CN101178447A - Optical Transmitter Module and Optical Receiver Module - Google Patents

Abstract

A plurality of first refraction surfaces (121) and a plurality of second refraction surfaces (122) are alternately provided on the emission surface of the lens element (120) to form each with an optical axis (113) at its center and with mutual Concentric circles with different diameters are refracted by the plurality of second refraction surfaces (122) and emit light reflected by a plurality of reflective surfaces (123), and the plurality of reflective surfaces (123) are arranged on the lens element to form concentric circles having an optical axis (113) at its center and having diameters different from each other. Therefore, it is possible to increase efficiency and emission intensity and reduce brightness variation of emitted light without increasing the diameter of the lens element (120), thereby realizing a light emission module (100) with favorable performance.

Description

Optical Transmitter Module and Optical Receiver Module

technical field

The present invention relates to an optical transmitting module and an optical receiving module respectively used in, for example, a wireless optical transmitter and a wireless optical receiver in a wireless optical transmission system for transmitting such as video data, audio signals through free space Information data as optical signals of digital data signals, and more particularly, the present invention relates to a light emitting module capable of reducing brightness variation (variation) of emitted light and improving efficiency, and a light receiving module having improved light collection efficiency .

Background technique

An advantageous feature of the wireless optical transmission system for transmitting optical signals through free space is that, since light enables broadband transmission, transmission can be performed at a higher speed than radio transmission using radio waves. To incorporate a wireless optical transmitter and a wireless optical receiver of a wireless optical transmission system in a mobile device, it is necessary to reduce the thickness and size of each of the optical transmitting module and the optical receiving module employed therein.

For some conventional light emitting modules, a Fresnel lens is used to change the emission angle of the light emitted by the light source, thereby reducing its thickness (for example, see Japanese Patent Laid-Open No. 2005-49367). FIG. 27 shows a schematic diagram of a conventional light emitting module disclosed in Japanese Patent Laid-Open Publication No. 2005-49367.

As shown in FIG. 27 , the light emitting module 10 includes a light source 1 and a lens 2 . The lens 2 has on its emitting surface a plurality of refractive surfaces 3 arranged to form concentric circles each having an optical axis at its center and having diameters different from each other, The lens 2 thus acts as a Fresnel lens, whereby the lens 2 refracts the light emitted by the light source 1 so that it emits light substantially parallel to the optical axis 4 . Fresnel lenses are allowed to have a thinner lens portion than spherical and aspheric lenses with continuous curvature, ie, the thickness of the lens portion of the Fresnel lens is allowed to be reduced to the thickness of the plate. In other words, the Fresnel lens is characterized in that the thickness of the Fresnel lens can be easily reduced. However, since, for example, there is a limitation in processing the plurality of refracting surfaces 3 to form their inclination angles, the Fresnel lens is constructed so that the acceptance angle 2β of the light emitted by the light source 1 has only a limited value. Therefore, when the angle at which the light source 1 emits light is large, the light emitting module 10 may not be able to efficiently emit light.

Furthermore, Japanese Patent Laid-Open Publication No. 2005-49367 discloses increasing the range of the acceptance angle of light emitted from the light source 1 . FIG. 28 is a schematic diagram showing another conventional light emitting module 11 disclosed in Japanese Patent Laid-Open Publication No. 2005-49367.

As shown in FIG. 28 , the light emitting module 11 includes a light source 1 and a lens 12 . The lens 12 has a plurality of refractive surfaces 13 on its emission surface, which are similar to the plurality of refractive surfaces 3 of the lens 2 shown in FIG. 27, and the lens 12 has a plurality of reflection surfaces on its incident surface. 15. The plurality of reflecting surfaces 15 are arranged to form concentric circles, each of the concentric circles has an optical axis at its center, and has different diameters from each other. A portion of the light emitted by the light source 1 at an emission angle greater than 2β is reflected by the plurality of reflective surfaces 15 so that it is emitted from the planar portion 16 of the emission surface of the lens 2 .

On the other hand, some conventional light-receiving modules for converting incident light into electrical signals incorporate a Fresnel lens as a collection lens that collects incident light on the light-receiving element, thereby reducing its thickness (for example, see Japanese Patent Laid-Open Document Special Open 3-60080). FIG. 30 is a schematic diagram showing a conventional light receiving module 20 disclosed in Japanese Patent Laid-Open No. 3-60080.

As shown in FIG. 30 , the light receiving module 20 includes a collecting lens 21 and a light receiving element 22 . The collecting lens 21 functions as a Fresnel lens having on its incident surface a plurality of refractive surfaces 23 arranged to form concentric circles each having a central optical axis and have mutually different diameters. The collecting lens 21 collects incident light on the light receiving element 22 . The collection lens 21 that functions as a Fresnel lens is allowed to have a reduced thickness compared to a convex lens or the like having a spherical surface.

FIG. 29 is an enlarged view of part A1 of the light emitting module 11 having the conventional configuration shown in FIG. 28 . As shown in FIG. 29 , each of the plurality of refractive surfaces 13 has a lens invalid portion at its tip, which prevents light emitted from the light source 1 from passing therethrough. Thus, a dark portion that prevents light from passing therethrough is created. Therefore, the light emitting module 11 has a problem that the light emitted from the lens 12 has a brightness variation.

In addition, the conventional light emission module 11 shown in FIG. The part of the perimeter that faces outward. Therefore, the diameter d2 of the plurality of reflective surfaces 15 must be larger than the diameter d1 of the plurality of refractive surfaces 13 , thereby increasing the diameter of the lens 12 .

In addition, FIG. 31 is an enlarged view of part A2 of the conventional light receiving module 20 shown in FIG. 30 . As shown in FIG. 31 , each of the plurality of refractive surfaces 23 has at its tip a lens ineffective portion that hinders collection of incident light thereon. Therefore, the light-receiving module 20 has a problem in that light collection efficiency is lowered due to a region where incident light cannot be collected.

Contents of the invention

Therefore, a first object of the present invention is to provide a light emitting module capable of reducing brightness variation of emitted light and improving efficiency while minimizing the diameter of a lens. Furthermore, a second object of the present invention is to provide a light receiving module capable of improving light collection efficiency while minimizing the diameter of a lens.

In order to achieve the first object, the present invention relates to a light emitting module, which includes a light source and a lens element for changing the light from the light source to have a predetermined directionality, wherein the lens element includes: a plurality of first refraction surfaces, which are provided on the emitting surface of the lens element to form concentric circles each having an optical axis at its center and having diameters different from each other, and the plurality of first refraction surfaces are used to refract light from the light source The first emission light is emitted at an emission angle in the range of 0 to θ ₀ so that the first emission light is emitted at a predetermined angle, wherein the emission angle refers to the optical axis and the emission of the first emission light The angle between the directions of the light; a light guiding portion for guiding the second emitted light emitted from the light source to the emitting surface of the lens element at an emission angle greater than θ ₀ , wherein the emission angle refers to the an angle between the optical axis and the direction in which the second emitted light is emitted; and a plurality of second refractive surfaces disposed on the emitting surface of the lens element to form each with an optical axis at its center, and having concentric circles with different diameters from each other, the plurality of second refraction surfaces are for refracting the second emitted light guided by the light guiding part, thereby emitting the second emitted light at a predetermined angle, and at the The plurality of second refractive surfaces and the plurality of first refractive surfaces are alternately provided on the emitting surface of the lens element.

The light guiding portion is preferably a reflecting portion for reflecting the second emitted light emitted by the light source.

The reflective portion preferably includes at least one total reflective surface.

The reflective portion is preferably a single reflective surface interacting with at least one of the plurality of second refractive surfaces, or the reflective portion is a plurality of reflective surfaces arranged on an incident surface of the lens element to Forming concentric circles each having an optical axis at its center and having diameters different from each other, the plurality of reflective surfaces interact with the plurality of second refractive surfaces in a substantially one-to-one correspondence.

The light emitting module further preferably includes a reflector for guiding the second emitted light emitted by the light source to the light guiding part.

The reflector reflects, preferably reflects, the second emitted light emitted by the light source at an emission angle in the range of _θ2 to _θ3 , thereby preventing the emitted light from directly reaching the lens element, Wherein, the emission angle refers to the angle between the optical axis and the direction in which the emitted light is emitted.

The light guiding portion is preferably a single refractive surface interacting with at least one of the plurality of second refractive surfaces, or the light guiding portion is a plurality of refractive surfaces, which are arranged on the entrance surface of the lens element , to form concentric circles each having an optical axis at its center and having diameters different from each other, the plurality of refraction surfaces interacting with the plurality of second refraction surfaces in substantially one-to-one correspondence .

A distance between the optical axis and an outermost circumference of the light guiding portion is preferably equal to or less than a distance between the optical axis and outermost circumferences of the plurality of first refractive surfaces.

The plurality of second refractive surfaces preferably have a shape that eliminates, from the emitting surface of the lens element, an ineffective part that hinders emission of emitted light emitted by the light source.

In order to achieve the second object, the present invention relates to a light receiving module, which includes a light receiving element and a lens element for collecting light onto the light receiving element, wherein the lens element includes: a plurality of first refractive surfaces, which are provided on the incident surface of the lens element to form concentric circles each having an optical axis at its center and having diameters different from each other, the plurality of first refraction surfaces are used to refract the a part of the incident light, so that the incident light is collected to the light receiving element; a plurality of second refraction surfaces, which are arranged on the incident surface of the lens element, to form axis, and have concentric circles with different diameters, the plurality of second refraction surfaces are used to refract other parts of the incident light, and the plurality of second refraction surfaces and the plurality of first refraction surfaces are alternately arranged on on the incident surface of the lens element; and a light guide portion provided at a position to prevent being refracted by the plurality of first refractive surfaces so that light collected on the light receiving element passes therebetween, The light guiding portion collects light refracted by the plurality of second refraction surfaces onto the light receiving element.

The light guiding portion is preferably a reflective portion for reflecting light refracted by the plurality of second refractive surfaces.

The reflective portion preferably includes at least one total reflective surface.

The reflective portion is preferably a single reflective surface interacting with at least one of the plurality of second refractive surfaces, or the reflective portion is a plurality of reflective surfaces arranged on an emitting surface of the lens element to Forming concentric circles each having an optical axis at its center and having diameters different from each other, the plurality of reflective surfaces interact with the plurality of second refractive surfaces in a substantially one-to-one correspondence.

The light receiving module also preferably includes a reflector for collecting the light guided by the light guiding portion onto the light receiving element.

The light guiding portion is preferably a refracting portion for refracting light refracted by the plurality of second refracting surfaces.

Said refractive portion is preferably a single third refractive surface interacting with at least one of said plurality of second refractive surfaces, or said refractive portion is a plurality of third refractive surfaces arranged at the emitting surface of said lens element. On the surface, to form concentric circles each having an optical axis at its center and having diameters different from each other, the plurality of third refracting surfaces are in substantially one-to-one correspondence with the plurality of second refracting surfaces. Refractive Surface Interaction.

A distance between the optical axis and the outermost circumference of the light guiding portion is preferably equal to or less than a distance between the optical axis and the outermost circumference of the plurality of first refractive surfaces.

The plurality of second refractive surfaces preferably have a shape that eliminates, from the incident surface of the lens element, an ineffective portion that prevents the incident light from being collected onto the light receiving element.

As described above, the light emitting module according to the present invention allows reducing brightness variation of emitted light while minimizing the diameter of a lens, and improving efficiency. In addition, the light receiving module according to the present invention allows improving light collection efficiency while minimizing the diameter of the lens.

These and other objects, features, aspects and advantages of the present invention will become more apparent through the following detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

1 is a top view and a side sectional view of a light emitting module according to a first embodiment of the present invention;

2 is a side sectional view of the main part of the light emitting module according to the first embodiment of the present invention;

3 is a side sectional view of the main part of the light emitting module according to the first embodiment of the present invention;

4 is a side sectional view of an exemplary modification of the light emitting module according to the first embodiment of the present invention;

5 is a side cross-sectional view of an exemplary modification of a lens element according to the first embodiment of the present invention;

6 is a side cross-sectional view of an exemplary modification of a lens element according to the first embodiment of the present invention;

7 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the first embodiment of the present invention;

8 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the first embodiment of the present invention;

9 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the first embodiment of the present invention;

10 is a top view of a light emitting module according to a second embodiment of the present invention;

11 is a side sectional view of a light emitting module according to a second embodiment of the present invention;

12 is a side sectional view of the main part of a light emitting module according to a second embodiment of the present invention;

13 is an enlarged side sectional view of a main part of a light emitting module according to a second embodiment of the present invention;

14 is a side sectional view of an exemplary modification of the light emitting module according to the second embodiment of the present invention;

15 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the second embodiment of the present invention;

16 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the second embodiment of the present invention;

17 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the second embodiment of the present invention;

18 is a side sectional view of main parts of an exemplary modification of the light emitting module according to the second embodiment of the present invention;

19 is a top view and a side sectional view of a light receiving module according to a third embodiment of the present invention;

20 is a side sectional view of a main part of a light receiving module according to a third embodiment of the present invention;

21 is a top view of a light receiving module according to a fourth embodiment of the present invention;

22 is a side sectional view of a light receiving module according to a fourth embodiment of the present invention;

23 is a side sectional view of a main part of a light receiving module according to a fourth embodiment of the present invention;

24 is a side sectional view of main parts of an exemplary modification of a light receiving module according to a fourth embodiment of the present invention;

25 is a side sectional view of main parts of an exemplary modification of a light receiving module according to a fourth embodiment of the present invention;

26 is a side sectional view of main parts of an exemplary modification of a light receiving module according to a fourth embodiment of the present invention;

Fig. 27 is a side sectional view of a conventional light emitting module;

28 is a side sectional view of a conventional light emitting module;

Fig. 29 is an enlarged side cross-sectional view of part A1 of the conventional light emitting module shown in Fig. 28;

30 is a side sectional view of a conventional light receiving module; and

Fig. 31 is an enlarged side sectional view of part A2 of the conventional light receiving module shown in Fig. 30 .

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(first embodiment)

FIG. 1 is a top view and a side sectional view of a light emitting module 100 according to a first embodiment of the present invention. FIG. 2 is a side sectional view of main parts of a light emitting module 100 according to a first embodiment of the present invention.

As shown in FIGS. 1 and 2 , the light emitting module 100 mainly includes a light source 110 and a lens element 120 . As the light source 110, for example, an LED or a semiconductor laser is used. The light source 110 is housed in a package 111 . Inside the housing 130, the package 111 and the lens element 120 are fixed at positions capable of satisfying a predetermined positional relationship therebetween. The modulated electrical signal is provided via terminal 112 to light source 110 , which emits an optical signal, for example, whose luminous intensity varies according to the modulation signal, such that the optical signal spreads out from an optical axis 113 . For example, when an LED is used as the light source 110, the spread of light emitted from the light source 110 basically exhibits a Lambertian distribution, where the emission intensity is proportional to cos θ, where θ represents the emission angle as the angle between the optical axis 113 and the emission direction.

The angle at which the light from the light source 110 is spread is changed to an appropriate spread angle using the lens element 120 . The transmitted optical signal is received by a wireless optical receiver (not shown) arranged to face the optical transmitting module 100, thereby realizing wireless optical transmission of information data. When the excessively wide spread of the light emitted by the light emitting module 100 reduces the radiation power density, the wireless optical transmission system can only provide a shortened transmission distance. Therefore, the lens element 120 is designed to reduce the spreading angle of the light emitted from the light source 110 to a predetermined angle and emit light at the predetermined angle. As shown in FIG. 2, the lens element 120 has a plurality of first refractive surfaces 121 on its emitting surface, and the plurality of first refractive surfaces 121 are arranged to form concentric circles, each of which has a The optical axis 113 has different diameters. Each of the plurality of first refraction surfaces 121 refracts light emitted by the light source 110 at an angle less than or equal to θ ₀ and emits the light in a direction indicated by a desired angle. FIG. 2 shows the case of changing the light emitted by the light source 110 into light parallel to the optical axis 113 as a simple example. That is to say, the plurality of first refracting surfaces 121 function as typical Fresnel lenses. Therefore, the plurality of first refraction surfaces 121 work in the same manner as the conventional light emitting module shown in FIGS. 27 and 28 .

Next, differences between a conventional light emitting module and the light emitting module 100 according to the first embodiment of the present invention will be described. In addition to the lens of a conventional light emitting module, the lens element 120 of the light emitting module 100 according to the first embodiment of the present invention has a plurality of second refraction surfaces 122 formed on its emitting surface. In addition, the plurality of reflective surfaces 123 are formed as a light guide portion for guiding light emitted by the light source 110 at an emission angle greater than θ ₀ toward the plurality of second refraction surfaces 122, the θ ₀ representing light The angle between the axis 113 and the emission direction.

The plurality of second refraction surfaces 122 and the plurality of first refraction surfaces 121 are alternately provided on the emission surface of the lens element 120 so as to form concentric circles each having an optical axis 113 at its center. The shape of the lens surfaces of the plurality of second refraction surfaces 122 can prevent the lens element 120 from including the lens ineffective portion (corresponding to the hatched portion in FIG. 2 ) of the lens 12 of the conventional light emitting module shown in FIG. 28 and FIG. ). That is, the lens element 120 does not include inactive portions that block light emission from the light source 110 .

A plurality of reflective surfaces 123 are provided on the incident surface of the lens element 120 to form concentric circles each having the optical axis 113 at the center thereof and having diameters different from each other. In addition, the multiple reflective surfaces 123 are multiple total reflective surfaces. In addition, the plurality of reflective surfaces 123 are provided to absorb light emitted from the light source 110 at an emission angle greater than θ ₀ . Light emitted from the light source 110 at an emission angle equal to or less than θ ₀ is refracted by the plurality of first refraction surfaces 121 and emitted from the lens element 120 . Therefore, when the light emitted from the light source 110 is emitted from the lens element ₁₂₀ at an emission angle of θ0 or less, no light loss occurs. The plurality of reflective surfaces 123 interact with the plurality of second refraction surfaces 122 basically in a one-to-one correspondence, therefore, according to the one-to-one correspondence, the light source 110 is placed in the range of θ ₀ to θ ₁ The light emitted at the emission angle within is reflected toward the plurality of second refraction surfaces 122 . The plurality of second refraction surfaces 122 refract the reflected light, and the refracted light will be emitted from the lens element 120 . In this case, the plurality of reflective surfaces 123 are angled such that light is emitted from lens element 120 at a desired angle (in FIG. 2 , light is emitted parallel to optical axis 113 ).

As described above, the plurality of second refraction surfaces 122 and the plurality of reflection surfaces 123 are formed so that the light emitted by the light source 110 at an emission angle in the range of θ ₀ to θ ₁ is from the angle corresponding to that shown in FIG. 29 . Partial emission of the dark portion shown, thereby reducing the brightness variation of the emitted light. In addition, the light emitted from the light source 110 with an emission angle less than or equal to θ ₀ and the light emitted from the light source 110 with an emission angle in the range of θ ₀ to θ ₁ all pass through the diameter of the plurality of first refracting surfaces 121 The radiation power density in the area of do is improved, and the light-emitting module 100 capable of achieving high-efficiency performance is realized. In addition, without increasing the diameter of the lens element 120, compared with a typical conventional Fresnel lens, when the distance between the optical axis 113 and the outermost circumference of the plurality of reflective surfaces 123 is less than or equal to the optical axis 113 and When the distance between the outermost circumferences of the plurality of first refracting surfaces 121 is small (that is, the diameter di is less than or equal to the diameter do), it is possible to improve the efficiency and intensity of light emitted by the light emitting module. More specifically, the conventional light emitting module 11 shown in FIG. 28 must increase the diameter of the lens 12, because the light reflected by the plurality of reflective surfaces 15 passes from the outermost perimeter line corresponding to the plurality of refractive surfaces 13. Part of the emitting surface (that is, from the area outside the diameter d1) emits. On the other hand, according to the first embodiment, the light reflected by the plurality of reflective surfaces 123 is respectively emitted from the plurality of second refraction surfaces 122, and the optical axis 113 and the outermost peripheral lines of the plurality of second refraction surfaces 122 The distance therebetween is configured to be smaller than the distance between the optical axis 113 and the outermost circumference (the edge of the diameter do) of the plurality of first refractive surfaces 121 . Therefore, it is possible to increase the efficiency without increasing the diameter of the lens element 120 .

As described above, according to the first embodiment, the plurality of first refraction surfaces 121 and the plurality of second refraction surfaces 122 are alternately provided on the emitting surface of the lens element 120 to form each having the optical axis 113 at its center. , and have concentric circles with different diameters from each other, a plurality of reflective surfaces 123 are provided on the incident surface of the lens element 120 to form concentric circles each with the optical axis 113 at its center and with different diameters from each other , the light reflected by the plurality of reflective surfaces 123 is respectively refracted and emitted by the plurality of second refraction surfaces 122 at a desired angle. Accordingly, it is possible to reduce brightness variation of emitted light and improve efficiency and emission intensity without increasing the diameter of the lens element 120, thereby realizing the light emitting module 100 with favorable performance.

Although, in the above description, the plurality of reflective surfaces 123 interact with the plurality of second refractive surfaces 122 in a substantially one-to-one correspondence, the plurality of reflective surfaces 123 may interact with the plurality of At least one of the second refractive surfaces 122 interacts. Still in this case, it is possible to reduce the luminance variation of the light emitted by the lens element 120 without increasing the diameter of the lens element 120, and to increase the efficiency and emission intensity, compared with conventional light emission modules, by This enables a light emitting module 100 with favorable properties.

Next, the angles of the lens surfaces of the plurality of second refraction surfaces 122 and the plurality of reflection surfaces 123 will be described in more detail. FIG. 3 is a side sectional view of main parts of the light emitting module 100 shown in FIG. 2 according to the first embodiment. The reflective surface 123a reflecting light emitted from the light source 110 at an emission angle of _α1 and the second refracting surface 122a to which the reflected light is directed will be described in detail hereinafter.

As shown in FIG. 3, the second refraction surface 122a is provided to be inclined along the ray 114 by refracting the light emitted from the light source 110 on the incident surface 124 of the lens element and passing the refracted light through the lens element 120. owned. The second refraction surface 122a has a shape such that it does not include the above-mentioned lens ineffective portion. The light emitted from the light source 110 at the emission angle _α1 is reflected at the reflection point P on the reflection surface 123a, where _α1 represents the angle between the optical axis 113 and the emission direction. The reflected light is directed to the second refraction surface 122a, and is refracted at the refraction point Q on the second refraction surface 122a, and then emitted as emitted light along a direction parallel to the optical axis 113.

_n1 denotes the refractive index of light between the light source 110 and the lens element 120, _n2 denotes the refractive index of light of the lens element 120, and _n3 denotes the refractive index of light between the lens element 120 and the wireless optical receiver (not shown). Each of the refractive indices n ₁ and n ₃ is nearly 1 when the lens element is located in air. β ₁ denotes the angle between the ray 114 and the optical axis 113 at a point O corresponding to the position of the light source 110 . _β2 represents the angle between the ray 114 and a line normal to the entrance surface 124 (in this embodiment a line parallel to the optical axis 113 because the entrance surface 124 is planar) at point R of the lens element 120. r represents the length of a line extending perpendicular to the optical axis 113 from the apex of the projection of the emitting surface of the lens element 120 including the second refractive surface 122a, L ₁ represents the length of a line extending from the light source 110 perpendicular to the incident surface 124, L ₂ denotes the length of a line extending perpendicular to the incident surface 124 from the apex of the protrusion of the emitting surface of the lens element 120 including the second refractive surface 122a. In this case, equations (1) and (2) are satisfied.

r＝L ₁ tanβ ₁ +L ₂ tanβ ₂ ... (1)

n ₁ · sinβ ₁ = n ₂ · sinβ ₂ ... (2)

Thus, the angle β ₂ of the second refraction surface 122a is determined based on the lengths r, L ₁ and L ₂ .

In addition, _α2 denotes an angle between a line parallel to the optical axis 113 at the reflection point P and reflected light obtained by reflecting light emitted by the light source 110 at the emission angle _α1 at the reflection point P. α ₂ ′ represents the angle between the light reflected at the reflection point P and the line perpendicular to the second refraction surface 122 a at the refraction point Q. γ represents an angle between a line parallel to the incident surface 124 and a line perpendicular to the reflection surface 123 a at the reflection point P. In this case, equations (3) to (5) are satisfied.

n ₃ ·sin(π/2-β ₂ )=n ₂ ·sinα ₂ '...(3)

α ₂ = π/2-β ₂ -α ₂ '...(4)

γ=(α ₁ -α ₂ )/2...(5)

Thus, the angle γ of the reflection surface 123a is determined based on the emission angle _α1 of the light emitted from the light source 110.

In addition, when the following equation (6) is satisfied, the plurality of reflection surfaces 123 may be formed as a plurality of total reflection surfaces. When the equation (6) is not satisfied, for example, the plurality of reflective surfaces 123 can be plated with metal to obtain the plurality of reflective surfaces 123 capable of achieving expected performance.

n ₂ ·sin{(π-α ₁ -α ₂ )/2}≥n ₁ …………(6)

According to the first embodiment shown in FIG. 1 , the light emission module 100 is configured such that the light source 110 is housed in the package 111 , and the package 111 and the lens element 120 are fixed to the housing 130 . However, it should be understood that any other configuration satisfying the aforementioned relationship may be employed to produce the same effect as above. For example, as shown in FIG. 4 , a package 140 may be used to replace the package 111 of the light emitting module 100 shown in FIG. 1 , and the light source 110 may be fixedly disposed on the package 140 .

Furthermore, according to the first embodiment, the lens element 120 is configured such that the distance between the optical axis 113 and the outermost circumference of the plurality of reflective surfaces 123 is equal to or less than the distance between the optical axis 113 and the outermost circumference of the plurality of first refractive surfaces 121 (that is, the diameter di is less than or equal to the diameter do), thereby avoiding increasing the diameter of the lens element 120 . The present invention is not limited thereto. As shown in FIG. 5 , the distance between the optical axis 113 and the outermost peripheral lines of the plurality of reflective surfaces 223 may be greater than the distance between the optical axis 113 and the outermost peripheral lines of the plurality of first refracting surfaces 121 (that is, The diameter di2 is greater than the diameter do). The configuration of the lens element 220 allows for increased efficiency and emission intensity, and enables reduced brightness variation of the emitted light while minimizing the diameter of the lens. It should be understood that, like the lens element 120 shown in FIG. 3 , the plurality of second refraction surfaces 122 and the plurality of reflection surfaces 223 both included in the lens element 220 satisfy the above equations (1) to (6).

Furthermore, according to the first embodiment, the lens element 120 is configured such that the incident surface 124 on which light emitted from the light source 110 at an emission angle of _θ0 or less is incident is a plane. However, the incident surface may be a curved surface, that is, the incident surface may be, for example, the incident surface 324 of the lens element 320 shown in FIG. 6 . When a plurality of first refraction surfaces 321 and a plurality of second refraction surfaces 322 are alternately provided on the emission surface of the lens element 320, and the plurality of second refraction surfaces 322 refract and emit light from the incident surface of the lens element 320 When the reflected light of the plurality of reflective surfaces 323 is used, the lens element 320 can produce the same effect as described above. Alternatively, the entrance surface 324 may be a Fresnel lens surface. When the incident surface 324 of the lens element 320 has the spherical surface of a sphere centered on the light source 110, the incident surface 324 does not refract the light emitted by the light source 110, therefore, the relationship between the angles _β1 and _β2 shown in FIG. 3 satisfies β ₁ = β ₂ . Therefore, the plurality of second refraction surfaces 322 and the plurality of reflection surfaces 323 both included in the lens element 320 satisfy the above-mentioned equations (1) to (6), thereby satisfying β ₁ =β ₂ . Also, when the incident surface 324 has another curved surface or a Fresnel lens surface, substitution into equation (2) can be performed in accordance with refraction on the incident surface 324 .

Furthermore, according to the first embodiment, a plurality of reflective surfaces 123 are provided. However, a lens element 420 in which a single reflective surface 423 is provided instead of a plurality of reflective surfaces 123 as shown in FIG. 7 may be used. In this case, each of the plurality of second refraction surfaces 422 may be designed to have an appropriate angle with respect to the single reflection surface 423 . In this case as well, it is possible to reduce the variation in luminance of emitted light and to increase the efficiency and emission intensity, thereby producing the same effects as described above.

Next, the angles of the lens surfaces of the single reflection surface 423 and the angles of the lens surfaces of the plurality of second refraction surfaces 422 will be described in more detail. FIG. 8 is a side sectional view of main parts of the light emitting module shown in FIG. 7 in which a lens element 420 is mounted to the light emitting module 100 of the first embodiment. In FIG. 8 , the same components as those shown in FIG. 3 are denoted by the same corresponding reference numerals, and descriptions thereof will be omitted.

As shown in FIG. 8, the light emitted from the light source 110 at the emission angle _α1 is reflected at the first reflection point Pa on the reflection surface 423, where _α1 represents the angle between the optical axis 113 and the emission direction. The reflected light is directed to the second refraction surface 422a, and is refracted at the refraction point Qa on the second refraction surface 422a, and then emitted as emitted light along a direction parallel to the optical axis 113. The relationship between the second refraction surface 422a and the reflection surface 423 is the same as the relationship between the second refraction surface 122a and the reflection surface 123a both included in the lens element 120 described with reference to FIG. 3 . Specifically, the lengths r, L ₁ and L ₂ and the angles β ₁ , β ₂ , α ₁ , α ₂ , α ₂ ′, and γ satisfy the above equations (1) to (6).

Next, the second refraction surface 422b disposed immediately surrounding the second refraction surface 422a viewed from the optical axis 113 will be described. Light emitted from the light source 110 at an angle smaller than the emission angle _α1 is reflected at the second reflection point Pb on the reflection surface 423 . The reflected light is directed to the second refraction surface 422b, and is refracted at the refraction point Qb on the second refraction surface 422b, and then emitted as emitted light along a direction parallel to the optical axis 113.

_α2b represents the angle between the light reflected at the second reflection point Pb and a line at the second refraction point Qb by causing the reflected light to occur at the second refraction point Qb The emitted light obtained by refraction is obtained by extending towards the interior of the lens element 420 . In addition, β _2b represents an angle between a straight line parallel to the optical axis 113 and a line obtained by extending the line of the inclined surface of the second refraction surface 422b toward the outside of the lens element 420 at the second refraction point Qb. In this case, when the angles _α2b and _β2b satisfy Equation (7), the emitted light refracted at the second refraction point Qb is parallel to the optical axis 113.

n ₃ ·sin(π/2-β _2b )=n ₂ ·sin(π/2-β _2b -α _2b )...(7)

Furthermore, instead of the lens element 420 shown in FIG. 7 , a lens element 520 shown in FIG. 9 surrounding the light source 110 may be provided. On the emission surface of the lens element 520, a plurality of first refraction surfaces 521 and a plurality of second refraction surfaces 522 are alternately provided, and the reflected light from the reflection surface 523 is refracted by the plurality of second refraction surfaces 522 and emitted, thereby Produces the same effect as described above. Needless to say, the relationship between the plurality of second refraction surfaces 522 and the reflection surface 523 is the same as the relationship between the plurality of second refraction surfaces 422 and the reflection surface 423 that are all included in the lens element 420, that is, the above equation ( 1) to (7).

(second embodiment)

In the first embodiment, the brightness variation of the emitted light is reduced by using the light emitted from the light source at an emission angle in the range of _θ0 to _θ1 , thereby realizing a light emission module with high efficiency performance, wherein the emission angle Refers to the angle between the optical axis and the emission direction. According to a second embodiment, instead of light emitted from the light source at an emission angle in the range of θ ₀ to θ ₁ , light emitted by the light source that does not directly reach the lens element is utilized, wherein said emission angle refers to the distance between the optical axis and Angle between emission directions.

FIG. 10 is a top view of a light emitting module 600 according to the second embodiment of the present invention, and FIG. 11 is a side cross-sectional view of the light emitting module 600 according to the second embodiment of the present invention. FIG. 12 is a side sectional view of main parts of a light emitting module 600 according to a second embodiment of the present invention. FIG. 13 is an enlarged view of part B of the light emitting module 600 shown in FIG. 12 . In FIGS. 10 to 13 , the same components as those shown in FIGS. 1 and 2 are denoted by the same corresponding reference numerals, and descriptions thereof will be omitted.

As shown in FIGS. 10 to 13 , the light emitting module 600 mainly includes a light source 110 and a lens element 620 . For example, the light source 110 is an LED. The light source 110 is bonded to the cathode electrode 612a, and is electrically connected to the anode electrode 612b by a wire 612c. The lens element 620, the cathode electrode 612a, and the anode electrode 612b are fixed to a case 630 made of resin and/or the like. In addition, the cathode electrode 612 a includes a reflector 641 . The reflector 641 has a reflective surface forming the inner shape of, for example, an inverted cone. A reflector 641 may be fixed to the cathode electrode 612a. Alternatively, the reflector 641 may be composed of the same material as the cathode electrode 612a so as to be integrated with the cathode electrode 612a.

Like the lens element 120 shown in FIG. 2 , on the emission surface of the lens element 620, a plurality of first refraction surfaces 121 and a plurality of second refraction surfaces 122 are alternately provided to form an optical axis 113 each having an optical axis 113 at its center. , and have concentric circles of different diameters. A plurality of reflective surfaces 623 are provided on the incident surface of the lens element 620 to form concentric circles each having the optical axis 113 at its center and having diameters different from each other. In addition, the multiple reflective surfaces 623 are multiple total reflective surfaces. The light emitting module 600 according to the second embodiment has the same configuration as the light emitting module according to the first embodiment, except that the light emitting module 600 has a reflector 641 for reflecting light emitted from the side of the light source 110, that is, Light emitted from the light source at an emission angle in the range of _θ2 to _θ3 , which refers to the angle between the optical axis 113 and the emission direction. The reflector 641 reflects light emitted from the side of the light source 110 and directs the reflected light to the plurality of reflective surfaces 623 provided on the incident surface of the lens element 620 . The plurality of reflective surfaces 623 interact with the plurality of second refraction surfaces 122 in a substantially one-to-one correspondence, so the reflected light guided by the reflector 641 is directed toward the The plurality of second refraction surfaces 122 reflect. The plurality of second refraction surfaces 122 refract the reflected light, and emit the refracted light from the lens element 620 . As described above, according to the first embodiment described with reference to FIG _. 2, the light emitted at the emission angle shown in _FIG . Light emitted from the side. Specifically, when an LED is used as the light source 110 , the light emitted from the side of the LED provides high power, so the electric power of the light emitted from the side of the light source can be utilized to improve the efficiency of the light emitting module 600 . The plurality of reflective surfaces 623 interact with the plurality of second refractive surfaces 122 in a substantially one-to-one correspondence, and direct the light emitted from the side of the light source 110 toward the The plurality of second refraction surfaces 122 reflect. The plurality of second refraction surfaces 122 refract the reflected light, and emit the refracted light from the lens element 620 . In this case, the plurality of reflective surfaces 623 are angled such that light is emitted from lens element 620 at a desired angle (in FIG. 12 , light is parallel to optical axis 113 ).

The plurality of second refraction surfaces 122, the plurality of reflection surfaces 623 and the reflector 641 are thus formed, so that the light emitted from the side of the light source 110 is emitted from a portion corresponding to the dark portion shown in FIG. The reduction of the brightness variation of the light. In addition, the light emitted from the light source 110 and the light emitted from the side of the light source 110 with an emission angle less than or equal to θ ₀ are all emitted from the region of the diameter of the plurality of first refracting surfaces 121, thereby increasing the diameter. is the emission power density in the region of do, and realizes the light-emitting module 600 capable of achieving high-efficiency performance.

As described above, according to the second embodiment, on the emitting surface of the lens element 620, a plurality of first refraction surfaces 121 and a plurality of second refraction surfaces 122 are alternately provided to form each with the optical axis 113 at its center, And have concentric circles of different diameters from each other, and provide a plurality of reflective surfaces 623 on the incident surface of the lens element 620 to form concentric circles each having the optical axis 113 at its center and have different diameters from each other . In addition, the reflector 641 surrounding the light source 110 is provided, thereby allowing the plurality of second refraction surfaces 122 to refract and emit light from the side of the light source 110 at a desired angle. Accordingly, it is possible to reduce brightness variation of emitted light and improve efficiency and emission intensity without increasing the diameter of the lens element 620, thereby realizing the light emitting module 600 with favorable performance.

According to the second embodiment described with reference to FIGS. 10 to 13 , the light emission module 600 is configured to direct the light from the side of the light source 110 to the plurality of second refraction surfaces 122 by providing a reflector 641 and a plurality of reflection surfaces 623. . However, the present invention is not limited thereto. Instead of the reflector 641 , a light deflector such as a prism may be employed so that deflection is performed using refraction, thereby deflecting light emitted from the light source 110 toward the plurality of reflective surfaces 623 as performed by the reflector 641 .

In addition, a plurality of refraction surfaces may be used instead of the plurality of reflection surfaces 623 . FIG. 14 is a side cross-sectional view of a light emitting module 700 including a plurality of refraction surfaces instead of a plurality of reflection surfaces 623 . FIG. 15 is a side sectional view of main parts of the light emitting module 700 . As shown in FIG. 15 , the light emitting module 700 is configured to direct reflected light from the reflector 741 to the plurality of second refraction surfaces 122 using the plurality of third refraction surfaces 725 provided on the incident surface of the lens element 720 . This configuration allows efficient use of light from the side of the light source 110, improves efficiency and emission intensity, and reduces luminance variation of emitted light.

The lens element 720 shown in FIG. 15 is configured to provide a plurality of third refraction surfaces 725 on its incident surface. However, the lens element 820 shown in FIG. 16 may be used, in which a single third refraction surface 825 is used instead of the plurality of third refraction surfaces 725 . In this case, each of the plurality of second refraction surfaces 822 may be designed to have an appropriate angle with respect to the single third refraction surface 825 . Thus, it is possible to reduce variations in luminance of emitted light, and to improve efficiency and emission intensity, thereby producing the same effects as described above.

In addition, the lens element 920 shown in FIG. 17 may be used instead of the lens element 820 shown in FIG. 16 so that the lens element 920 surrounds the light source 110 and the reflector 941 . Also in this case, a plurality of first refraction surfaces 921 and a plurality of second refraction surfaces 922 are alternately provided on the emission surface of the lens element 920, so that the light from the reflector 941 is refracted and emitted by the plurality of second refraction surfaces 922 reflected light. Therefore, it is possible to effectively utilize light from the side of the light source 110, reduce luminance variation of emitted light, and improve efficiency and emission intensity, thereby producing the same effects as described above.

In addition, according to the second embodiment, the reflector reflects light from the side of the light source 110 to improve the efficiency of the light emitting module. However, as shown in FIG. 18 , the reflector 1041 can reflect light emitted from the light source 110 at an emission angle in the range of _θ0 to _θ1 , which can be incident on a single third refracting surface 1025 of the lens element 1020. Therefore, it is refracted by the plurality of second refraction surfaces 1022, and the refracted light can be used, thereby reducing the brightness variation of the emitted light and improving the efficiency.

(third embodiment)

FIG. 19 is a top view and a side sectional view of a light receiving module 2100 according to a third embodiment of the present invention. FIG. 20 is a side sectional view of main parts of a light receiving module 2100 according to a third embodiment of the present invention.

As shown in FIGS. 19 and 20 , the light receiving module 2100 mainly includes a light receiving element 2110 and a lens element 2120 . For example, a photodiode (PD) can be employed as the light receiving element 2110 . The light receiving element 2110 is housed in a package 2111 . Inside the housing 2130, the package 2111 and the lens element 2120 are fixed at positions capable of satisfying a predetermined positional relationship therebetween. The optical receiving module 2100 receives an optical signal (for example, an optical signal transmitted by the optical transmitting module 100 of the first embodiment) from a wireless optical transmitter (not shown), which is arranged to face the optical receiving module 2100. Module 2100.

The lens element 2120 collects incident light on the light receiving element 2110 . The light receiving element 2110 converts the received light signal into an electric signal, and outputs the electric signal from the terminal 2112, thereby realizing wireless optical transmission of information data. Such wireless optical transmission systems can only provide reduced transmission distances when inefficient collection of incident light reduces the power of received light. Accordingly, lens element 2120 is designed to increase light collection efficiency. As shown in FIG. 20, the lens element 2120 has a plurality of first refraction surfaces 2121 on its incident surface, and the plurality of first refraction surfaces 2121 are arranged to form concentric circles, each of which has a The optical axes 2113, and have different diameters. Each of the plurality of first refraction surfaces 2121 refracts a part of the incident light to collect the incident light on the light receiving element 2110 . FIG. 20 shows the case of collecting incident light parallel to the optical axis 2113 as an example. That is to say, the multiple first refracting surfaces 2121 function as typical Fresnel lenses. Therefore, the plurality of first refraction surfaces 2121 are the same as those employed in the conventional light receiving module shown in FIG. 30 .

Next, differences between a conventional light receiving module and the light receiving module 2100 according to the third embodiment of the present invention will be described. The lens element 2120 of the light receiving module 2100 according to the third embodiment of the present invention has a plurality of second refraction surfaces 2122 formed on the incident surface of the lens element 2120 in addition to the lens of the conventional light receiving module. In addition, the plurality of reflection surfaces 2123 are formed as a light guide portion for collecting light refracted by the plurality of second refraction surfaces so as to be directed to the light receiving element.

The plurality of second refraction surfaces 2122 and the plurality of first refraction surfaces 2121 are alternately provided on the incident surface of the lens element 2120 so as to form concentric circles each having an optical axis 2113 at its center. The shape of the lens surfaces of the plurality of second refraction surfaces 2122 prevents the lens element 2120 from including the lens ineffective portion (corresponding to the hatched portion in FIG. 20 ) of the lens 21 of the conventional light receiving module shown in FIGS. 30 and 31 . ). That is, the lens element 2120 does not include an inactive portion that hinders collection of incident light onto the light receiving element 2110 .

A plurality of reflective surfaces 2123 are provided on the emitting surface of the lens element 2120 to form concentric circles each having an optical axis 2113 at its center and having diameters different from each other. In addition, the multiple reflective surfaces 2123 are multiple total reflective surfaces. In addition, the plurality of reflective surfaces 2123 are provided outside a region through which the light refracted by the plurality of first refraction surfaces 2121 passes to be collected on the light receiving element 2110 . The light incident on the plurality of first refraction surfaces 2121 is refracted by the plurality of first refraction surfaces 2121 and collected on the light receiving element 2110 . Therefore, no light loss occurs when the light incident on the plurality of first refraction surfaces 2121 is collected on the light receiving element 2110 . The multiple reflective surfaces 2123 interact with the multiple second refractive surfaces 2122 in a substantially one-to-one correspondence. The plurality of second refraction surfaces 2122 refract the incident light toward the plurality of reflection surfaces 2123 according to the one-to-one correspondence. The plurality of reflective surfaces 2123 reflect the refracted light toward the light receiving element 2110 . In this case, the angles of the plurality of reflection surfaces 2123 are set so that the light refracted by the plurality of second refraction surfaces 2122 is reflected toward the light receiving element 2110 .

As described above, the plurality of second refraction surfaces 2122 and the plurality of reflection surfaces 2123 are formed to allow the incident light from the non-light collection portion shown in FIG. 31 to be collected on the light receiving element 2110, thereby achieving a The light receiving module 2100 with enhanced light collection efficiency. In addition, compared with the conventional typical Fresnel lens, without increasing the diameter of the lens element 2120, when the distance between the optical axis 2113 and the outermost circumference of the plurality of reflective surfaces 2123 is less than or equal to the optical axis 2113 and the plurality of second The light collection efficiency of the light receiving module 2100 may be improved if the distance between the outermost circumferences of the refraction surface 2121 is constant (that is, the diameter di is less than or equal to the diameter do). More specifically, in a conventional light receiving element through which light passes in the opposite manner to the way in which light passes through the conventional light emitting module shown in FIG. The incident light on the incident surface of the part outside the outermost peripheral line of the plurality of refraction surfaces 13 (that is, the part located outside the area with the diameter d1). On the other hand, according to the third embodiment, the incident light on the plurality of second refraction surfaces 2122 is refracted, and the refracted light is reflected by the plurality of reflection surfaces 2123 to be collected, wherein the plurality of The second refraction surface 2122 is configured such that the distance between the optical axis 2113 and the outermost circumference of the plurality of second refraction surfaces 2122 is smaller than the distance between the optical axis 2113 and the outermost circumference of the plurality of first refraction surfaces 2121 (the edge of the diameter do). the distance between. Therefore, it is possible to increase the efficiency without increasing the diameter of the lens element 2120 .

As described above, according to the third embodiment, the plurality of first refraction surfaces 2121 and the plurality of second refraction surfaces 2122 are alternately provided on the incident surface of the lens element 2120 to form each with the optical axis 2113 at its center. , and have concentric circles with different diameters from each other, refract the incident light on the plurality of second refraction surfaces 2122 toward the plurality of reflection surfaces 2123 provided on the emission surface of the lens element 2120, thereby Concentric circles each having an optical axis 2113 at its center and having diameters different from each other are formed, and the plurality of reflecting surfaces 2123 reflect the refracted light toward the light receiving element 2110 . Therefore, it is possible to collect the incident light on the part corresponding to the non-light collecting part of the Fresnel lens onto the light receiving element 2110, so that it is possible to realize a function having favorable performance and being able to increase its diameter without increasing the diameter of the lens element 2120. Light collection efficiency of the light receiving module 2100.

In addition, the light incident on the light receiving module of the third embodiment passes therethrough in the opposite manner to the way in which the light emitted from the light emitting module of the first embodiment passes therethrough. Therefore, the light-transmitting module of the first embodiment can be used as the light-receiving module of the third embodiment.

The lenses of the plurality of second refraction surfaces 2122 and the plurality of reflection surfaces 2123 included in the lens element 2120 of the light receiving module according to the third embodiment can be designed in the same manner as that employed in the lens element 120 shown in FIG. 3 the corners of the surface. In addition, like the plurality of reflective surfaces 123, the plurality of reflective surfaces 2123 may be a plurality of total reflection surfaces. Or, for example, the plurality of reflective surfaces can be plated with metal to form a plurality of reflective surfaces 2123 capable of achieving expected performance.

Like the light-emitting module shown in FIG. 4 , the light-receiving module of the third embodiment can be configured such that the light-receiving element is fixedly arranged on the package.

Like the lens element 220 shown in FIG. 5 , the lens element of the light-receiving module of the third embodiment may be configured such that the distance between the optical axis 2113 and the outermost perimeter of the plurality of reflective surfaces is greater than the distance between the optical axis 2113 and the plurality of reflective surfaces. The distance between the outermost perimeters of the first refracting surfaces, that is, the diameter di is greater than the diameter do.

Like the lens element 320 shown in FIG. 6 , on the lens element of the light receiving module of the third embodiment, the emitting surface other than the plurality of reflecting surfaces 2123 may include a curved surface. Alternatively, the emitting surface may comprise a Fresnel lens surface instead of reflective surfaces 2123 .

Like the lens element 420 shown in FIG. 7 , the lens element of the light receiving module of the third embodiment may have a single reflective surface instead of multiple reflective surfaces 2123 . In this case, the angles of the lens surfaces of the single reflection surface and the plurality of second refraction surfaces included in the lens element of the light receiving module may be designed in the same manner as the lens element 420 shown in FIG. 8 .

Like the lens element 520 shown in FIG. 9 , the lens element of the light receiving module of the third embodiment may be configured such that the lens element surrounds the light receiving element.

A light-receiving module having favorable performance and improved light collection efficiency can be realized by employing any of the above configurations.

(fourth embodiment)

FIG. 21 is a top view of a light receiving module 2600 according to the fourth embodiment of the present invention, and FIG. 22 is a side cross-sectional view of the light receiving module 2600 according to the fourth embodiment of the present invention. FIG. 23 is a side sectional view of main parts of a light receiving module 2600 according to a fourth embodiment of the present invention. In FIGS. 21 to 23 , the same components as those shown in FIGS. 19 and 20 are denoted by the same corresponding reference numerals, and descriptions thereof will be omitted.

As shown in FIGS. 21 to 23 , the light receiving module 2600 mainly includes a light receiving element 2110 and a lens element 2620 . For example, a photodiode (PD) can be employed as the light receiving element 2110 . The light receiving element 2110 is joined to an anode electrode 2612a, and is electrically connected to a cathode electrode 2612b through a wire 2612c. The lens element 2620, the anode electrode 2612a, and the cathode electrode 2612b are fixed to a case 2630 made of resin and/or the like. In addition, the anode electrode 2612a includes a reflector 2641 . The reflector 2641 has a light reflecting surface forming the inner shape of, for example, an inverted cone. A reflector 2641 may be fixed to the anode electrode 2612a. Alternatively, the reflector 2641 may be formed of the same material as the anode electrode 2612a so as to be integrated with the anode electrode 2612a.

Like the lens element 2120 shown in FIG. 20 , on the incident surface of the lens element 2620, a plurality of first refraction surfaces 2121 and a plurality of second refraction surfaces 2122 are alternately arranged to form a lens element each having an optical axis 2113 at its center. concentric circles. A plurality of reflective surfaces 2623 are provided on the emitting surface of the lens element 2620 to form concentric circles each having an optical axis 2113 at its center and having diameters different from each other. In addition, the multiple reflective surfaces 2623 are multiple total reflective surfaces. The light receiving module 2600 according to the fourth embodiment has the same configuration as the light receiving module according to the third embodiment except that the light receiving module 2600 has a reflector 2641 for further reflecting light reflected by a plurality of reflecting surfaces 2623 . The plurality of reflective surfaces 2623 interact with the plurality of second refraction surfaces 2122 in a substantially one-to-one correspondence. The plurality of second refraction surfaces 2122 refract the incident light toward the plurality of reflection surfaces 2623 according to the one-to-one correspondence. The plurality of reflective surfaces 2623 reflect the refracted light toward the reflector 2641 . The reflector 2641 reflects the reflected light toward the light receiving element 2110 . In this case, the angles of the plurality of reflection surfaces 2623 are set such that the plurality of reflection surfaces 2623 reflect light toward the light receiving element 2110 at a desired angle.

As described for the third embodiment, the plurality of second refraction surfaces 2122, the plurality of reflection surfaces 2623, and the reflector 2641 are formed to collect incident light from the non-light collection portion shown in FIG. on the receiving element 2110.

As described above, according to the fourth embodiment, a plurality of first refraction surfaces 2121 and a plurality of second refraction surfaces 2122 are alternately provided on the incident surface of the lens element 2620 to form an optical axis 2113 at the center thereof and have mutual Concentric circles of different diameters provide a plurality of reflective surfaces 2623 on the emitting surface of the lens element 2620, and in addition provide reflectors 2641 surrounding the light receiving element 2110, thus, it is possible to integrate light from the non-light collecting portion of the Fresnel lens The incident light is collected on the light receiving element 2110 . Accordingly, it is possible to realize the light receiving module 2600 having favorable performance and improved light collection efficiency while minimizing the diameter of the lens element 2620 .

According to the fourth embodiment described with reference to FIGS. 21 to 23 , the light receiving module 2600 is configured to direct the incident light on the plurality of second refraction surfaces 2122 toward the light receiving element 2110 by providing the reflector 2641 and the plurality of reflection surfaces 2623 guide. However, the present invention is not limited thereto. Instead of the reflector 2641 , a light deflector such as a prism for performing deflection using refraction to deflect light reflected by the plurality of reflection surfaces 2623 toward the light receiving element 2110 as the reflector 2641 performs may be employed.

In addition, the light incident on the light receiving module of the fourth embodiment passes therethrough in the opposite manner to the way in which the light emitted from the light emitting module of the second embodiment passes therethrough. Therefore, the light-transmitting module of the second embodiment can be used as the light-receiving module of the fourth embodiment.

The light receiving module of the fourth embodiment may have the lens element 2720 shown in FIG. 24 , in which a plurality of third refraction surfaces 2725 are provided instead of the plurality of reflection surfaces 2623 . In this case, the reflector 2741 is provided so that the light refracted by the plurality of third refraction surfaces 2725 is collected onto the light receiving element 2110 .

The lens element 2720 shown in FIG. 24 has a plurality of third refractive surfaces 2725 on the emitting surface of the lens element 2720 . However, a lens element 2820 as shown in FIG. 25 may be provided in which a single third refractive surface 2825 is employed instead of a plurality of third refractive surfaces 2725 . In this case, the reflector 2841 is provided so that the light refracted by the single third refraction surface 2825 is collected onto the light receiving element 2110 .

Furthermore, instead of the lens element 2820 shown in FIG. 25 , the lens element 2920 surrounding the light receiving element 2110 and the reflector 2941 shown in FIG. 26 may be employed.

A light-receiving module having favorable performance and improved light collection efficiency can be realized by employing any of the above configurations.

In the above description, each of the above embodiments is applied to a wireless optical transmission system. However, the present invention is not limited thereto. The light emitting module according to each of the first embodiment and the second embodiment is allowed to reduce luminance variation with a reduced thickness, and to improve the radiation power density of efficiency. The light receiving module according to each of the third embodiment and the fourth embodiment is allowed to improve light collection efficiency. Therefore, the present invention can be effectively applied to other uses. For example, the present invention is applicable to lighting, optical sensors utilizing light transmitted in free space, and the like.

While the invention has been described in detail, in any event the foregoing description has been presented for purposes of illustration and not limitation. It should be understood that many other modifications and variations can be devised without departing from the scope of the invention.

Claims (22)

1. light emission module, it comprises light source and is used to change light from described light source to make it to have predetermined party tropism's lens element, wherein

Described lens element comprises

A plurality of first planes of refraction, it is arranged on the emitting surface of described lens element, has the optical axis that is positioned at its center to form every person, and has the concentric circles of mutually different diameter, and described a plurality of first planes of refraction are used for reflecting from described light source to be in 0 to θ ₀Scope in the first emission light of emission angle emission, thereby launch the described first emission light at a predetermined angle, this emission angle is meant described optical axis and launches angle between the described first radiative direction,

Light guiding section, its be used for from described light source with greater than θ ₀The second emission light of emission angle emission guide to the described emitting surface of described lens element, this emission angle is meant described optical axis and the angle of launching between the described second radiative direction, and

A plurality of second planes of refraction, it is arranged on the described emitting surface of described lens element, has the optical axis that is positioned at its center to form every person, and concentric circles with mutually different diameter, described a plurality of second plane of refraction is used to reflect the described second emission light by described light guiding section guiding, thereby launch the described second emission light at a predetermined angle, wherein, described a plurality of second planes of refraction and described a plurality of first plane of refraction are arranged alternately on the described emitting surface of described lens element.

2. light emission module according to claim 1, wherein, described light guiding section is the described second radiative reflecting part that is used to reflect described light emitted.

3. light emission module according to claim 2, wherein, described reflecting part comprises at least one fully reflecting surface.

4. light emission module according to claim 2, wherein, described reflecting part be with described a plurality of second planes of refraction at least one interactional single reflecting surface.

5. light emission module according to claim 2, wherein

Described reflecting part is a plurality of reflectings surface, and it is arranged on the incidence surface of described lens element, have the optical axis that is positioned at its center to form every person, and have the concentric circles of mutually different diameter, and

Described a plurality of reflecting surface is so that man-to-man corresponded manner and described a plurality of second plane of refraction interact basically.

6. light emission module according to claim 1 also comprises reverberator, and it is used for the described second emission light of described light emitted is guided to described light guiding section.

7. light emission module according to claim 6, wherein, described reverberator reflects described second of described light emitted to be launched in the light to be in θ ₂To θ ₃Scope in the emission light of emission angle emission, described emission light can't directly arrive at described lens element, wherein, described emission angle is meant described optical axis and the angle of launching between the described radiative direction.

8. light emission module according to claim 7, wherein, described light guiding section be with described a plurality of second planes of refraction at least one interactional single plane of refraction.

9. light emission module according to claim 7, wherein

Described light guiding section is a plurality of planes of refraction, and it is arranged on the incidence surface of described lens element, have the optical axis that is positioned at its center to form every person, and have the concentric circles of mutually different diameter, and

Described a plurality of plane of refraction is so that man-to-man corresponded manner and described a plurality of second plane of refraction interact basically.

10. light emission module according to claim 1, wherein, the distance between the outermost contour of described optical axis and described light guiding section is smaller or equal to the distance between the outermost contour of described optical axis and described a plurality of first planes of refraction.

11. light emission module according to claim 1, wherein, the shape that described a plurality of second planes of refraction have has been eliminated the photoemissive invalid part of the emission that hinders described light emitted from the described emitting surface of described lens element.

12. an Optical Receivers, it comprises light receiving element and is used for light is collected lens element on the described light receiving element, wherein

Described lens element comprises

A plurality of first planes of refraction, it is arranged on the incidence surface of described lens element, has the optical axis that is positioned at its center to form every person, and has a concentric circles of mutually different diameter, described a plurality of first plane of refraction is used to reflect the part of incident light, thereby described incident light is collected on the described light receiving element

A plurality of second planes of refraction, it is arranged on the described incidence surface of described lens element, has the optical axis that is positioned at its center to form every person, and has a concentric circles of mutually different diameter, described a plurality of second plane of refraction is used for reflecting other parts of described incident light, wherein, described a plurality of second planes of refraction and described a plurality of first plane of refraction are arranged alternately on the described incidence surface of described lens element, and

Light guiding section, it is arranged on such position, to prevent to be subjected to described a plurality of first plane of refraction refraction, so that the light that is collected on the described light receiving element passes therethrough, described light guiding section is used for the light that is subjected to described a plurality of second plane of refraction refractions is collected described light receiving element.

13. Optical Receivers according to claim 12, wherein, described light guiding section is the reflecting part, and it is used to reflect the light that is subjected to described a plurality of second plane of refraction refractions.

14. Optical Receivers according to claim 13, wherein, described reflecting part comprises at least one fully reflecting surface.

15. Optical Receivers according to claim 13, wherein, described reflecting part be with described a plurality of second planes of refraction at least one interactional single reflecting surface.

16. Optical Receivers according to claim 13, wherein

Described reflecting part is a plurality of reflectings surface, and it is arranged on the emitting surface of described lens element, have the optical axis that is positioned at its center to form every person, and have the concentric circles of mutually different diameter, and

Described a plurality of reflecting surface is so that man-to-man corresponded manner and described a plurality of second plane of refraction interact basically.

17. Optical Receivers according to claim 12 also comprises reverberator, it is used for and will collects described light receiving element by the light of described light guiding section guiding.

18. Optical Receivers according to claim 17, wherein, described light guiding section is a refracted portion, and it is used to reflect the light that is subjected to described a plurality of second plane of refraction refractions.

19. Optical Receivers according to claim 18, wherein, described light guiding section be with described a plurality of second planes of refraction at least one interactional single third reflect face.

20. Optical Receivers according to claim 18, wherein

Described refracted portion is a plurality of third reflect faces, and it is arranged on the emitting surface of described lens element, have the optical axis that is positioned at its center to form every person, and have the concentric circles of mutually different diameter, and

Described a plurality of third reflect face is so that man-to-man corresponded manner and described a plurality of second plane of refraction interact basically.

21. Optical Receivers according to claim 12, wherein, the distance between the outermost contour of described optical axis and described light guiding section is smaller or equal to the distance between the outermost contour of described optical axis and described a plurality of first planes of refraction.

22. Optical Receivers according to claim 12, wherein, the shape that described a plurality of second planes of refraction have has been eliminated from the described incidence surface of described lens element and has been hindered described incident light and be collected into invalid part on the described light receiving element.

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