JP5909162B2 - Light emitting element - Google Patents

Description

  The present invention relates to a light emitting element used in a display device for stereoscopic images and the like.

  Typical methods of image reproduction type stereoscopic display include holography, parallax stereogram, lenticular sheet, integral photography (hereinafter referred to as IP), etc. (for example, refer to Non-Patent Document 1). Is a method that can express parallax information in the vertical direction without using coherent light, and is considered promising for early realization of a device capable of natural stereoscopic display with less fatigue (for example, Non-Patent Document 2). reference).

  The IP display system includes a lens array in which a large number of minute lenses (element lenses) that reproduce light rays are arranged, and a display that displays a large number of images (element images) corresponding to each lens. The observer visually obtains partial information corresponding to the position of the observer from one element image corresponding to one element lens, and observes a stereoscopic image in which these are arranged by the number of element lenses. . That is, the resolution of the stereoscopic image is determined by the resolution of the element lens, the resolution of the element image, and the viewing distance, and the performance of the element lens is a dominant factor for the viewing zone angle of the system. Under such circumstances, in order to generate a practical stereoscopic image by the IP method, it is indispensable to increase the definition and function of the light emitting element and the optical element (for example, see Non-Patent Document 3).

  However, even if the definition of the light emitting element and the optical element is increased, there are performance limits that cannot be removed in principle, such as the diffraction limit of the lens and the focal length, in the system using the lens. For example, if the pixel size of the display becomes smaller than the minimum spot size of the element lens, image blurring occurs, so it is necessary to simultaneously reduce the spot size, but it is impossible in principle to make this smaller than the Abbe diffraction limit. It is. The viewing zone angle in a system using a lens is inversely proportional to the focal length of the element lens, but it cannot be made infinitely small. Furthermore, since the viewing zone angle is proportional to the pitch of the element lens, there is a trade-off relationship between the resolution and the viewing zone angle in the system using the lens. Therefore, if a light-emitting element that can form a light beam with a minute width according to the surface shape of the element and control the radiation direction without using a lens can be realized, the stereoscopic image forming technology can be dramatically advanced. Become.

  In recent years, LEDs that have been attracting attention in various applications due to their improved light emission characteristics are so strong in the straightness of emitted light that a mechanism for diffusing light is required for application to lighting equipment or the like (see, for example, Patent Documents 1 and 2). ) And excellent light emission characteristics such as high color purity, it is considered to be a promising device that can be used for applications in which the radiation direction can be controlled. A basic characteristic required for a directional light-emitting element is to form a narrow light beam (light beam formation) while suppressing the intensity of light (stray light) other than a desired light beam, and radiate it in an arbitrary direction (azimuth control). . As described above, the LED has a strong straightness, but structural ingenuity is indispensable for forming a light beam that travels in one direction while suppressing stray light, and proposals aiming at this have been made (for example, Patent Documents 3 and 3). 4, 5, 6).

  However, since these are structures in which the light emitting part and the light beam forming or diffusing part (hereinafter collectively referred to as the light wave control part) are independent, it is difficult to align the light emitting part and the diffusing part. This is a big problem in a display device in which a large number of elements are arranged. Furthermore, since the resolution of the three-dimensional image formed by the IP method is a resolution corresponding to the density of the light beam, it is necessary to keep the light beam width corresponding to the reciprocal of the maximum value of the light beam density. If the light wave control unit is separated, miniaturization is difficult. The orientation control can be realized by a structural device or a combination of many fine structures (see, for example, Patent Documents 7, 8, and 9). However, for example, in order to achieve a VGA class resolution with a viewing angle of 20 degrees using a substrate of about 50 type, it is necessary to suppress the size of the light emitting element used for forming one light beam to about 10 μm. As described above, complicated or many fine structures cannot be used. However, for LEDs, it is possible to form a fine structure by applying a fine processing technique or controlling crystal growth (see, for example, Patent Documents 10 and 11). If the (or patterning range) becomes clear, application to a stereoscopic display device is possible.

JP 2008-258302 A JP 2010-257573 A JP 2007-79093 A JP 2008-147182 A JP 2008-293858 A JP 2009-53345 A JP-A-10-240165 JP 2009-4443 A JP 2010-27875 A JP 2010-257573 A JP 2010-285640 A

Yasuo Taki et al., "Image Engineering", Corona, 1972, pp.277-326 “The Journal of the Institute of Electrical, Information and Communication Engineers”, May 2010, Vol.93, No.5, pp.372-381 Japan Association for Mechanical Systems Promotion and Japan Optical Industry Technology Promotion Association, “Survey Report on Formation of Spatial Image that Enables Natural Stereoscopic Viewing—Abstract”, System Technology Development Survey 19-R-5, pp .14-16, March 2008

  As described above, in the conventional technology, it is impossible to control the radiation direction by forming a light beam with a single light emitting element, so in the IP display system, a three-dimensional image must be displayed using a lens array, Performance limits such as lens diffraction limit and focal length could not be exceeded.

  This invention is made | formed in view of this point, Comprising: It aims at providing the light emitting element which can form a light ray with a single light emitting element, and can control a radiation direction.

  In order to solve the above-described problem, a light emitting device according to claim 1 is a light emitting device including a semiconductor light emitting layer between an n type semiconductor layer and a p type semiconductor layer, on the n type semiconductor layer or the p type semiconductor layer. A transparent dielectric layer formed on the transparent dielectric layer having a dielectric constant smaller than that of the n-type semiconductor layer and the p-type semiconductor layer, and the same transparent dielectric as the transparent dielectric layer formed on the transparent dielectric layer And a plurality of dielectric columnar portions that serve as waveguides for light generated in the semiconductor light emitting layer, and the plurality of dielectric columnar portions are annularly arranged on the transparent dielectric layer, and are the same The first column group composed of at least one dielectric columnar part having a height is different from the dielectric columnar part constituting the first column group, and each has at least the same height. Second pillar composed of one dielectric pillar And it was to consist of configuration.

  The light emitting device having such a configuration can form a light beam by interference of light emitted from the radiation surfaces of the plurality of dielectric columnar portions, and the dielectric columnar portions constituting the first column group; By making the heights of the dielectric columnar portions constituting the second column group different from each other, the light propagating inside the dielectric columnar portion having a low height is more than the light propagating inside the dielectric columnar portion having a high height. It quickly reaches the radiation surface at the tip of the column and advances quickly through the air. Therefore, the light emitting element can provide a phase difference between light traveling through the dielectric columnar portions having different heights, and can emit a light beam in a direction corresponding to the phase difference. The first column group and the second column group include a case where only one dielectric columnar portion is provided here.

  In addition, the light emitting element needs to grow the columnar structure by crystal growth as in the case where the columnar structure is formed of a semiconductor material by forming the columnar structure with a transparent dielectric that is easier to process than the semiconductor material. Therefore, strict control of crystal growth conditions and the like is not necessary, and the applicable processing method is not limited as in the case where the columnar structure is formed of a semiconductor material. In the light emitting element, since the columnar structure is formed of a transparent dielectric, light absorption by the columnar structure can be suppressed compared to the case where the columnar structure is formed of an opaque material. The amount of light that can be extracted from the light emitting element can be increased.

  The light-emitting element according to claim 2 is the light-emitting element according to claim 1, wherein a plurality of dielectric columnar portions are arranged in an annular shape on the transparent dielectric layer, and the second column group is It was set as the structure comprised from the dielectric pillar part less than the half of the total number of several dielectric pillar part.

  In the light emitting device having such a configuration, the dielectric columnar portions constituting the second column group are set to half or less of the total number of the dielectric columnar portions, and the dielectric columnar portions constituting the first column group By making it different from the height, a phase difference can be provided in the light emitted from each radiation surface, and a light beam can be emitted in a direction corresponding to the phase difference.

  A light emitting device according to claim 3 is the light emitting device according to claim 1, wherein a plurality of dielectric columnar portions are arranged in a ring shape on the transparent dielectric layer, and the first column group and the second column are arranged. Each group was composed of three dielectric pillars.

  The light emitting element having such a configuration can form a light beam by interference of light radiated from the radiation surfaces of the six dielectric columnar portions, and 3 of the six dielectric columnar portions. By making the heights of the books different, the light propagating inside the three dielectric columnar portions having a low height is emitted at the tip of the column more than the light propagating inside the three dielectric columnar portions having a high height. Reach the surface early and advance quickly in the air. Therefore, the light emitting element can provide a phase difference between light traveling through the dielectric columnar portions having different heights, and can emit a light beam in a direction corresponding to the phase difference.

  The light-emitting device according to claim 4 is the light-emitting device according to claim 2 or claim 3, wherein the plurality of dielectric columnar portions are on the same circumference on the transparent dielectric layer. It was set as the structure arrange | positioned circularly so that it may be located at equal intervals.

  A light emitting device having such a configuration has a plurality of dielectric columnar portions arranged at equal intervals on the circumference, so that when light is emitted from the emission surface of the plurality of dielectric columnar portions, As a result, extra light (stray light) other than the light that is formed as follows will not be disturbed by being fixed at a specific location.

  The light-emitting device according to claim 5 is the light-emitting device according to any one of claims 1 to 4, wherein the dielectric columnar portion constituting the first column group and the dielectric columnar shape constituting the second column group. The difference in height from the part is equal to or less than the wavelength of light propagating through the dielectric columnar part.

  A light-emitting element having such a configuration has a difference in height between a plurality of dielectric columnar portions that is equal to or less than the wavelength of light propagating through the dielectric columnar portions, so that the position of the radiation surface of each dielectric columnar portion is reduced. Is not too far away, the light emitted from the respective emission surfaces can be easily interfered with, and the generation of stray light can be suppressed.

  According to the first aspect of the present invention, by providing a plurality of dielectric columnar portions, a light beam can be formed by a single light emitting element, and the dielectric columnar portions and the second column group constituting the first column group are provided. The azimuth angle of the formed light beam can be controlled by making the heights of the dielectric columnar parts to be configured different. According to the first aspect of the present invention, the light emitting element can be easily manufactured and the output of the light emitting element can be enhanced by forming the dielectric columnar portion with the transparent dielectric. .

  According to the invention which concerns on Claim 2, the azimuth angle of the formed light beam can be controlled by making the heights of the dielectric columnar portions equal to or less than half of the three to six dielectric columnar portions differ. .

  According to the invention of claim 3, by providing six dielectric columnar portions, light can be formed by a single light emitting element, and the height of three columns of the six dielectric columnar portions can be increased. By making the heights different, the azimuth angle of the formed light beam can be controlled.

  According to the fourth aspect of the present invention, extra light (stray light) other than the light formed as a light beam does not get stuck in a specific location and can be prevented, so that the quality of the formed light beam can be improved. .

  According to the invention which concerns on Claim 5, since the influence of a stray light can be suppressed when forming a light ray, it can make it easier to control the radiation | emission direction of the formed light ray.

It is a perspective view which shows the light emitting element which concerns on embodiment of this invention. 1A and 1B are diagrams showing a light emitting element according to an embodiment of the present invention, wherein FIG. 1A is a plan view of the light emitting element, and FIG. In the light emitting element concerning the embodiment of the present invention, it is a schematic diagram for explaining the relation between the ratio of the height difference of a dielectric columnar part, and the phase on a central axis. (A)-(f) is schematic which shows an example of the manufacturing method of the light emitting element which concerns on embodiment of this invention. (A)-(f) is schematic which shows the other example of the manufacturing method of the light emitting element which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the light emitting element used in the simulation of the Example of the light emitting element which concerns on embodiment of this invention, and a comparative example, (a) is sectional drawing which shows the light emitting element of an Example, (b) is a comparison. It is sectional drawing which shows the light emitting element of an example. It is a figure which shows the simulation result of the Example of the light emitting element which concerns on embodiment of this invention, and a comparative example, Comprising: The intensity | strength of light when changing the ratio of the difference of the column height with respect to the height of a waveguide column is shown. FIG. It is a figure which shows the simulation result of the Example of the light emitting element which concerns on embodiment of this invention, and a comparative example, Comprising: The ratio of the difference of the height of a pillar with respect to the height of a waveguide pillar, and the azimuth | direction of the light ray emitted from a light emitting element It is a graph which shows the relationship with a corner. It is a figure which shows the simulation result of the light emitting element which concerns on embodiment of this invention, Comprising: The transmittance | permeability of a light emitting element in the case of laminating | stacking a medium on an n-type semiconductor layer or a p-type semiconductor layer, and an n-type semiconductor layer or p It is a graph which shows the relationship between the ratio with the transmittance | permeability when not laminating | stacking a medium on a type | mold semiconductor layer, and the refractive index of a medium. FIG. 6 is a schematic diagram for explaining a method for calculating the transmittance of a light emitting device according to an embodiment of the present invention, where (a) illustrates a case where a medium is not stacked on an n-type semiconductor layer or a p-type semiconductor layer; ) Is a case where a medium is stacked on the n-type semiconductor layer or the p-type semiconductor layer. It is the schematic which shows the example which applied the light emitting element which concerns on this invention to IP stereoscopic display, Comprising: (a) is a front view of IP stereoscopic display, (b) is a perspective view of IP stereoscopic display.

  Hereinafter, light-emitting elements according to embodiments of the present invention will be described with reference to the drawings. In addition, the size, positional relationship, and the like of members shown in each drawing may be exaggerated for convenience of explanation. Furthermore, in the following description, the same name and reference sign indicate the same or the same members in principle, and the detailed description will be omitted as appropriate.

[Structure of light-emitting element]
The structure of the light-emitting element 1 according to the embodiment of the present invention will be described with reference to FIGS. The light-emitting element (light-emitting light-emitting element) 1 is a semiconductor element that emits light by applying a voltage. Examples of the light emitting element 1 include a solid light emitting element having a substantially flat surface such as an LED. As shown in FIG. 1, the light emitting element 1 has a structure in which a semiconductor light emitting layer 10, an n-type semiconductor layer 20, a p-type semiconductor layer 30, and a transparent dielectric layer 40 are laminated.

  Although not shown in FIG. 1, an electrode for causing the semiconductor light emitting layer 10 to emit light is interposed between the n-type semiconductor layer 20 and the p-type semiconductor layer 30, for example, like a general LED element. A step can be provided, and an ohmic contact can be formed in a portion drawn from the step. However, the structure of the electrode is not particularly limited. For example, a p-electrode is provided on the lower surface of the n-type semiconductor layer 20 or the upper surface of the p-type semiconductor layer 30, and the n-electrode is provided on the side surface of the n-type semiconductor layer 20 or the p-type semiconductor layer 30. It does not matter as a structure to provide. A general metal electrode can be used as an electrode material. Further, the light emitting element 1 may have a configuration including a substrate (not shown) under the n-type semiconductor layer 20.

  The semiconductor light emitting layer 10 is a layer that emits as light energy generated by recombination of electrons and holes injected from the n-type semiconductor layer 20 and the p-type semiconductor layer 30. The semiconductor light emitting layer 10 is formed by adding an impurity such as In to the junction between the n-type semiconductor layer 20 and the p-type semiconductor layer 30, and is formed as an InGaN quantum well layer, for example. As shown in FIG. 1, the semiconductor light emitting layer 10 is formed between the n-type semiconductor layer 20 and the p-type semiconductor layer 30, and is formed in a rectangular shape here. The thickness of the semiconductor light emitting layer 10 is not particularly limited.

  The n-type semiconductor layer 20 is a layer that injects electrons into the semiconductor light emitting layer 10. The n-type semiconductor layer 20 is formed by stacking, for example, an n-type GaN layer and an n-type GaN / InGaN barrier layer sequentially from the bottom. As shown in FIG. 1, the n-type semiconductor layer 20 is formed in the lower part of the semiconductor light emitting layer 10, and is formed in a rectangular shape here. Note that the thickness of the n-type semiconductor layer 20 is not particularly limited.

  The p-type semiconductor layer 30 is a layer that injects holes into the semiconductor light emitting layer 10. The p-type semiconductor layer 30 is formed, for example, by laminating a p-type GaN / InGaN barrier layer and a p-type GaN layer sequentially from the bottom. As shown in FIG. 1, the p-type semiconductor layer 30 is formed on the semiconductor light emitting layer 10, and is formed in a rectangular shape here. Note that the thickness of the p-type semiconductor layer 30 is not particularly limited.

  The transparent dielectric layer 40 is a layer made of a dielectric material that transmits light. The transparent dielectric layer 40 is made of a transparent dielectric having a dielectric constant (relative dielectric constant) smaller than that of the n-type semiconductor layer 20 and the p-type semiconductor layer 30 described above. More specifically, the transparent dielectric layer 40 is higher than the dielectric constant (= about 1) of air, and is higher than the dielectric constant of the light emitting material (for example, GaN) constituting the n-type semiconductor layer 20 and the p-type semiconductor layer 30. It has a low dielectric constant. This relationship is the same in the case of the refractive index (square root of the dielectric constant), and the transparent dielectric layer 40 is higher than the refractive index of air (= about 1), and the n-type semiconductor layer 20 and the p-type semiconductor layer. 30 has a refractive index lower than the refractive index of the light emitting material (for example, GaN) constituting 30.

When the n-type semiconductor layer 20 and the p-type semiconductor layer 30 are made of, for example, GaN, the transparent dielectric layer 40 is made of SiO ₂ , SiO, SiN, MgF ₂ , ZrO having a lower dielectric constant and refractive index than GaN. It is formed of a transparent dielectric such as ₂ . However, the transparent dielectric is not limited to these, and a resin material such as a thermoplastic resin or a photocurable resin can also be used. On the transparent dielectric layer 40, as shown in FIG. 1, a plurality of dielectric columnar portions 41 and 42 made of the same transparent dielectric as the transparent dielectric layer 40 are formed. The thickness of the transparent dielectric layer 40 is not particularly limited.

  The dielectric columnar portions 41 and 42 form a light beam and control the direction of the light beam. Here, as shown in FIG. 1, six dielectric columnar portions 41 and 42 are formed on the transparent dielectric layer 40. Further, the dielectric columnar portions 41 and 42 are each formed in a columnar shape as shown in FIG.

  The dielectric columnar portions 41 and 42 function as a waveguide for light generated from the semiconductor light emitting layer 10. Here, for example, an LED generally has a coherence length of about 10 to 50 μm, so that light having different path lengths in the minute space as described above forms a spatial distribution due to the interference effect. Therefore, the light propagating through the dielectric columnar portions 41 and 42 is directed in a direction perpendicular to the element surface from the radiation surfaces 41a and 42a (see FIG. 2B) which are the uppermost surfaces of the dielectric columnar portions 41 and 42, that is, After being radiated upward in FIG. 1, the light interferes with the light interference effect, and one light beam is generated in the direction perpendicular to the element surface from the center of gravity O (see FIG. 2A) of the element surface. The The element surface here means specifically the upper surface of the transparent dielectric layer 40 shown in FIG.

  Here, as shown in FIG. 1, the dielectric columnar portions 41 and 42 are formed at different heights for every three. That is, the dielectric columnar portions 41 and 42 are formed so that the height of the three dielectric columnar portions 42 is different from the height of the other three dielectric columnar portions 41, as shown in FIG. Here, the dielectric columnar portion 42 is formed so that its height is lower than the height of the dielectric columnar portion 41. Further, as shown in FIG. 1, the three dielectric columnar portions 41 have the same height, and the three dielectric columnar portions 42 have the same height. Further, as shown in FIG. 1, among the six dielectric columnar portions 41, 42, the three high dielectric columnar portions 41 are arranged adjacent to each other on the transparent dielectric layer 40. In addition, the three dielectric columnar portions 41 having low heights are also arranged adjacent to each other on the transparent dielectric layer 40.

  Here, a column group constituted by three dielectric columnar portions 41 having a high height is defined as a “first column group”, and three dielectric columnar portions 42 having a low height are defined. The group of pillars to be configured is defined as “second pillar group”. In this case, as shown in FIG. 1, the first column group and the second column group are each composed of three dielectric columnar portions 41 and three dielectric columnar portions 42.

  As described above, the light emitting element 1 is configured so that the three dielectric columnar portions 42 of the dielectric columnar portions 41 and 42 have different heights from the other three dielectric columnar portions 41. The direction of light (azimuth angle) can be controlled according to the difference. If the heights of the dielectric columnar portions 41 and 42 are all the same (when there is no difference in height), the light beam formed by the dielectric columnar portions 41 and 42 is emitted in a direction perpendicular to the element surface. The Details of the direction control of the light beam by the dielectric columnar portions 41 and 42 will be described later.

  As shown in FIGS. 1 and 2B, the dielectric columnar portions 41 and 42 are configured integrally with the transparent dielectric layer 40. The dielectric columnar portions 41 and 42 can be formed, for example, by processing the rectangular transparent dielectric layer 40 formed up to the height of the dielectric columnar portions 41 and 42 in the manufacturing stage of the light emitting element 1. . Specifically, the dielectric columnar portions 41 and 42 are formed by using a known technique such as a focused ion beam (FIB), photolithography, a combination of electron beam lithography and etching, or the like. Can be formed on top.

As the light emitting element 1, for example, the p-type semiconductor layer 30 or the n-type semiconductor layer 20 is crystal-grown or etched without providing the transparent dielectric layer 40, so that the p-type semiconductor layer 30 or the n-type semiconductor layer 20 is formed. It is also conceivable to form a columnar structure made of the same semiconductor material (for example, GaN) as above. However, in this case, strict control of crystal growth conditions is required, applicable processing methods are limited depending on the semiconductor material, and physical and chemical damage to the semiconductor is also taken into consideration. Manufacture is not easy because it must be done. In addition, since the semiconductor material such as GaN constituting the columnar structure is an opaque material, there is a drawback that the amount of light that can be extracted from the light emitting element 1 is not sufficient. On the other hand, as shown in FIG. 1, the dielectric columnar portions 41 and 42 are formed of a transparent dielectric material such as SiO ₂ that is much easier to process than a semiconductor material such as GaN. The directional light emitting device 1 that can be formed and whose emission direction can be controlled can be easily manufactured, and the output of the light emitting device 1 can be enhanced.

As shown in FIG. 2A, the dielectric columnar portions 41 and 42 are each formed in a circular shape in plan view, and are formed on the transparent dielectric layer 40 with the same cross-sectional area. Further, the ratio of the cross-sectional area of the dielectric columnar portions 41 and 42 to the area of the upper surface of the transparent dielectric layer 40 is not particularly limited. As shown in FIG. 2A, the dielectric columnar portions 41 and 42 are formed to have the same diameter, and are specifically set to the wavelength of light in free space (in the air). ing. In the following description, the wavelength of light in the above-described free space is described as “external wavelength λ ₀ ”.

As shown in FIG. 2A, the dielectric columnar portions 41 and 42 are annularly arranged so that the central axes of the respective columns are positioned on the same circumference C at equal intervals. In other words, as shown in FIG. 2A, the dielectric columnar portions 41 and 42 are arranged adjacent to each other on a circumference C centering on the center of gravity O formed by the dielectric columnar portions 41 and 42. Yes. Further, as shown in FIG. 2A, the circumference C has a radius set to λ ₀ (or a diameter of 2λ ₀ ). The dielectric columnar portions 41 and 42 arranged symmetrically with respect to the center of gravity O on the circumference C set the distance connecting the central axes of the respective columns to 2λ ₀ as shown in FIG. Has been. As described above, the light emitting element 1 has the dielectric columnar portions 41 and 42 arranged at equal intervals on the circumference, so that light is emitted from the radiation surfaces 41a and 42a of the dielectric columnar portions 41 and 42. Since extra light (stray light) other than the light formed as a light beam does not get stuck in a specific place and interfere with it, the quality of the formed light beam can be improved.

The height of the dielectric columnar portion 41 constituting the first column group and the height of the dielectric columnar portion 42 constituting the second column group are approximately the wavelength of light propagating inside the dielectric columnar portions 41 and 42, respectively. Alternatively, the height is set several times higher. In the following description, the height of the dielectric columnar portion 41 is described as “H”, the difference in height between the dielectric columnar portion 41 and the dielectric columnar portion 42 is defined as “d”, and the dielectric columnar portion The height of 42 will be described as “Hd”, and the wavelength of light propagating through the dielectric columnar portions 41 and will be described as “internal wavelength λ ₁ ”. The internal wavelength λ ₁ and the external wavelength λ ₀ have a relationship of “λ ₁ = λ ₀ / n” where n is the refractive index of the dielectric columnar portions 41 and 42.

  Here, when the ratio of the column height difference d to the height H of the dielectric columnar portion 41 (= d / H) is “δ”, the height between the dielectric columnar portion 41 and the dielectric columnar portion 42 is high. The difference d can be expressed by d = δH. In the following description, the height difference d between the dielectric columnar portion 41 and the dielectric columnar portion 42 is referred to as “column height difference δH”, and the difference in column height with respect to the height H of the dielectric columnar portion 41. The ratio δ of d will be described as “column height difference ratio δ”.

The difference in height of the pillar height difference δH and the dielectric pillar portion 41 constituting the first pillar group a dielectric columnar portion 42 constituting the second pillar group is adjusted on the basis of the internal wavelength lambda ₁ described above It is specifically set below the internal wavelength lambda _1. Thereby, since the light emitting element 1 does not leave the radiation surfaces 41a and 42a of the dielectric columnar portions 41 and 42 too far apart, the light emitted from the radiation surfaces 41a and 42a can easily interfere with each other. Generation of stray light can be suppressed, and the emission direction of the formed light beam can be controlled more easily.

Here, as will be described later, when the value of the column height difference ratio δ (or column height difference δH) is increased, the angle θ ₁ (hereinafter referred to as the azimuth angle θ ₁ ) formed by the light with respect to the direction perpendicular to the element surface increases. To do. Hereinafter, the relationship between the column height difference δH and the azimuth angle θ ₁ will be described with reference to FIG. 3 (refer to FIG. 2B as appropriate).

FIG. 3 schematically shows only the p-type semiconductor layer 30, the transparent dielectric layer 40, and the dielectric columnar portions 41 and 42 extracted from the light-emitting element 1 shown in FIG. 3 indicates a light propagation path in the dielectric columnar portion 41, and an optical path B indicates a light propagation path in the dielectric columnar portion. As shown in FIG. 3, since the light passing through the optical paths A and B travels in the same medium up to altitude h1 (height Hd of the dielectric columnar portion 42), it remains in the same phase, but the altitude h1. To the height h2 (height H of the dielectric columnar portion 41), the medium is different. Therefore, the phase θ ₂ + α of the light passing through the optical path A at the point of the altitude h2 and the phase θ ₂ + β of the light passing through the optical path B at the point of the altitude h2 are expressed by the following equations (1) and (2). As such, the values are different.

θ ₂ + α = θ ₂ + 2πδH / (λ ₀ / n) (1)
θ ₂ + β = θ ₂ + 2πδH / λ ₀ Formula (2)

Further, since the space between the altitude h2 and the altitude h3 is a free space, the length of the optical path from the upper end (h2) to the central axis is equal to the medium, and the phase difference Ψ () between the phase θ ₂ + α and the phase θ ₂ + β is described above. = (Θ ₂ + α) − (θ ₂ + β)) is stored as shown in the following equation (3).

Ψ = (2πδH / λ ₀ ) (n−1) (3)

Therefore, as shown in the following formula (4), the phase difference Ψ between the dielectric columnar part 41 and the dielectric columnar part 42 is adjusted by adjusting the column height difference δH between the dielectric columnar part 41 and the dielectric columnar part 42. It can be seen that can be controlled. Since the light emitted from the radiation surface 41a of the dielectric columnar part 41 and the radiation surface 42a of the dielectric columnar part 42 has a phase difference Ψ at the point of the altitude h2 in FIG. When the light interferes with each other, one light beam is generated in a direction inclined by a predetermined angle θ _{1 with} respect to the direction perpendicular to the element surface in accordance with the phase difference Ψ described above. Therefore, by adjusting the column height difference δH between the dielectric columnar part 41 and the dielectric columnar part 42 to control the phase difference Ψ, the light beam can be emitted in the direction of the desired azimuth angle θ ₁ . As shown in FIG. 3, when the dielectric columnar portion 42 is lower than the dielectric columnar portion 41 by the column height difference δH, this one light beam has a predetermined angle θ ₁ toward the dielectric columnar portion 42. Only tilted and radiated. Since H in the column height difference δH is a fixed value, the phase difference Ψ between the dielectric columnar portion 41 and the dielectric columnar portion 42 can be controlled by adjusting the column height difference ratio δ.

δH = (Ψ / 2π) {1 / (n−1)} λ ₀ Formula (4)

  Since the light passing through the dielectric columnar portion 41 is delayed as compared with the light passing through the dielectric columnar portion 42, when they are mixed, a wave having a completely different wavefront from the wavefront of the two lights is generated. Is done. That is, the wavefronts of light emitted from the radiation surfaces 41a and 42a of the dielectric columnar portions 41 and 42 interfere with each other, and the relative positions of the radiation surfaces 41a and 42a of the two dielectric columnar portions 41 and 42 (3 Light is emitted in an orientation determined by the position of the dimensional space.

Next, interference of light radiated from the dielectric columnar part 41 as the wave source at the position r ₁ in the three-dimensional space and the dielectric columnar part 42 as the wave source at the position r ₂ in the three-dimensional space will be described. The intensity I (r) of the light synthesized at the time r in the three-dimensional space r by the light emitted from the wave source at the position r ₁ and the wave source at the position r ₂ is expressed by the following equation (5) ).

  In Equation (5), since the third term representing the interference of light exists, the light generated in the semiconductor light emitting layer 10 is superimposed after being emitted from the two wave sources, and the wavefront is changed. It becomes possible to change the traveling direction of the wave. In equation (5), the real part of γ in equation (6) is used. As shown in Expression (6), γ takes a value from 0 to 1, and indicates how much the light emitted from the two wave sources is correlated in time and space. Therefore, γ can be divided into cases as shown in the following equations (7) to (9).

  The case of Equation (7) is called fully coherent, the case of Equation (8) is called incoherent, and the case of Equation (9) is called partial coherent. Here, since the light source of LED is used as the light emitting element 1, it is partially coherent. Therefore, in the light-emitting element 1 of FIG. 3, since the contribution of the third term of the formula (5) is large in the light intensity, the light traveling direction can be greatly bent.

  In FIG. 3, for the sake of simplicity, the direction of the light beam caused by the interference of light emitted from the two dielectric columnar portions 41 and 42 having different heights has been described. However, the six dielectric columnar portions 41 serve as wave sources. , 42 can also be used to extend Equation (5). For example, the equation (5) is applied to each combination of two columns of the six dielectric columnar portions 41 and 42 (a total of 15 combinations), and by adding these 15 combinations, the wave source The relational expression for the case where there are six dielectric columnar portions 41 and 42 can be obtained.

The light-emitting element 1 having the above-described configuration can form a light beam by interference of light emitted from the radiation surfaces 41a and 42a of the six dielectric columnar portions 41 and 42, and six be to different three height of the dielectric column portions 41 and 42, light, three tall dielectric columnar propagating high low three dielectric columnar portion 42 inside The light reaches the radiation surface 42a at the tip of the column earlier than the light propagating through the inside of the portion 41, and proceeds faster in the air. Therefore, the light emitting element 1 can provide a phase difference Ψ between lights traveling through the dielectric columnar portions 41 and 42 having different heights, and can emit light in a direction corresponding to the phase difference Ψ. Therefore, according to the light emitting element 1, by providing the six dielectric columnar portions 41 and 42, a light beam can be formed by the light emitting element 1 alone, and of the six dielectric columnar portions 41 and 42. By making the heights of the three columns different, the azimuth angle θ ₁ of the formed light beam can be controlled.

  Further, the light emitting element 1 is formed by forming the columnar structure (dielectric columnar portions 41 and 42) with a transparent dielectric that is easier to process than the semiconductor material, for example, when the columnar structure is formed of a semiconductor material. Thus, there is no need for crystal growth of the columnar structure, so that strict control of crystal growth conditions and the like is not necessary, and applicable processing methods are limited as in the case where the columnar structure is formed of a semiconductor material. It never happens. And the light emitting element 1 can suppress the absorption of the light by the said columnar structure compared with the case where the said columnar structure is formed with an opaque material by forming a columnar structure with a transparent dielectric material. Therefore, the amount of light that can be extracted from the light emitting element 1 can be increased. Therefore, according to the light emitting element 1, the dielectric columnar portions 41 and 42 are formed of a transparent dielectric, whereby the light emitting element 1 can be easily manufactured and the output of the light emitting element 1 is enhanced. Can do.

[Operation of light emitting element]
Hereinafter, the operation of the light-emitting element 1 will be described with reference to FIG. 1 (refer to FIG. 3 as appropriate). When a current is supplied to the semiconductor light emitting layer 10 through an electrode (not shown), the light emitting element 1 recycles electrons and holes injected from the n-type semiconductor layer 20 and the p-type semiconductor layer 30 in the semiconductor light emitting layer 10. The energy generated by the binding is released as light. Thus, the light generated in the semiconductor light emitting layer 10 propagates through the dielectric columnar portions 41 and 42 on the transparent dielectric layer 40 and is emitted from the respective radiation surfaces 41a and 42a (see FIG. 3) to the outside. .

Here, as shown in FIG. 3, the dielectric columnar portions 41 and 42 are such that the height of the dielectric columnar portion 42 is lower than the height of the other dielectric columnar portions 41 by the column height difference δH. It is configured. Therefore, the light emitted from the radiation surface 41a of the dielectric columnar section 41 and the radiation surface 42a of the dielectric columnar section 42 has a phase difference ψ at the point of the altitude h2 in FIG. When There interfering with each other, wherein the in accordance with the phase difference [psi, rays one at a predetermined angle theta ₁ inclined direction is generated for the element surface perpendicular direction. As described above, according to the light emitting element 1, the six dielectric columnar portions 41 and 42 are provided, and the height of the three of the six dielectric columnar portions 41 and 42 is made different, thereby emitting light. The element 1 alone can form a light beam, and the azimuth angle θ _{1 of the} light beam can be controlled.

[Method for Manufacturing Light-Emitting Element]
Hereinafter, an example of a method for manufacturing the light-emitting element 1 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. In the following description, a method for manufacturing an element group of the light-emitting element 1 in which a plurality of light-emitting elements 1 shown in FIG. 1 are two-dimensionally arranged and provided with a p-electrode and an n-electrode will be described.

  First, as shown in FIG. 4A, a substrate (substrate with a pin electrode array) 50 having a plurality of pin-shaped p-electrodes 71 provided thereon is prepared, and a resin 60 is filled from above the substrate 50. Although not shown here, a strip-shaped thin film electrode is provided between the lower surface of each p electrode 71 and the substrate 50, and the p electrode 71 is connected to an external power source. The

  Next, as shown in FIG. 4B, a sapphire substrate 100 on which a light emitting element layer 80 made of GaN or the like is formed via a buffer layer 90 is prepared, and the light emitting element layer 80 and the resin 60 are heated to about 300 ° C. Fuse with. Although not shown here, the light emitting element layer 80 is specifically a layer composed of the semiconductor light emitting layer 10, the n-type semiconductor layer 20, and the p-type semiconductor layer 30 shown in FIG. The light emitting element layer 80 is formed by laminating an n-type semiconductor layer 20 and a p-type semiconductor layer 30 by a film forming method such as a molecular beam epitaxy (MBE) method or a metal organic chemical vapor deposition (MOCVD) method. The semiconductor light emitting layer 10 can be formed by adding an impurity such as In to the junction.

Next, as shown in FIG. 4C, the sapphire substrate 100 and the buffer layer 90 are peeled using a laser lift-off method, a chemical lift-off method, a void formation peeling method, or the like. Next, as shown in FIG. 4D, an n-electrode 72 is formed at a position other than the light emitting point, that is, the upper portion of the light emitting element layer 80. Next, as shown in FIG. 4E, a transparent dielectric layer 40a made of SiO ₂ or the like is formed on the light emitting element layer 80 by using a vapor deposition method (CVD method) or the like. Next, as shown in FIG. 4 (f), the transparent dielectric layer 40a is etched using a focused ion beam (FIB) or the like to form the transparent dielectric layer 40 and the dielectric columnar portions 41 and 42. An element group in which a plurality of light emitting elements 1 shown in FIG. 1 are arranged is created. When the heights of the dielectric columnar portion 41 and the dielectric columnar portion 42 are changed as in the light-emitting element 1 shown in FIG. 1, only the dielectric columnar portion 42 is further etched in the step of FIG. That's fine.

  According to the method for manufacturing the light emitting element 1, when the dielectric columnar portions 41 and 42 are etched, the etching is performed so as to leave the transparent dielectric layer 40 as shown in FIG. Physical and chemical damage to the light emitting element layer 80 can be reduced.

  The light emitting element 1 can be manufactured not only by the method shown in FIG. 4 but also by the method shown in FIG. In this case, first, the sapphire substrate 100 on which the light emitting element layer 80 made of GaN or the like is formed via the buffer layer 90 is prepared. Then, as shown in FIG. 5A, the sapphire substrate 100 and the buffer layer 90 are peeled using a laser lift-off method, a chemical lift-off method, a void formation peeling method, or the like. Next, as shown in FIG. 5B, one or more n-electrodes 72 are formed on the light emitting element layer 80 (here, the lower surface) by metal vapor deposition using a mask or the like. At that time, a fusion layer such as Sn may be provided on the n-electrode 72.

  Next, as shown in FIG. 5C, the light emitting element layer 80 provided with the n-electrode 72 is disposed on the substrate 50, and both are bonded by a surface activated bonding method or the like. In the surface activated bonding method, specifically, the surface of the light emitting element layer 80 is activated by Ar plasma or the like, and is bonded to the substrate 50. However, in the above-described step of FIG. 5B, when a fusion layer of Sn or the like is provided on the n-electrode 72, only the heating is performed in this step to bond the light emitting element layer 80 and the substrate 50.

Next, as shown in FIG. 5D, a large number of p-electrodes 71 are formed in a direction orthogonal to the n-electrode 72 so as to intersect the n-electrode 72. Next, as shown in FIG. 5E, a transparent dielectric layer 40a made of SiO ₂ or the like is formed on the p-electrode 71 by using a vapor deposition method (CVD method) or the like. Next, as shown in FIG. 5 (f), the transparent dielectric layer 40a is etched using a focused ion beam (FIB) or the like to form the transparent dielectric layer 40 and the dielectric columnar portions 41 and 42, An element group in which a plurality of light emitting elements 1 shown in FIG. 1 are arranged is created. When the heights of the dielectric columnar portion 41 and the dielectric columnar portion 42 are changed as in the light emitting element 1 shown in FIG. 1, only the dielectric columnar portion 42 is further etched in the process of FIG. That's fine.

  According to the method for manufacturing the light emitting element 1, when the dielectric columnar portions 41 and 42 are etched, the etching is performed so as to leave the transparent dielectric layer 40 as shown in FIG. Physical and chemical damage to the light emitting element layer 80 can be reduced.

  Embodiments of the present invention will be described below with reference to FIGS.

<First Experimental Example>
In the first experimental example, the formation of light rays by the dielectric columnar portions 41 and 42 of the light-emitting element 1 and the control of the azimuth angle θ _{1 of the} light rays are evaluated by simulation using a FDTD (Finite-Difference Time-Domain) method. It was. In this experimental example, the light-emitting elements of Examples and Comparative Examples were prepared, and LEDs each having a size of 6000 nm in length and 6000 nm in width where In was added to GaN were used.

(Light Emitting Element of Example)
As shown in FIG. 6A, the light-emitting element 1 of the example has a transparent dielectric layer 40 laminated on a p-type semiconductor layer 30, and six dielectric columnar portions 41, 42 was formed integrally. 6A is a cross-sectional view of the light-emitting element 1, and therefore only two dielectric columnar portions 41 and 42 are shown here. 6A, the thickness of the p-type semiconductor layer 30 is set to 130 nm and the thickness of the transparent dielectric layer 40 is set to 275 nm, so that the upper surface of the semiconductor light-emitting layer 10 is obtained. Is located at a depth of 405 nm corresponding to the external wavelength λ ₀ from the bottom surface of the dielectric columnar portions 41, 42.

Further, as shown in FIG. 6A, the height H of the dielectric columnar portion 41 is obtained by dividing the center wavelength (external wavelength λ ₀ = 405 nm) of the emission spectrum by the refractive index (= 1.5) of SiO _2. Thus, the internal wavelength λ ₁ in the SiO ₂ was calculated and set to 540 nm corresponding to the two wavelengths. Thus, the light emitting element 1 assumes that the transparent dielectric layer 40 and the dielectric columnar portions 41 and 42 are formed of SiO ₂ that is a dielectric. In the following description, the dielectric columnar portion 41 is described as the “waveguide column 41”, and the dielectric columnar portion 42 is described as the “control column 42”.

(Light emitting device of comparative example)
In the light emitting device 101 of the comparative example, as shown in FIG. 6B, six semiconductor columnar portions 31 and 32 are formed on the p-type semiconductor layer 30. Note that FIG. 6B is a cross-sectional view of the light emitting element 101, and therefore, only two semiconductor columnar portions 31 and 32 are illustrated here. The light emitting element 101, as shown in FIG. 6 (b), was 405nm which corresponds to the thickness of the p-type semiconductor layer 30 outside the wavelength lambda _0.

Further, as shown in FIG. 6B, the height H of the semiconductor columnar portion 31 is obtained by dividing the center wavelength of the emission spectrum (external wavelength λ ₀ = 405 nm) by the refractive index of GaN (= 3.1). The internal wavelength λ ₁ in the GaN was calculated and set to 263 nm corresponding to the two wavelengths. The refractive index of GaN was calculated by taking the square root of the dielectric constant of GaN (= 9.5). In the following description, the semiconductor columnar portion 31 will be described as the “waveguide column 31” and the semiconductor columnar portion 32 will be described as the “control column 32”.

  In this experimental example, first, for each of the example and the comparative example, a region of 3000 nm above the surface of the light emitting device 1,101 is based on a square region having a size of 6000 nm in length and 6000 nm in width parallel to the surface of the light emitting device 1,101. The beam shape was observed by changing the column height difference ratio δ between the waveguide columns 41 and 31 and the control columns 42 and 32. Further, in the evaluation of this experimental example, the intensity distribution of the light reaching the upper end of the calculation region (the 3000 nm point) of the light emitting element 1,101 was integrated, and the point having the strongest intensity was set as the center of the light beam.

FIG. 7 shows the intensity distribution of the beam when the column height difference ratio δ is changed. Red is a region where light that has reached is strong (0.4 W / m ² ), and blue is a region where light does not reach (0.4 W / m ² ). 0.0 W / m ² ). In this experimental example, in addition to the shape of the region where the light that reached the strongest (main beam), in addition to the main beam, the beam shape is evaluated based on the presence or absence of the region where the light reaches (side beam). If an area of about 50% intensity (0.2 W / m ² ) shown in yellow other than the vicinity of the main beam was observed, it was determined that the side beam was too large to be used (failed). In FIG. 7, the intensity distribution of the beam determined to be acceptable is surrounded by a broken line.

In the comparative example, as shown in FIG. 7, when δ = 0.0 to 0.2, it was determined to be acceptable, and when δ = 0.3 to 0.6, a yellow region y was observed. It was determined to pass. On the other hand, as shown in FIG. 7, in the example, when δ = 0.0 to 0.5, it was determined to be acceptable, and when δ = 0.6, a yellow region y was observed. It was judged. This indicates that the yellow region y is generated earlier in the comparative example than in the example, that is, the side beam is likely to be larger in the comparative example than in the example. About the shape of a beam, it turns out that it is an equivalent shape in an Example and a comparative example. Thus, when the waveguide pillar 41 and the control pillar 42 are formed of a transparent dielectric such as SiO ₂ (Example), the waveguide pillar 31 and the control pillar 32 are formed of a semiconductor material such as GaN (Comparative Example). ), It can be seen that even when the column height difference ratio δ is made larger, a good beam with no side beam can be obtained.

FIG. 8 shows the orientation of the main beam from the normal to the surface of the light-emitting element 1, 101 passing through the center of gravity O (see FIG. 2A) of the region where the waveguide pillars 41, 31 and the control pillars 42, 32 are arranged. The angle θ ₁ is shown. The vertical axis of the graph shown in FIG. 8 is the azimuth angle θ ₁ of the light beam, and the horizontal axis is the column height difference ratio δ. In the graph shown in FIG. 8, specifically, when the side beam intensity is yellow (intensity of about 50%), it is determined that a side beam having an intensity comparable to the main beam has appeared and the beam has collapsed. The column height difference ratio δ until the beam collapses was plotted.

Referring to FIG. 8, it can be seen that the azimuth angle θ _{1 is} about 8 degrees at the same level in the example and the comparative example. However, in the comparative example, the maximum value of the azimuth angle θ ₁ is obtained when the column height difference ratio δ is 0.2, but in the example, the maximum value of the azimuth angle θ ₁ is the column height difference ratio δ. It is obtained in the case of 0.5, and the change in the azimuth angle θ ₁ with respect to the change in the column height difference ratio δ is small. This is because when the column (waveguide column and control column) is formed to obtain a certain azimuth angle θ ₁ , the height of the formed column is deviated from the design value in the example rather than the comparative example. shows that can reduce the deviation of the azimuth angle theta ₁ at. That is, according to the light emitting element 1 according to the present invention, the processing accuracy requirement regarding the height of the columns (waveguide columns and control columns) at the time of creation is relaxed.

  As described above, in the first experimental example, the columnar structure is formed of a transparent dielectric (see FIG. 6A), and the columnar structure is formed of a semiconductor material (see FIG. 6B). As a result, it was confirmed that a good beam can be obtained and the workability can be improved.

<Second Experimental Example>
In the second experimental example, the transmission of the light emitting element 1 when the medium X (that is, the transparent dielectric layer 40, the waveguide column 41, and the control column 42) is stacked on the n-type semiconductor layer 20 or the p-type semiconductor layer 30. and 'the ratio between the transmittance _{T 10} when the on ₁₀ and n-type semiconductor layer 20 or on the p-type semiconductor layer 30 is not laminated medium X (T' rate T ₁₀ / _{T 10),} the refractive index n of the medium X The relationship was confirmed. In the following description, T ′ ₁₀ / T ₁₀ is described as “transmittance ratio T ′ ₁₀ / T ₁₀ ”.

The vertical axis of the graph shown in FIG. 9 is the transmittance ratio T ′ ₁₀ / T ₁₀ , and the horizontal axis is the refractive index n of the medium X. In the graph shown in FIG. 9, specifically, the refractive index on the n-type semiconductor layer 20 or the p-type semiconductor layer 30 formed of various light emitting materials (GaN, GaAs, AIN, ZnSe, ZnO, InN, Si). The transmittance ratio T ′ ₁₀ / T ₁₀ in the case where the medium X having n is stacked is plotted for each predetermined refractive index n. The transmittance ratio T ′ ₁₀ / T ₁₀ is greater than 1 if the transmittance T ′ ₁₀ when the medium X is stacked is larger than the transmittance T ₁₀ when the medium X is not stacked. If the transmittance T ′ ₁₀ in the case of laminating is smaller than the transmittance T _{10 in the} case of not laminating the medium X, it becomes smaller than 1.

That is, in the graph shown in FIG. 9, for example, “1” on the vertical axis indicates that the transmittance T ′ ₁₀ when the medium X is stacked and the transmittance T ₁₀ when the medium X is not stacked are the same. Show. Further, in the graph shown in FIG. 9, the vertical axis "1.2", the transmittance T _'10 in the case of stacking the medium X is, is 20% increase in transmittance T ₁₀ when no laminating medium X It is shown that. Then, in the graph shown in FIG. 9, the vertical axis "1.4", the transmittance T _'10 in the case of stacking the medium X is, is 40% increase of the transmittance T ₁₀ when no laminating medium X It is shown that. Accordingly, by referring to the graph of FIG. 9, how much the transmittance is improved by using a medium X having a refractive index n on the n-type semiconductor layer 20 or the p-type semiconductor layer 30 ( It is possible to easily grasp how much the output is increased.

For example, when SiO ₂ having a refractive index n of 1.5 is used as the medium X, GaN is used as the light emitting material (n-type semiconductor layer 20 and p-type semiconductor layer 30) as shown in part D of FIG. Thus, an output enhancement effect of about 15% can be obtained, and even when other light emitting materials are used, an output enhancement effect of about 10 to 20% can be obtained. For example, even if the medium X is other than SiO ₂ , the medium X having a refractive index n between 1 (= same as air) and the refractive index of the light emitting material can be used to transmit into the air. It can be seen that the amount of light coming can be increased. Examples of such a medium X include SiO, SiN, MgF ₂ , ZrO _{2 and the} like in addition to the above-described SiO ₂ .

Here, a method of calculating the transmittances T ′ ₁₀ and T ₁₀ in FIG. 9 will be described with reference to FIG. For example, the reflectance R when light enters from a medium with a refractive index n _{1 to} a medium with a refractive index n ₀ can be expressed by the following equation (11).

R = (n ₁ −n ₀ ) ² / (n ₁ + n ₀ ) ² Formula (11)

Here, as shown in FIG. 10 (a), a light-emitting material if medium X on the GaN is not stacked, that is, when the light emitting element 101 as shown in FIG. 6 (b), the refractive index n ₁ The medium is GaN, and the medium having a refractive index n ₀ is air. Then, the transmittance T ₁₀ in such a case can be represented by the following equation (12). For example, if the refractive index n _{1 of} GaN is 3 for simplicity, the refractive index of air is about 1, so that T ₁₀ = 0.75 from the above-described equations (11) and (12).

T ₁₀ = 1−R (12)

On the other hand, as shown in FIG. 10B, in the case where the medium X is laminated on GaN as the light emitting material, that is, in the case of the light emitting element 1 as shown in FIG. 6A, the medium having the refractive index n ₁ . Is GaN, the medium having the refractive index n ₀ is the medium X, and when the medium having the refractive index n ₁ is the medium X, the medium having the refractive index n ₀ is air. The transmittance T ′ _{10 in} such a case can be expressed by the following equation (13).

T ′ ₁₀ = T ₁₂ × T ₂₀ Formula (13)

T ₁₂ in the above equation (13) is a transmittance when the medium having the refractive index n ₁ is GaN and the medium having the refractive index n ₀ is the medium X, and T ₁₂ in the above equation (13). ₂₀ is the transmittance when the medium having the refractive index n ₁ is GaN and the medium having the refractive index n ₀ is the medium X. These transmittances T ₁₂ and T ₂₀ can be calculated by the aforementioned equation (12).

Here, when the medium X shown in FIG. 10B is GaN, it is substantially the same as FIG. 10A, and the transmittance of both is the same (T ₁₀ = T ′ ₁₀ ). Similarly, when the medium X shown in FIG. 10B is air, it is substantially the same as FIG. 10A, and the transmittance of both is the same (T ₁₀ = T ′ ₁₀ ). . On the other hand, when the medium X shown in FIG. 10B is a substance having a refractive index larger than that of air and smaller than that of GaN, a surface E from which light is emitted as shown in FIG. Compared to the case of GaN, the difference in refractive index between the surface F from which the light is emitted and air is small. Therefore, as shown in FIGS. 9 and 10, by using a material that is larger than the refractive index of air and smaller than the refractive index of GaN as the medium X, the transmittance is improved and the output is enhanced. Can do. Further, since the refractive index is the square root of the dielectric constant, the same relationship is obtained even if the refractive index is replaced with the dielectric constant.

  Thus, in the second experimental example, as shown in FIG. 1, a transparent dielectric made of a transparent dielectric having a refractive index (or dielectric constant) smaller than that of the p-type semiconductor layer 30 on the p-type semiconductor layer 30. It was confirmed that by laminating the body layer 40 and the dielectric columnar portions 41 and 42, the light transmittance was improved and the output enhancement effect was obtained.

  The light-emitting element 1 according to the present invention has been specifically described above with reference to embodiments for carrying out the invention. However, the gist of the present invention is not limited to these descriptions, and is based on the description of the claims. Must be interpreted widely. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

  For example, as shown in FIG. 1, the light emitting element 1 has the semiconductor light emitting layer 10 formed in a rectangular shape, but the semiconductor light emitting layer 10 is formed only directly below the dielectric columnar portions 41 and 42. It doesn't matter.

  Moreover, the manufacturing method of the above-mentioned light emitting element 1 is not limited to what was shown in FIG.4 and FIG.5. For example, the light-emitting element 1 includes a dielectric reflection film having a window having a shape similar to a column cross section on the surface of the light-emitting element layer 80 in which the semiconductor light-emitting layer 10, the n-type semiconductor layer 20, and the p-type semiconductor layer 30 are stacked. A transparent dielectric substrate having a plurality of dielectric columnar portions 41 and 42 formed on the surface thereof is prepared separately, and a surface having a dielectric reflection film of the light emitting element layer 80 and a back surface of the transparent dielectric substrate (dielectric) It can also be created by pasting together the surfaces on which the body columnar portions 41 and 42 are not formed.

  Further, as shown in FIG. 1, the light emitting element 1 has the dielectric columnar portions 41 and 42 formed in a circular cross section and a cylindrical shape. However, the dielectric columnar portions 41 and 42 are polygonal in cross section. It may be formed in a polygonal column shape.

  In addition, as shown in FIG. 1, the light-emitting element 1 described above is stacked in order of the n-type semiconductor layer 20, the semiconductor light-emitting layer 10, and the p-type semiconductor layer 30 from the bottom. The order of the semiconductor layers 30 may be changed.

  Further, as shown in FIG. 1, the light-emitting element 1 described above includes three dielectric columnar portions (waveguide columns) 41 constituting the first column group and three dielectrics constituting the second column group. Although a total of six columnar structures (columns (control columns) 42) are provided, the number of columnar structures may be smaller than this. That is, the light emitting element 1 includes a first column group by at least one dielectric columnar portion 41 having the same height, and the height is different from that of the dielectric columnar portion 41 configuring the first column group. In addition, the second column group may be configured by at least one dielectric columnar portion 42 having the same height. In this case, the first column group includes an embodiment in which only one dielectric columnar portion 41 is included, and the second column group also includes an embodiment in which only one dielectric columnar portion 42 is included. ing.

  Further, in the light emitting element 1 described above, the plurality of dielectric columnar portions 41 and 42 are arranged on the transparent dielectric layer 40 in an annular shape, and the second column group includes the plurality of dielectric columnar portions 41. , 42 may be composed of dielectric columnar portions 42 that are not more than half of the total number. Even with such a configuration, the light emitting element 1 can form a light beam by itself and can control the azimuth angle of the formed light beam.

  In the light-emitting element 1, the plurality of dielectric columnar portions 41 and 42 are arranged on the transparent dielectric layer 40 in an annular shape, and the first column group is formed from the two dielectric columnar portions 41. The second column group may be configured by one dielectric columnar portion 42. Even in such a configuration, the light emitting element 1 can form a light beam by itself, and the dielectric columnar portion 41 constituting the first column group and the dielectric columnar shape constituting the second column group. By making the height of the portion 42 different, the azimuth angle of the formed light beam can be controlled.

  Further, as shown in FIGS. 11A and 11B, a large number of the light emitting elements 1 are arranged on the substrate BD, thereby providing an IP stereoscopic display DSP that is an IP display. . Although illustration is omitted, it is possible to display (reproduce) a stereoscopic image by capturing an object such as a cylinder or a cube shown in FIG. 11B in advance by an IP stereoscopic imaging apparatus corresponding to the IP stereoscopic display DSP via a lens plate. ). As a result, as shown in FIG. 11B, each light emitting element 1 of the IP stereoscopic display DSP projects the element images onto the space, and these are integrated to form a reproduced image (stereoscopic image) of the subject, for example, a cylinder. Or a cube is displayed.

  In each of the light emitting elements 1 corresponding to the pixels of the IP stereoscopic display DSP, the column height difference δH is determined in advance for each pixel, and is set so as to define the direction of light rays emitted from the pixel. In FIG. 11B, for example, a thick arrow whose end point is a cylinder or a cube indicates the direction of light. In the IP stereoscopic display DSP, the light emitting elements 1 arranged in the leftmost column toward the screen and the light emitting elements 1 arranged in the rightmost column toward the screen are composed of the dielectric columnar portions 41. , 42 are symmetrical.

Further, in the IP stereoscopic display DSP, the light emitting elements 1 arranged in the uppermost row toward the screen and the light emitting elements 1 arranged in the lowermost row toward the screen are composed of dielectric columnar portions. The arrangement of 41 and 42 is symmetric. Furthermore, the light emitting elements 1 arranged in other screen areas are also arranged in accordance with the location. Therefore, intensity modulation can be performed in the pixel by the light emitted from each of the six wave sources in the pixel structure of the element unit (light emitting element 1). Depending on the position of the pixel, there is a position where the heights of the dielectric columnar portions 41 and 42 should be equal in order to set the azimuth angle θ ₁ = 0 degree.

A display element (FPD) in which a large number of light emitting elements 1 having such a fine structure are arranged has the same function as an apparatus in which a lens plate and a light emitting surface are joined in the prior art. In the IP stereoscopic display DSP created in this way, the resolution of the stereoscopic display depends only on the definition of the light emitting element 1, and image blur due to insufficient resolution of the optical system does not occur. Further, the viewing zone angle in the IP display using the light emitting element 1 depends only on the maximum value of the angle θ ₂ formed by the radiated light with respect to the direction perpendicular to the element surface, and the resolution and the viewing zone angle are independently improved. It is possible.

As described above, it is possible to provide the IP stereoscopic display DSP by arranging a large number of the light emitting elements 1 on the substrate BD instead of the element lens. In this case, the light emitting element 1 itself is provided on the substrate BD. By disposing it with respect to it, the azimuth angle θ ₁ can be controlled over a wider range.

  The light-emitting element 1 can also be applied to general devices that require the formation of light rays and the control of the radiation direction. For example, a light source for a projector, a connector used for spatial light interconnection, and a diffusion plate are not required. It can also be used as a light source for illumination.

1,101 Light-emitting element (light-emitting light-emitting element)
DESCRIPTION OF SYMBOLS 10 Semiconductor light emitting layer 20 N-type semiconductor layer 30, 30A p-type semiconductor layer 31 Semiconductor columnar part (waveguide pillar)
32 Semiconductor pillar (control pillar)
40 Transparent dielectric layer 41 Dielectric column (waveguide column)
42 Dielectric Column (Control Column)
41a, 42a Radiation surface 50 substrate (substrate with pin electrode array)
60 resin 71 p electrode 72 n electrode 80 light emitting element layer 90 buffer layer 100 sapphire substrate BD substrate DSP IP stereoscopic display

Claims (5)

A light emitting device comprising a semiconductor light emitting layer between an n type semiconductor layer and a p type semiconductor layer,
A transparent dielectric layer formed on the n-type semiconductor layer or the p-type semiconductor layer and made of a transparent dielectric having a dielectric constant smaller than that of the n-type semiconductor layer and the p-type semiconductor layer;
A plurality of dielectric pillars formed on the transparent dielectric layer, made of the same transparent dielectric as the transparent dielectric layer, and serving as a waveguide of light generated in the semiconductor light emitting layer;
The plurality of dielectric columnar portions are annularly arranged on the transparent dielectric layer, and each of the first column group including at least one dielectric columnar portion having the same height, The dielectric columnar portion constituting one column group is different in height and includes a second column group composed of at least one dielectric columnar portion having the same height. A light emitting element. The plurality of dielectric columnar portions are arranged in a ring shape on the transparent dielectric layer in a group of 3 to 6,
2. The light emitting device according to claim 1, wherein the second column group includes the dielectric columnar portions that are half or less of the total number of the plurality of dielectric columnar portions. The plurality of dielectric columnar portions are arranged in a ring on the transparent dielectric layer in a group of six,
2. The light emitting device according to claim 1, wherein each of the first column group and the second column group includes three dielectric columnar portions.   The plurality of dielectric columnar portions are arranged in an annular shape on the transparent dielectric layer so that the central axes of the respective columns are positioned at equal intervals on the same circumference. Or the light emitting element of Claim 3.   The difference in height between the dielectric columnar portion constituting the first column group and the dielectric columnar portion constituting the second column group is less than or equal to the wavelength of light propagating through the dielectric columnar portion. The light emitting element according to claim 1, wherein the light emitting element is provided.