US 11,777,276 B2 · Semiconductor light emitting array with phase modulation regions for generating beam projection patterns

Abstract

The present embodiment relates to a single semiconductor light-emitting element including a plurality of light-emitting portions each of which is capable of generating light of a desired beam projection pattern and a method for manufacturing the semiconductor light-emitting element. In the semiconductor light-emitting element, an active layer and a phase modulation layer are formed on a common substrate layer, and the phase modulation layer includes at least a plurality of phase modulation regions arranged along the common substrate layer. The plurality of phase modulation regions are obtained by separating the phase modulation layer into a plurality of places after manufacturing the phase modulation layer, and as a result, the semiconductor light-emitting element provided with a plurality of light-emitting portions that have been accurately aligned can be obtained through a simple manufacturing process as compared with the related art.

A semiconductor light-emitting element comprising a first surface and a second surface opposing the first surface, one of the first surface and the second surface functioning as a light emission surface that outputs light and another functioning as a support surface,

the semiconductor light-emitting element further comprising:
an active layer positioned between the first surface and the second surface;
a phase modulation layer positioned between the first surface and the second surface and including a plurality of phase modulation regions each of which is optically coupled to the active layer, the plurality of phase modulation regions each including a base region having a first refractive index and a plurality of modified refractive index regions each of which is provided in the base region and has a second refractive index different from the first refractive index;
a first cladding layer positioned on a side where the first surface is arranged with respect to a stacked structure including at least the active layer and the phase modulation layer;
a second cladding layer arranged on a side where the second surface is positioned with respect to the stacked structure;
a first-surface-side electrode arranged on a side where the first surface is positioned with respect to the first cladding layer;
a plurality of second-surface-side electrodes arranged on a side where the second surface is arranged with respect to the second cladding layer and corresponding to the plurality of phase modulation regions, respectively, the plurality of second-surface-side electrodes arranged in a plurality of regions overlapping the plurality of phase modulation regions, respectively, as viewed along a stacking direction of the stacked structure;
and
a common substrate layer arranged between the first cladding layer and the first-surface-side electrode, the common substrate layer having a continuous surface that holds the plurality of phase modulation regions,
wherein, in each of the plurality of phase modulation regions included in the phase modulation layer, the plurality of modified refractive index regions are arranged at predetermined positions in the base region according to an arrangement pattern, configured to make a beam projection pattern, which is a projection pattern of light outputted from the light emission surface when a drive current is supplied from a corresponding second-surface-side electrode among the plurality of second-surface-side electrodes, and a beam projection region where the beam projection pattern is formed coincide with a target beam projection pattern and a target beam projection region, respectively,
wherein, in a state that a virtual square lattice constituted by M1 (an integer of one or more)×N1 (an integer of one or more) unit configuration regions R each having a square shape is set on an X-Y plane in an XYZ orthogonal coordinate system defined by a Z-axis coinciding with a normal direction of the light emission surface and the X-Y plane, which includes X and Y axes orthogonal to each other and coincides with one surface of the phase modulation layer including the plurality of modified refractive index regions,
wherein, the arrangement pattern is defined such that a gravity center G1 of the modified refractive index region positioned in a unit configuration region R(x, y) is separated from a lattice point O(x, y) as a center of the unit configuration region R(x, y) by a distance r in the unit configuration region R(x, y) on the X-Y plane, specified by a coordinate component x (an integer of one or more and M1 or less) in an X-axis direction and a coordinate component y (an integer of one or more and N1 or less) in a Y-axis direction, and a vector from the lattice point O(x, y) to the gravity center G1 is directed in a specific direction, and
wherein, in a state that the phase modulation layer satisfies the following first to sixth conditions:
the first condition defined such that coordinates (x, y, z) in the XYZ orthogonal coordinate system satisfy relationships represented by following Formulas (1) to (3) with respect to spherical coordinates (d1, θtilt, θrot) defined by a length d1 of a radius vector, a tilt angle θtilt from the Z-axis, and a rotation angle θrot from the X-axis specified on the X-Y plane:
x=d1 sin θtilt cos θrot (1)
y=d1 sin θtilt sin θrot (2)
z=d1 cos θtilt (3);
the second condition defined such that a target beam projection pattern is a set of bright spots directed in directions defined by the angles θtilt and θrot, the angles θtilt and θrot are converted to a coordinate value kx, which is a normalized wave number defined by a following Formula (4), on a Kx-axis corresponding to the X-axis and a coordinate value ky which is a normalized wave number defined by a following Formula (5), on a Ky-axis corresponds to the Y-axis and orthogonal to the Kx-axis:
k
x
=
a
λ
⁢
sin
⁢
θ
tilt
⁢
cos
⁢
θ
r
⁢
o
⁢
t
(
4
)
k
y
=
a
λ
⁢
sin
⁢
θ
tilt
⁢
sin
⁢
θ
rot
(
5
)
a:
Lattice constant of virtual square lattice
λ:
Oscillation wavelength;
the third condition defined such that a specific wave number range including the beam projection pattern is constituted by M2 (an integer of one or more)×N2 (an integer of one or more) image regions FR each having a square shape in a wave number space defined by the Kx-axis and the Ky-axis;
the fourth condition defined such that a complex amplitude F(x, y, which is obtained by two-dimensional inverse Fourier transform of each image region FR(kx, ky), specified by the coordinate component kx (an integer of from 0 to M2−1) in the Kx-axis direction and the coordinate component ky (an integer of from 0 to N2−1) in the Ky-axis direction, to the unit configuration region R(x, y) on the X-Y plane in the wave number space, is given by a following Formula (6) with j as an imaginary unit:
F
⁡
(
x
,
y
)
=
∑
k
x
=
0
M
⁢
2
-
1
⁢
∑
k
y
=
0
N
⁢
2
-
1
⁢
F
⁢
R
⁡
(
k
x
,
k
y
)
⁢
exp
⁡
[
j
⁢
2
⁢
π
⁡
(
k
x
M
⁢
2
⁢
x
+
k
y
N
⁢
2
⁢
y
)
]
;
(
6
)
the fifth condition defined such that the complex amplitude F(x, y) is defined by a following Formula (7) when an amplitude term is A(x, y) and a phase term is P(x, y) in the unit configuration region R(x, y):
F(x,y)=A(x,y)×exp[jP(x,y)] (7);
and
the sixth condition defined such that the unit configuration region R(x, y) is defined by an s-axis and a t-axis which are parallel to the X-axis and the Y-axis and orthogonal to each other at the lattice point O(x, y),
the phase modulation layer is configured such that the corresponding modified refractive index region, which satisfies a relationship that a gravity center G1 of the corresponding modified refractive index region is positioned on a straight line passing through the lattice point O(x, y) and tilted from the s-axis and a line segment length r(x,y) from the lattice point O(x, y) to the gravity center G1 of the corresponding modified refractive index region is
r(x,y)=C×(P(x,y)−P0)
(C:
a proportional constant,
P0:
an arbitrary constant),
is arranged inside the unit configuration region R(x,y).

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Semiconductor light emitting array with phase modulation regions for generating beam projection patterns

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Semiconductor light emitting array with phase modulation regions for generating beam projection patterns

Life of this patent

Abstract

Claims14