JP7579499B2 - Light source - Google Patents

Description

The present invention relates to a light source device.

For example, there is a light source device that uses a laser diode. In light source devices, it is desirable to improve the uniformity of the light intensity distribution.

JP 2004-252275 A

The present invention provides a light source device that can improve the uniformity of the light intensity distribution.

According to one embodiment of the present invention, a light source device includes a first light source that emits a first light, and a first lens that includes a first surface and a second surface. The first light is incident on the first surface, and a second light is emitted from the second surface. The intensity of the first light is a first value on a first optical axis of the first light. The intensity of the first light is 0.7 times the first value in a direction of a first angle from the first optical axis. The intensity of the first light is 0.5 times the first value in a direction of a second angle from the first optical axis. The intensity of the first light is 0.3 times the first value in a direction of a third angle from the first optical axis. The intensity of the second light is a second value on a second optical axis of the second light. The intensity of the second light is 0.7 times the second value in a direction of a fourth angle from the second optical axis. The intensity of the second light is 0.5 times the second value in a direction of a fifth angle from the second optical axis. The intensity of the second light is 0.3 times the second value in a direction of a sixth angle from the second optical axis. The direction of the first angle, the direction of the second angle, the direction of the fourth angle, the direction of the fifth angle, and the direction of the sixth angle are along a first plane that includes the direction of the third angle and the first optical axis. The angle along the first plane from the first optical axis at which the intensity of the first light is 0.135 times the first value is 3 degrees or greater. The first lens has a second ratio lower than the first ratio. The first ratio is the ratio of the absolute value of the difference between the first angle and the third angle to the second angle. The second ratio is the ratio of the absolute value of the difference between the fourth angle and the sixth angle to the fifth angle.

According to one embodiment of the present invention, a light source device is provided that can improve the uniformity of the light intensity distribution.

FIG. 1 is a schematic perspective view illustrating a light source device according to the first embodiment. FIG. 2 is a schematic view illustrating the light source device according to the first embodiment. FIG. 3 is a schematic view illustrating the light source device according to the first embodiment. FIG. 4 is a schematic view illustrating the light source device according to the first embodiment. FIG. 5A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 5B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 6A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 6B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 7A is a schematic diagram illustrating the characteristics of a light source device. FIG. 7B is a schematic diagram illustrating the characteristics of the light source device. FIG. 8 is a schematic view illustrating the light source device according to the first embodiment. FIG. 9 is a schematic view illustrating the light source device according to the first embodiment. FIG. 10A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 10B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 11A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 11B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 12 is a schematic view illustrating the light source device according to the first embodiment. FIG. 13A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 13B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 14A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 14B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 15A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 15B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 16B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 16B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 17A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 17B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 18A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 18B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 19A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 19B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 20A is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 20B is a graph illustrating the characteristics of the light source device according to the first embodiment. FIG. 21 is a schematic view illustrating the light source device according to the second embodiment. FIG. 22 is a schematic view illustrating the light source device according to the second embodiment. FIG. 23A is a schematic side view illustrating the light source device according to the embodiment. FIG. 23B is a schematic side view illustrating the light source device according to the embodiment. FIG. 24A is a schematic side view illustrating the light source device according to the embodiment. FIG. 24B is a schematic side view illustrating the light source device according to the embodiment. FIG. 25 is a schematic perspective view illustrating a part of the light source device according to the embodiment. FIG. 26 is a schematic perspective view illustrating a part of the light source device according to the embodiment. FIG. 27 is a schematic side view illustrating a part of the light source device according to the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios of each part may be different depending on the drawing.
In this specification, elements similar to those described above with reference to the previous figures are given the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

First Embodiment
FIG. 1 is a schematic perspective view illustrating a light source device according to the first embodiment.
FIG. 2 is a schematic view illustrating the light source device according to the first embodiment.
As shown in Fig. 1, a light source device 110 according to the embodiment includes a first light source 11 and a first lens 21. The first light source 11 emits a first light L1. The first light L1 is incident on the first lens 21. The first light source 11 includes, for example, a laser. The laser is, for example, a semiconductor laser. The first light L1 is, for example, a laser beam. In one example, the peak wavelength of the first light L1 is not less than 300 nm and not more than 800 nm.

The first lens 21 includes a first surface 21a and a second surface 21b. A first light L1 is incident on the first surface 21a. A second light L2 is emitted from the second surface 21b. The first surface 21a is the incident surface of the first lens 21. The second surface 21b is the exit surface of the first lens 21. The first light L1 incident on the first surface 21a becomes the second light L2 and is emitted from the second surface 21b.

The first lens 21 may include, for example, resin, glass, or quartz.

The direction from the first surface 21a of the first lens 21 toward the second surface 21b of the first lens 21 is defined as the Z-axis direction. For example, the Z-axis direction corresponds to the travel of the first light L1 when it is incident on the first surface 21a.

The direction perpendicular to the Z-axis direction is the X-axis direction. The direction perpendicular to the Z-axis direction and the X-axis direction is the Y-axis direction.

For example, when the first light L1 is a laser light, the fast axis Af and the slow axis As are perpendicular to the Z-axis direction. For example, the fast axis Af may be aligned along the Y-axis direction. For example, the slow axis As may be aligned along the X-axis direction.

In the embodiment, the first light L1 emitted from the first light source 11 may be directly incident on the first surface 21a. The first light L1 emitted from the first light source 11 may be incident on the first surface 21a via an optical element (e.g., a reflective surface) or the like. Below, an example in which the first light L1 emitted from the first light source 11 is directly incident on the first surface 21a will be described.

The first light L1 incident on the first surface 21a is along the first optical axis La1. The second light L2 emerging from the second surface 21b travels along the second optical axis La2.

As shown in FIG. 1, in one example, the second light L2 is incident on the optical element 31. The optical element 31 collects the second light L2. In this example, the optical element 31 is a lens. The third light L3 emitted from the optical element 31 is collected at the collecting position 31P. At the collecting position 31P, for example, an entrance region 31S of the third light L3 is formed. The entrance region 31S is, for example, rectangular. For example, a wavelength conversion member or the like may be provided in the entrance region 31S to convert the wavelength of the third light L3. In one example, the light irradiated to the entrance region 31S (the third light L3) may be used as the light obtained from the light source device 110. The light source device 110 may include the optical element 31. The light source device 110 may include the above-mentioned wavelength conversion member.

When the light source device 110 includes a first light source 11 and a first lens 21, the second light L2 may be used as the light obtained from the light source device 110.

As shown in FIG. 2, for example, the first surface 21a is substantially flat and the second surface 21b is convex. The first surface 21a may be convex and the second surface 21b may be substantially flat. The first surface 21a may be concave or convex. The second surface 21b may be concave or convex.

As shown in FIG. 1, it is possible to define a first plane PL1 and a second plane PL2. The first plane PL1 includes a first optical axis La1 of the first light L1 and one direction intersecting the first optical axis La1. In the example of FIG. 1, the first plane PL1 includes the first optical axis La1 (e.g., the Z-axis direction) and the Y-axis direction. For example, the first plane PL1 is along the fast axis Af.

The second plane PL2 is perpendicular to the first plane PL1. The second plane PL2 includes the first optical axis La1 of the first light L1. In the example of FIG. 1, the second plane PL2 includes the first optical axis La1 (e.g., the Z-axis direction) and the X-axis direction. For example, the second plane PL2 is along the slow axis As.

The following describes an example of the characteristics of the first lens 21. For example, the first lens 21 converts the distribution of the first light L1 incident on the first surface 21a into the distribution of the second light L2 emitted from the second surface 21b.

3 and 4 are schematic views illustrating the light source device according to the first embodiment.
3 and 4 are schematic diagrams along a first plane PL1. The first plane PL1 is, for example, along the YZ plane.

3 and 4 show a schematic example of the distribution of the intensity Ls1 of the first light L1. One axis Lv1 in the left-right direction shown in FIG. 3 and FIG. 4 corresponds to the intensity Ls1 of the first light L1. As shown in FIG. 3 and FIG. 4, the intensity Ls1 of the first light L1 is a first value v1 on the first optical axis La1 of the first light L1. The first value v1 may substantially correspond to the peak value of the intensity Ls1 of the first light L1. The distribution of the intensity Ls1 of the first light L1 may show a small amplitude increase or decrease. In such a case, for example, the first value v1 may correspond to an average value of the small amplitude increase or decrease.

3 and 4 show a schematic example of the distribution of the intensity Ls2 of the second light L2. One axis Lv2 in the left-right direction shown in FIG. 3 and FIG. 4 corresponds to the intensity Ls2 of the second light L2. As shown in FIG. 3 and FIG. 4, the intensity Ls2 of the second light L2 is a second value v2 on the second optical axis La2 of the second light L2. The second value v2 may substantially correspond to the peak value of the intensity Ls2 of the second light L2. The distribution of the intensity Ls2 of the second light L2 may show a small amplitude increase or decrease. In such a case, for example, the second value v2 may correspond to an average value of the small amplitude increase or decrease.

The angle θ01 shown in FIG. 3 can be defined for the angular distribution of the intensity Ls1 of the first light L1. The angle θ01 is an angle along the first plane PL1 with respect to the first optical axis La1. The angle θ01 includes, for example, the first to third angles θ1 to θ3 described below.

The angle θ02 shown in FIG. 3 can be defined for the angular distribution of the intensity Ls2 of the second light L2. The angle θ02 is an angle along the first plane PL1 with respect to the second optical axis La2. The angle θ02 includes, for example, the fourth to sixth angles θ4 to θ6 described below.

Regarding the distance distribution of the intensity Ls1 of the first light L1, the distance d01 shown in FIG. 4 can be defined. The distance d01 is the distance along the first axis Ax1 based on the first optical axis La1. The first axis Ax1 is along the first plane PL1. The first axis Ax1 intersects with the first optical axis La1. For example, the first axis Ax1 is perpendicular to the first optical axis La1. The position of the first axis Ax1 on the first optical axis La1 may be, for example, the position on the first optical axis La1 of the first surface 21a. There are first to third positions py1 to py3 on the first axis Ax1. The first distance d1 corresponds to the distance along the first axis Ax1 between the first optical axis La1 and the first position py1. The second distance d2 corresponds to the distance along the first axis Ax1 between the first optical axis La1 and the second position py2. The third distance d3 corresponds to the distance along the first axis Ax1 between the first optical axis La1 and the third position py3.

Regarding the distance distribution of the intensity Ls2 of the second light L2, the distance d02 shown in FIG. 4 can be defined. The distance d02 is the distance along the second axis Ax2 based on the second optical axis La2. The second axis Ax2 is along the first plane PL1. The second axis Ax2 intersects with the second optical axis La2. For example, the second axis Ax2 is perpendicular to the second optical axis La2. The position of the second axis Ax2 on the second optical axis La2 may be, for example, the position on the second optical axis La2 at the apex of the second surface 21b. There are fourth to sixth positions py4 to py6 on the second axis Ax2. The fourth distance d4 corresponds to the distance along the second axis Ax2 between the second optical axis La2 and the fourth position py4. The fifth distance d5 corresponds to the distance along the second axis Ax2 between the second optical axis La2 and the fifth position py5. The sixth distance d6 corresponds to the distance along the second axis Ax2 between the second optical axis La2 and the sixth position py6.

FIGS. 5A and 5B are graphs illustrating the characteristics of the light source device according to the first embodiment. The horizontal axis of FIG. 5A is the angle θ01 (degrees). The horizontal axis of FIG. 5B is the angle θ02 (degrees). The vertical axis of FIG. 5A is the intensity Ls1 of the first light L1. The vertical axis of FIG. 5B is the intensity Ls2 of the second light L2. Intensities Ls1 and Ls2 are normalized values.

As shown in FIG. 5A, the intensity Ls1 of the first light L1 when the angle θ01 is 0 is substantially "1". The intensity Ls1 of the first light L1 when the angle θ01 is 0 corresponds to the value (first value v1) of the first light L1 on the first optical axis La1. As shown in FIG. 5B, the intensity Ls2 of the second light L2 when the angle θ02 is 0 is substantially "1". The intensity Ls2 of the second light L2 when the angle θ02 is 0 corresponds to the value (second value v2) of the second light L2 on the second optical axis La2.

As shown in FIG. 5A, the angular distribution of the intensity Ls1 of the first light L1 incident on the first surface 21a is a "Gaussian distribution." As shown in FIG. 5B, in the angular distribution of the intensity Ls2 of the second light L2 exiting from the second surface 21b, the angles over which the intensity is uniform are wider than in the "Gaussian distribution." The angular distribution of the intensity Ls2 is, for example, a "top hat" shape.

The first lens 21 converts the angular distribution of the intensity Ls1 of the first light L1 illustrated in FIG. 5A into the angular distribution of the intensity Ls2 of the second light L2 illustrated in FIG. 5B. Below, examples of parameters related to the angular distributions of the intensity Ls1 and the intensity Ls2 are described.

As shown in FIG. 5A, the intensity Ls1 of the first light L1 is 0.7 times the first value v1 in the direction of the first angle θ1 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.5 times the first value v1 in the direction of the second angle θ2 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.3 times the first value v1 in the direction of the third angle θ3 from the first optical axis La1.

As shown in FIG. 5B, the intensity Ls2 of the second light L2 is 0.7 times the second value v2 in the direction of the fourth angle θ4 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.5 times the second value v2 in the direction of the fifth angle θ5 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.3 times the second value v2 in the direction of the sixth angle θ6 from the second optical axis La2.

The direction of the first angle θ1, the direction of the second angle θ2, the direction of the fourth angle θ4, the direction of the fifth angle θ5, and the direction of the sixth angle θ6 are aligned along the first plane PL1, which includes the direction of the third angle θ3 and the first optical axis La1. For example, the first to sixth angles θ1 to θ6 and the first optical axis La1 are aligned along the first plane PL1.

The first ratio α1 and the second ratio α2 are introduced as parameters. The first ratio α1 is the ratio of the absolute value of the difference between the first angle θ1 and the third angle θ3 to the second angle θ2. The second ratio α2 is the ratio of the absolute value of the difference between the fourth angle θ4 and the sixth angle θ6 to the fifth angle θ5.

The first ratio α1 and the second ratio α2 are
α1=|θ1-θ3|/θ2
α2=|θ4-θ6|/θ5
It is expressed as:

For example, when these ratios are high, the angular distribution of light intensity is closer to a "Gaussian distribution." When these ratios are low, the angular distribution of light intensity is closer to a "top hat distribution."

In the embodiment, the first lens 21 makes the second ratio α2 lower than the first ratio α1. For example, the angular distribution of the intensity Ls2 of the second light L2 emitted from the first lens 21 is closer to a "top hat shape" than the angular distribution of the intensity Ls1 of the first light L1 incident on the first lens 21. For example, the first lens 21 converts the Gaussian-distribution-like angular distribution of the intensity Ls1 of the first light L1 into a top hat-shaped angular distribution of the intensity Ls2 of the second light L2.

For example, in the example of FIG. 5A, the first ratio α1 is 0.617. In the example of FIG. 5B, the second ratio α2 is 0.297.

Such second light L2 has a narrower angular distribution of intensity than the first light L1. For example, when such second light L2 is focused by an optical element 31 or the like, a more uniform light intensity distribution (brightness distribution) is obtained in the entrance region 31S. For example, the light intensity distribution is highly uniform in the rectangular entrance region 31S. According to the embodiment, a light source device that can improve the uniformity of the light intensity distribution can be provided.

In the embodiment, the first light L1 is not a completely parallel light. For example, the angular distribution of the intensity Ls1 of the first light L1 is a Gaussian distribution. For example, the intensity Ls1 of the first light L1 decreases as the angle θ01 from the first optical axis La1 increases. The angle θ01 from the first optical axis La1 along the first plane PL1 at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 is 3 degrees or more. "0.135 times" corresponds to "1/ ^e2 times" when "e" is the Napier's number. "e" is approximately 2.7182812814.

Below, an example of the distance distribution of the intensity Ls1 of the first light L1 and the intensity Ls2 of the second light L2 with respect to the first lens 21 will be described.

Figures 6A and 6B are graphs illustrating the characteristics of the light source device according to the first embodiment. The horizontal axis of Figure 6A is the distance d01 (arbitrary units). As already explained, the distance d01 is the distance along the first plane PL1 based on the first optical axis La1. The horizontal axis of Figure 6B is the distance d02 (arbitrary units). As already explained, the distance d02 is the distance along the first plane PL1 based on the second optical axis La2. The vertical axis of Figure 6A is the intensity Ls1 of the first light L1. The vertical axis of Figure 6B is the intensity Ls2 of the second light L2. The intensities Ls1 and Ls2 are normalized values.

As shown in FIG. 6A, the intensity Ls1 of the first light L1 is substantially "1" when the distance d01 is 0. The intensity Ls1 of the first light L1 when the distance d01 is 0 corresponds to the value (first value v1) of the first light L1 on the first optical axis La1. As shown in FIG. 6B, the intensity Ls2 of the second light L2 when the distance d02 is 0 is substantially "1". The intensity Ls2 of the second light L2 when the distance d02 is 0 corresponds to the value (second value v2) of the second light L2 on the second optical axis La2.

As shown in FIG. 6A, the distance distribution of the intensity Ls1 of the first light L1 incident on the first surface 21a is a "Gaussian distribution". As shown in FIG. 6B, the distance distribution of the intensity Ls2 of the second light L2 emerging from the second surface 21b is also a "Gaussian distribution". Below, examples of parameters relating to the distance distribution (position distribution) of the intensity Ls1 and the intensity Ls2 are described.

As shown in FIG. 6A, the intensity Ls1 of the first light L1 is 0.7 times the first value v1 at the position of the first distance d1. As already explained, the first distance d1 is the distance along the first axis Ax1 between the first optical axis La1 and the first position py1. The intensity Ls1 of the first light L1 is 0.7 times the first value v1 at the first position py1 on the first axis Ax1.

As shown in FIG. 6A, the intensity Ls1 of the first light L1 is 0.5 times the first value v1 at the position of the second distance d2. As already explained, the second distance d2 is the distance along the first axis Ax1 between the first optical axis La1 and the second position py2. The intensity Ls1 of the first light L1 is 0.5 times the first value v1 at the second position py2 on the first axis Ax1.

As shown in FIG. 6A, the intensity Ls1 of the first light L1 is 0.3 times the first value v1 at the third distance d3. As already explained, the third distance d3 is the distance along the first axis Ax1 between the first optical axis La1 and the third position py3. The intensity Ls1 of the first light L1 is 0.3 times the first value v1 at the third position py3 on the first axis Ax1.

As shown in FIG. 6B, the intensity Ls2 of the second light L2 is 0.7 times the second value v2 at the fourth distance d4. As already explained, the fourth distance d4 is the distance along the second axis Ax2 between the second optical axis La2 and the fourth position py4. The intensity Ls2 of the second light L2 is 0.7 times the second value v2 at the fourth position py4 on the second axis Ax2.

As shown in FIG. 6B, the intensity Ls2 of the second light L2 is 0.5 times the second value v2 at the fifth distance d5. As already explained, the fifth distance d5 is the distance along the second axis Ax2 between the second optical axis La2 and the fifth position py5. The intensity Ls2 of the second light L2 is 0.5 times the second value v2 at the fifth position py5 on the second axis Ax2.

As shown in FIG. 6B, the intensity Ls2 of the second light L2 is 0.3 times the second value v2 at the sixth distance d6. As already explained, the sixth distance d6 is the distance along the second axis Ax2 between the second optical axis La2 and the sixth position py6. The intensity Ls2 of the second light L2 is 0.3 times the second value v2 at the sixth position py6 on the second axis Ax2.

For example, a third ratio α3 and a fourth ratio α4 are introduced as parameters. The third ratio α3 is the ratio of the absolute value of the difference between the first distance d1 and the third distance d3 to the second distance d2. The fourth ratio α4 is the ratio of the absolute value of the difference between the fourth distance d4 and the sixth distance d6 to the fifth distance d5.

The third ratio α3 and the fourth ratio α4 are
α3=|d1-d3|/d2
α4=|d4-d6|/d5
It is expressed as:

For example, when these ratios are high, the distance (or position) distribution of light intensity is closer to a "Gaussian distribution." When these ratios are low, the distance (or position) distribution of light intensity is closer to a "top hat" distribution.

In the embodiment, the degree of difference between the third ratio α3 and the fourth ratio α4 in the distance distribution is smaller than the degree of difference between the first ratio α1 and the second ratio α2 in the angle distribution. For example, in the example of FIG. 6A, the third ratio α3 is 0.576. In the example of FIG. 6B, the fourth ratio α4 is 0.573.

For example, the first lens 21 makes the absolute value of the difference between the first ratio α1 and the second ratio α2 greater than the absolute value of the difference between the third ratio α3 and the fourth ratio α4. For example, in the example of Figures 5A and 5B, the difference between the first ratio α1 and the second ratio α2 is 0.32. For example, in the example of Figures 6A and 6B, the difference between the third ratio α3 and the fourth ratio α4 is 0.003.

Thus, in the embodiment, the difference between the first ratio α1 and the second ratio α2 regarding the angular distribution is greater than the difference between the third ratio α3 and the fourth ratio α4 regarding the distance distribution. At the intensity Ls2 of the second light L2, the angular distribution is highly uniform. According to the embodiment, it is possible to provide a light source device that can improve the uniformity of the light intensity distribution.

For example, consider the reference optical system that uses a collimating lens. In such reference examples, the idea of making the distance distribution of light intensity "top hat shaped" is generally used. In this case, the angular distribution of light intensity is usually not taken into consideration.

In contrast, in the embodiment, the uniformity of the angular distribution of the light intensity is improved. For example, the second ratio α2 regarding the angular distribution of the intensity Ls2 of the outgoing second light L2 is made lower than the first ratio α1 regarding the angular distribution of the intensity Ls1 of the incident first light L1.

In the embodiment, by lowering the second ratio α2, for example, when the second light L2 is focused by the optical element 31 or the like, a more uniform light intensity distribution is obtained in the entrance region 31S. For example, the light intensity distribution is highly uniform in the rectangular entrance region 31S. According to the embodiment, a light source device that can improve the uniformity of the light intensity distribution can be provided.

For example, the absolute value of the difference between the first ratio α1 and the second ratio α2 is greater than 0.3. For example, the second ratio α2 is equal to or less than 0.297.

The above-mentioned first to sixth angles θ1 to θ6 are angles along the first plane PL1. The above-mentioned first to sixth distances d1 to d6 are distances along the first plane PL1. When the first light L1 is a first laser light, the first plane PL1 may be aligned along, for example, the fast axis Af of the first laser light. The first plane PL1 may be aligned along, for example, the slow axis As of the first laser light.

For example, the angle θ01 from the first optical axis La1 along the first plane PL1 at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 is, for example, 15 degrees or more. At the fast axis Af, for example, the angle θ01 is 15 degrees or more. In the embodiment, the angle θ01 from the first optical axis La1 along the first plane PL1 at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 may be, for example, 3 degrees or more and 40 degrees or less.

7A and 7B are schematic diagrams illustrating the characteristics of a light source device.
Fig. 7A corresponds to the light source device 110 according to the embodiment. Fig. 7B corresponds to the light source device 119 of the reference example. In the light source device 119, a collimating optical system is used. Fig. 7A and Fig. 7B illustrate the angular distribution of the intensity Ls1 of the first light L1 and the angular distribution of the intensity Ls2 of the second light L2.

As shown in FIG. 7B, in the light source device 119 of the reference example, the first light L1 emitted from the first light source 11 is incident on the first optical component 91 and then on the second optical component 92. The first optical component 91 and the second optical component 92 function as a collimator lens. In the light source device 119, when the angular distribution of the intensity Ls1 of the first light L1 is "Gaussian distribution", the angular distribution of the intensity Ls2 of the second light L2 emitted from the second optical component 92 is also "Gaussian distribution". Such second light L2 is focused at the focusing position 31P by the optical element 31. The intensity Ls3 in the entrance region 31S of the focusing position 31P has a Gaussian distribution. In the light source device 119, the uniformity of the light intensity distribution is low.

As shown in FIG. 7A, in the light source device 110 according to the embodiment, when the angular distribution of the intensity Ls1 of the first light L1 is "Gaussian distribution", the angular distribution of the intensity Ls2 of the second light L2 emitted from the first lens 21 is "top hat". When such second light L2 is focused at the focusing position 31P by the optical element 31, the intensity Ls3 at the entrance region 31S of the focusing position 31P becomes "top hat". In the embodiment, the light intensity distribution is highly uniform.

In the above example, the first plane PL1 is aligned along the fast axis Af of the first light L1. An example of the optical characteristics along the slow axis As in this case is described below.

8 and 9 are schematic views illustrating the light source device according to the first embodiment.
8 and 9 are schematic diagrams along the second plane PL2. The second plane PL2 is, for example, along the XZ plane.

Figures 8 and 9 show a schematic example of the distribution of the intensity Ls1 of the first light L1 in the X-axis direction. One axis Lv1 in the left-right direction shown in Figures 8 and 9 corresponds to the intensity Ls1 of the first light L1. As shown in Figures 8 and 9, the intensity Ls1 of the first light L1 is a first value v1 on the first optical axis La1 of the first light L1.

Figures 8 and 9 show a schematic example of the distribution of the intensity Ls2 of the second light L2 in the X-axis direction. One axis Lv2 in the left-right direction shown in Figures 8 and 9 corresponds to the intensity Ls2 of the second light L2. As shown in Figures 8 and 9, the intensity Ls2 of the second light L2 is a second value v2 on the second optical axis La2 of the second light L2.

The angle θ03 shown in FIG. 8 can be defined for the angular distribution of the intensity Ls1 of the first light L1. The angle θ03 is an angle along the second plane PL2 with respect to the first optical axis La1. The angle θ03 includes, for example, the seventh to ninth angles θ7 to θ9, which will be described later.

The angle θ04 shown in FIG. 8 can be defined for the angular distribution of the intensity Ls2 of the second light L2. The angle θ04 is an angle along the second plane PL2 and based on the second optical axis La2. The angle θ04 includes, for example, the tenth to twelfth angles θ10 to θ12, which will be described later.

Regarding the distance distribution of the intensity Ls1 of the first light L1, the distance d03 shown in FIG. 9 can be defined. The distance d03 is the distance along the third axis Ax3 based on the first optical axis La1. The third axis Ax3 is along the second plane PL2. The third axis Ax3 intersects with the first optical axis La1. For example, the third axis Ax3 is perpendicular to the first optical axis La1 and intersects with the first axis Ax1. For example, the third axis Ax3 is perpendicular to the first axis Ax1. The position of the third axis Ax3 on the first optical axis La1 may be, for example, the position on the first optical axis La1 of the first surface 21a. There are seventh to ninth positions py7 to py9 on the third axis Ax3. The seventh distance d7 corresponds to the distance along the third axis Ax3 between the first optical axis La1 and the seventh position py7. The eighth distance d8 corresponds to the distance along the third axis Ax3 between the first optical axis La1 and the eighth position py8. The ninth distance d9 corresponds to the distance along the third axis Ax3 between the first optical axis La1 and the ninth position py9.

Regarding the distance distribution of the intensity Ls2 of the second light L2, the distance d04 shown in FIG. 9 can be defined. The distance d04 is the distance along the fourth axis Ax4 based on the second optical axis La2. The fourth axis Ax4 is along the second plane PL2. The fourth axis Ax4 intersects with the second optical axis La2. For example, the fourth axis Ax4 is perpendicular to the first optical axis La1 and intersects with the second axis Ax2. For example, the fourth axis Ax4 is perpendicular to the second axis Ax2. The position of the fourth axis Ax4 on the second optical axis La2 may be, for example, the position on the second optical axis La2 at the apex of the second surface 21b. There are tenth to twelfth positions py10 to py12 on the fourth axis Ax4. The tenth distance d10 corresponds to the distance along the fourth axis Ax4 between the second optical axis La2 and the tenth position py10. The eleventh distance d11 corresponds to the distance along the fourth axis Ax4 between the second optical axis La2 and the eleventh position py11. The twelfth distance d12 corresponds to the distance along the fourth axis Ax4 between the second optical axis La2 and the twelfth position py12.

10A and 10B are graphs illustrating the characteristics of the light source device according to the first embodiment.
The horizontal axis of Fig. 10A is the angle θ03 (degrees). The horizontal axis of Fig. 10B is the angle θ04 (degrees). The vertical axis of Fig. 10A is the intensity Ls1 of the first light L1. The vertical axis of Fig. 10B is the intensity Ls2 of the second light L2. The intensities Ls1 and Ls2 are normalized values.

As shown in Figure 10A, when the angle θ01 is 0, the intensity Ls1 of the first light L1 is substantially "1" and corresponds to the value (first value v1) of the first light L1 on the first optical axis La1. As shown in Figure 10B, when the angle θ02 is 0, the intensity Ls2 of the second light L2 is substantially "1" and corresponds to the value (second value v2) of the second light L2 on the second optical axis La2.

Below, we explain examples of parameters related to the angular distribution of intensity Ls1 and intensity Ls2 in the direction along the second plane PL2.

As shown in FIG. 10A, the intensity Ls1 of the first light L1 is 0.7 times the first value v1 in the direction of the seventh angle θ7 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.5 times the first value v1 in the direction of the eighth angle θ8 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.3 times the first value v1 in the direction of the ninth angle θ9 from the first optical axis La1.

As shown in FIG. 10B, the intensity Ls2 of the second light L2 is 0.7 times the second value v2 in the direction of the tenth angle θ10 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.5 times the second value v2 in the direction of the eleventh angle θ11 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.3 times the second value v2 in the direction of the twelfth angle θ12 from the second optical axis La2.

The direction of the seventh angle θ7, the direction of the eighth angle θ8, the direction of the tenth angle θ10, the direction of the eleventh angle θ11, and the direction of the twelfth angle θ12 are along the second plane PL2. The second plane PL2 includes the direction of the ninth angle θ9 and the first optical axis La1, and intersects with the first plane PL1. For example, the second plane PL2 is perpendicular to the first plane PL1.

The fifth ratio α5 and sixth ratio α6 are introduced as parameters. The fifth ratio α5 is the ratio of the absolute value of the difference between the seventh angle θ7 and the ninth angle θ9 to the eighth angle θ8. The sixth ratio α6 is the ratio of the absolute value of the difference between the tenth angle θ10 and the twelfth angle θ12 to the eleventh angle θ11.

The fifth ratio α5 and the sixth ratio α6 are
α5=|θ7−θ9|/θ8
α6=|θ10-θ12|/θ11
It is expressed as:

For example, when these ratios are high, the angular distribution of light intensity is closer to a "Gaussian distribution." When these ratios are low, the angular distribution of light intensity is closer to a "top hat distribution."

In the embodiment, the first lens 21 has a sixth ratio α6 that is lower than the fifth ratio α5. In the example of Figures 10A and 10B, the fifth ratio α5 is 0.595 and the sixth ratio α6 is 0.297.

In the embodiment, the sixth ratio α6 is lower than the fifth ratio α5 in the direction along the second plane PL2. When the angular distribution of the intensity Ls1 of the first light L1 is "Gaussian" in the direction along the second plane PL2, the angular distribution of the intensity Ls2 of the second light L2 emitted from the second optical component 92 is "top hat". For example, when such second light L2 is focused at the focusing position 31P by the optical element 31, the intensity Ls3 at the entrance region 31S of the focusing position 31P becomes "top hat". In the embodiment, the light intensity distribution is highly uniform.

For example, with respect to the seventh to ninth angles θ7 to θ9, the angle θ03 from the first optical axis La1 along the second plane PL2 at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 is, for example, 3 degrees or more. This angle θ03 is, for example, 40 degrees or less.

11A and 11B are graphs illustrating the characteristics of the light source device according to the first embodiment.
The horizontal axis of FIG. 11A is distance d03 (arbitrary units). Distance d03 is the distance along the second plane PL2, based on the first optical axis La1. The horizontal axis of FIG. 11B is distance d04 (arbitrary units). Distance d04 is the distance along the second plane PL2, based on the second optical axis La2. The vertical axis of FIG. 11A is intensity Ls1 of the first light L1. The vertical axis of FIG. 11B is intensity Ls2 of the second light L2. Intensities Ls1 and Ls2 are normalized values.

As shown in Figure 11A, when the distance d03 is 0, the intensity Ls1 of the first light L1 is substantially "1" and corresponds to the value (first value v1) of the first light L1 on the first optical axis La1. As shown in Figure 11B, when the distance d04 is 0, the intensity Ls2 of the second light L2 is substantially "1" and corresponds to the value (second value v2) of the second light L2 on the second optical axis La2.

Below, we will explain examples of parameters related to the distance distribution (position distribution) of intensity Ls1 and intensity Ls2 in the direction along the second plane PL2.

As shown in FIG. 11A, the intensity Ls1 of the first light L1 is 0.7 times the first value v1 at the seventh distance d7. As already explained, the seventh distance d7 is the distance along the third axis Ax3 between the first optical axis La1 and the seventh position py7. The intensity Ls1 of the first light L1 is 0.7 times the first value v1 at the seventh position py7 on the third axis Ax3.

As shown in FIG. 11A, the intensity Ls1 of the first light L1 is 0.5 times the first value v1 at the eighth distance d8. As already explained, the eighth distance d8 is the distance along the third axis Ax3 between the first optical axis La1 and the eighth position py8. The intensity Ls1 of the first light L1 is 0.5 times the first value v1 at the eighth position py8 on the third axis Ax3.

As shown in FIG. 11A, the intensity Ls1 of the first light L1 is 0.3 times the first value v1 at the ninth distance d9. As already explained, the ninth distance d9 is the distance along the third axis Ax3 between the first optical axis La1 and the ninth position py9. The intensity Ls1 of the first light L1 is 0.3 times the first value v1 at the ninth position py9 on the third axis Ax3.

As shown in FIG. 11B, the intensity Ls2 of the second light L2 is 0.7 times the second value v2 at the tenth distance d10. As already explained, the tenth distance d10 is the distance along the fourth axis Ax4 between the second optical axis La2 and the tenth position py10. The intensity Ls2 of the second light L2 is 0.7 times the second value v2 at the tenth position py10 on the fourth axis Ax4.

As shown in FIG. 11B, the intensity Ls2 of the second light L2 is 0.5 times the second value v2 at the eleventh distance d11. As already explained, the eleventh distance d11 is the distance along the fourth axis Ax4 between the second optical axis La2 and the eleventh position py11. The intensity Ls2 of the second light L2 is 0.5 times the second value v2 at the eleventh position py11 on the fourth axis Ax4.

As shown in FIG. 11B, the intensity Ls2 of the second light L2 is 0.3 times the second value v2 at the twelfth distance d12. As already explained, the twelfth distance d12 is the distance along the fourth axis Ax4 between the second optical axis La2 and the twelfth position py12. The intensity Ls2 of the second light L2 is 0.3 times the second value v2 at the twelfth position py12 on the fourth axis Ax4.

For example, a seventh ratio α7 and an eighth ratio α8 are introduced as parameters. The seventh ratio α7 is the ratio of the absolute value of the difference between the seventh distance d7 and the ninth distance d9 to the eighth distance d8. The eighth ratio α8 is the ratio of the difference between the tenth distance d10 and the twelfth distance d12 to the eleventh distance d11.

The seventh ratio α7 and the eighth ratio α8 are
α7=|d7-d9|/d8
α8=|d10-d12|/d11
It is expressed as:

For example, when these ratios are high, the distance (or position) distribution of light intensity is closer to a "Gaussian distribution." When these ratios are low, the distance (or position) distribution of light intensity is closer to a "top hat" distribution.

In the embodiment, the first lens 21 makes the absolute value of the difference between the fifth ratio α5 and the sixth ratio α6 greater than the absolute value of the difference between the seventh ratio α7 and the eighth ratio α8. In the example of Figures 11A and 11B, the seventh ratio α7 is 0.61, and the eighth ratio α8 is 0.552. Therefore, in the examples of Figures 10A, 10B, 11A, and 11B, the difference (absolute value) between the fifth ratio and the sixth ratio is 0.298, and the difference (absolute value) between the seventh ratio and the eighth ratio is 0.058.

Even in the direction along the second plane PL2, the degree of difference between the fifth ratio α5 and the sixth ratio α6 in terms of the angular distribution is greater than the degree of difference between the seventh ratio α7 and the eighth ratio α8 in terms of the distance distribution. Even in the direction along the second plane PL2, when the second light L2, which has a top hat shape, is focused at the focusing position 31P by the optical element 31, the intensity Ls3 in the entrance region 31S of the focusing position 31P becomes "top hat" in the direction corresponding to the second plane PL2. According to the embodiment, a light source device that can improve the uniformity of the light intensity distribution can be provided.

In one example, for example, the absolute value of the difference between the fifth ratio α5 and the sixth ratio α6 is 0.3 or more. For example, the sixth ratio α6 is 0.297 or less.

For example, the angle θ03 from the first optical axis La1 along the second plane PL2 at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 is, for example, 3 degrees or more and 40 degrees or less.

For example, when the first light L1 is a first laser light, the first plane PL1 is aligned along the fast axis Af of the first laser light, and the second plane PL2 is aligned along the slow axis As of the first laser light.

FIG. 12 is a schematic view illustrating the light source device according to the first embodiment.
In the light source device 110 according to the embodiment, the focal length of the first lens 21 is the focal length fL. The length y is 1/2 of the length of the first light source 11 along the second plane PL2. At this time, the angular distribution width Ws along the second plane PL2 of the second light L2 emitted from the first lens 21 is, for example, greater than 1.5 times arctan (y/fL). The angular distribution width Ws corresponds to, for example, an angle θ04 at which the intensity Ls2 of the second light L2 is 0.135 times the second value v2 of the intensity Ls2 of the second light L2 on the second optical axis La2.

For example, a reference example using a collimated optical system can be considered. In this reference example, for example, by defocusing, the "Gaussian distribution" component along the slow axis As of the first light L1 may be transformed into a "top hat" shape. When a "top hat" shape is obtained by defocusing, the angular distribution width Ws is 1.3 times or less of arctan (y/fL). In such a reference example, it is practically difficult to make the angular distribution width Ws 1.5 times or more of arctan (y/fL).

In the embodiment, the technical idea of controlling the angular distribution is used, rather than the technical idea of using a collimating optical system. According to the embodiment, the angular distribution width Ws can be increased to 1.5 times or more the arctan (y/fL).

In an embodiment, for example, a "top hat" distribution can be obtained while widening the light angle.

13A, 13B, 14A, 14B, 15A, 15B, 16A, and 16B are graphs illustrating the characteristics of the light source device according to the first embodiment.
These figures illustrate the characteristics of the light source device 111 (see FIG. 1) according to the embodiment. The light source device 111 is one example of the light source device according to the embodiment. FIGS. 13A, 13B, 14A, and 14B correspond to the characteristics along the first plane PL1, for example, the characteristics along the fast axis Af of the first light L1. FIGS. 15A, 15B, 16A, and 16B correspond to the characteristics along the second plane PL2, for example, the characteristics along the slow axis As of the first light L1. The horizontal axis of FIG. 13A is the angle θ01 (degrees). The horizontal axis of FIG. 13B is the angle θ02 (degrees). The horizontal axis of FIG. 14A is the distance d01 (arbitrary unit). The horizontal axis of FIG. 14B is the distance d02 (arbitrary unit). The horizontal axis of FIG. 15A is the angle θ03 (degrees). The horizontal axis of Fig. 15B is the angle θ04 (degrees). The horizontal axis of Fig. 16A is the distance d03 (arbitrary unit). The horizontal axis of Fig. 16B is the distance d04 (arbitrary unit). The vertical axis of these figures is the intensity Ls1 of the first light L1 or the intensity Ls2 of the first light L2.

In the light source device 111, the first ratio α1 is 0.617, the second ratio α2 is 0.042, the third ratio α3 is 0.576, and the fourth ratio α4 is 0.573. The fifth ratio α5 is 0.595, and the sixth ratio α6 is 0.057. The seventh ratio α7 is 0.610, and the eighth ratio α8 is 0.552.

17A, 17B, 18A, 18B, 19A, 19B, 20A, and 20B are graphs illustrating the characteristics of the light source device according to the first embodiment.
These figures illustrate the characteristics of the light source device 112 (see FIG. 1) according to the embodiment. The light source device 112 is one example of the light source device according to the embodiment. FIGS. 17A, 17B, 18A, and 18B correspond to the characteristics along the first plane PL1, for example, the characteristics along the fast axis Af of the first light L1. FIGS. 19A, 19B, 20A, and 20B correspond to the characteristics along the second plane PL2, for example, the characteristics along the slow axis As of the first light L1. The horizontal axis of FIG. 17A is the angle θ01 (degrees). The horizontal axis of FIG. 17B is the angle θ02 (degrees). The horizontal axis of FIG. 18A is the distance d01 (arbitrary unit). The horizontal axis of FIG. 18B is the distance d02 (arbitrary unit). The horizontal axis of FIG. 19A is the angle θ03 (degrees). The horizontal axis of Fig. 19B is the angle θ04 (degrees). The horizontal axis of Fig. 20A is the distance d03 (arbitrary unit). The horizontal axis of Fig. 20B is the distance d04 (arbitrary unit). The vertical axis of these figures is the intensity Ls1 of the first light L1 or the intensity Ls2 of the first light L2.

In the light source device 112, the first ratio α1 is 0.617, the second ratio α2 is 0.16, the third ratio α3 is 0.576, and the fourth ratio α4 is 0.573. The fifth ratio α5 is 0.595, and the sixth ratio α6 is 0.192. The seventh ratio α7 is 0.610, and the eighth ratio α8 is 0.552.

In the light source devices 111 and 112 as well, the angular distribution of the intensity Ls2 of the second light L2 is "top hat shaped." For example, when the second light L2 with improved uniformity of the angular distribution is focused by the optical element 31 or the like, a more uniform light intensity distribution is obtained in the entrance region 31S. For example, the light intensity distribution is highly uniform in the rectangular entrance region 31S. According to the embodiment, a light source device capable of improving the uniformity of the light intensity distribution can be provided.

The light source device according to the embodiment includes, for example, a first light source 11 that emits a first light L1, and a first lens 21 that includes a first surface 21a and a second surface 21b. As already described, the first light L1 is incident on the first surface 21a, and the second light L2 is emitted from the second surface 21b. The intensity Ls1 of the first light L1 has a first value v1 on the first optical axis La1 of the first light L1. The intensity Ls1 of the first light L1 is 0.7 times the first value v1 in the direction of the first angle θ1 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.5 times the first value v1 in the direction of the second angle θ2 from the first optical axis La1. The intensity Ls1 of the first light L1 is 0.3 times the first value v1 in the direction of the third angle θ3 from the first optical axis La1. The intensity Ls2 of the second light L2 is a second value v2 on the second optical axis La2 of the second light L2. The intensity Ls2 of the second light L2 is 0.7 times the second value v2 in the direction of the fourth angle θ4 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.5 times the second value v2 in the direction of the fifth angle θ5 from the second optical axis La2. The intensity Ls2 of the second light L2 is 0.3 times the second value v2 in the direction of the sixth angle θ6 from the second optical axis La2. The direction of the first angle θ1, the direction of the second angle θ2, the direction of the fourth angle θ4, the direction of the fifth angle θ5, and the direction of the sixth angle θ6 are along a first plane PL1 including the direction of the third angle θ3 and the first optical axis La1. The first lens 21 makes the second ratio α2 lower than the first ratio α1. The first ratio α1 is the ratio of the absolute value of the difference between the first angle θ1 and the third angle θ3 to the second angle θ2. The second ratio α2 is the ratio of the absolute value of the difference between the fourth angle θ4 and the sixth angle θ6 to the fifth angle θ5. The angular distribution width Ws (see FIG. 12) of the second light L2 along the first plane PL1 is greater than 1.5 times arctan (y/fL). "fL" is the focal length of the first lens 21. "y" is 1/2 the length of the first light source 11 along the first plane PL1. The angular distribution width Ws corresponds to, for example, an angle θ02 at which the intensity Ls2 of the second light L2 is 0.135 times the second value v2 of the intensity Ls2 of the second light L2 on the second optical axis La2.

For example, in the light source device according to the embodiment, the shape of the second surface 21b of the first lens 21 can be approximately expressed by the following first formula:

In the first equation, "z" is the amount of sag. "k" is the conic coefficient. "r" is the radius of curvature. "h" is the center distance. In the first equation, "A", "B", "C", and "D" are coefficients.

For example, in the above light source device 111, the first surface 21a is a substantially flat surface. In this case, in the shape of the second surface 21b along the first plane PL1 (for example, the shape along the fast axis Af), the coefficients are as follows: "r" is -2.237, "k" is -0.035, "A" is 8.4702× ^10-3 , "B" is 3.0393× ^10-3 , "C" is -8.9688× ^10-4 , and "D" is ^3.499910-4 .

In the above light source device 111, when the first surface 21a is substantially a plane, in a shape of the second surface 21b along the second plane PL2 (for example, a shape along the slow axis As), the coefficients are as follows: "r" is -7.284, "k" is 26.305, "A" is -6.5943×10 ^-1 , "B" is 1.6014, "C" is -1.2907, and "D" is 0.

In the first lens 21 having such a shape, the focal length fL is, for example, 4.76 mm. On the other hand, in the first light L1 emitted from the first light source 11 and incident on the first surface 21a of the first lens 21, the divergence angle in the fast axis Af direction is 51 degrees, and the divergence angle in the slow axis As direction is 9.5 degrees. The divergence angle corresponds to the angle between the first optical axis La1 and the direction at which the intensity Ls1 of the first light L1 is 0.135 times the first value v1 of the intensity Ls1 on the first optical axis La1. The divergence angle corresponds to, for example, the angular distribution width Ws.

In the embodiment, the angular distribution of the intensity Ls1 of the first light L1 is, for example, a "Gaussian distribution." The Gaussian distribution is expressed, for example, by the following second formula:

In the second formula, when the super-Gaussian coefficient N is 1, the distribution becomes a general Gaussian distribution. As the super-Gaussian coefficient N increases, the distribution transitions to a "top hat shape." In an embodiment, the super-Gaussian coefficient N of the angular distribution of the intensity Ls2 of the second light L2 is, for example, 2 or more. In an embodiment, the super-Gaussian coefficient N of the angular distribution of the intensity Ls2 of the second light L2 may be, for example, 4 or more.

For example, in the first lens 21, the curvature of at least a portion of the first surface 21a is lower than the curvature of at least a portion of the second surface 21b. For example, the first surface 21a may be substantially flat, and the second surface 21b may be convex.

Second Embodiment
FIG. 21 is a schematic view illustrating the light source device according to the second embodiment.
As shown in FIG. 21 , a light source device 120 according to the embodiment includes a plurality of first light sources 11 and a plurality of first lenses 21 .

The first light L1 emitted from one of the multiple first light sources 11 is incident on one of the multiple first lenses 21. The first light L1 emitted from another of the multiple first light sources 11 is incident on another of the multiple first lenses 21. The direction from the one of the multiple first light sources 11 to the other one of the multiple first light sources 11 is, for example, along the first plane PL1.

In this manner, a plurality of first light sources 11 and a plurality of first lenses 21 may be combined. The second light L2 is emitted from each of the plurality of first lenses 21. One of the plurality of second lights L2 is emitted from the second surface 21b of one of the plurality of first lenses 21. The plurality of second lights L2 are incident on the optical element 31. A plurality of third lights L3 based on the plurality of second lights L2 are emitted from the optical element 31. The plurality of third lights L3 are focused at the focusing position 31P. At the focusing position 31P, for example, an entrance region 31S of the third light L3 is formed. The entrance region 31S is, for example, rectangular.

For example, the multiple first light sources 11 and the multiple first lenses 21 may be arranged in correspondence with the incident area 31S.

In the embodiment, the first light L1 emitted from one of the multiple first light sources 11 has a first divergence angle along the first plane PL1. The distance along the first plane PL1 between the center of one of the multiple first light sources 11 and the center of another of the multiple first light sources 11 is greater than twice the product of the focal length fL of one of the multiple first lenses 21 and the tangent of the first divergence angle. This makes it possible to prevent the light emitted from the multiple first light sources 11 from being incident on the first plane PL1 into a first lens 21 corresponding to another one of the multiple first light sources 11. The multiple first light lights L1 are incident on the corresponding first lens 21.

The direction from one of the first light sources 11 to another of the first light sources 11 may be along a plane intersecting with the first plane PL1. The plane intersecting with the first plane PL1 may be, for example, the second plane PL2. The first light L1 emitted from the one of the first light sources 11 has a first divergence angle along the plane (for example, the second plane) intersecting with the first plane PL1. The distance along the plane intersecting with the first plane PL1 between the center of the one of the first light sources 11 and the center of the other of the first light sources 11 is greater than twice the product of the focal length fL of the one of the first lenses 21 and the tangent of the first divergence angle. This makes it possible to suppress the light emitted from the first light sources 11 from being incident on the first lens 21 corresponding to the other of the first light sources 11 on the plane intersecting with the first plane PL1. The multiple first lights L1 are incident on the corresponding first lenses 21.

FIG. 22 is a schematic view illustrating the light source device according to the second embodiment.
As shown in Fig. 22, the light source device 130 according to the embodiment includes a plurality of first lenses 21. The plurality of first lenses 21 are aligned, for example, along the X-axis direction and the Y-axis direction. A plurality of first light sources 11 (see Fig. 21) are provided corresponding to the plurality of first lenses 21. In this example, the plurality of first light sources 11 are also aligned, for example, along the X-axis direction and the Y-axis direction.

The light source device 130 may further include an optical element 31 and a wavelength conversion member 32. The second light L2 is incident on the optical element 31. The third light L3 emitted from the optical element 31 is incident on the wavelength conversion member 32. In this way, the second light L2 collected by the optical element 31 is incident on the wavelength conversion member 32 as the third light L3. The dominant wavelength of the light emitted from the wavelength conversion member 32 is different from the dominant wavelength of the second light L2 (or the third light L3). The second light L2 is, for example, blue, and the dominant wavelength of the light emitted from the wavelength conversion member 32 is white including blue and yellow.

In this example, the wavelength conversion member 32 is provided on the first member 33. The first member 33 is rotated by the drive unit 35 around the shaft 34. The wavelength conversion member 32 is provided on the first member 33 around the shaft 34. By rotating the first member 33, the position on the wavelength conversion member 32 at which the third light L3 is incident changes. This makes it possible to prevent excessively high intensity light from continuously being incident on one position. For example, deterioration of the wavelength conversion member 32 and the like can be suppressed.

Hereinafter, examples of light source devices according to the embodiments will be described.
23A and 23B are schematic side views illustrating the light source device according to the embodiment.
23A and 23B illustrate one of the plurality of first light sources 11 and one of the plurality of first lenses 21. FIG. 23A is a side view when viewed along the X-axis direction. FIG. 23B is a side view when viewed along the Y-axis direction. As shown in FIGS. 23A and 23B, the light source device 140 according to the embodiment may include an optical component 15. The optical component 15 is provided at least between one of the plurality of first light sources 11 and one of the plurality of first lenses 21. The optical component 15 may be provided between the plurality of first light sources 11 and the plurality of first lenses 21. The optical component 15 is, for example, sapphire glass. The length Lz15 (thickness) of the optical component 15 along the Z-axis direction is, for example, about 0.5 mm.

The length Lz21 (thickness) of one of the multiple first lenses 21 along the Z-axis direction is, for example, about 2.0 mm. The distance Dz1 along the Z-axis direction between one of the multiple first light sources 11 and the optical component 15 is, for example, about 1.3 mm. The distance Dz2 along the Z-axis direction between the optical component 15 and one of the multiple first lenses 21 is, for example, about 0.3 mm.

In one example, the peak wavelength of each of the multiple first light sources 11 (lasers) is about 455 nm. In the Y-axis direction (fast axis Af), the width of the emitted light is about 60 nm, the divergence angle is 22.75 degrees, and the super-Gaussian coefficient is 2. In the X-axis direction (slow axis As), the width of the emitted light is about 45 μm, the divergence angle is 4.75 degrees, and the super-Gaussian coefficient is 2. The divergence angle is the angle (full width) at which the intensity of the emitted light is 1/e ² times the peak value (e is Napier's constant).

24A and 24B are schematic side views illustrating the light source device according to the embodiment.
Fig. 24A is a side view when viewed along the X-axis direction. Fig. 24B is a side view when viewed along the Y-axis direction. As shown in Fig. 24A, in the light source device 140, two first light sources 11 are lined up in the Y-axis direction. As shown in Fig. 24B, seven first light sources 11 are lined up in the X-axis direction. The pitch pY of the multiple light sources 11 in the Y-axis direction (fast axis Af) is about 6.0 mm. The pitch pX of the multiple light sources 11 in the X-axis direction (slow axis As) is about 2.4 mm.
A first lens 21 is provided corresponding to each of the multiple light sources 11. In the light source device 140, a distance Dz3 along the Z-axis direction between the first lens 21 and the optical element 31 is about 2.5 mm. The distance Dz3 may be determined, for example, according to the effective diameter of the optical element 31. In one example, the NA (numerical aperture) of the optical element 31 is about 0.65. As the optical element 31, for example, Edmund Optics' product code #49-101 may be used.

FIG. 25 is a schematic perspective view illustrating a part of the light source device according to the embodiment.
Fig. 25 illustrates the shape of one of the multiple first lenses 21. As shown in Fig. 25, the length of one of the multiple first lenses 21 along the Y-axis direction is longer than the length of one of the multiple first lenses 21 along the X-axis direction.

The shape of one of the second surfaces 21b of the first lenses 21 is substantially expressed by the following third formula:

In the third formula, "αi" and "βi" are the high-order aspheric coefficients in the x direction (X-axis direction) and y direction (Y-axis direction).

In one example, in the Y-axis direction (fast axis Af), "r" is -2.237, "k" is -0.035, the fourth-order aspheric coefficient is -8.4702 x 10 ^-3 , the sixth-order aspheric coefficient is 3.0393 x 10 ^-3 , the eighth-order aspheric coefficient is -8.9688 x 10 ^-4 , and the tenth-order aspheric coefficient is 3.499910 x 10 ^-4 . In the X-axis direction (slow axis As), "r" is -7.284, "k" is 26.305, the fourth-order aspheric coefficient is -6.594 x 10 ^-1 , the sixth-order aspheric coefficient is 1.601, the eighth-order aspheric coefficient is -1.2907, and the tenth-order aspheric coefficient is 0.

One of the multiple first lenses 21 is, for example, an aspheric toroidal lens. One of the multiple first lenses 21 is, for example, a biconic Zernike lens. For example, K-PBK40 (e.g., Ohara Corporation) may be used as the material of the multiple first lenses 21.

FIG. 26 is a schematic perspective view illustrating a part of the light source device according to the embodiment.
As shown in FIG. 26 , the multiple first lenses 21 may be provided on a base portion 25. The multiple first lenses 21 and the base portion 25 are included in a lens element 26. When the base portion 25 is provided, the first surface 21a (incident surface) corresponds to the back surface of the base portion 25. The second surface 21b (exit surface) corresponds to the front surface of the first lens 21. The multiple first lenses 21 and the base portion 25 may be integrally formed. The material of the base portion 25 may be the same as the material of the multiple first lenses 21. The multiple first lenses 21 are provided in a matrix along the X-axis direction and the Y-axis direction.

The length Lx of the base portion 25 along the X-axis direction is, for example, approximately 21.4 mm. The length Ly of the base portion 25 along the Y-axis direction is, for example, approximately 21.4 mm.

FIG. 27 is a schematic side view illustrating a part of the light source device according to the embodiment.
The thickness of the base portion 25 (length Lz25 along the Z-axis direction) is, for example, 1.5 mm. The sum Lz of the length of the first lens 21 along the Z-axis direction and the length Lz25 of the base portion 25 along the Z-axis direction is, for example, 2.85 mm.

The above values for length (thickness), distance, etc. are examples and can be changed in the embodiment.

According to the embodiment, a light source device can be provided that can improve the uniformity of the light intensity distribution.

In this specification, "vertical" and "parallel" do not only mean strictly vertical and strictly parallel, but also include, for example, variations in the manufacturing process, and may mean substantially vertical and substantially parallel.

The above describes the embodiments of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of the light source, lens, optical element, wavelength conversion member, etc. included in the light source device are included within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting from the known range.

In addition, any combination of two or more elements of each specific example, within the scope of technical feasibility, is also included in the scope of the present invention as long as it includes the gist of the present invention.

In addition, all light source devices that can be implemented by a person skilled in the art through appropriate design modifications based on the light source device described above as an embodiment of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention.

In addition, within the scope of the concept of this invention, a person skilled in the art may conceive of various modifications and alterations, and these modifications and alterations are also considered to fall within the scope of this invention.

11...first light source, 15...optical component, 21...first lens, 21a, 21b...first and second surfaces, 25...base portion, 26...lens element, 31...optical element, 31P...focusing position, 31S...entrance area, 32...wavelength conversion member, 33...first member, 34...axis, 35...driver, 91...first optical component, 92...second optical component, θ01-θ04...angles, θ1-θ12...first to twelfth angles, 110, 111, 112, 119, 120, 130, 140...light source device, Af...fast axis, As...slow axis, Ax1-Ax4...first to fourth axes, Dz1-Dz3...distance, L1-L3...first to third lights, La1, La2...first and second optical axes, Ls1-Ls3...intensity, Lv1, Lv2...axis, Lx-Lz...length, Lz15, Lz21, Lz25...length, PL1, PL2...first and second planes, d01-d04...distance, d1-d12...first to twelfth distances, fL...focal length, pX, pY...pitch, py1-py12...first to twelfth positions, v1, v2...first and second values, y...length

Claims (16)

A first light source that emits a first light;
a first lens including a first surface and a second surface;
Equipped with
The first light is incident on the first surface, and the second light is emitted from the second surface,
the intensity of the first light is a first value on a first optical axis of the first light,
the intensity of the first light is 0.7 times the first value in a direction at a first angle from the first optical axis;
the intensity of the first light is 0.5 times the first value in a direction at a second angle from the first optical axis;
the intensity of the first light is 0.3 times the first value in a direction at a third angle from the first optical axis;
the intensity of the second light is a second value on a second optical axis of the second light;
the intensity of the second light is 0.7 times the second value in a direction at a fourth angle from the second optical axis;
the intensity of the second light is 0.5 times the second value in a direction at a fifth angle from the second optical axis;
the intensity of the second light is 0.3 times the second value in a direction at a sixth angle from the second optical axis;
the direction of the first angle, the direction of the second angle, the direction of the fourth angle, the direction of the fifth angle, and the direction of the sixth angle are aligned along a first plane that includes the direction of the third angle and the first optical axis,
the intensity of the first light is 0.135 times the first value at an angle from the first optical axis along the first plane that is greater than or equal to 3 degrees;
The first lens has a second ratio lower than the first ratio;
the first ratio is a ratio of an absolute value of a difference between the first angle and the third angle to the second angle;
the second ratio is a ratio of an absolute value of a difference between the fourth angle and the sixth angle to the fifth angle;
the intensity of the first light is 0.7 times the first value in a direction at a seventh angle from the first optical axis;
the intensity of the first light is 0.5 times the first value in a direction at an eighth angle from the first optical axis;
the intensity of the first light is 0.3 times the first value in a direction at a ninth angle from the first optical axis;
the intensity of the second light is 0.7 times the second value in a direction at a tenth angle from the second optical axis;
the intensity of the second light is 0.5 times the second value in a direction at an eleventh angle from the second optical axis;
the intensity of the second light is 0.3 times the second value in a direction at a twelfth angle from the second optical axis;
the direction of the seventh angle, the direction of the eighth angle, the direction of the tenth angle, the direction of the eleventh angle, and the direction of the twelfth angle are along a second plane, the second plane includes the direction of the ninth angle and the first optical axis, and intersects with the first plane;
the angle along the second plane from the first optical axis at which the intensity of the first light is 0.135 times the first value is greater than or equal to 3 degrees;
The first lens has a sixth ratio lower than a fifth ratio;
the fifth ratio is a ratio of an absolute value of a difference between the seventh angle and the ninth angle to the eighth angle;
the sixth ratio is a ratio of an absolute value of a difference between the tenth angle and the twelfth angle to the eleventh angle;
the first light is a first laser light,
the first plane is aligned along the fast axis of the first laser light,
The second plane is aligned with a slow axis of the first laser light . the intensity of the first light is 0.7 times the first value at a first position on a first axis along the first plane;
the intensity of the first light is 0.5 times the first value at a second position on the first axis;
the intensity of the first light is 0.3 times the first value at a third position on the first axis;
the intensity of the second light is 0.7 times the second value at a fourth location on a second axis along the first plane;
the intensity of the second light is 0.5 times the second value at a fifth position on the second axis;
the intensity of the second light is 0.3 times the second value at a sixth position on the second axis;
the first lens sets an absolute value of a difference between the first ratio and the second ratio to be greater than an absolute value of a difference between the third ratio and the fourth ratio;
the third ratio is a ratio of an absolute value of a difference between a first distance along the first axis between the first optical axis and the first position and a third distance along the first axis between the first optical axis and the third position to a second distance along the first axis between the first optical axis and the second position;
2. The light source device of claim 1, wherein the fourth ratio is a ratio of an absolute value of a difference between a fourth distance along the second axis between the second optical axis and the fourth position and a sixth distance along the second axis between the second optical axis and the sixth position to a fifth distance along the second axis between the second optical axis and the fifth position. The light source device according to claim 1 or 2, wherein the absolute value of the difference between the first ratio and the second ratio is greater than 0.3. The light source device according to any one of claims 1 to 3, wherein the second ratio is 0.297 or less. The light source device according to any one of claims 1 to 4, wherein the angle from the first optical axis along the first plane at which the intensity of the first light is 0.135 times the first value is 15 degrees or more. the intensity of the first light is 0.7 times the first value at a seventh position on a third axis along the second plane;
the intensity of the first light is 0.5 times the first value at an eighth position on the third axis;
the intensity of the first light is 0.3 times the first value at a ninth position on the third axis;
the intensity of the second light is 0.7 times the second value at a tenth position on a fourth axis along the second plane;
the intensity of the second light is 0.5 times the second value at an eleventh position on the fourth axis;
the intensity of the second light is 0.3 times the second value at a twelfth position on the fourth axis;
the first lens sets an absolute value of a difference between the fifth ratio and the sixth ratio to be greater than an absolute value of a difference between the seventh ratio and the eighth ratio;
the seventh ratio is a ratio of an absolute value of a difference between a seventh distance along the third axis between the first optical axis and the seventh position and a ninth distance along the third axis between the first optical axis and the ninth position to an eighth distance along the third axis between the first optical axis and the eighth position,
The light source device of any one of claims 1 to 5, wherein the eighth ratio is a ratio of an absolute value of a difference between a tenth distance along the fourth axis between the second optical axis and the tenth position and a twelfth distance along the fourth axis between the second optical axis and the twelfth position to an eleventh distance along the fourth axis between the second optical axis and the eleventh position. 7. The light source device according to claim 1, wherein an absolute value of a difference between the fifth ratio and the sixth ratio is 0.3 or more. 8. The light source device according to claim 1 , wherein the angle from the first optical axis along the second plane at which the intensity of the first light is 0.135 times the first value is greater than or equal to 3 degrees and less than or equal to 40 degrees. The light source device according to claim 1 , wherein the sixth ratio is equal to or smaller than 0.297. The angular distribution width of the second light along the second plane is greater than 1.5 times arctan(y/fL);
fL is the focal length of the first lens,
10. The light source device according to claim 1 , wherein the y is half a length of the first light source along the second plane. 11. The light source device according to claim 1, wherein a curvature of the first surface is smaller than a curvature of the second surface. A plurality of the first light sources;
A plurality of the first lenses;
Equipped with
the first light emitted from one of the plurality of first light sources is incident on one of the plurality of first lenses,
the first light emitted from another one of the plurality of first light sources is incident on another one of the plurality of first lenses,
a direction from the one of the plurality of first light sources to the other one of the plurality of first light sources is along the first plane;
the first light emitted from the one of the plurality of first light sources has a first divergence angle along the first plane;
A light source device as described in any one of claims 1 to 11, wherein a distance along the first plane between a center of the one of the plurality of first light sources and a center of another of the plurality of first light sources is greater than twice the product of a focal length of the one of the plurality of first lenses and a tangent of the first divergence angle. A plurality of the first light sources;
A plurality of the first lenses;
Equipped with
the first light emitted from one of the plurality of first light sources is incident on one of the plurality of first lenses,
the first light emitted from another one of the plurality of first light sources is incident on another one of the plurality of first lenses,
a direction from the one of the plurality of first light sources to the other one of the plurality of first light sources is along a plane that intersects the first plane;
the first light emitted from the one of the plurality of first light sources has a first divergence angle along the plane that intersects with the first plane;
A light source device as described in any one of claims 1 to 11, wherein a distance along the plane intersecting the first plane between the center of one of the plurality of first light sources and the center of another of the plurality of first light sources is greater than twice the product of the focal length of one of the plurality of first lenses and the tangent of the first divergence angle. Further comprising an optical element,
The second light is incident on the optical element,
The light source device according to claim 1 , wherein the optical element condenses the second light. Further comprising a wavelength conversion member,
the second light condensed by the optical element is incident on the wavelength conversion member,
The light source device according to claim 14 , wherein a dominant wavelength of the light emitted from the wavelength conversion member is different from a dominant wavelength of the second light. The light source device according to any one of claims 1 to 15 , wherein the peak wavelength of the first light is not less than 300 nm and not more than 800 nm.

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