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Light-emitting diode incorporating optical component

IPC classes for russian patent Light-emitting diode incorporating optical component (RU 2265916):

H01L33 - Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof (H01L0051500000 takes precedence;devices consisting of a plurality of semiconductor components formed in or on a common substrate and including semiconductor components with at least one potential-jump barrier or surface barrier, specially adapted for light emission H01L0027150000; semiconductor lasers H01S0005000000)

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Light-emitting diode incorporating optical component / 2265916
Proposed light-emitting diode has chip covered with optical component made of translucent material whose outer surface is of aspherical shape obtained due to rotation of f(x) curve constructed considering optical properties of light-emitting chip and optical component material about symmetry axis of light-emitting diode; it is light-emitting surface. Curve f(x) in coordinate system whose origin point coincides with geometric center of light-emitting chip active area has initial point A₀ disposed on ordinate axis at distance corresponding to characteristic size of light-emitting diode; used as this size is desired height of optical component or its desired diameter; active area is formed by plurality of points A_i (i = 1, 2..., n). Taken as coordinates of each point are coordinates of intersection point of straight line coming from coordinate origin point at angle α_ini to ordinate axis and straight line coming from preceding point A_{i - 1} at angle G_i to abscissa axis drawn to point A_{i - 1}; α_ini is angle of propagation of i_in light beam pertaining to plurality of beams emitted by light emitting chip and chosen between angles 0 and 90 deg.; angle G_i is found from given dependence.

Light-emitting diode incorporating optical component / 2265917
Proposed light-emitting diode has light-emitting chip covered by optical component made of translucent material whose outer surface is aspherical in shape due to rotation of curve f(x) built considering optical properties of light-emitting chip and optical component material about symmetry axis of light-emitting diode. This surface emits light and f(x) curve in coordinate system whose origin coincides with geometric center of active area of light-emitting diode has initial point A₀ disposed on ordinate axis at distance corresponding to characteristic size of light-emitting diode which is, essentially, optical component height or its desired diameter, and is formed by plurality of points A, (i = 1, 2... n); coordinates of intersection point of straight line drawn from coordinate origin point at angle α_ini to ordinate axis drawn from preceding point A_{i - 1} at angle G_i to abscissa axis drawn to point A_{i - 1} are taken as coordinates of each of them;; α_ini is angle of propagation of i_in light beam pertaining to plurality of beams emitted by light-emitting chip chosen between 0 and 90 deg. Angle G_i is found from given dependence. Angle α_outi is found by pre-construction of directivity pattern DP_in of beam emitted by light-emitting chip. Coordinates of A points are checked by means of light-emitting diode simulator that has optical component whose outline is formed by plurality of A_i points as well as light-emitting chip whose beam directivity pattern is DP_in; this chip is used as distributed light source having three-dimensional emitting area whose size and appearance correspond to those of emitting area used in light-emitting diode of light-emitting chip. Light emitting points in light-emitting chip of simulator under discussion are offset relative to origin of coordinates within its emitting area; coordinates of A_i points are checked by comparing directivity pattern DP_out and directivity pattern DP_sim of beam emitted by light-emitting diode simulator, both displayed in same coordinate system. When these directivity patterns coincide, coordinates of points A_i function as coordinates of points forming curve f(x); if otherwise, coordinates of points A_i are found again, and DP_outj is given as directivity pattern DP_out whose points are disposed above or below the latter, respectively, depending on disposition of directivity pattern DP_sim below or above directivity pattern DP_out in the course of check.

FIELD: semiconductor optoelectronics; various emitters built around light-emitting diodes.

SUBSTANCE: proposed light-emitting diode has chip covered with optical component made of translucent material whose outer surface is of aspherical shape obtained due to rotation of f(x) curve constructed considering optical properties of light-emitting chip and optical component material about symmetry axis of light-emitting diode; it is light-emitting surface. Curve f(x) in coordinate system whose origin point coincides with geometric center of light-emitting chip active area has initial point A₀ disposed on ordinate axis at distance corresponding to characteristic size of light-emitting diode; used as this size is desired height of optical component or its desired diameter; active area is formed by plurality of points A_i (i = 1, 2..., n). Taken as coordinates of each point are coordinates of intersection point of straight line coming from coordinate origin point at angle α_ini to ordinate axis and straight line coming from preceding point A_{i - 1} at angle G_i to abscissa axis drawn to point A_{i - 1}; α_ini is angle of propagation of i_in light beam pertaining to plurality of beams emitted by light emitting chip and chosen between angles 0 and 90 deg.; angle G_i is found from given dependence.

EFFECT: ability of shaping desired light-beam emission directivity pattern.

1 cl, 3 dwg

The invention relates to a semiconductor optoelectronics and can be used in the manufacture of various types of emitters based on light-emitting diodes (LEDs).

A known design of LEDs, which use optical elements, the shape, size and material are chosen so as to ensure the formation of a defined optical characteristics of the device.

For example, the famous led [EN 2207663], which includes a semiconductor light-emitting crystals, coated optical element containing a cone-shaped reflector side radiation and collecting radiation from the lens, which is a hemisphere with a cylindrical base.

The shape and geometrical dimensions of the reflector and lens are selected so that the optical element provides the efficiency of lateral radiation of the crystals, thereby increasing the radiation power led.

Known led with an optical element [EN 2055420], which is selected by the inventors as the nearest equivalent.

This contains led light-emitting crystal, covered with made of translucent material of the optical element, a portion of the outer surface which is a plane and is light guiding surface, and others who Gaya part is not displaying the radiation surface has an aspherical shape, formed by rotation around the axis of symmetry of the curve f(x), the equation which satisfies the conditions of total internal reflection of light emitted by the crystal, at any point of this surface. In this case the curve f(x) is obtained taking into account the optical properties of the crystal and the optical element, namely taking into account the values of their refractive indices.

In this device, the optical element collects and displays through the light guiding surface, almost all the radiation emitted by the crystal, which causes the increase of output power of radiation of the led.

However, using this device cannot obtain the desired distribution of the light flux in a predetermined spatial angle.

The task of the claimed invention is to provide an led capable of forming a desired pattern of radiation of the light flux.

The invention consists in that the led containing a light-emitting crystal, covered with made of translucent material of the optical element which has an aspherical shape of the outer surface obtained by rotating around the symmetry axis of the led curve f(x)built taking into account the optical properties of light-emitting crystal and the material of the optical element according to the invention the specified behavior is knosti is a light guiding, in this case the curve f(x) in the coordinate system, the point of which coincides with the geometric center of the active light-emitting region of the crystal that has a starting point And₀located on the ordinate axis at a distance corresponding to the characteristic size of the led, which used the set value of the height of the optical element or set the value of its diameter, and is formed by a set of points Ai (i=1, 2,..., n), the coordinates of each of which are taken coordinates of the point of intersection of the line emanating from the origin at an angle α_WHto the axis of the ordinate, direct, outbound from the previous point And_i-1angle G_ito x-axis, shown at point A_i-1when this angle α_WHis the angle that extends i_Ia beam of light that belongs to the set of rays emitted by the light emitting crystal, which is selected from a range of angles from 0 to 90 degrees, and the angle G_idetermined based on dependencies

α_wyh- the angle at which dissemination is aneesa i _oa beam of light that belongs to the set of rays emitted by the led, which lies in the range of angles from 0 to 90 degrees, and α_wyhfound by pre-building pattern DN_Iradiation emitted by the used in the led light-emitting crystal, which is determined on the basis of experimental data, and also display in the same coordinate system of the pattern bottoms_othe radiation that you get from the led, and the subsequent graphical location for each selected angle α_WHsuch angle α_wyhwhere the magnitude of the light flux on the diagrams DN_Iand DN_oequal.

The invention is illustrated by drawings, are presented in figures 1-3, where figure 1 shows a General view of the proposed led; figure 2 presents the pattern of light-emitting crystal bottoms_Iand led DN_oin Fig 3 shows an example graphical determination of the coordinates of points A_i.

For part of the claimed led optical element provided required distribution of light flux in a predetermined spatial angle, the coordinates of the points of his profile determined from the condition of normalization pattern svetol the expectation of the crystal (CF _I), which is determined experimentally, and pattern (CF_o)that you want to get from the led, the same luminous flux.

The basis of this approach is the idea (see figure 1)that for any solid angle (Θ_{I i}), which applies a luminous flux emitted by the crystal, and which is defined in the selected location of the points of the profile of the optical element coordinate system flat angle α_WHthat there was such a solid angle (Θ_{o i}), which applies the same amount of luminous flux emitted by the led, and which is determined in the above coordinate system flat angle α_wyh.

In accordance with the above (see figure 2) for each corner α_WHfind the angle α_wyhwhere the magnitude of the light flux on the diagrams DN_Iand DN_oequal. This operation is performed for the set of rays emanating from a point Of origin, which adopted the geometric center of the active region of the crystal angles α_WHin the range [0; 90] degrees.

Next (see figure 3) for each beam i_Icoming from the point Of angle α_WHincident on the surface of the optical element at the point the Ai will have the Yat (relative to the x-axis) angle G _ithe tangent to the refractive surface of the optical element that the refracted beam i_oout of the led at an angle α_wyh. However, based on geometric constructions, based on the laws of geometrical optics, the angle G_imust satisfy the following system of equations:

q is the angle of incidence of the beam i_Ion the refracting surface having the angle of G_iat the point A_iand q' is the angle of refraction of a given beam of a specified refractive surface.

Since the incidence angle q and angle of refraction q' bound by the law of Snell's law:

where n₂is the refractive index of air, a n₁is the refractive index of the material of the optical element, the angle G_ican be expressed as follows:

where n₂₁the relative refractive index at the interface optical element external environment", defined as the ratio of the refractive index of the external environment n₂the refractive index of the material of the optical element n₁. If the external medium is air, then n₂₁equal to the inverse value of the refractive index of the optical element.

Because as the initial parameter set characteristics is th size of the optical element, that is, the maximum linear dimension, which is the set value of the height of the optical element or set the value of its diameter, the initial point of the profile of the optical element And₀take the coordinates of a point lying on the axis of ordinates at distances equal to the height or diameter of the optical element, from the starting point of the coordinate system O.

The coordinates of each subsequent point of the profile of the optical element A_iin the selected coordinate system are defined as the coordinates of the point of intersection of the line emanating from the origin O at an angle α_WHdirect, outbound from the previous point A_i-1angle G_ito x-axis, shown in dot And_i-1.

It is essential that when the coordinates of the points of the profile of the optical element takes into account not only the optical properties of its material, but the individual character of the luminescence light-emitting crystal, which is caused by the material and the topology of the crystal. Pattern DN_Iis determined by measuring the spatial distribution of the light flux in the spatial angle of 360 degrees with the help of the measuring system including the optical bench installed on the sensor with the appropriate recording equipment and turning the tol with located on it and is placed in the holder of the investigated crystal, covered with a material, which is made of the optical element.

Thus, the claimed led, through the use of the optical element, the profile of which is defined in the manner described above with regard to the optical properties of the material and the optical characteristics of light-emitting crystal, provides the formation of a desired pattern of radiation of the light beam with a high degree of accuracy.

The inventive led (figure 1) comprises a base 1, which is used, in particular, the mounting plate is installed on the light emitting crystal 2. The crystal 2 is covered with the optical element 3, made of a translucent material, which has a light guiding aspherical outer surface formed by rotating the curve f(x) around the axis of symmetry O-O' of the led, the coordinates of the points in the coordinate system, the beginning Of which coincides with the geometric center of the active region of the crystal 2 and the y-axis is along the symmetry axis of the crystal 2, determined in the manner described above.

For determining the angular coordinates of G_ieach of the points A_ipreviously (figure 2) for each α_wyha graphical way to find it α_wyhwhere the light flows in the diagrams of Dnfh, Dnyh represented in the same coordinate system, equal. Then determine the values of the angles G_iin accordance with the dependence (3).

Next, find the coordinates of the points of the profile of the optical element (figure 3). To do this, lay along the ordinate axis a distance equal to the height or diameter of the optical element, and get the value of the coordinates of the initial point And₀. Then find the coordinates of points A₁why spend from a point On the ray with angle α_WHand from point a₀carry out a direct angle G₁and for the coordinates of points A₁take the coordinates of the point of intersection of these lines. Then find the coordinates of point a₂why spend from a point On the ray with angle α_WHand from point A₁carry out a direct angle G₂to x-axis, shown at point A₁and for the coordinates of points A₂take the coordinates of the point of intersection of these lines. This operation is carried out for many (about 1500-2000) rays emitted by the crystal angles αVH lying in the range of angles from 0 to 90 degrees.

For the manufacture of an led using a semiconductor light-emitting crystal 2, for example, semiconductor light-emitting crystal-based solid solutions of elements of the III and V groups of the periodic table. The crystal 2 and the elements of the electric circuit (not shown) is asmamaw based (circuit Board) 1 and close the optical element 3, made of translucent material, for example, organic or inorganic optically transparent compound by casting of a specified compound in filling the form.

The device operates as follows. When power is supplied, the light-emitting crystal 2 emits a luminous flux, which is emitted by the led after passing through the light guiding surface of the optical element 3. The led provides obtaining the required luminous flux at a given angle of radiation.

Led containing a light-emitting crystal, covered with made of translucent material of the optical element which has an aspherical shape of the outer surface obtained by rotating around the symmetry axis of the led curve f(x)built taking into account the optical properties of light-emitting crystal and the material of the optical element, wherein the light guiding surface is, in this case the curve f(x) in the coordinate system, the point of which coincides with the geometric center of the active light-emitting region of the crystal that has a starting point And₀located on the ordinate axis at a distance corresponding to the characteristic size of the led, which used the set value of the height of the optical element or the acceptable value of its diameter, and is formed by a set of points And_i(i=1, 2,..., n), the coordinates of each of which are taken coordinates of the point of intersection of the line emanating from the origin at an angle α_WHto the axis of the ordinate, direct, outbound from the previous point And_i-1angle G_ito x-axis, shown at point A_i-1when this angle α_WHis the angle that extends i_Ia beam of light that belongs to the set of rays emitted by the light emitting crystal, which is selected from a range of angles from 0 to 90°and the angle G_iis determined based on dependencies

α_wyh- the angle that extends i_oa beam of light that belongs to the set of rays emitted by the led, which is in the range of angles from 0 to 90°, and α_wyhfound by pre-building pattern DN_Iradiation emitted by the used in the led light-emitting crystal, which is determined on the basis of experimental d is the R, and display in the same coordinate system of the pattern bottoms_othe radiation that you get from the led, and the subsequent graphical location for each selected angle α_WHsuch angle α_wyhwhere the magnitude of the light flux on the diagrams DN_Iand DN_oequal.