61. The individual LED elements 41R, 41G, and 41B include a light emission layer 64 formed on one side of the substrate 61. Display light is generated on a basis of light emitted from the light emission layer 64 of the individual LED elements 41R, 41G, and 41B which has passed through the substrate 61. Between at least two adjacent LED elements out of the plurality of LED elements 41R, 41G, and 41B on the substrate 61, a trench 61a for forming a plane for reflecting or blocking light is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device using an LED element.

  Patent Document 1 listed below discloses a display device (display) including a plurality of LED elements provided two-dimensionally on a substrate. In this display device, each LED element has a light emitting layer that emits ultraviolet light and a fluorescent layer that contains a fluorescent material that emits visible light when excited by the ultraviolet light. As the fluorescent layer of each LED element, one that emits red light, green light, or blue light is used for each LED element, so that full color display can be performed.

In such a display device, a substrate that transmits light in a predetermined wavelength range is used as the substrate, and the display is based on light that is based on light from the light emitting layer of each LED element and is transmitted through the substrate. It is conceivable to configure so that light is generated.
Japanese National Patent Publication No. 11-510968

  However, in a display device using LED elements, when the display light is generated based on the light from the light emitting layer of each LED element and transmitted through the substrate, the substrate is If a normal substrate without any contrivance is used, light based on light from the light emitting layer of each LED element and light transmitted through the substrate (for example, ultraviolet light from the light emitting layer or converted by the fluorescent layer) Visible light) is light based on light from the light emitting layer of the adjacent LED element, and crosstalk occurs with the light transmitted through the substrate, resulting in a decrease in display contrast.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a display device that can reduce crosstalk between adjacent LED elements and can increase display contrast.

  In order to solve the above problems, a display device according to a first aspect of the present invention is a display device that performs color display or monochrome display based on a video signal or other display control signal, and emits light in a predetermined wavelength range. A transparent substrate and a plurality of LED elements provided two-dimensionally on the substrate, each LED element having a light emitting layer provided on one side of the substrate, Display light is generated based on light based on light from the light emitting layer and transmitted through the substrate, and at a position between at least two adjacent LED elements of the plurality of LED elements on the substrate. A groove for forming a surface for reflecting or blocking light is formed.

  In the first aspect, the light based on the light from the light emitting layer of each LED element and transmitted through the substrate may be the light itself from the light emitting layer, or the fourth aspect described later. When the fluorescent layer is included, the light emitted from the fluorescent layer excited by the light from the light emitting layer may be used.

  A display device according to a second aspect of the present invention is the display device according to the first aspect, wherein the groove is empty.

  A display device according to a third aspect of the present invention is the display device according to the first aspect, wherein the groove is filled with a light reflecting material or a light reflecting material is formed on a surface of the groove.

  The display device according to a fourth aspect of the present invention is the display device according to any one of the first to third aspects, wherein at least one LED element of the plurality of LED elements is caused by light from the light emitting layer of the LED element. It has a fluorescent layer containing a fluorescent substance that emits light when excited.

  In the display device according to a fifth aspect of the present invention, in the fourth aspect, the fluorescent layer is provided on the opposite side of the substrate from the light emitting layer of the LED element.

  The display device according to a sixth aspect of the present invention is the display device according to the fourth aspect, wherein the fluorescent layer is provided between the light emitting layer of the LED element and the substrate.

  A display device according to a seventh aspect of the present invention is the display device according to any one of the first to sixth aspects, and includes a drive circuit that drives the plurality of LED elements based on the video signal or the display control signal. A circuit board electrically connected to the plurality of LED elements is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the crosstalk between adjacent LED elements can be reduced and the display apparatus which can raise the contrast of a display can be provided.

  Hereinafter, a display device according to the present invention will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a schematic block diagram showing a display device 21 according to the first embodiment of the present invention.

  The display device 21 according to the present embodiment is configured as a display device that emits and displays a color image corresponding to a video signal. The display device 21 according to the present embodiment can be configured as a so-called micro display having a screen of 1 inch or less, for example. As shown in FIG. 1, the display device 21 according to the present embodiment includes a plurality of unit pixels 30 arranged two-dimensionally, and LED elements 41R, 41G, and 41B of each color of the unit pixel 30 (not shown in FIG. 1). 2), a vertical scanning circuit 32 for selecting each row, a horizontal scanning circuit 33 for selecting each color LED element 41R, 41G, 41B of each unit pixel 30 for each column, and an external And a video signal processing circuit 34 for controlling the vertical scanning circuit 32 and the horizontal scanning circuit 33 so as to process the video signal input from the video signal and display an image corresponding to the video signal. In FIG. 1, the number of unit pixels 30 is 3 × 3, but is not limited thereto.

  In the present embodiment, the LED elements 41R, 41G are constituted by elements other than the LED elements 41R, 41G, 41B in the unit pixel 30 (see FIG. 2 described later), the vertical scanning circuit 32, the horizontal scanning circuit 33, and the video signal processing circuit 34. , 41B is configured.

  FIG. 2 is a circuit diagram showing the unit pixel 30 in FIG. Each unit pixel 30 selects a pixel row of a red LED element 41R that emits red light, a green LED element 41G that emits green light, a blue LED element 41B that emits blue light, and a red LED element 41R. It has a column selection switch 42R, a green column selection switch 42G for selecting the pixel column of the green LED element 41G, and a blue column selection switch 42B for selecting the pixel column of the blue LED element 41B. The column selection switches 42R, 42G, and 42B are composed of MOS transistors.

  The cathodes of the LED elements 41R, 41G, 41B of all the unit pixels 30 are connected in common by a ground line 43. The anodes of the LED elements 41R, 41G, and 41B are connected to the drains of the corresponding selection switches 42R, 42G, and 42B, respectively. The source of the red column selection switch 42R is commonly connected to each pixel row by the horizontal source line 44R, and has a size corresponding to the red luminance value from the vertical scanning circuit 32 operating under the control of the video signal processing circuit 34. A voltage is received as a drive signal. The source of the green column selection switch 42G is commonly connected to each pixel row by the horizontal source line 44G, and receives a voltage having a magnitude corresponding to the green luminance value from the vertical scanning circuit 32 as a drive signal. The source of the blue column selection switch 42B is commonly connected to each pixel row by the horizontal source line 44B, and receives a voltage having a magnitude corresponding to the blue luminance value from the vertical scanning circuit 32 as a drive signal.

  The gate of the red column selection switch 42R is commonly connected to each pixel column by the vertical selection line 45R, and receives a red column selection signal from the horizontal scanning circuit 33 operating under the control of the video signal processing circuit 34. The gate of the green column selection switch 42G is connected to each pixel column in common by a vertical selection line 45G, and receives a green column selection signal from the horizontal scanning circuit 33. The gates of the blue column selection switch 42B are commonly connected to each column by the vertical selection line 45B, and receive a blue column selection signal from the horizontal scanning circuit 33.

  Referring to FIG. 1 again, when a video signal is input from the outside, the video signal processing circuit 34 obtains the luminance of each color of each pixel 30 based on the video signal, and applies the control signal corresponding to the value to the vertical. It outputs to the scanning circuit 32 and the horizontal scanning circuit 33, respectively. The vertical scanning circuit 32 and the horizontal scanning circuit 33 turn on the column selection switches 42R, 42G, and 42B for each color for each pixel column at a predetermined timing based on the control signal at a predetermined timing, a pixel row A voltage having a magnitude corresponding to the luminance value is output to the horizontal source lines 44R, 44G, and 44B for each color every time. In this manner, a voltage (and current) having a magnitude corresponding to the luminance value is applied to each unit pixel 30 to the LED elements 41R, 41G, and 41B of the respective colors, and light is emitted with a desired color and luminance for each unit pixel 30. As a result, the image indicated by the input video signal is displayed by light emission.

  FIG. 3 is a plan view schematically showing the arrangement of the LED elements 41R, 41G, 41B of the respective colors employed in the present embodiment. In FIG. 3, “R” indicates a red LED element 41R, “G” indicates a green LED element 41G, and “B” indicates a blue LED element 41B. Also in FIG. 3, the number of unit pixels 30 is 3 × 3. These points are the same in FIGS. 4 and 5 described later.

  In the present embodiment, as shown in FIG. 3, each unit pixel 30 is composed of a total of three LED elements 41R, 41G, and 41B, one for each color arranged in the row direction (left and right direction). In the present embodiment, as shown in FIG. 3, the arrangement order of the LED elements 41R, 41G, 41B of the respective colors in the unit pixels 30 in the same row is the same, but in the unit pixels 30 in the rows adjacent in the column direction. The arrangement order of the LED elements 41R, 41G, 41B is shifted.

  However, the arrangement of the LED elements 41R, 41G, and 41B for each color is not limited to the example shown in FIG. 3, and for example, the arrangement shown in FIG. 4 or the arrangement shown in FIG. In FIG. 4, the arrangement order of the LED elements 41R, 41G, and 41B of each color in all the unit pixels 30 is the same. In FIG. 5, each unit pixel 30 is composed of a total of 2 × 2 LED elements, one red LED element 41R, two green LED elements 41G, and one blue LED element 41B.

  FIG. 6 is a schematic sectional view showing the display device 21 according to the present embodiment. FIG. 7 is a schematic enlarged cross-sectional view showing the hybridized chip 51 in FIG. 6 in an enlarged manner. FIG. 8 is a schematic plan view schematically showing a part of one unit pixel 30 (only some of the elements) of the LED substrate 52 constituting the chip 51 shown in FIGS. 6 and 7. FIG. 9 is a schematic diagram schematically showing a part of the unit pixel 30 corresponding to FIG. 8 (only some of the elements) of the drive circuit board 53 constituting the chip 51 shown in FIGS. 6 and 7. It is a top view. 8 and 9 are both viewed from the upper side in FIG. 7, but the lines that should originally be hidden lines are also indicated by solid lines. The cross section along the line AA ′ in FIG. 3, the cross section along the line BB ′ in FIG. 8, and the cross section along the line CC ′ in FIG. 9 are within one plane. Although included, the cross sections shown in FIGS. 6 and 7 are cross sections in the plane.

  The LED substrate 52 includes a single substrate (second substrate) 61 such as a glass substrate that transmits light in a predetermined wavelength range (visible region in the present embodiment), and all units provided on the substrate 61. The pixel 30 includes LED elements 41R, 41G, and 41B for each color.

As shown in FIGS. 7 and 8, the red LED element 41 </ b> R includes a fluorescent layer 62 </ b> R, an n-type impurity layer 63, an active layer 64 as a light emitting layer, and a p-type layer, which are sequentially stacked from the substrate 61 side on the lower surface side of the substrate 61. An impurity layer 65 and electrodes 66 and 67 are included. The n-type impurity layer 63, the active layer 64, and the p-type impurity layer 65 are each composed of an epitaxial growth layer. A part of the n-type impurity layer 63 is not covered with the active layer 64 and the p-type impurity layer 65, and one electrode 66 is formed in the region. The other electrode 67 is formed on the p-type impurity layer 65. In the present embodiment, as is known, the materials of the layers 63 to 65 are set such that ultraviolet light is emitted from the active layer 64. In practice, as is known, each of the layers 63 to 65 may be composed of a plurality of layers or a buffer layer may be added as necessary. However, the detailed illustration and description of the structure are omitted. To do. The fluorescent layer 62R is a fluorescent material that emits red light when excited by the ultraviolet light from the active layer 64 of the LED element 41R (for example, Ca _0.950 Al ₂ Si ₄ O _0.075 N _7.917 : Eu _{0. 050} , Y ₂ O ₂ S: Eu, or the like) and a layer of light-transmitting resin (for example, epoxy resin or silicon resin).

  The green LED element 41G is different from the red LED element 41R only in that a fluorescent layer 62G is formed instead of the fluorescent layer 62R, and the blue LED element 41B is different from the red LED element 41R in place of the fluorescent layer 62R. Since only the fluorescent layer 62B is formed, the overlapping description thereof is omitted.

The fluorescent layer 62G is a fluorescent material that emits green light when excited by the ultraviolet light from the active layer 64 of the LED element 41G (for example, ZnS: Cu, Al or (Ba, Sr, Ca) ₂ SiO ₄ : Eu). It is comprised by the layer of resin (for example, an epoxy resin or a silicon resin) which contains translucency.

The fluorescent layer 62B is a fluorescent material that emits blue light when excited by the ultraviolet light from the active layer 64 of the LED element 41B (for example, BAM: Eu (BaMgAl ₁₀ O ₁₇ : Eu or (Sr, Ca, Ba, Mg)). ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu or the like) and a layer of light-transmitting resin (for example, epoxy resin or silicon resin).

  As can be seen from the above description, in the present embodiment, in each LED element 41R, 41G, 41B, the n-type impurity layer 63, the active layer 64, the p-type impurity layer 65, and the electrodes 66, 67 are as a whole. The LED constituent layers (excluding the fluorescent layers 62R, 62G, 62B) constituting the LED element 70 are provided, and the fluorescent layers 62R, 62G, 62B are disposed between the LED constituent layers 70 and the substrate 61, respectively. Has been.

  The drive circuit 31 which is a part other than the LED elements 41R, 41G, and 41B in the circuits shown in FIGS. 1 and 2 is mounted on one drive circuit board 53 using a known semiconductor process technique. In the present embodiment, a silicon substrate is used as the drive circuit substrate 53. The drive circuit board 53 is electrically connected to the electrodes 66 and 67 of the LED elements 41R, 41G, and 41B of the LED board 52 by bumps 71 and 72 as shown in FIGS. The chip 51 includes an LED substrate 52 and a drive circuit substrate 53 that are bonded to each other by bumps 71 and 72.

  The above-described red column selection switch 42R includes a source and drain (not shown) formed by a predetermined diffusion layer formed on the drive circuit board 53, and a gate electrode 73 (see FIG. 9) disposed on a region between them. Are configured as MOS transistors. The source is connected to a wiring pattern connected to the horizontal source line 44R. The drain is connected to an electrode 74 formed thereon and connected by a bump 71. The gate electrode 73 is connected to the vertical selection line 45R by a wiring pattern. The same applies to the green column selection switch 42G and the blue column selection switch 42B. The ground line 43 also serves as an electrode for connecting to the LED elements 41R, 41G, and 41B. In FIG. 7, reference numeral 75 denotes an insulating film such as a silicon oxide film.

  As shown in FIG. 7, the anode of the red LED element 41 </ b> R and the drain of the red column selection switch 42 </ b> R are electrically connected by a bump 72 provided between the electrodes 67 and 74. The cathode of the red LED element 41 </ b> R and the ground line 43 are electrically connected by a bump 71 provided between the electrode 66 and the ground line 43. Similarly, the anodes of the LED elements 41G and 41B and the drains of the selection switches 42G and 42B are electrically connected by the bumps 72, respectively, and the cathodes of the LED elements 41G and 42B and the ground line 43 are electrically connected by the bumps 71, respectively. Connected. The bumps 71 and 72 are made of, for example, copper or gold.

  In the red LED element 41 </ b> R, when current is passed between the electrodes 66 and 67, ultraviolet light is emitted from the active layer 64. In the red LED element 41R, the fluorescent layer 62R is excited by the ultraviolet light from the active layer 64 to emit red light, and this red light is transmitted through the substrate 61 and emitted upward to generate display light. In the green LED element 41G, the fluorescent layer 62G is excited by the ultraviolet light from the active layer 64 to emit green light, and the green light passes through the substrate 61 and is emitted upward to generate display light. In the blue LED element 41G, the fluorescent layer 62B is excited by the ultraviolet light from the active layer 64 to emit blue light, and this blue light is transmitted through the substrate 61 and emitted upward to generate display light.

  In the present embodiment, as shown in FIG. 7, grooves 61 a are formed at positions between adjacent LED elements on the substrate 61. The groove 61 a is formed substantially perpendicular to the surface of the substrate 61.

  Light emitted from the fluorescent layers 62R, 62G, and 62B of the LED elements 41R, 41G, and 41B tends to travel not only upward but also in various directions. Therefore, if there is no groove 61a, the light emitted from the fluorescent layer of each LED element mixes with the light emitted from the fluorescent layer of the adjacent LED element, and crosstalk occurs. On the other hand, since the groove 61a is formed in the substrate 61, the light is totally reflected on the surface of the groove 61a, and thus the direction in which the light emitted from the fluorescent layer of one LED element is emitted is collected to some extent. Sex is determined. For this reason, it is possible to suppress crosstalk where light emitted from adjacent fluorescent layers intersects, and display with high contrast is possible. The groove 61a may be left empty, but the same crosstalk suppressing effect can be obtained even if the groove 61a is filled with a light reflecting material such as metal or formed on the surface of the groove 61a by vapor deposition or the like. . Further, the surface of the groove 61a may be a surface that blocks light by embedding a light absorbing material or the like in the groove 61a. In this case, although the light utilization efficiency is lowered, the crosstalk suppressing effect can still be obtained.

  Referring again to FIG. 6, in the display device 21 according to the present embodiment, the chip 51 is mounted on the support substrate 54, and between the predetermined electrode of the drive circuit board 53 of the chip 51 and the electrode 55 on the support substrate 54. Are wire-bonded by a wire 56, and a portion of the wire 56 is sealed with a resin 57.

  In general, a chip having LED elements is sealed with a resin including a transparent substrate corresponding to the substrate 61 in FIG. This is because, in a general chip, unless this is done, the durability deteriorates or the light extraction efficiency decreases due to the high refractive index of the LED light emitting layer.

  However, in the display device 21 according to the present embodiment, the LED substrate 52 and the drive circuit substrate 53 are hybridized by the bumps 71 and 72. Further, in the display device 21 according to the present embodiment, as shown in FIG. 7, in each LED element 41R, 41G, 41B, the fluorescent layers 62R, 62G, 62B are sandwiched between the LED constituent layer 70 and the substrate 61, respectively. Therefore, the fluorescent layers 62R, 62G, and 62B are not exposed to the outside even if they are not covered with a special protective film or the like. Therefore, according to the present embodiment, the influence of the outside world on the fluorescent layers 62R, 62G, and 62B can be reduced without being covered with a special protective film or the like, and the durability can be improved. In addition, by setting the refractive index of the substrate 61 to an intermediate refractive index between the refractive index of air and the refractive index of the LED light emitting layer, it is possible to suppress a decrease in light extraction efficiency. Therefore, in the present embodiment, it is not necessary to seal the entire chip 51 with resin. However, since the portion of the wire 56 is mechanically weak, only the portion of the wire 56 is sealed with the resin 57 in the present embodiment.

  However, in the present invention, for example, the chip 51 may be accommodated in the package 81 as shown in FIG. The package 81 includes a package body 81a and a sealing lid 81b that also serves as a display window, and is a so-called ball grid package. Each solder ball 82 provided on the bottom surface of the package body 81a is electrically connected to each electrode 84 bonded to the electrode of the drive circuit board 53 with a wire 83 through a path (not shown).

  Next, an example of a method for manufacturing the display device 21 according to the present embodiment will be described with reference to FIGS. 11 to 13 and 15 are schematic cross-sectional views schematically showing each step of the manufacturing method. FIG. 14 is a schematic perspective view schematically showing a predetermined step of this manufacturing method.

  First, a substrate (first substrate) 91 serving as a basis for epitaxially growing the n-type impurity layer 63 and the like of the LED component layer 70 is prepared. As the substrate 91, for example, a sapphire substrate or a SiC substrate is used. Next, the LED component layer 70 is formed on the substrate 91 by the amount of the LED elements 41R, 41G, and 41B of the plurality of chips 51 to be manufactured collectively. That is, the n-type impurity layer 63, the active layer 64, and the p-type impurity layer 65 are sequentially formed on the substrate 91 by epitaxial growth, and unnecessary regions of the active layer 64 and the p-type impurity layer 65 are removed by etching. At this time, the n-type impurity layer 63 remains formed on the entire surface of the substrate 91. Then, the electrodes 66 and 67 are formed of gold or the like and patterned into a predetermined shape by etching. FIG. 11A shows this state.

  Next, a substrate (third substrate) 92 for holding the LED component layer 70 and protecting it from mechanical damage is bonded to the surface of the LED component layer 70 opposite to the substrate 91. This bonding is temporary and will be peeled off later. Here, the substrate 12 is bonded to the LED constituent layer 10 by the thermoplastic wax 93. Next, the substrate 91 is removed from the LED constituent layer 70 to which the substrate 92 is bonded. FIG. 11B shows this state.

  On the other hand, a substrate (second substrate) 61 such as a glass substrate that transmits light in a predetermined wavelength region (visible region in the present embodiment) is prepared. On the substrate 61, the above-described fluorescent layers 62R, 62G, 62B are formed at positions corresponding to the LED elements 41R, 41G, and 41B of the respective colors. FIG. 11C shows this state. Note that the method of finally forming the fluorescent layers 62R, 62G, and 62B only in a partial region is well known. The surface of the substrate 61 is not uneven due to a patterned layer, and the substrate 61 that has not undergone a process involving high-temperature processing such as formation of an epitaxial growth layer can be used. There is no curvature. Therefore, the thickness of the fluorescent layers 62R, 62G, and 62B can be made uniform with higher accuracy. In order to make the thicknesses of the fluorescent layers 62R, 62G, and 62B even more accurate, the substrate 61 is polished and planarized as necessary before applying the fluorescent layers 62R, 62G, and 62B; and Alternatively, after forming the fluorescent layers 62R, 62G, and 62B, the fluorescent layers 62R, 62G, and 62B may be polished and planarized. The fluorescent layers 62R, 62G, and 62B may be formed by silk screen printing, for example.

  Next, the lower surface of the LED constituent layer 70 in the state shown in FIG. 11B and the upper surfaces of the fluorescent layers 62R, 62G, and 62B in the state shown in FIG. In the present embodiment, since the fluorescent layers 62R, 62G, and 62B are configured using an adhesive resin such as an epoxy resin or a silicon resin, the adhesive properties of the fluorescent layers 62R, 62G, and 62B are utilized. The LED constituent layer 70 and the fluorescent layers 62R, 62G, and 62B are joined. However, apart from the fluorescent layers 62R, 62G, and 62B, the LED constituent layer 70 and the fluorescent layers 62R, 62G, and 62B may be bonded using a translucent adhesive. Thereafter, the substrate 92 is peeled off from the LED constituent layer 70 by removing the thermoplastic wax 93. FIG. 12A shows this state.

  Next, a groove 61a is formed at a position between adjacent LED elements on the substrate 61 by dry etching or the like (FIG. 12B).

  On the other hand, the drive circuit board 53 is prepared using a known semiconductor process technology (FIG. 12C). Here, the drive circuit board 53 is provided with a CMOS circuit by a general CMOS process, for example. Then, as shown in FIG. 13A, bumps 71 and 72 for electrically connecting to the LED elements 41R, 41G, and 41B are formed on the driving circuit board 53.

  Next, the substrate in the state shown in FIG. 12A and the drive circuit substrate 53 on which the bumps 71 and 72 are formed are aligned as shown in FIG. FIG. 14 schematically shows the state of this alignment. In FIG. 14, 101 indicates the substrate in the state shown in FIG. 12A, and 102 indicates the drive circuit substrate 53 on which bumps 71 and 72 are formed. In FIG. 14, reference numerals 101a and 102b schematically show areas for one chip in the substrates 101 and 102, respectively.

  Such alignment is performed, and the electrodes 66 and 67 and the bumps 71 and 72 are bonded to each other. FIG. 13B shows this state. Such bonding by bumps and hybridization by this are well-known techniques.

  Next, the hybridized substrate shown in FIG. 13B is divided into chips 51 by dicing. FIG. 15 shows this state. Thus, a plurality of chips 51 are completed at once.

  Thereafter, through known steps such as wire bonding and resin sealing, the display device 21 according to the present embodiment shown in FIG. 6 is completed.

  According to the display device 21 of the present invention, as described above, since the groove 61a is formed in the substrate 61, it is possible to suppress crosstalk in which light emitted from adjacent fluorescent layers intersects, and display with high contrast is possible. Become.

  [Second Embodiment]

  FIG. 16 is a schematic enlarged cross-sectional view showing a hybridized chip 111 of the display device according to the second embodiment of the present invention, and corresponds to FIG. 16, elements that are the same as or correspond to those in FIG. 7 are given the same reference numerals, and redundant descriptions thereof are omitted.

  The display device according to the present embodiment is different from the display device 21 according to the first embodiment only in the points described below.

  In the present embodiment, a chip 111 is used instead of the chip 51 shown in FIG. The only difference between the chip 111 and the chip 51 is that the LED substrate 112 is used instead of the LED substrate 52. The LED substrate 112 is different from the LED substrate 52 in that the substrate 113 is used instead of the substrate 61, and the fluorescent layers 62R, 62G, and 62B are provided on the opposite side of the active layer 64 from the substrate 113. It is only a point.

  In the present embodiment, the substrate 113 is a substrate serving as a basis for epitaxial growth of the n-type impurity layer 63 and the like of the LED component layer 70, and for example, a sapphire substrate or a SiC substrate is used, and ultraviolet light from the active layer 64 is emitted. To Penetrate. Similar to the groove 61 a of the substrate 61, a groove 113 a is formed at a position between adjacent LED elements on the substrate 113. The groove 113 a is formed substantially perpendicular to the surface of the substrate 113.

  In the red LED element 41R, when a current flows between the electrodes 66 and 67, ultraviolet light is emitted from the active layer 64, and the ultraviolet light passes through the substrate 113 and enters the fluorescent layer 62R. The fluorescent layer 62R is excited by the incident ultraviolet light to emit red light, and the red light generates display light above.

  In the green LED element 41G, when a current is passed between the electrodes 66 and 67, ultraviolet light is emitted from the active layer 64, and this ultraviolet light passes through the substrate 113 and enters the fluorescent layer 62G. The fluorescent layer 62G is excited by the incident ultraviolet light to emit green light, and the green light generates display light on the upper side.

  In the blue LED element 41B, when a current flows between the electrodes 66 and 67, ultraviolet light is emitted from the active layer 64, and this ultraviolet light passes through the substrate 113 and enters the fluorescent layer 62B. The fluorescent layer 62B emits blue light when excited by the incident ultraviolet light, and the blue light generates display light upward.

  The ultraviolet light emitted from each active layer 64 of the LED elements 41R, 41G, and 41B tends to travel not only upward but also in various directions. Therefore, if there is no groove 113a, the ultraviolet light emitted from the active layer 64 of each LED element mixes with the ultraviolet light emitted from the active layer 64 of the adjacent LED element, and crosstalk occurs. For example, ultraviolet light emitted from the active layer 64 of the red LED element 41R enters the fluorescent layer 62G of the green LED element 41G, and thereby green light is emitted from the fluorescent layer 62G of the green LED element 41G. On the other hand, since the groove 113a is formed in the substrate 113, the ultraviolet light is totally reflected on the surface of the groove 113a, so that the direction in which the ultraviolet light emitted from the active layer 64 of one LED element is emitted is concentrated to some extent. The directionality is determined. For this reason, it is possible to suppress crosstalk in which ultraviolet light emitted from the adjacent active layer 64 intersects, and display with high contrast becomes possible. The groove 113a may be left empty, but the same crosstalk suppressing effect can be obtained even if the groove 113a is embedded with a light reflecting material such as metal or formed on the surface of the groove 113a by vapor deposition or the like. . Further, the surface of the groove 113a may be a surface that blocks light by embedding a light absorbing material or the like in the groove 113a. In this case, although the light utilization efficiency is lowered, the crosstalk suppressing effect can still be obtained.

  In the display device according to the present embodiment, the portions other than the chip 111 may be configured similarly to the portions other than the chip 51 in FIG. 6, but the fluorescent layers 62R, 62G, and 62B are formed on the upper surface of the substrate 113a. Since it is formed, it is preferable to configure in the same manner as the portion other than the chip 51 in FIG.

  Next, an example of a method for manufacturing the display device according to the present embodiment will be described with reference to FIGS. 17 to 19 are schematic cross-sectional views schematically showing each step of the manufacturing method.

  First, a substrate 113 serving as a basis for epitaxially growing the n-type impurity layer 63 and the like of the LED constituent layer 70 is prepared. As the substrate 113, for example, a sapphire substrate or a SiC substrate is used. Next, the LED constituent layer 70 is formed on the substrate 113 by the amount of the LED elements 41R, 41G, and 41B of the plurality of chips 111 to be manufactured at once. That is, the n-type impurity layer 63, the active layer 64, and the p-type impurity layer 65 are sequentially formed on the substrate 113 by epitaxial growth, and unnecessary regions of the active layer 64 and the p-type impurity layer 65 are removed by etching. At this time, the n-type impurity layer 63 remains formed on the entire surface of the substrate 91. Then, the electrodes 66 and 67 are formed of gold or the like and patterned into a predetermined shape by etching. FIG. 17A shows this state.

  Next, a groove 113a is formed at a position between adjacent LED elements on the substrate 113 by dry etching or the like (FIG. 17B).

  On the other hand, the drive circuit board 53 is prepared using a known semiconductor process technique (FIG. 17C). Here, the drive circuit board 53 is provided with a CMOS circuit by a general CMOS process, for example. Then, as shown in FIG. 18A, bumps 71 and 72 for electrically connecting to the LED elements 41R, 41G, and 41B are formed on the driving circuit board 53.

  Next, the substrate in the state shown in FIG. 17B and the drive circuit substrate 53 on which the bumps 71 and 72 are formed are aligned as shown in FIG. Such alignment is performed, and the electrodes 66 and 67 and the bumps 71 and 72 are bonded to each other. FIG. 18B shows this state. Such bonding by bumps and hybridization by this are well-known techniques.

  Next, the fluorescent layers 62R, 62G, and 62B are formed on the substrate 113 by, for example, silk screen printing. FIG. 19 shows this state.

  Subsequently, the hybridized substrate in the state shown in FIG. 19 is divided into chips 111 by dicing. As a result, a plurality of chips 111 are completed at once. Thereafter, the display device according to this embodiment is completed through known processes such as wire bonding and resin sealing.

  According to the display device of the present invention, as described above, since the groove 113a is formed in the substrate 113, it is possible to suppress crosstalk in which ultraviolet light emitted from the adjacent active layer 64 intersects, and display with high contrast is possible. It becomes.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

  For example, in the display device according to the first or second embodiment, if each unit pixel is composed of only one of the red LED element 41, the green LED element 41G, and the blue LED element 41B, a display device that performs monochrome display. It can be. Further, for example, in the display device according to the second embodiment, the fluorescent layers 62R, 62G, and 62B are removed, and the active layer 64 in each LED element is made of a material that emits visible light of any predetermined color. Therefore, a display device that performs monochrome display can be obtained.

1 is a schematic block diagram showing a display device according to a first embodiment of the present invention. It is a circuit diagram which shows the unit pixel in FIG. It is a figure which shows arrangement | positioning of the LED element of the display apparatus by the 1st Embodiment of this invention. It is a figure which shows the other example of arrangement | positioning of an LED element. It is a figure which shows the other example of arrangement | positioning of an LED element. It is a schematic sectional drawing which shows the display apparatus by the 1st Embodiment of this invention. It is a general | schematic expanded sectional view which expands and shows the chip | tip in FIG. FIG. 8 is a schematic plan view schematically showing a unit pixel portion of the LED substrate of the chip shown in FIGS. 6 and 7. FIG. 8 is a schematic plan view schematically showing a unit pixel portion of a drive circuit board of the chip shown in FIGS. 6 and 7. It is a schematic sectional drawing which shows the modification of the display apparatus by the 1st Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the display apparatus by the 1st Embodiment of this invention. FIG. 12 is a cross-sectional view showing a step that follows FIG. 11. FIG. 13 is a cross-sectional view showing a step that follows the step in FIG. 12. It is a schematic perspective view which shows typically 1 process of the manufacturing method of the display apparatus by the 1st Embodiment of this invention. FIG. 14 is a cross-sectional view showing a step that follows the step in FIG. 13. It is a general | schematic expanded sectional view which expands and shows the hybridized chip | tip of the display apparatus by the 2nd Embodiment of this invention. It is sectional drawing which shows 1 process of the manufacturing method of the display apparatus by the 2nd Embodiment of this invention. FIG. 18 is a cross-sectional view showing a step that follows the step in FIG. 17. FIG. 19 is a cross-sectional view showing a step that follows the step in FIG. 18.

Explanation of symbols

21 display device 41R, 41G, 41B LED element 51, 111 chip 52, 112 LED substrate 53 drive circuit substrate 61, 113 substrate 61a, 113a groove 62R, 62G, 62B fluorescent layer 64 active layer (light emitting layer)
70 LED component layers

Claims (7)

A display device that performs color display or monochrome display based on a video signal or other display control signal,
A substrate that transmits light in a predetermined wavelength range;
A plurality of LED elements provided two-dimensionally on the substrate;
Each LED element has a light emitting layer provided on one side of the substrate,
Display light is generated based on light from the light emitting layer of each LED element and light transmitted through the substrate,
A display device, wherein a groove for forming a surface that reflects or blocks light is formed at a position between at least two adjacent LED elements of the plurality of LED elements on the substrate.   The display device according to claim 1, wherein the groove is empty.   The display device according to claim 1, wherein the groove is embedded with a light reflecting material, or a light reflecting material is formed on a surface of the groove.   The at least one LED element of the plurality of LED elements has a fluorescent layer including a fluorescent material that emits light when excited by light from the light emitting layer of the LED element. The display apparatus in any one of.   The display device according to claim 4, wherein the fluorescent layer is provided on a side of the substrate opposite to the light emitting layer of the LED element.   The display device according to claim 4, wherein the fluorescent layer is provided between the light emitting layer of the LED element and the substrate.   2. A circuit board mounted with a drive circuit for driving the plurality of LED elements based on the video signal or the display control signal and electrically connected to the plurality of LED elements. The display device according to any one of 1 to 6.

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