Optical system device and optical element manufacturing method

Abstract

The purpose of the present invention is to provide: an optical system device capable of emitting light having a high contrast; and a method for manufacturing the optical system device.　This optical system device comprises: an optical element 2 in which lenses, which have a focal distance f and through which light having a wavelength λ passes, are periodically arranged at a pitch P; an irradiation unit 1 that has a light source and that irradiates the lenses with light having said wavelength λ; a bottom member to which the irradiation unit is fixed; a side member for fixing the optical element and the bottom member; and one or both of an upper end-side adhesive layer for bonding the optical element with the upper end of the side member and a lower end-side adhesive layer for bonding the bottom member with the lower end of the side member. When L1 represents the distance between the irradiation unit and the focal position of the optical element and n represents a natural number not less than 1, the distance L1 satisfies the following formula.

Description

[Technical field]

[0001] The present invention relates to an optical system device and a method for manufacturing an optical element. [Background technology]

[0002] Three-dimensional measurement sensors using the time-of-flight (TOF) method are being adopted for mobile devices, cars, robots, etc. This is a method of measuring the distance to an object from the time it takes for light irradiated from a light source to be reflected and returned. If the light from the light source is irradiated uniformly on a specified area of ​​the object, the distance at each irradiated point can be measured and the three-dimensional structure of the object can be detected.

[0003] The sensor system is composed of a light irradiation unit that irradiates light onto an object, a camera unit that detects light reflected from each point on the object, and a calculation unit that calculates the distance to the object from the signal received by the camera.

[0004] The camera and computing units can use existing CMOS imagers and CPUs, so the unique part of the system is the light irradiation unit, which consists of a laser and an optical filter. In particular, the diffusion filter, which shapes the laser beam by passing it through a microlens array and uniformly irradiates the target area in a controlled manner, is a distinctive component of the system.

[0005] Conventional diffusion filters have a problem in that the microlens array has a periodic structure, which causes unevenness in the light intensity due to diffraction. In order to suppress this unevenness, various measures have been taken, such as randomly arranging the lenses (for example, Patent Document 1).

[0006] On the other hand, there is a need for long-distance measurement in TOF, and the intensity of the irradiated light must be strong enough to enable long-distance measurement. However, a randomly arranged microlens array is not suitable for long-distance measurement because the intensity is low due to the high uniformity of the irradiated light.

[0007] As a method for saving power while still being able to process strong light signals, studies are being conducted on irradiating a dot pattern and performing three-dimensional measurements from the time-of-flight of this light.

[0008] Conventionally, optical system devices that utilize the Lau effect are known for converting incident light into a dot pattern (for example, Non-Patent Document 1). This is composed of a diffraction grating with a specific pitch P and a light source, and is arranged so that the distance L0 between the diffraction grating and the light source satisfies the following formula A, where λ is the wavelength of the light from the light source and n is a natural number equal to or greater than 1. [Formula A] JPEG0007623743000001.jpg1323 Also, a device in which the diffraction grating is replaced with a microlens is under study (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special table 2006-500621 [Patent Document 2] International Publication No. 2017 / 131585 [Non-Patent Document 1] H. Hamam, Lau Array Illuminator, Applied Optics, 43(14):2888-2894, May 10, 2004. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0010] However, when the diffraction grating is replaced with a microlens, there are problems such as low contrast of the dot pattern and difficulty in adjusting the distance between the light source and the microlens.

[0011] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an optical system device capable of emitting light with high contrast, and a method for manufacturing the same.

Means for Solving the Problem

[0012] In order to achieve the above object, the optical system device of the present invention includes an optical element in which lenses that transmit light with a wavelength λ and have a focal length f are periodically arranged at a pitch P, an irradiation unit having a light source that irradiates a plurality of the lenses with light of wavelength λ, a bottom member that fixes the irradiation unit, a side member for fixing the optical element and the bottom member, and either one or both of an upper-end-side adhesive layer that adheres the upper ends of the optical element and the side member or a lower-end-side adhesive layer that adheres the lower ends of the bottom member and the side member. When the distance between the irradiation unit and the focal position of the optical element is L1 and n is a natural number of 1 or more, the distance L1 satisfies the following formula JPEG0007623743000002.jpg1357.

[0013] In this case, when the height from the upper surface of the bottom member to the irradiation surface of the irradiation unit is H0, it is preferable that the height H1 from the upper surface of the bottom member to the upper end of the side member satisfies the following formula JPEG0007623743000003.jpg1297.

[0014] Further, it is preferable that the height H1 satisfies the following formula JPEG0007623743000004.jpg1272 and the thickness δ1 of the upper-end-side adhesive layer satisfies 0 < δ1 < f.

[0015] Further, the light source is a VCSEL having a resonator length t in terms of the distance in the medium between the irradiation unit and the optical element. It is preferable that the height H1 satisfies the following formula JPEG0007623743000005.jpg1389 and the thickness δ1 of the upper-end-side adhesive layer satisfies 0 < δ1 < t.

[0016] In addition, when the height from the upper surface of the bottom member to the irradiation surface of the irradiation unit is H0, the height H2 from the lower end of the side member to the lower surface of the optical element satisfies the following formula It is preferable to satisfy JPEG0007623743000006.jpg1585.

[0017] Also, the height H2 satisfies the following formula JPEG0007623743000007.jpg1479 and it is preferable that the thickness δ2 of the lower-end side adhesive layer satisfies 0 < δ2 < f.

[0018] Also, the light source is a VCSEL having a resonator length t in terms of the distance in the medium between the irradiation unit and the optical element, and the height H2 satisfies the following formula JPEG0007623743000008.jpg1394 and it is preferable that the thickness δ2 of the lower-end side adhesive layer satisfies 0 < δ2 < t.

[0019] Also, it is preferable to include a mask that is disposed between the irradiation unit and the optical element and scatters or absorbs the light reflected from the surface of the optical element.

[0020] The electrode of the irradiation unit is preferably disposed at a position where the light reflected from the surface of the optical element is not reflected back to the optical element again.

[0021] Also, a method for manufacturing an optical system device of the present invention is a method for manufacturing an optical system device including an optical element in which lenses that transmit light with a wavelength λ and have a focal length f are periodically arranged at a pitch P, an irradiation unit having a light source that irradiates a plurality of the lenses with light having a wavelength λ, a bottom member that fixes the irradiation unit, and a side member that fixes the optical element and the bottom member. The method includes an upper-end side adhesive arrangement step of disposing an adhesive between the optical element and the upper end of the side member or a lower-end side adhesive arrangement step of disposing an adhesive between the bottom member and the lower end of the side member. When the distance between the irradiation unit and the focal position of the optical element is L1 and n is a natural number of 1 or more, the distance L1 satisfies the following formula A distance adjustment step of pressing the adhesive so as to satisfy JPEG0007623743000009.jpg1465 and adjusting the distance between the irradiation unit and the optical element, and an adhesive curing step of curing the adhesive while maintaining the distance L1. It is characterized by having these steps.

[0022] In this case, when the height from the upper surface of the bottom member to the irradiation surface of the irradiation unit is H0, before the distance adjustment step, the height H1 from the upper surface of the bottom member to the upper end of the side member satisfies the following formula It is preferable to have a side member forming step of forming the side member on the bottom member so as to satisfy JPEG0007623743000010.jpg15110.

[0023] Further, in the side member forming step, the height H1 satisfies the following formula The side member is formed on the bottom member so as to satisfy JPEG0007623743000011.jpg1382, and in the distance adjustment step, it is preferable to press the adhesive so that the thickness δ1 of the adhesive disposed in the upper end side adhesive disposition step satisfies 0 < δ1 < f.

[0024] Further, the light source is a VCSEL having a resonator length t in terms of the distance in the medium between the irradiation unit and the optical element. In the side member forming step, the height H1 satisfies the following formula The side member is formed on the bottom member so as to satisfy JPEG0007623743000012.jpg14101, and in the distance adjustment step, it is preferable to press the adhesive so that the thickness δ1 of the adhesive disposed in the upper end side adhesive disposition step satisfies 0 < δ1 < t.

[0025] Also, when the height from the upper surface of the bottom member to the irradiation surface of the irradiation unit is H0, before the distance adjustment step, the height H2 from the lower end of the side member to the lower surface of the optical element satisfies the following formula It is preferable to have a side member forming step of forming the side member on the optical element so as to satisfy JPEG0007623743000013.jpg14110.

[0026] Further, in the side member forming step, the side member is formed on the optical element such that the height H2 satisfies the following formula JPEG0007623743000014.jpg1382, and in the distance adjusting step, it is preferable to press the adhesive arranged in the lower end side adhesive arranging step so that the thickness δ2 of the adhesive satisfies 0 < δ2 < f.

[0027] Further, the light source is a VCSEL having a resonator length t in terms of the distance in the medium between the irradiation unit and the optical element, and in the side member forming step, the side member is formed on the optical element such that the height H2 satisfies the following formula JPEG0007623743000015.jpg14101, and in the distance adjusting step, it is preferable to press the adhesive arranged in the lower end side adhesive arranging step so that the thickness δ2 of the adhesive satisfies 0 < δ2 < t.

[0028] Further, the distance adjusting step may be to adjust the distance between the irradiation unit and the optical element by pressing the adhesive until the contrast of the dot pattern obtained by irradiating the optical element with the light of the irradiation unit becomes equal to or greater than a predetermined value.

Advantages of the Invention

[0029] The optical system device of the present invention can irradiate light with high contrast. Further, the manufacturing method of the optical system device of the present invention can easily and surely manufacture an optical system device capable of irradiating light with high contrast.

Brief Description of the Drawings

[0030] [Figure 1] It is a schematic cross-sectional view showing the optical system device of the present invention. [Diagram 2] It is a schematic cross-sectional view showing the irradiation unit and the optical element of the present invention. [Diagram 3] It is a diagram showing the light intensity in the far field for each emission mode. [Figure 4] It is a diagram showing the light intensity in the far field for each emission mode classified and synthesized. [Diagram 5] 11 is a diagram showing the light intensity in the far field of light combined by changing the ratio of each light emission mode. FIG. [Figure 6] 1 is a schematic plan view showing an optical element according to the present invention. [Figure 7] FIG. 11 is a schematic cross-sectional view showing a conventional optical system device. [Figure 8] 4 is a schematic plan view showing the positional relationship between an irradiation unit and an optical element according to the present invention. FIG. [Figure 9] 3 is a schematic cross-sectional view illustrating reflection on the surface of an optical element according to the present invention. FIG. [Figure 10] 5 is a schematic cross-sectional view illustrating the position of an electrode of the irradiation unit according to the present invention. FIG. [Figure 11] 1 is a schematic cross-sectional view illustrating a mask according to the present invention. [Figure 12] 5A to 5C are diagrams illustrating a method for manufacturing an optical device according to the present invention. [Figure 13] 5A to 5C are diagrams illustrating a method for manufacturing an optical device according to the present invention. [Figure 14] 1A to 1C are diagrams showing a method for bonding a side member and a bottom member according to the present invention. [Figure 15] 1A to 1C are diagrams showing a method for bonding a side member and an optical element according to the present invention. [Figure 16] FIG. 13 is a diagram showing a light distribution in the far field of an irradiation unit used in a simulation. [Figure 17] FIG. 1 is a diagram showing the propagation of light from a lens used in Simulation 1. [Figure 18] FIG. 13 is a diagram showing optical characteristics based on simulation 1 (focal length 20 μm). [Figure 19] FIG. 13 is a diagram showing optical characteristics based on simulation 1 (focal length 40 μm). [Figure 20] FIG. 13 is a diagram showing optical characteristics based on simulation 1 (focal length 60 μm). [Figure 21] FIG. 13 is a diagram showing the state of light when parallel light is incident on the lens (focal length 20 μm) used in Simulation 2. [Figure 22]FIG. 13 is a diagram showing the state of light when parallel light is incident on the lens (focal length 40 μm) used in Simulation 2. [Diagram 23] FIG. 13 is a diagram showing the state of light when parallel light is incident on the lens (focal length 60 μm) used in Simulation 2. [Figure 24] 13 is a projection diagram for different δ in simulation 2 (focal length 20 μm). [Diagram 25] 13 is a projection diagram for different δ in simulation 2 (focal length 40 μm). [Figure 26] 13 is a projection diagram for different δ in simulation 2 (focal length 60 μm). [Figure 27] This is the light distribution due to differences in δ in Simulation 2 (focal length 20 μm). [Figure 28] This is the light distribution due to differences in δ in Simulation 2 (focal length 40 μm). [Figure 29] This is the light distribution due to differences in δ in Simulation 2 (focal length 60 μm). [Diagram 30] FIG. 13 is a diagram showing maximum light intensity depending on δ in Simulation 2 (focal length 20 μm). [Diagram 31] FIG. 13 is a diagram showing maximum light intensity depending on δ in Simulation 2 (focal length 40 μm). [Diagram 32] FIG. 13 is a diagram showing maximum light intensity depending on δ in Simulation 2 (focal length 60 μm). [Diagram 33] FIG. 1 is a diagram illustrating a lens of the present invention. [Diagram 34] FIG. 13 is a diagram showing the state of light when parallel light is incident on the lens used in simulation 3. [Diagram 35] 13 is a projection diagram for different δ in simulation 3 (focal length 20 μm). [Diagram 36] This shows the light distribution (x-axis direction) depending on the difference in δ in simulation 3. [Figure 37]This shows the light distribution (in the y-axis direction) depending on the difference in δ in simulation 3. [Figure 38] FIG. 13 is a diagram showing maximum light intensity depending on differences in δ in Simulation 3. [Figure 39] FIG. 1 is a diagram showing contrast, dot size, and background according to different δ in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The optical system device of the present invention will be described below. As shown in Figures 1 and 2, the optical system device of the present invention is mainly composed of an irradiation unit 1 that irradiates light of wavelength λ, an optical element 2 having periodic lenses 21, a bottom member 3 that fixes the irradiation unit 1, a side member 4 that fixes the optical element 2 and the bottom member 3, and either or both of an upper end side adhesive layer 51 that bonds the upper ends of the optical element 2 and the side member 4 and a lower end side adhesive layer 52 that bonds the lower ends of the bottom member 3 and the side member 4.

[0032] The irradiation unit 1 may be any type having a light source that irradiates a plurality of lenses 21 with light of wavelength λ. The irradiation unit 1 may be a single light source or multiple light sources. The irradiation unit 1 may be a multiple light source by passing light from a single light source through an aperture having multiple fine holes. When the irradiation unit is composed of multiple light sources, it is preferable that the light sources are formed on the same plane. The surface from which the light of the irradiation unit 1 is emitted is defined as the irradiation surface. A specific example of the irradiation unit 1 is a VCSEL (Vertical Cavity Surface Emitting LASER) that can achieve high output with low power. The VCSEL may be a single emitter VCSEL having one light source 10 that can irradiate light in a direction perpendicular to the light emitting surface, or a multi-emitter VCSEL having multiple light sources 10.

[0033] [Lighting mode] Furthermore, when the light intensity of a VCSEL is increased, it is known that the light from the VCSEL contains multiple emission modes, such as single mode and multimode. Specific examples of emission modes are shown in Figure 3. Of the emission modes shown in Figure 3, (2) and (3), (4) and (6), (7) and (9), and (8) and (10), which are rotationally symmetric to each other, always exist at the same rate, so when these similar modes are each combined, they can be summarized into six types, A, B, C, D, E, and F, as shown in Figure 4.

[0034] When these six types of modes are combined in the same ratio (A:B:C:D:E:F=1:1:1:1:1:1:1), the result is as shown in Figure 5(a), and the maximum intensity is 0.0271. Note that the figure shows the light intensity in the far field at each light distribution angle when the power of the light source is set to 1. On the other hand, when these six modes are synthesized by making only one mode twice the intensity of the other modes, as shown in FIG. 5(b), the maximum intensity is 0.03 for A:B:C:D:E:F=2:1:1:1:1:1, 0.0389 for A:B:C:D:E:F=1:1:1:2:1:1, and 0.0285 for A:B:C:D:E:F=1:1:1:1:1:2. In other words, when the ratio of modes A or D, whose maximum intensity is at the center of the optical axis, or mode F, whose maximum intensity is close to the center of the optical axis, increases, the maximum intensity of the synthesized light increases compared to when the six modes are in the same ratio. FIG. 5(c) shows the synthesis of the six modes by making only modes A, D, and F five times the intensity of the other modes. The maximum intensity of A:B:C:D:E:F=5:1:1:1:1:1 was 0.0354, the maximum intensity of A:B:C:D:E:F=1:1:1:5:1:1 was 0.0608, and the maximum intensity of A:B:C:D:E:F=1:1:1:1:1:5 was 0.0343. In other words, the light synthesized by multiplying mode D by 5 (A:B:C:D:E:F=1:1:1:5:1:1) had a particularly notable increase in the maximum intensity of the synthesized light.

[0035] From the above, when using a VCSEL having multiple emission modes, it is preferable that the VCSEL light source has a higher proportion of emission modes having maximum intensity at the center of the optical axis, in order to increase the light intensity of the generated dots and to increase the contrast. Therefore, the proportion of modes having maximum intensity at the center of the optical axis among the emission modes of the light source is 40% or more, preferably 45% or more, and more preferably 60% or more. The emission mode may be adjusted by a conventionally known method, such as controlling the current injection path of the VCSEL light-emitting layer.

[0036] The optical element 2 has lenses 21 arranged periodically, each of which transmits light of wavelength λ. Here, the lens 21 has a focal point at a position a predetermined distance f (f>0) away from the lens 21. The optical element of the present invention can improve contrast compared to conventional elements as the focal length f increases, such as 10 μm or more, 20 μm or more, 40 μm or more, or 60 μm or more.

[0037] The shape of the lens 21 can be freely designed according to the spreading pattern of the dots to be irradiated (hereinafter, referred to as the dot pattern). For example, if the dot pattern is to be circular, the shape of the lens 21 can be a spherical lens. If the dot pattern is to be noncircular, the shape of the lens 21 can be an aspherical lens and appropriately adjusted. Specific lens shapes include, for example, convex lenses, concave lenses, and saddle-shaped lenses that look like convex lenses or concave lenses depending on the cross section. The periodic arrangement includes a square arrangement of square or rectangular lenses 21 in a plan view as shown in FIG. 6(a), and a hexagonal arrangement of hexagonal lenses 21 in a plan view as shown in FIG. 6(b). The lens 21 may be any type that functions as a lens, and for example, a Fresnel lens, a DOE lens, a metalens, or the like can be used. It is preferable that the lens 21 is provided with an anti-reflection film that prevents light from the irradiated portion from being reflected.

[0038] The irradiation unit 1 and the optical element 2 are arranged so that the optical axis direction of the light source of the irradiation unit 1 and the optical axis direction of the lens 21 of the optical element 2 are aligned.

[0039] [Distance between the irradiation unit and the optical element] Conventionally, it has been thought that, assuming n to be any natural number equal to or greater than 1, the wavelength of light incident from the irradiation unit 1 to be λ, the pitch of the lenses 21 of the optical element 2 to be P, and the distance between the irradiation unit 1 and the optical element 2 to be L0, the light will be greatly reinforced when the distance L0 is as expressed by the following formula A (see FIG. 7). [Formula A] JPEG0007623743000016.jpg1426

[0040] However, as a result of intensive research by the present inventors, when the focal length of the optical element is f, the distance L0 is expressed by the following formula B [Formula B] It was found that JPEG0007623743000017.jpg1357 enhances the light more. In particular, it was found that the light is most enhanced when the following formula C is satisfied. [Formula C] JPEG0007623743000018.jpg1434

[0041] If equations B and C are expressed in terms of the distance L1 (L1=L0-f) between the irradiation unit 1 and the focal position 9 of the optical element 2, as shown in Figure 2, rather than the distance L0 between the irradiation unit 1 and the optical element 2, we obtain the following equations D and E. [Formula D] JPEG0007623743000019.jpg1462[Formula E] JPEG0007623743000020.jpg1426

[0042] Furthermore, the lenses 21 may have a plurality of periods. For example, as shown in FIG. 6(a), when the lenses 21, which are square in plan view, are arranged in a square array, various pitches exist, such as pitch P2 (=√2P1) in the diagonal direction and pitch P3 (=√5P1) in addition to pitch P1 between adjacent lenses. Furthermore, as shown in FIG. 6(b), when the lenses 21, which are regular hexagonal in plan view, are arranged in a hexagonal array, in addition to pitch P1 between adjacent lenses, pitch P2 (=√3P1) and the like exist. Furthermore, as in the case of regularly arranging rectangular lenses in a plan view, the lenses 21 may have a plurality of different periods. In this case, the size of the smallest k-th pitch (k is a natural number equal to or greater than 1) among the pitches of the lenses 21 is defined as P k , n k Let a be any natural number equal to or greater than 1, and let 0≦a≦f and 0≦b≦f. If any of these pitches P k Regarding the distance L1 between the irradiation unit and the focal position 9 of the optical element, the following formula 1 is satisfied. [Formula 1] Just make sure it satisfies JPEG0007623743000021.jpg1571.

[0043] Here, the smaller a in formula 1 is preferable, such as a=f, a=0.5f, a=0.3f, or a=0.1f. Also, the smaller b is preferable, such as b=f, b=0.5f, b=0.3f, or b=0.1f. Also, it is most preferable that the distance L1 satisfies the following formula 2 where a=b=0. [Formula 2] JPEG0007623743000022.jpg1531

[0044] [Irradiation part pitch] Furthermore, when the irradiation unit 1 has a plurality of light sources 10, they need to be arranged so that the number of light sources 10 for each lens 21 of the optical element 2 remains the same in plan view even when each light source 10 and the optical element 2 are moved in parallel relative to one another. Specifically, when m is a natural number of 1 or more, the irradiation unit may be arranged such that a plurality of light sources are regularly arranged at m times or 1 / m times the period in any direction of the period of the lenses 21 of the optical element. In other words, the light sources 10 of the irradiation unit 1 are arranged such that the lenses 21 of the optical element 2 are arranged at a pitch P kWith respect to the direction of the pitch mP k Or P k It is preferable to arrange the light sources 10 regularly at a pitch of mP1 / m. In particular, it is preferable to set the pitch to mP1 or P1 / m. In (a) and (b) of FIG. 8, m=1 and the pitch of the light sources 10 is equal to the pitch P1 of the lenses 21 of the optical element 2. In FIG. 8(c), m=2 and the pitch of the light sources 10 is 1 / 2 the pitch P1 of the lenses 21 of the optical element 2, i.e., P1 / 2. In FIG. 8(d), m=2 and the pitch of the light sources 10 is twice the pitch P1 of the lenses 21 of the optical element 2, i.e., 2P1.

[0045] Preferably, any two or more pitches P k It is preferable to adjust the distance L1 between the irradiation unit 1 and the focal position 9 of the optical element 2 so as to satisfy the formula 1. In that case, since the influence of diffraction is greatest for the smallest pitch, it is preferable to satisfy the formula 1 for the smallest pitch P1, and more preferably, to satisfy the formula 1 for the second smallest pitch P2 as well.

[0046] In addition, when the irradiation unit 1 has light sources 10 arranged in a hexagonal array, it is preferable to make the planar shape of the lenses 21 of the optical element rectangular, set the ratio of the short side to the long side of the rectangle to P1:P2=1:√3, and set the pitch of the light sources 10 to mP1 or P1 / m, since this makes the number of light sources 10 for each lens 21 uniform. In this case, in order to satisfy formula 1 for the smallest pitch P1 (the size of the short side of the rectangle) and the second smallest pitch P2 (the size of the long side of the rectangle), P2=√3P1, that is, (P2) 2 =3(P1) 2 In consideration of the above, it is preferable that the distance L1 between the irradiation unit 1 and the optical element 2 satisfies the following formula 3: [Formula 3] JPEG0007623743000023.jpg1671 It is even more preferable that the following formula 4 is satisfied. [Formula 4] JPEG0007623743000024.jpg1630

[0047] Furthermore, as a result of intensive research by the present inventors, it was found that when a VCSEL with a cavity length of t is used as a light source, the contrast does not change much if 0≦a≦t and 0≦b≦t are within the ranges in formula 1. Therefore, the distance L1 is determined by the following formula 5: [Formula 5] It is preferable that the resonator length t satisfies JPEG0007623743000025.jpg1672. Note that the resonator length t here means the distance between the irradiation unit and the optical element converted into the distance in the medium.

[0048] In addition, pitch P k If the pitch P is too small compared to the wavelength λ of the light from the light source 10, diffraction is difficult to occur. Therefore, as long as the light distribution angle of the light source 10 includes a sufficient number of lenses 21 to cause diffraction, the pitch P k In particular, the pitch P1 should be sufficiently larger than the wavelength λ of the light from the light source 10, for example, 5 times or more, and preferably 10 times or more.

[0049] The bottom member 3 is for fixing the irradiation unit 1. The surface of the bottom member 3 for fixing the irradiation unit 1 may be flat, or may have a concave groove formed thereon so that the irradiation unit 1 can be embedded. The irradiation unit 1 may be fixed to the bottom member 3 by a general method such as fixing the irradiation unit 1 to the bottom member 3 with an adhesive.

[0050] The side member 4 is for fixing the optical element 2 and the bottom member 3 with a predetermined distance therebetween. The upper ends of the optical element 2 and the side member 4 are bonded via an upper end side adhesive layer 51. The lower ends of the bottom member 3 and the side member 4 are bonded via a lower end side adhesive layer 52. As shown in FIG. 1(b), the side member 4 may be formed integrally with the bottom member 3 without using the lower end side adhesive layer 52 if it has the upper end side adhesive layer 51. As shown in FIG. 1(d), the side member 4 may be formed integrally with the optical element without using the upper end side adhesive layer 51 if it has the lower end side adhesive layer 52.

[0051] The side member 4 may be formed in a cylindrical shape that surrounds the periphery of the irradiation unit 1 so that the irradiation unit 1 can be sealed when the optical element 2, the bottom member 3, and the side member 4 are bonded with an adhesive.

[0052] The bottom member 3 and the side members 4 may be made of any known material, but it is preferable that they are less susceptible to deformation due to the surrounding environment, and that they are not deformed or deteriorated by the resin that forms the adhesive layer.

[0053] The upper end side adhesive layer 51 is formed between the upper end of the side member 4 and the optical element in order to dispose the irradiation unit 1 between the optical element 2 and the bottom member 3, and serves to bond the optical element 2 and the side member 4. The lower end side adhesive layer 52 is formed between the lower end of the side member 4 and the bottom member 3, and serves to bond the bottom member 3 and the side member 4. The upper end side adhesive layer 51 and the lower end side adhesive layer 52 have the function of adjusting the distance L1 between the irradiation surface of the irradiation unit 1 and the focal position of the lens of the optical element 2 in a fluid adhesive state before solidification.

[0054] The upper end side adhesive layer 51 or the lower end side adhesive layer 52 may be formed on the entire surface of the end of the side member 4, or may be formed only on a part of the end. The material of the upper end side adhesive layer 51 or the lower end side adhesive layer 52 may be any material capable of bonding the side member 4 to the optical element 2 or the bottom member 3, and may be, for example, an adhesive such as a silicon-based resin, an epoxy-based resin, or an acrylic-based resin. The type of adhesive may be, for example, a photocurable adhesive, a UV addition type adhesive, or a thermosetting adhesive.

[0055] Here, the height from the upper surface of the bottom member 3 to the irradiation surface of the irradiation unit 1 when the side member 4 and the bottom member 3 are bonded with the lower end side adhesive layer 52 as shown in FIG. 1(a) or are integrally formed as shown in FIG. 1(b) is defined as H0. In this case, the height H1 from the upper surface of the bottom member 3 to the upper end of the side member 4 is at least as large as the following formula 6. [Formula 6] It is preferable to satisfy JPEG0007623743000026.jpg14110.

[0056] More preferably, the height H1 is expressed by the following formula 7. [Formula 7] After being formed to satisfy JPEG0007623743000027.jpg1382, it is better to control the thickness δ1 of the upper-end side adhesive layer 51 such that 0 < δ1 < f. Thereby, the distance L1 surely satisfies the following formula 8 [Formula 8] JPEG0007623743000028.jpg1466 is satisfied.

[0057] Also, when the light source is a VCSEL having a resonator length of t, the height H1 satisfies the following formula 9 after being formed to satisfy JPEG0007623743000029.jpg14101, and it is preferable to control the thickness δ1 of the upper-end side adhesive layer 51 such that 0 < δ1 < t. Thereby, the distance L1 surely satisfies the following formula 10 [Formula 9] JPEG0007623743000029.jpg14101 is satisfied. [Formula 10] JPEG0007623743000030.jpg1364 is satisfied.

[0058] Also, when the side member 4 and the optical element are adhered with the upper-end side adhesive layer 51 as shown in FIG. 1(c), or are integrally formed as shown in FIG. 1(d), let the height from the upper surface of the bottom member 3 to the irradiation surface of the irradiation unit 1 be H0. In this case, the height H2 from the lower end of the side member 4 to the lower surface of the optical element 2 preferably satisfies at least the following formula 11 [Formula 11] JPEG0007623743000031.jpg13109 is satisfied.

[0059] More preferably, after being formed to satisfy the height H2 of the following formula 12, it is better to control the thickness δ2 of the upper-end side adhesive layer 51 such that 0 < δ2 < f. Thereby, the distance L1 surely satisfies the following formula 8 [Formula 12] JPEG0007623743000032.jpg1381 is satisfied. [Formula 8] JPEG0007623743000033.jpg1465 is satisfied.

[0060] Also, when the light source is a VCSEL having a resonator length of t, the height H2 satisfies the following formula 13 [Formula 13] After forming to satisfy JPEG0007623743000034.jpg13100, it is preferable to control the thickness δ2 of the lower end side adhesive layer 52 to 0 < δ2 < t. Thereby, the distance L1 surely satisfies the following formula 10 [Formula 10] JPEG0007623743000035.jpg1464 is satisfied.

[0061] Further, as a result of the present inventor's intensive research, as shown in FIG. 9, when the light reflected from the surface of the optical element 2 of the light irradiated from the irradiation unit 1 to the optical element 2 is irradiated again to the optical element 2 by, for example, the electrode 15 of the irradiation unit 1 or the like, it causes noise and ghost, and it has been found that the contrast decreases. Therefore, it is preferable that no object (for example, the electrode 15) that reflects the light back to the optical element 2 is arranged at the position where the light reflected from the surface of the optical element 2 passes. Further, even when such an object is arranged at the position where the light reflected from the surface of the optical element 2 passes, it is preferable to arrange it at a position where the light is not reflected back to the optical element 2 again. For this purpose, for example, as shown in FIG. 10(a), the electrode 15 of the irradiation unit 1 may be largely shifted from the position where the light reflected from the surface of the optical element 2 passes. Further, as shown in FIG. 10(b), the irradiation unit 1 may be of a flip-chip type, and the electrode 15 may be arranged on the back side of the light source 10.

[0062] In addition, there may be a case where it is necessary to place something that reflects the light reflected on the surface of the optical element 2 again at a position through which the light passes, as shown in FIG. 11, between the irradiation unit 1 and the optical element 2, and a mask 6 that scatters or absorbs the light reflected on the surface of the optical element 2 may be placed. The position of the mask 6 may be anywhere between the irradiation unit 1 and the optical element 2 as long as it does not block the light emitted from the irradiation unit 1 to the optical element 2. For example, as shown in FIG. 11(a), the mask may be placed on the electrode 15, as shown in FIG. 11(b), in the space between the electrode 15 and the optical element 2, as shown in FIG. 11(c), or on the optical element 2. For example, a black resist may be used as a material that absorbs light. In addition, when scattering light, a material that does not have a mirror surface may be used.

[0063] Next, a manufacturing method for the optical system device of the present invention will be described with reference to Figures 12 and 13. The manufacturing method is a manufacturing method for an optical system device including an optical element 2 in which lenses 21 having a focal length f and transmitting light of wavelength λ are periodically arranged at a pitch P, an irradiation unit 1 having a light source that irradiates a plurality of lenses 21 with light of wavelength λ, a bottom member 3 for fixing the irradiation unit 1, and a side member 4 for fixing the optical element 2 and the bottom member 3, and is mainly composed of an upper end side adhesive placing step of placing an adhesive between the upper end of the optical element 2 and the side member 4 or a lower end side adhesive placing step of placing an adhesive between the lower end of the bottom member 3 and the side member 4, a distance adjusting step of adjusting the distance between the irradiation unit 1 and the optical element 2, and an adhesive hardening step of hardening the adhesive.

[0064] First, a method for manufacturing the optical element 2 used in the optical system device of the present invention will be described. The lens 21 of the optical element 2 may be manufactured in any manner, for example, by using an imprint method. Specifically, the material of the lens 21 is applied to a substrate 25 in a predetermined thickness by a well-known method such as a spin coater (application step). Any material may be used as long as it can form the lens 21 that transmits light of wavelength λ, and for example, polydimethylsiloxane (PDMS) can be used.

[0065] Next, a mold having an inverted pattern of the pattern in which the lenses 21 are periodically arranged is prepared, and the mold is pressed against the material applied onto the substrate 25 to transfer the pattern (imprint process).

[0066] This makes it possible to manufacture an optical element 2 with small variation in focal position 9 of lens 21, thereby making it possible to reduce error in distance L1.

[0067] In the upper end adhesive placement step, as shown in FIG. 12(a), an adhesive 51a is placed between the upper end of the optical element 2 and the side member 4. In the lower end adhesive placement step, as shown in FIG. 13(a), an adhesive 52a is placed between the bottom member 3 and the lower end of the side member 4. The adhesive may be placed over the entire end (upper end or lower end) of the side member 4, or may be placed only on a part of the end. The adhesive may be placed at a position on the side of the optical element 2 or the bottom member 3 where the side member 4 is to be bonded. Any adhesive may be used as long as it can bond the side member 4 to the optical element 2 or the bottom member 3. For example, an adhesive such as a silicon resin, an epoxy resin, or an acrylic resin may be used. For example, a photocurable adhesive, a UV-additive adhesive, or a heat-curable adhesive may be used as the type of adhesive.

[0068] In the distance adjustment process, as shown in FIG. 12(b) or FIG. 13(b), the distance between the irradiation unit and the focal position of the optical element is L1, and n is a natural number of 1 or more. The distance L1 is calculated by the following formula 11. [Formula 11] The adhesive is pressed to adjust the distance between the irradiation unit and the optical element so as to satisfy JPEG0007623743000036.jpg1362. Any method may be used for adjusting the distance as long as it can be adjusted to satisfy Expression 11. For example, a conventionally known sensor may be used to measure the distance between the irradiation unit and the optical element, and the irradiation unit and the optical element may be brought closer to each other until the distance L1 satisfies Expression 11. As another method, the adhesive may be pressed to adjust the distance between the irradiation unit and the optical element until the contrast of a dot pattern obtained by irradiating the optical element with light from the irradiation unit becomes equal to or greater than a predetermined value.

[0069] In the adhesive curing step, as shown in FIG. 12(c) or FIG. 13(c), the adhesive is cured while maintaining the distance L1 adjusted in the distance adjustment step. As a result, an upper end side adhesive layer 51 that bonds the upper end of the optical element and the side member 4, or a lower end side adhesive layer 52 that bonds the lower end of the bottom member 3 and the side member 4, is formed. If the adhesive is a photocurable adhesive, the adhesive may be cured by irradiating it with light. If the adhesive is a thermosetting adhesive, the adhesive may be cured by applying heat. If the adhesive is a UV additive adhesive, after irradiating the adhesive with light, the distance adjustment step may adjust the distance L1 between the irradiating part and the focal position of the optical element, and then the distance L1 may be maintained until the adhesive is sufficiently cured.

[0070] In the distance adjustment process, when adjusting the distance by the thickness of the adhesive placed at the upper end of the side member 4 (the thickness of the upper end side adhesive layer 51), if the height from the upper surface of the bottom member 3 to the irradiation surface of the irradiation unit is H0, the height H1 from the upper surface of the bottom member 3 to the upper end of the side member 4 before the distance adjustment process is calculated by the following formula 12. [Formula 12] It is preferable to have a side member forming step of forming the side member 4 on the bottom member 3 so as to satisfy JPEG0007623743000037.jpg1399. In this case, the side member 4 may be formed by disposing an adhesive 52a between the bottom member 3 and the lower end of the side member 4 as shown in Fig. 14(a), pressing the side member 4 against the adhesive 52a to adjust the height H1 as shown in Fig. 14(b), and curing the adhesive 52a as shown in Fig. 14(c). Alternatively, the side member 4 may be formed integrally with the bottom member 3 so as to have a predetermined height H1.

[0071] More preferably, in the side member forming step, the height H1 is determined to be within the range of the following formula 13: [Formula 13] The side member 4 is formed on the bottom member 3 so as to satisfy JPEG0007623743000038.jpg1474, and in the distance adjustment step, it is preferable to press the adhesive arranged in the upper end side adhesive arrangement step so that the thickness δ1 of the adhesive satisfies 0 < δ1 < f. Thereby, an optical system device in which the distance L1 between the irradiation unit and the focal position of the optical element surely satisfies Equation 11 can be manufactured.

[0072] Further, as described above, as a result of the intensive research by the present inventor, it has been found that when a VCSEL having a resonator length t converted to the distance in the medium between the irradiation unit and the optical element as a light source is used, the contrast does not change much within the range of Equation 10. Therefore, in this case, in the side member forming step, the height H1 satisfies the following Equation 14 [Equation 14] The side member 4 is formed on the bottom member 3 so as to satisfy JPEG0007623743000039.jpg1491, and in the distance adjustment step, it is preferable to press the adhesive 51a arranged in the upper end side adhesive arrangement step so that the thickness δ1 of the adhesive satisfies 0 < δ1 < t.

[0073] Further, in the distance adjustment step, when adjusting the distance by the thickness of the adhesive arranged at the lower end of the side member 4 (the thickness of the lower end side adhesive layer 52), if the height from the upper surface of the bottom member 3 to the irradiation surface of the irradiation unit is H0, before the distance adjustment step, the height H2 from the lower end of the side member 4 to the lower surface of the optical element satisfies the following Equation 15 [Equation 15] It is preferable to have a side member forming step of forming the side member 4 on the optical element so as to satisfy JPEG0007623743000040.jpg1399. In this case, as shown in FIG. 15(a), the side member 4 arranges the adhesive 51a between the optical element 2 and the upper end of the side member 4, and as shown in FIG. 15(b), presses the side member 4 against the adhesive 51a to adjust the height H2, and as shown in FIG. 15(c), the adhesive 51a may be cured and formed. Further, the side member 4 may be integrally formed with the optical element 2 so as to have a predetermined height H2.

[0074] More preferably, in the side member forming step, the side member 4 is formed on the optical element such that the height H2 satisfies the following formula 16 [Formula 16] JPEG0007623743000041.jpg1374. In the distance adjustment step, it is preferable to press the adhesive such that the thickness δ2 of the adhesive disposed in the lower end side adhesive disposition step satisfies 0 < δ2 < f. Thereby, an optical system device can be manufactured in which the distance L1 between the irradiation unit and the focal position of the optical element surely satisfies formula 11.

[0075] Also, as described above, as a result of the inventor's intensive research, it has been found that when a VCSEL having a resonator length t converted into the distance in the medium between the irradiation unit and the optical element as a light source is used, the contrast does not change much within the range of formula 10. Therefore, in this case, in the side member forming step, the side member 4 is formed on the optical element such that the height H2 satisfies the following formula 17 [Formula 17] JPEG0007623743000042.jpg1390. In the distance adjustment step, it is preferable to press the adhesive such that the thickness δ2 of the adhesive disposed in the lower end side adhesive disposition step satisfies 0 < δ2 < t.

[0076] [Simulation] Next, the distance L1 between the irradiation unit 1 and the focal position 9 of the optical element 2 was set as the following formula 18, and a simulation was performed on the light intensity distribution in the far field when δ was varied variously. [Formula 18] TIFF0007623743000043.tif1731

[0077] [Simulation 1] The irradiating unit 1 was a single light source that irradiated light with a wavelength of 940 nm (λ=0.94) and a Gaussian light distribution as shown in FIG. 16. The optical element 2 used was a plurality of lenses 21 periodically arranged with a pitch P1 of 30 μm (P1=30) as shown in FIG. 2. Three types of lenses 21 were used, each with a diameter of 30 μm, a refractive index of 1.5, and focal lengths f of (a) 20 μm, (b) 40 μm, and (c) 60 μm. FIG. 17(a) is a diagram showing the state of light propagation when each lens is irradiated with parallel light as shown in FIG. 17(b). Note that n in Equation 18 k was set to 2. Figures 18 to 20 show the results of a simulation using optical simulation software BeamPROP (Synopsys). This simulation is a 2D calculation result that does not take into account the depth direction in Figure 2 in order to simplify the calculation.

[0078] The graphs in (a) of FIGS. 18 to 20 show the light intensity distribution in the case where the distance L0 between the irradiation unit 1 and the optical element 2 satisfies the above-mentioned formula A, as in the conventional case. 18 to 20(b) show the light intensity distribution when the distance L1 between the irradiation unit 1 and the focal position 9 of the optical element 2 satisfies the above-mentioned formula 2. In FIG. Moreover, the graphs in (c) of FIGS. 18 to 20 show the difference in maximum light intensity in each light intensity distribution versus the value of δ. 18 to 20(a) and (b), the horizontal axis indicates the light distribution angle, and the vertical axis indicates the light intensity in the far field when the power of the light source is set to 1. Moreover, in Fig. 18 to 20(c), the horizontal axis indicates δ, and the vertical axis indicates the light intensity in the far field when the power of the light source is set to 1.

[0079] The simulation results show that the optical element 2 that satisfies formula 1 produces a clearer peak and has a greater peak light intensity than the optical element 2 that satisfies formula A. It is also clear that the peak light intensity is greatest when formula 2 is satisfied.

[0080] [Simulation 2] The irradiating unit 1 was a single light source that irradiated light with a wavelength of 940 nm (λ=0.94) and a Gaussian light distribution as shown in FIG. 16. As shown in FIG. 2, the optical element 2 was a square array of multiple lenses 21 with a pitch P1 of 30 μm (P1=30), and had a refractive index of 1.5. The lens surface was rotationally symmetric with the same curvature in the x-axis direction and the y-axis direction. As shown in FIGS. 21 to 23, three types of lenses 21 were used with focal lengths f of 20 μm, 40 μm, and 60 μm. Note that n in formula 3 k was set to 2. The results of a simulation using optical simulation software BeamPROP (manufactured by Synopsys) are shown in Fig. 24 to Fig. 32. This simulation is a 3D calculation result that also takes into account the depth direction in Fig. 2.

[0081] Figures 24 to 26 show projected images 50 cm away from the optical element when δ in formula 18 is changed for three types of lenses. Figures 27 to 29 show light intensity distributions when δ in formula 18 is changed for three types of lenses. Figures 30 to 32 show the maximum light intensity of each light intensity distribution versus the value of δ for the three types of lenses.

[0082] 27 to 29, the horizontal axis represents the light distribution angle, and the vertical axis represents the light intensity in the far field when the power of the light source is set to 1. In addition, in Figs. 30 to 32, the horizontal axis represents δ, and the vertical axis represents the light intensity in the far field when the power of the light source is set to 1.

[0083] The simulation results show that the optical element 2 that satisfies formula 1 produces a clearer peak and has a greater peak light intensity than the optical element 2 that satisfies formula A. It is also clear that the peak light intensity is greatest when formula 2 is satisfied.

[0084] [Simulation 3] The irradiating unit 1 was a single light source that irradiated light with a wavelength of 940 nm (λ=0.94) and a Gaussian light distribution as shown in FIG. 16. As shown in FIG. 2, the optical element 2 was a square arrangement of a plurality of lenses 21 with a pitch P1 of 30 μm (P1=30), and had a refractive index of 1.5. The shape of the lens 21 was a square with a side length of 30 μm in a plan view and a height of 16.26 μm, as shown in FIG. 33(a). The lens surface was a rotationally symmetric aspheric surface with different curvatures in the x-axis direction and the y-axis direction. FIG. 33(b) is a projection diagram of the light distribution in the far field when parallel light is incident on the optical element. FIG. 33(c) is the light distribution with respect to the angle in the x-axis direction and the y-axis direction in the far field. The focal length f of the lens 21 was 20 μm, as shown in FIG. 34. FIG. 34(b) is a projection diagram of the emitted light when parallel light is incident on the lens 21. Note that the way in which the light is focused differs between the x-axis direction and the y-axis direction, but the point where the light is most focused is set as the focal position (0 μm). k was set to 2. The results of a simulation using optical simulation software BeamPROP (Synopsys, Inc.) are shown in Figures 35 to 38. This simulation is a 3D calculation result that also takes into account the depth direction in Figure 2.

[0085] Fig. 35 shows a projected image 50 cm away from the optical element when δ in formula 18 is changed variously. Fig. 36 shows the light intensity distribution in the x-axis direction when δ in formula 3 is changed variously. Fig. 37 shows the light intensity distribution in the y-axis direction when δ in formula 18 is changed variously. Fig. 38 shows the maximum light intensity of each light intensity distribution in the x-axis and y-axis directions for the value of δ.

[0086] 36 and 37, the horizontal axis indicates the light distribution angle, and the vertical axis indicates the light intensity in the far field when the power of the light source is set to 1. In addition, in FIG. 38, the horizontal axis indicates δ, and the vertical axis indicates the light intensity in the far field when the power of the light source is set to 1.

[0087] The simulation results show that the optical element 2 that satisfies formula 18 produces a clearer peak and has a greater peak light intensity than the optical element 2 that satisfies formula A. In addition, because a rotationally asymmetric lens with different curvatures in the x-axis and y-axis directions is used, the positions at which the peak light intensity is maximum differ between the x-axis and y-axis directions; however, it can be seen that as long as formula 18 is satisfied, sufficient light intensity is obtained.

[0088] [Example 1] The irradiating unit 1 was a VCSEL in which a light source irradiating light with a wavelength of 945 nm (λ=0.945) and a batwing light distribution was arranged in a square with a pitch of 32 μm. The cavity length of the VCSEL converted into air was 30 μm. The optical element 2 was a square arrangement of a plurality of lenses 21 with a pitch P1 of 32 μm (P1=32) and a refractive index of 1.53. The lens 21 was shaped like a square with a side of 32 μm in plan view and a height of 17 μm. The lens surface was an aspheric surface with different curvatures in the x-axis direction and the y-axis direction. The focal length f of the lens 21 was 20 μm. The distance between the irradiating unit 1 and the focal position 9 of the optical element 2 was set to 1084 μm, and the contrast and dot size of the dot pattern were examined when the difference δ from this distance was changed in various ways. Figure 39(a) shows the results of measuring the contrast of the dot at the center when a dot pattern was projected onto a screen 1.5 m away from the optical element, Figure 39(b) shows the results of measuring the dot size, and Figure 39(c) shows the results of measuring the background.

[0089] As shown in FIG. 39, it was found that the contrast and dot size did not change significantly within the range of −30≦δ≦30, that is, within the error range equivalent to the resonator length.

[0090] [Explanation of symbols]

[0091] 1. Irradiation unit 2. Optical elements 3 Bottom member 4 Side members 9 Focus position 10 light source 21 Lens 51 Upper end adhesive layer 52 Bottom side adhesive layer 51a Adhesive 52a Adhesive

Claims

1. An optical element in which lenses having a focal length f and transmitting light of wavelength λ are periodically arranged at a pitch P; an irradiation unit having a light source that irradiates light of wavelength λ onto the lenses; A bottom member that fixes the irradiation unit; a side member for fixing the optical element and the bottom member; an upper end side adhesive layer that bonds the optical element and the upper end of the side member, or a lower end side adhesive layer that bonds the bottom member and the lower end of the side member, or both of these; Equipped with When the distance between the irradiation unit and the focal position of the optical element is L 1 , and n is a natural number of 1 or more, the distance L 1 is expressed by the following formula: [0010] Fulfilling The height from the top surface of the bottom member to the irradiation surface of the irradiation unit is H ０ Then, the height H from the top surface of the bottom member to the top end of the side member is １ But the following formula [0025] and wherein the thickness δ1 of the upper end side adhesive layer satisfies 0<δ1<f.

2. The height H １ But the following formula [0030] 2. The optical system according to claim 1, wherein the thickness δ1 of the upper end adhesive layer satisfies 0<δ1<f.

3. the light source is a VCSEL having a cavity length t converted into a distance in a medium between the irradiation unit and the optical element, The height H １ But the following formula [0045] 2. The optical device according to claim 1, wherein the thickness δ1 of the upper end side adhesive layer satisfies 0<δ1<t.

4. An optical element in which lenses having a focal length f and transmitting light of wavelength λ are periodically arranged at a pitch P; an irradiation unit having a light source that irradiates light of wavelength λ onto the lenses; A bottom member that fixes the irradiation unit; a side member for fixing the optical element and the bottom member; an upper end side adhesive layer that bonds the optical element and the upper end of the side member, or a lower end side adhesive layer that bonds the bottom member and the lower end of the side member, or both of these; Equipped with When the distance between the irradiation unit and the focal position of the optical element is L 1 , and n is a natural number of 1 or more, the distance L 1 is expressed by the following formula: [0010] Fulfilling The height from the top surface of the bottom member to the irradiation surface of the irradiation unit is H ０ Then, the height H from the lower end of the side member to the lower surface of the optical element is ２ But the following formula [0050] An optical system device characterized by satisfying the above.

5. The height H ２ But the following formula [006] 5. The optical system according to claim 4, wherein the thickness δ2 of the lower end side adhesive layer satisfies 0<δ2<f.

6. the light source is a VCSEL having a cavity length t converted into a distance in a medium between the irradiation unit and the optical element, The height H ２ But the following formula [0070] 5. The optical system according to claim 4, wherein the thickness δ2 of the lower end side adhesive layer satisfies 0<δ2<t.

7. 7. The optical system according to claim 1, further comprising a mask disposed between the irradiation unit and the optical element, for scattering or absorbing light reflected by a surface of the optical element.

8. 7. The optical system device according to claim 1, wherein the electrode of the irradiation section is disposed at a position where the light reflected by the surface of the optical element is not reflected back to the optical element.

9. A method for manufacturing an optical system device comprising: an optical element having lenses, each having a focal length f and transmitting light of wavelength λ, periodically arranged at a pitch P; an irradiation unit having a light source that irradiates a plurality of the lenses with light of wavelength λ; a bottom member that fixes the irradiation unit; and a side member that fixes the optical element and the bottom member, the method comprising the steps of: an upper end adhesive placing step of placing an adhesive between the optical element and an upper end of the side member, or a lower end adhesive placing step of placing an adhesive between the bottom member and a lower end of the side member; The distance between the irradiation unit and the focal position of the optical element is L １ , where n is a natural number equal to or greater than 1, the distance L １ But the following formula [0080] a distance adjusting step of adjusting a distance between the irradiation unit and the optical element by pressing the adhesive so as to satisfy The distance L １ an adhesive curing step of curing the adhesive while maintaining the adhesive; 2. A method for manufacturing an optical system device comprising:

10. The height from the top surface of the bottom member to the irradiation surface of the irradiation unit is H ０ Then, before the distance adjustment step, the height H from the upper surface of the bottom member to the upper end of the side member is １ But the following formula [0090] 10. The method for manufacturing an optical device according to claim 9, further comprising a side member forming step of forming the side members on the bottom member so as to satisfy the following:

11. The side member forming step is performed by forming the side member １ But the following formula [0010] forming the side members on the bottom member so as to satisfy 11. The method for manufacturing an optical device according to claim 10, wherein the distance adjusting step presses the adhesive applied in the upper end side adhesive applying step so that a thickness δ1 of the adhesive is in the range of 0<δ1<f.

12. the light source is a VCSEL having a cavity length t converted into a distance in a medium between the irradiation unit and the optical element; The side member forming step is performed by forming the side member １ But the following formula ##EQU00011## forming the side members on the bottom member so as to satisfy 11. The method for manufacturing an optical device according to claim 10, wherein the distance adjusting step presses the adhesive applied in the upper end side adhesive applying step so that a thickness δ1 of the adhesive is in the range of 0<δ1<t.

13. The height from the top surface of the bottom member to the irradiation surface of the irradiation unit is H ０ Then, before the distance adjustment step, the height H from the lower end of the side member to the lower surface of the optical element is ２ But the following formula ##EQU00012## 10. The method for manufacturing an optical system according to claim 9, further comprising a side member forming step of forming the side members on the optical element so as to satisfy the following:

14. The side member forming step is performed by forming the side member ２ But the following formula ##EQU00013## forming the side members on the optical element so as to satisfy 11. The method for manufacturing an optical device according to claim 10, wherein the distance adjusting step presses the adhesive applied in the lower end side adhesive applying step so that a thickness δ2 of the adhesive is in the range of 0<δ2<f.

15. the light source is a VCSEL having a cavity length t converted into a distance in a medium between the irradiation unit and the optical element; The side member forming step is performed by forming the side member ２ But the following formula ##EQU14## forming the side members on the optical element so as to satisfy 11. The method for manufacturing an optical device according to claim 10, wherein the distance adjusting step presses the adhesive applied in the lower end side adhesive applying step so that a thickness δ2 of the adhesive is in the range of 0<δ2<t.

16. 10. The method for manufacturing an optical system device according to claim 9, wherein the distance adjustment step includes adjusting the distance between the irradiation unit and the optical element by pressing the adhesive until the contrast of a dot pattern obtained by irradiating the optical element with light from the irradiation unit becomes equal to or greater than a predetermined value.

Images