Optical waveguide mold, method for manufacturing optical waveguide, and optical waveguide

Abstract

The purpose of the present invention is to provide an optical waveguide in which undulation of a transfer part is small and a residual film of an incident part or an emission part is small, an optical waveguide mold for manufacturing same, and a manufacturing method of the optical waveguide.　Provided is an optical waveguide mold which is for manufacturing an optical waveguide composed of a transfer part 1, an incident part 2, and an emission part 3, and is formed of a transparent substrate 4 and a resin 5, wherein the optical waveguide mold has: a flat transfer part pattern 61 for forming the transfer part 1 on the resin 5; and one or both of an incident part pattern 62 for forming the incident part 2 and an emission part pattern 63 for forming the emission part 3. When the depth of a recessed portion of the incident part pattern 62 or the emission part pattern 63 is B, the fill factor of a protruding portion is FF, and the difference between the height of the incident part pattern 62 or the emission part pattern 63 and the height of the transfer part pattern 61 is D, the following expression 0.9 × B × (1-FF) ≤ D ≤ 1.1 × B × (1-FF) is satisfied.

Description

Mold for optical waveguide, method for manufacturing optical waveguide, and optical waveguide

[0001] The present invention relates to a mold for an optical waveguide, a method for manufacturing an optical waveguide, and an optical waveguide.

[0002] Waveguides for augmented reality (AR) glasses are expected to have a large market share, and active development is underway to develop high-refractive index resin materials to achieve a wide viewing angle, as well as various input / output coupler structures to achieve high image transfer efficiency and uniform output. Optical waveguides are used in various electronic devices because they are lightweight and capable of high-speed signal transmission. In recent years, pattern formation techniques using imprinting have been attracting attention for such optical waveguides, replacing photolithography techniques (e.g., Patent Document 1).

[0003] Patent Publication No. 2016-207717

[0004] However, when creating an optical waveguide using the imprint method, if the gaps in the transfer section pattern of the mold are large, problems arise such as undulations occurring in the transfer section of the waveguide, reducing efficiency and causing color shifts. Therefore, if the resin film thickness is increased to fill the gaps, the remaining film under the patterns of the incident and exit sections becomes larger, resulting in a problem of reduced efficiency on the wide-angle side.

[0005] Therefore, an object of the present invention is to provide an optical waveguide having small undulations in the transfer section and small residual films in the incident and exit sections, an optical waveguide mold for manufacturing such an optical waveguide, and a method for manufacturing an optical waveguide.

[0006] In order to achieve the above object, the optical waveguide mold of the present invention is an optical waveguide mold for manufacturing an optical waveguide, which is formed of a transparent substrate and a resin formed on the surface of the transparent substrate, and which comprises a transfer section for transferring light, an incident section for making light incident on the transfer section, and an exit section for making the light exit from the transfer section, and which has a flat transfer section pattern for forming the transfer section in the resin, and at least one or both of an incident section pattern for forming the incident section in the resin and an exit section pattern for forming the exit section in the resin, and is characterized in that, where the depth of the concaves of the incident section pattern or the exit section pattern is B, the fill factor of the convex sections of the incident section pattern or the exit section pattern is FF, and the difference in height between the height of the incident section pattern or the exit section pattern and the height of the transfer section pattern is D, the following formula is satisfied: 0.9×B×(1-FF)≦D≦1.1×B×(1-FF).

[0007] In this case, it is preferable to satisfy D=B×(1−FF).

[0008] The optical waveguide mold of the present invention is an optical waveguide mold for manufacturing an optical waveguide, which is formed of a transparent substrate and a resin formed on the surface of the transparent substrate, and which comprises a transfer section for transferring light, an incident section for making light incident on the transfer section, and an emission section for making the light exit from the transfer section, and has a flat transfer section pattern for forming the transfer section in the resin, an incident section pattern for forming the incident section in the resin, and an emission section pattern for forming the emission section in the resin, and the depth of a recess in the incident section pattern is set to B. １ , the fill factor of the convex part is FF １ and the depth of the recess of the pattern for the emission part is B ２ , the fill factor of the convex part is FF ２ The difference between the height of the pattern for the incident part and the height of the pattern for the transfer part is D １ The difference between the height of the pattern for the emission part and the height of the pattern for the transfer part is D ２ Then, the following formula: 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B１ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) is satisfied.

[0009] In this case, D １ =D ２ Also, B １ -D １ =B ２ -D ２ may be.

[0010] Also, D １ =B １ × (1-FF １ ) D ２ =B ２ × (1-FF ２ ) is preferably satisfied.

[0011] Further, the optical waveguide mold of the present invention is an optical waveguide mold for manufacturing an optical waveguide, which is formed of a transparent substrate and a resin formed on the surface of the transparent substrate, and which comprises a first transfer section and a second transfer section for transferring light, an incident section for making light incident on the first transfer section, an expansion section disposed between the first transfer section and the second transfer section for controlling the light incident from the first transfer section and outputting it to the second transfer section in order to expand an exit pupil, and an output section for outputting the light from the second transfer section, and which has a flat first transfer section pattern for forming the first transfer section in the resin, a flat second transfer section pattern for forming the second transfer section in the resin, an incident section pattern for forming the incident section in the resin, an output section pattern for forming the output section in the resin, and an output section pattern for forming the output section in the resin, and １ , the fill factor of the convex part is FF １ , the depth of the recess of the pattern for the emission part is B ２ , the fill factor of the convex part is FF ２ , the depth of the recess of the pattern for the enlarged portion is B ３ , the fill factor of the convex part is FF３ , the difference D between the height of the pattern for the incident portion and the height of the pattern for the first transfer portion １ , the difference D between the height of the pattern for the emission part and the height of the pattern for the second transfer part ２ , the difference D between the height of the pattern for the enlarged portion and the height of the pattern for the first transfer portion or the pattern for the second transfer portion ３ is calculated using the following formula: 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B １ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) 0.9 x B ３ × (1-FF ３ ) ≦D ３ ≦1.1×B ３ × (1-FF ３ ) is satisfied.

[0012] In this case, D １ =D ２ =D ３ Also, B １ -D １ =B ２ -D ２ =B ３ -D ３ may be.

[0013] Also, D １ =B １ × (1-FF １ ) D ２ =B ２ × (1-FF ２ ) D ３ =B ３ × (1-FF ３ ) is preferably satisfied.

[0014] The method for producing an optical waveguide of the present invention is characterized in that imprint molding is carried out using the above-mentioned mold for an optical waveguide.

[0015] The refractive index of the resin is preferably 1.8 or more.

[0016] Furthermore, it is preferable that the imprint molding is performed so that the thickness of the residual resin film formed by at least one of the incident portion pattern, the emission portion pattern, and the expansion portion pattern is 100 nm or less.

[0017] The optical waveguide of the present invention is an optical waveguide comprising a transparent substrate and a resin formed on the surface of the transparent substrate, the optical waveguide comprising: a transfer section for transferring light, the transfer section being made of the transparent substrate and resin formed flat on the surface of the transparent substrate; an incident section for making light incident on the transfer section, the resin being formed as a grating pattern on the surface of the transparent substrate; and an exit section for emitting the light from the transfer section, the resin being formed as a grating pattern on the surface of the transparent substrate, １ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ , the height of the convex portion of the grating pattern of the emission portion is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ Then, the thickness t of the resin in the transfer portion is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ ) is satisfied.

[0018] In this case, d １ = d ２ Also, b １ +d １ = b ２ +d ２ may be.

[0019] Also, t = d １ +b １ ×ff １ = d２ +b ２ ×ff ２ It is preferable to satisfy the following.

[0020] Further, an optical waveguide of the present invention is an optical waveguide comprising a transparent substrate and a resin formed on the surface of the transparent substrate, the optical waveguide comprising: a first transfer section and a second transfer section for transferring light, the first transfer section and the second transfer section being made of the transparent substrate and the resin formed flat on the surface of the transparent substrate; an incident section made of resin formed as a grating pattern on the surface of the transparent substrate for making light incident on the first transfer section; an expansion section disposed between the first transfer section and the second transfer section, the expansion section being made of resin formed as an expansion pattern on the surface of the transparent substrate for controlling the light incident from the first transfer section and outputting it to the second transfer section in order to expand an exit pupil; and an exit section made of resin formed as a grating pattern on the surface of the transparent substrate for outputting the light from the second transfer section, １ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ , the height of the convex portion of the grating pattern of the emission portion is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ , the height of the convex portion of the expansion pattern of the expansion portion is b ３ , the fill factor of the convex part is ff ３ , the thickness of the remaining film is d ３ Then, the thickness t of the resin in the first transfer section and the second transfer section is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ ) 0.9 × (d ３ +b ３ ×ff ３ ) ≦t≦1.1 × (d ３ +b３ ×ff ３ ) is satisfied.

[0021] In this case, d １ = d ２ = d ３ Also, b １ +d １ = b ２ +d ２ = b ３ +d ３ may be.

[0022] Also, t = d １ +b １ ×ff １ = d ２ +b ２ ×ff ２ = d ３ +b ３ ×ff ３ It is preferable to satisfy the following.

[0023] The refractive index of the resin is preferably 1.8 or more.

[0024] Furthermore, it is preferable that the thickness of the remaining film of at least one of the grating patterns of the incident portion and the exit portion and the expansion pattern of the expansion portion is 100 nm or less.

[0025] It is possible to provide a waveguide with small undulations in the transfer section and small residual films in the incident section and the exit section, an optical waveguide mold for manufacturing the waveguide, and a method for manufacturing the optical waveguide.

[0026] 1 is a schematic cross-sectional view showing the configuration of an optical waveguide; FIG. 2 is a diagram showing the relationship between the refractive index of a substrate and diffraction efficiency; FIG. 3 is a diagram showing the relationship between the thickness of a residual film and diffraction efficiency; FIG. 4 is a diagram showing a method for manufacturing an optical waveguide using a conventional mold; FIG. 5 is a diagram showing a method for manufacturing another optical waveguide using a conventional mold; FIG. 6 is a diagram showing the state of a flat portion of an optical waveguide manufactured using a conventional mold; FIG. 7 is a diagram showing a method for manufacturing yet another optical waveguide using a conventional mold; FIG. 8 is a schematic cross-sectional view showing a method for manufacturing an optical waveguide of the present invention; FIG. 9 is a diagram for explaining filling of resin due to mold deflection; FIG. 10 is a diagram explaining conditions for filling that leaves voids due to deflection; FIG. 11 is a diagram explaining the limit value for mold deflection due to pressure; FIG. 12 is a diagram showing filling conditions for a mold when the flat portion length is 3 mm; FIG. 13 is a diagram showing filling conditions for a mold when the flat portion length is 2 mm; FIG. 14 is a schematic cross-sectional view showing a method for manufacturing an optical waveguide of the present invention; FIG. 15 is a schematic perspective view showing an optical waveguide having an enlarged portion of the present invention; FIG. 16 is a schematic cross-sectional view showing a method for manufacturing an optical waveguide of the present invention; FIG. 17 is a schematic cross-sectional view showing a method for manufacturing an optical waveguide of the present invention;

[0027] 1, the optical waveguide is made up of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4. The optical waveguide is mainly made up of a transfer section 1, an incident section 2, and an exit section 3.

[0028] The transfer unit 1 is for transferring light and is made up of a transparent substrate 4 and a resin 5 formed flat on the surface of the transparent substrate 4. Light incident from the incident unit 2 is transferred while being totally reflected by the transfer unit 1 and is emitted from the exit unit 3.

[0029] The incident section 2 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to allow light to be incident on the transfer section 1. The grating pattern may have any shape as long as it can allow light to be incident on the transfer section 1. For example, it can be a pattern that can diffract light so that it travels through the transfer section 1 by total reflection, and can be a line-and-space pattern in which inclined convex sections are periodically arranged.

[0030] The emission section 3 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to emit light from the transfer section 1. The grating pattern may have any shape as long as it can emit light from the transfer section 1, but for example, it can be a pattern that can diffract light so that it is emitted to the outside from the transparent substrate 4, and can be a line-and-space pattern in which inclined convex portions are periodically arranged.

[0031] A simulation was performed on this type of optical waveguide. The pitch of the grating pattern at the entrance was 420 nm, the height of the inclined convex portions was 350 nm, the width was 210 nm, and the angle was 55 degrees. The wavelength of the incident light was 630 nm. Figure 2 shows the relationship between the angle of incidence and the diffraction efficiency of the entrance portion 2 for each refractive index of the transparent substrate 4. As shown in Figure 2, it can be seen that the higher the refractive index, the higher the diffraction efficiency can be obtained at a wider angle of incidence. For this reason, a high refractive index material is required for the optical waveguide. Specifically, it is preferable that the refractive index of the transparent substrate 4 and resin 5 be 1.8 or higher.

[0032] Furthermore, when the grating pattern is created using the imprinting method, a residual film 51 is left under the pattern. If there were no difference in refractive index between the transparent substrate 4 and the resin 5, there would be no effect of the residual film. However, currently, the refractive index of the substrate is higher than that of the resin 5, with the substrate's refractive index being 2.0 and the resin 5's refractive index being 1.9, a difference of approximately 0.1. Furthermore, the relationship between the refractive indices of the substrate and the resin 5 is expected to remain such that the refractive index of the substrate is higher than that of the resin 5, even if the refractive index of the materials improves in the future. Therefore, we performed a simulation to determine how the thickness of the residual film 51 affects the diffraction efficiency of the incident portion 2 when the grating pattern at the incident portion 2 has a residual film 51. The pitch of the grating pattern at the incident portion was 420 nm, and the height, width, and angle of the inclined convex portion were 350 nm, 210 nm, and 55°, respectively. The wavelength of the incident light was 630 nm. The refractive indices of the substrate, resin 5, and residual film 51 thickness used in the simulation are shown in Table 1 and Figure 3(a). The results are shown in Figure 3(b).

[0033] Simulation results showed that when a grating pattern with a refractive index of 1.9 was placed on a substrate with a refractive index of 2.0, an incident angle of ±30° was obtained. However, it was found that as the residual film 51 becomes thicker, the efficiency on the wide-angle side decreases, so it is preferable to keep the residual film 51 to 30 nm or less. Furthermore, the simulation also confirmed that when the refractive index of the resin 5 increases to 1.95, the efficiency on the wide-angle side can be maintained if the residual film 51 is 100 nm or less.

[0034] Here, we will consider the case where the grating patterns of the incident portion 2 and the exit portion 3 of the optical waveguide and the flat portion of the transfer portion 1 are molded in resin 5 on a transparent substrate 4 by imprinting. As shown in Figure 4, the optical waveguide mold 6 used in the imprinting method is mainly composed of a transfer portion pattern 61 and at least one or both of an incident portion pattern 62 and an exit portion pattern 63. The material of the optical waveguide mold 6 may be any material that can be used in the imprinting method, and for example, glass or resin can be used.

[0035] The transfer portion pattern 61 is a flat pattern for forming the flat portion of the transfer portion 1 in the resin 5 .

[0036] The incident portion pattern 62 is used to form the incident portion 2 in the resin 5. The incident portion pattern 62 may be of any type as long as it can form the incident portion 2 in the resin 5, but for example, it may be a pattern that is an inversion of the grating pattern of the incident portion 2 described above.

[0037] The pattern 63 for the emission portion is used to form the emission portion 3 in the resin 5. The pattern 63 for the emission portion may be any pattern as long as it can form the emission portion 3 in the resin 5, but for example, it may be a pattern that is an inversion of the grating pattern of the emission portion 3 described above.

[0038] 4(a) is a diagram showing the state of the resin 5 during molding when the thickness of the resin 5 applied to the transparent substrate 4 before imprint molding is thick. If the thickness of the resin 5 before molding is thick, when the resin 5 is pressed by the optical waveguide mold 6, the resin 5 tends to move laterally from the grating pattern side to the flat portion side as shown in FIGS. 4(b) and 4(c), making molding possible, but the residual film 51 becomes thick as shown in FIG. 4(d).

[0039] Conversely, Figure 5(a) is a diagram showing the state of the resin 5 during molding when the film thickness of the resin 5 applied to the transparent substrate 4 before imprint molding is thin. If the film thickness of the resin 5 before molding is thin, when the resin 5 is pressed by the optical waveguide mold 6, it becomes difficult for the resin 5 to move laterally from the grating pattern side to the flat portion side, as shown in Figures 5(b) and (c), and voids 9 remain after molding, causing undulations in the flat portion, as shown in Figures 5(d) and 6.

[0040] 7(a) is a diagram showing the state of resin 5 during molding when the voids in transfer pattern 61 of optical waveguide mold 6 are eliminated so that no voids 9 remain after molding. If the voids in transfer pattern 61 of optical waveguide mold 6 are eliminated, when resin 5 is pressurized by optical waveguide mold 6, resin 5 moves laterally from the transfer pattern 61 side to the grating pattern side, as shown in FIGS. 7(b) and (c), and therefore the residual film 51 of the grating pattern becomes thicker after molding, as shown in FIG. 7(d).

[0041] Therefore, in view of the above, if it is desired to thin the residual film 51 of the grating pattern, it is desirable to form the transfer section 1, the incident section 2 and the exit section 3 in a manner that minimizes lateral movement of the resin 5 when pressurizing the resin 5 with the optical waveguide mold 6.

[0042] Therefore, the following describes the optical waveguide mold 6 of the present invention, which is less likely to cause lateral movement of the resin 5 when the resin 5 is pressurized by the optical waveguide mold 6. The optical waveguide mold 6 of the present invention is formed from a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and is used to manufacture an optical waveguide comprising a transfer section 1 for transferring light, an incident section 2 for making light incident on the transfer section 1, and an exit section 3 for making the light exit from the transfer section 1. As described above, the optical waveguide mold 6 is mainly composed of a transfer section pattern 61 and at least one or both of an incident section pattern 62 and an exit section pattern 63. The material of the optical waveguide mold 6 may be any material that can be used for imprinting, and well-known materials such as glass can be used, for example.

[0043] Here, in order to prevent lateral movement of the resin 5 when pressurizing the resin 5 with the optical waveguide mold 6, it is sufficient to balance the volume per unit space of the voids (recesses) in the incident portion pattern 62 or the emission portion pattern 63 with the voids in the transfer portion pattern 61 adjacent to the incident portion pattern 62 or the emission portion pattern 63. Specifically, as shown in Figure 8(a), if the pitch of the incident portion pattern 62 or the emission portion pattern 63 is P, the depth of the recesses is B, the fill factor of the protrusions is FF, and the difference in height between the incident portion pattern 62 or the emission portion pattern 63 and the transfer portion pattern 61 is D, then it is preferable that P x D = P x B x (1 - FF), i.e., D = B x (1 - FF).

[0044] Here, the fill factor of the convex portion refers to the ratio of the area of ​​the convex portion to the area of ​​the pattern surface (hereinafter referred to as the pattern surface) on which the incident portion pattern 62, the emission portion pattern 63, etc. of the optical waveguide mold 6 are located. Furthermore, the depth of the concave portion refers to the height of the top of the convex portion relative to the bottom of the concave portion. If the depth of the concave portions of the pattern varies, the average depth of the entire concave portions of each pattern may be used. Furthermore, the difference in height between the incident portion pattern 62 or the emission portion pattern 63 and the transfer portion pattern 61 refers to the height of the top of the convex portion of the incident portion pattern 62 or the emission portion pattern 63 relative to the flat surface of the transfer portion pattern 61, as shown in FIG. 8( a).

[0045] Even if D = B × (1 - FF) is not satisfied and the volume per unit space of the voids described above is not balanced, it is possible to mold the optical waveguide mold 6 by bending it convexly toward the resin 5 or the opposite side, provided there is a small error. Specifically, as shown in Figure 9(a), the resin 5 at the bottom of the incident portion pattern 62 and the emission portion pattern 63 moves when pressure is applied, spreading the filling area near the patterns, and narrowing the void 9 in the transfer portion pattern 61. When further pressure is applied, the optical waveguide mold 6 bends, pushing the resin 5 to the periphery, as shown in Figure 9(b). At this time, if the bending of the optical waveguide mold 6 is small, void 9 remains, but if there is sufficient bending, the resin 5 pushed from the center can fill the surrounding voids, as shown in Figure 9(c).

[0046] Therefore, it is preferable that the error in volume per unit space between voids be at least 10% or less. In this case, it is sufficient to satisfy the following formula: 0.9×B×(1-FF)≦D≦1.1×B×(1-FF). Of course, the smaller the error, the better, preferably 5% or less, and more preferably 3% or less.

[0047] As a result, when the resin 5 is pressurized by the optical waveguide mold 6, as shown in Figures 8(b) and 8(c), there is almost no lateral movement of the resin 5. Therefore, as shown in Figure 8(d), it is possible to make the remaining film 51 of the grating pattern after molding thin, and to give the transfer section 1 a good shape without undulations or voids 9.

[0048] Let us now consider the conditions under which molding can be performed without leaving voids 9 due to bending of the optical waveguide mold 6. First, as shown in Figure 10, let Y be the area where the resin 5 is pushed aside when the optical waveguide mold 6 bends, and Z be the area of ​​the gap at the end of the optical waveguide mold 6 after it has bent. If the radius of curvature of the bending is approximated as R, the maximum depth when the resin 5 is pushed aside is x, the height of the gap is s', the angle from the vertical line to the boundary point between the resin 5 and the gap is α, and the angle from the vertical line to the point of maximum height of the gap is θ, then Y=R ２ (α-cos α sin α) *Area αR of a sector with radius R and angle 2α ２ and the area R of a triangle whose height is R cos α and whose base length is 2R sin α. ２ Difference from cosα sinα *cosα=cosθ+(s' / R) Z≒s'(a-Rsinα) / 2 *Area of ​​a triangle with a base length of a-Rsinα and a height of s'. Here, the condition for filling without leaving any voids due to the bending of the optical waveguide mold 6 is when Y=2Z, so the following formula (1) is established. R ２ (α-cosαsinα)=s'(a-Rsinα)...Formula (1)

[0049] Furthermore, the limit value of the deflection of the optical waveguide mold 6 due to pressure is given by the following formula (2) when the radius of curvature is R', the length of the beam is L, and the magnitude of deflection in the vertical direction is δ, based on a model of a doubly supported beam to which a uniform pressure p is applied, as shown in Figure 11: R' = (L / 2) ２ / (2δ)...Formula (2) *δ=5pL ４ / (384EI) I=g ３ / 12 E: Young's modulus of the optical waveguide mold g: Thickness of the optical waveguide mold

[0050] Therefore, the mold can be bent until the gap is completely filled only when the curvature radius R of the filling condition is equal to or greater than the curvature radius R' that bends under pressure (R≧R'). However, the coating thickness t must be thicker than the beam indentation depth χ for filling to occur.

[0051] 12 is a diagram showing the relationship between the height s' of the gap 9 between the resin 5 and the optical waveguide mold 6, calculated based on formula (1), and the radius of curvature R due to the deflection of the optical waveguide mold 6 required to fill the resin 5 without leaving any gaps. The dashed lines (1) to (5) in Fig. 12 indicate the value of the radius of curvature R' calculated based on formula (2) from the differential pressure applied to both sides of the optical waveguide mold 6 during imprint molding and the thickness of the optical waveguide mold 6. The thickness g of the transfer portion pattern 61 of the optical waveguide mold and the pressure p are as follows: Dashed line (1) g: 0.7 mm, p: 0.25 MPa Dashed line (2) g: 0.7 mm, p: 0.5 MPa Dashed line (3) g: 0.7 mm, p: 0.75 MPa Dashed line (4) g: 0.5 mm, p: 0.25 MPa Dashed line (5) g: 0.5 mm, p: 0.5 MPa The width L of the transfer portion pattern 61 of the optical waveguide mold was 3 mm. The material of the optical waveguide mold was glass with a Young's modulus E of 73.6 GPa.

[0052] Since the radius of curvature R' is proportional to the cube of the thickness α of the transfer portion pattern 61 of the waveguide mold, by changing the thickness α from 0.7 mm to 0.5 mm, a bending with a radius of curvature sufficient for filling by pressure can be achieved.

[0053] We also investigated a case where the width L of the transfer pattern 61 of the optical waveguide mold was set to 2 mm. Figure 13 shows the relationship between the height s' of the gap between the resin 5 and the optical waveguide mold 6, calculated based on equation (1), and the radius of curvature R due to the deflection of the optical waveguide mold 6 required to fill the resin 5 without leaving any gaps. The dashed lines (1) to (4) in Figure 13 indicate the value of the radius of curvature R' calculated based on equation (2) from the differential pressure applied to both sides of the optical waveguide mold 6 during imprint molding and the thickness of the optical waveguide mold 6. The thickness g of the transfer pattern 61 of the optical waveguide mold and the pressure p are as follows: Dashed line (1) g: 0.7 mm, p: 0.75 MPa Dashed line (2) g: 0.7 mm, p: 1.5 MPa Dashed line (3) g: 0.7 mm, p: 2 MPa Dashed line (4) g: 0.7 mm, p: 0.1 MPa The material of the optical waveguide mold was glass with a Young's modulus E of 73.6 GPa for dashed lines (1) to (3), and polyethylene terephthalate (PET) with a Young's modulus E of 4 GPa for dashed line (4).

[0054] As shown in Figure 13, when the width L is set to 2 mm, the optical waveguide mold must bend more to fill the gaps without creating gaps, making filling even more difficult. Even with a pressure of 2 MPa, filling is only possible if the gaps are 50 nm or less, making filling by deflection alone nearly impossible. Therefore, it is important to balance the volume per unit space between the gaps (recesses) in the incident pattern 62 or the exit pattern 63 and the gaps in the transfer pattern 61 adjacent to the incident pattern 62 or the exit pattern 63. Note that, to ensure filling, the required coating thickness t is 27 nm or greater for a 50 nm gap, so there is little need to consider the effect of the coating thickness t.

[0055] Next, a method for manufacturing an optical waveguide of the present invention will be described with reference to Fig. 8. The method for manufacturing an optical waveguide of the present invention is a method for manufacturing an optical waveguide formed of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and comprising a transfer section 1 for transferring light, an incident section 2 for making light incident on the transfer section 1, and an exit section 3 for making light exit from the transfer section 1, and involves imprint molding using the optical waveguide mold 6 of the present invention described above. As described above, the optical waveguide mold 6 satisfies at least 0.9×B×(1-FF)≦D≦1.1×B×(1-FF), preferably 0.95×B×(1-FF)≦D≦1.05×B×(1-FF), and more preferably 0.97×B×(1-FF)≦D≦1.03×B×(1-FF), where P is the pitch of the incident portion pattern 62 or the emission portion pattern 63, B is the depth of the recesses, FF is the fill factor of the protrusions, and D is the depth of the transfer portion pattern 61 adjacent to the incident portion pattern 62 or the emission portion pattern 63. Most preferably, one that satisfies D=B×(1-FF) is used.

[0056] First, resin 5 is applied to the surface of transparent substrate 4. The resin 5 may be any transparent resin that can be used in imprint molding, such as a photocurable resin, a thermosetting resin, or a thermoplastic resin. Specifically, an acrylic photocurable resin can be used. The resin 5 can be applied to the transparent substrate 4 by a well-known method such as a spin coater. The refractive index of resin 5 is preferably 1.8 or higher.

[0057] Next, at least one or both of the incident portion 2 and the exit portion 3 constituting the grating pattern and the transfer portion 1 constituting the flat surface are transferred to the photocurable resin by an imprinting method using an optical waveguide mold 6. Specifically, as shown in Figures 8(b) and 8(c), the optical waveguide mold 6 is pressed against the fluid resin 5 on the transparent substrate 4, and the resin 5 is filled into the transfer portion pattern 61, the incident portion pattern 62, and the exit portion pattern 63. At this time, it is preferable to pressurize the optical waveguide mold 6 until the thickness d of the residual film 51 of the resin 5 is 100 nm or less, preferably 30 nm or less. Here, the residual film 51 refers to the thinnest portion of the resin for the grating pattern of the incident portion 2 formed by the incident portion pattern 62 or the grating pattern of the exit portion 3 formed by the exit portion pattern 63.

[0058] Thereafter, the resin 5 is solidified and released from the mold as shown in FIG. 8(d), thereby completing the manufacture of the optical waveguide of the present invention.

[0059] Next, the optical waveguide of the present invention manufactured in this manner will be described. The optical waveguide of the present invention comprises a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4. The optical waveguide is mainly composed of an input section 2, an output section 3, and a transfer section 1.

[0060] The transfer unit 1 is for transferring light and is made up of a transparent substrate 4 and a resin 5 formed flat on the surface of the transparent substrate 4. Light incident from the incident unit 2 is transferred while being totally reflected by the transfer unit 1 and is emitted from the exit unit 3.

[0061] The incident section 2 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to allow light to be incident on the transfer section 1. The grating pattern may have any shape as long as it can allow light to be incident on the transfer section 1. For example, it can be a pattern that can diffract light so that it travels through the transfer section 1 by total reflection, and can be a line-and-space pattern in which inclined convex sections are periodically arranged.

[0062] The emission section 3 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to emit light from the transfer section 1. The grating pattern may have any shape as long as it can emit light from the transfer section 1, but for example, it can be a pattern that can diffract light so that it is emitted to the outside from the transparent substrate 4, and can be a line-and-space pattern in which inclined convex portions are periodically arranged.

[0063] The transparent substrate 4 is a base portion for forming a pattern on the flat portion of the transfer portion 1 and the resin 5 of the incident portion 2 and the exit portion 3. It also serves to transfer light incident from the incident portion 2 to the exit portion 3. Any material may be used as long as it can transfer light from the incident portion 2 to the exit portion 3, and glass, for example, can be used. Furthermore, from the results of the above-mentioned simulation, the refractive index of the transparent substrate 4 is preferably 1.8 or higher, more preferably 1.9 or higher, and even more preferably 2.0 or higher.

[0064] The resin 5 is used to form the patterns of the incident portion 2, the exit portion 3, and the transfer portion 1. Any material may be used as long as it can form the patterns of the transfer portion 1, the incident portion 2, and the exit portion 3. Furthermore, based on the results of the above-mentioned simulation, the refractive index of the transparent substrate 4 and the resin 5 is preferably 1.8 or more, more preferably 1.9 or more, and even more preferably 1.95 or more.

[0065] Furthermore, the optical waveguide of the present invention is preferably formed so that, where b is the height of the convex portion of the grating pattern of the input section 2 or output section 3, ff is the fill factor of the convex portion, d is the thickness of the residual film 51, and t is the thickness of the resin 5 of the transfer section 1 adjacent to the grating pattern, the following relationship holds: at least 0.9 × (d + b × ff) ≦ t ≦ 1.1 × (d + b × ff), preferably 0.95 × (d + b × ff) ≦ t ≦ 1.05 × (d + b × ff), and more preferably 0.97 × (d + b × ff) ≦ t ≦ 1.03 × (d + b × ff). Most preferably, when t = d + b × ff, the transfer section 1 has a good shape with minimal waviness and voids 9. The fill factor of the convex portion means the ratio of the area of ​​the convex portion to the area of ​​the pattern surface. The fill factor ff of the convex portions of the grating pattern of the incident portion 2 or the exit portion 3 of the optical waveguide is basically the same as the fill factor (1-FF) of the concave portions of the incident portion pattern 62 or the exit portion pattern 63. The depth D of the transfer portion pattern 61 refers to the difference in height between the flat surface of the transfer portion pattern 61 and the height of the apex of the convex portion of the incident portion pattern 62 or the exit portion pattern 63, as shown in FIG.

[0066] Furthermore, the thickness d of the remaining film 51 of the grating pattern at the entrance portion 2 and the exit portion 3 is preferably 100 nm or less, more preferably 30 nm or less, since this improves the diffraction efficiency on the wide angle side.

[0067] In the above description, the optical waveguide mold 6 has been described in which the depth B of the incident portion pattern 62 and the emission portion pattern 63 are the same, and the difference D between the height of the incident portion pattern 62 or the emission portion pattern 63 and the height of the transfer portion pattern 61 is also the same, but these may be different. In this case, the optical waveguide mold 6 is formed of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and is used to manufacture an optical waveguide consisting of a transfer portion 1 for transferring light, an incident portion 2 for making light incident on the transfer portion 1, and an emission portion 3 for making light exit from the transfer portion 1, and is composed of a flat transfer portion pattern for forming the transfer portion 1 in the resin 5, an incident portion pattern for forming the incident portion 2 in the resin 5, and an emission portion pattern for forming the emission portion 3 in the resin 5. In addition, the optical waveguide mold 6 has a depth B of the recess of the incident portion pattern. １ , the fill factor of the convex part is FF １ The depth of the recess of the pattern for the emission part is B ２ , the fill factor of the convex part is FF ２ The difference between the height of the pattern for the incident part and the height of the pattern for the transfer part is D １ The difference between the height of the pattern for the emission part and the height of the pattern for the transfer part is D ２ Then, the following formula: 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B １ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) is satisfied. In this formula, an error of ±10% is allowed, but of course, the smaller the error, the better, preferably 5% or less, and more preferably 3% or less.

[0068] When imprint molding is performed using the optical waveguide mold 6, the manufactured optical waveguide is made up of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and has a transfer section 1 for transferring light, which is made up of the transparent substrate 4 and the resin 5 formed flat on the surface of the transparent substrate 4, an incident section 2 for making light incident on the transfer section 1, which is made up of the resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and an exit section 3 for emitting light from the transfer section 1, which is made up of the resin 5 formed as a grating pattern on the surface of the transparent substrate 4. In addition, when the height of the convex portion of the grating pattern of the incident section 2 is set to b １ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ , the height of the convex portion of the grating pattern of the emission section 3 is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ Then, the thickness t of the resin 5 of the transfer section 1 is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ )

[0069] FIG. 14 shows that the positions of the tops of the incident part pattern 62 and the emission part pattern 63 are aligned with the flat surface of the transfer part pattern 61 of the optical waveguide mold 6 (D １ =D ２ 10 is a schematic cross-sectional view showing a manufacturing process of an optical waveguide when the positions of the bottoms of the incident portion pattern 62 and the exit portion pattern 63 of the optical waveguide mold 6 are different.

[0070] In this case, as shown in FIG. 14(d), the thickness of the remaining film of the grating pattern in the incident part 2 and the outgoing part 3 of the manufactured optical waveguide is the same (d １ = d ２), but the height b of the convex part of the grating pattern of the incident part 2 １ and the height b of the convex portion of the grating pattern of the emission section 3 ２ will be different.

[0071] 15, the positions of the bottoms of the incident part pattern 62 and the emission part pattern 63 are aligned with the flat surface of the transfer part pattern 61 of the optical waveguide mold 6 (B １ -D １ =B ２ -D ２ 10 is a schematic cross-sectional view showing a manufacturing process of an optical waveguide when the positions of the apexes of the pattern 62 for the incident portion and the pattern 63 for the emission portion of the optical waveguide mold 6 are different.

[0072] In this case, as shown in FIG. 15(d), the positions of the tops of the grating patterns of the incident part 2 and the outgoing part 3 of the manufactured optical waveguide are the same (b １ +d １ = b ２ +d ２ ), but the thickness of the remaining film of the grating pattern at the entrance part 2 and the exit part 3 is different.

[0073] The optical waveguide mold 6 is １ =B １ × (1-FF １ ) D ２ =B ２ × (1-FF ２ ) is satisfied, the resin 5 is least likely to move laterally, which is preferable.

[0074] In this case, the manufactured optical waveguide has a thickness t of the resin 5 of the transfer section 1 that satisfies the following formula: t=d １ +b １ ×ff １ = d ２ +b ２ ×ff ２ = d ３ +b ３ ×ff ３ It will satisfy the following.

[0075] The thickness d of the grating pattern of the incident part 2 and the outgoing part 3 １ , d ２It is preferable that the thickness is 100 nm or less because this improves the diffraction efficiency on the wide-angle side. Here, the residual film 51 means the portion where the resin is thinnest for the grating pattern of the incident portion 2 formed by the pattern for the incident portion 62 and the grating pattern of the exit portion 3 formed by the pattern for the exit portion 63. １ , d ２ Preferably, either or both of the above is 100 nm or less, more preferably 30 nm or less.

[0076] The optical waveguide may also have an expansion section 7 for expanding the exit pupil, as shown in Fig. 16. In this case, the optical waveguide 8A is made of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and is mainly composed of a first transfer section 1A, a second transfer section 1B, an incident section 2, an expansion section 7, and an exit section 3, as shown in Fig. 17(d).

[0077] The first transfer section 1A and the second transfer section 1B are made of a transparent substrate 4 and a resin 5 formed flat on the surface of the transparent substrate 4, and are used to transfer light. Light incident from the incident section 2 is transferred to the magnifying section 7 while being totally reflected by the first transfer section 1A. Light incident from the magnifying section 7 is transferred to the second transfer section 1B while being totally reflected, and is emitted from the exit section 3.

[0078] The incident section 2 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to allow light to be incident on the first transfer section 1A. The grating pattern may have any shape as long as it can allow light to be incident on the first transfer section 1A. For example, it can be a line-and-space pattern in which inclined convex sections are periodically arranged, and can diffract light so that it travels through the first transfer section 1A by total reflection.

[0079] The emission section 3 is made of resin 5 formed as a grating pattern on the surface of the transparent substrate 4, and is used to emit light from the second transfer section 1B. The grating pattern may have any shape as long as it can emit light from the second transfer section 1B, but for example, it can be a line-and-space pattern in which inclined convex portions are periodically arranged, and can diffract light so that it is emitted to the outside from the transparent substrate 4.

[0080] The expansion section 7 is disposed between the first transfer section 1A and the second transfer section 1B and is made of resin 5 formed as an expansion pattern on the surface of the transparent substrate 4. The expansion pattern controls the light incident from the first transfer section 1A and outputs it to the second transfer section 1B to expand the exit pupil. The expansion pattern may have any shape as long as it can control the light incident from the first transfer section 1A and output it to the second transfer section 1B to expand the exit pupil. For example, the expansion pattern can be a line-and-space grating pattern with periodically arranged convex portions, which can replicate the light incident from the first transfer section 1A and expand the exit pupil. In this case, the pitch of the convex portions of the expansion pattern may be 1 / √2 times the grating pattern of the entrance section 2 and the exit section 3.

[0081] The transparent substrate 4 is a base portion for forming patterns on the flat portions of the first transfer section 1A and the second transfer section 1B and on the resin 5 of the incident section 2 and the exit section 3. It also serves to transfer light incident from the incident section 2 to the exit section 3. Any material may be used as long as it can transfer light from the incident section 2 to the exit section 3, and glass, for example, can be used. Furthermore, from the results of the above-mentioned simulation, the refractive index of the transparent substrate 4 is preferably 1.8 or higher, more preferably 1.9 or higher, and even more preferably 2.0 or higher.

[0082] The resin 5 is used to form the patterns of the incident section 2, the exit section 3, the magnification section 7, the first transfer section 1A, and the second transfer section 1B. Any material may be used as long as it can form the patterns of the transfer section 1, the incident section 2, and the exit section 3. Furthermore, based on the results of the above-mentioned simulation, the refractive index of the transparent substrate 4 and the resin 5 is preferably 1.8 or higher, more preferably 1.9 or higher, and even more preferably 1.95 or higher.

[0083] 17(a), the optical waveguide mold 6A for manufacturing an optical waveguide having this enlarged portion 7 is mainly composed of a first transfer portion pattern 61A, a second transfer portion pattern 61B, an incident portion pattern 62A, an exit portion pattern 63A, and an enlarged portion pattern 67. Any material that can be used for imprinting may be used as the material for the optical waveguide mold 6A, and well-known materials such as glass can be used.

[0084] The first transfer part pattern 61A is a flat pattern for forming the flat part of the first transfer part 1A in the resin 5. The second transfer part pattern 61B is a flat pattern for forming the flat part of the second transfer part 1B in the resin 5.

[0085] The incident portion pattern 62A is used to form the incident portion 2 in the resin 5. The incident portion pattern 62 may be of any type as long as it can form the incident portion 2 in the resin 5, but for example, it may be a pattern that is an inverted version of the grating pattern of the incident portion 2 described above.

[0086] The pattern 63A for the emission portion is used to form the emission portion 3 in the resin 5. The pattern 63 for the emission portion may be any pattern as long as it can form the emission portion 3 in the resin 5, but for example, it may be a pattern that is an inversion of the grating pattern of the emission portion 3 described above.

[0087] The pattern 67 for the enlarged portion is used to form the enlarged portion 7 in the resin 5. The pattern 67 for the enlarged portion may be any pattern as long as it can form the enlarged portion 7 in the resin 5, but for example, it may be a pattern that is an inverted version of the pattern for enlarging the enlarged portion 3 described above.

[0088] Here, in order to prevent lateral movement of the resin 5 when pressurizing the resin 5 with the optical waveguide mold 6A, it is sufficient that the volumes per unit space of the gaps (recesses) of the incident portion pattern 62A and the enlarged portion pattern 67, the gaps of the first transfer portion pattern 61A adjacent to the incident portion pattern 62A and the enlarged portion pattern 67, and the gaps of the emission portion pattern 63A and the second transfer portion pattern 61B adjacent to the enlarged portion pattern 67 are balanced. Specifically, the depth of the recesses of the incident portion pattern 62A is set to B １ , the fill factor of the convex part is FF １ , the depth of the recess of the emission part pattern 63A is B ２ , the fill factor of the convex part is FF ２ , the depth of the recess of the enlarged portion pattern 67 is B ３ , the fill factor of the convex part is FF ３ , the difference D between the height of the incident part pattern 62A and the height of the first transfer part pattern 61A １ , the difference D between the height of the pattern for the emission part 63A and the height of the pattern for the second transfer part 61B ２ , the difference D between the height of the pattern 67 for the enlarged portion and the height of the pattern 61A for the first transfer portion or the pattern 61B for the second transfer portion ３ is calculated using the following formula: 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B １ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) 0.9 x B ３ × (1-FF ３ ) ≦D ３ ≦1.1×B ３ × (1-FF ３ ) is satisfied. In this formula, an error of ±10% is allowed, but of course, the smaller the error, the better, preferably 5% or less, and more preferably 3% or less.

[0089] In this case, the optical waveguide 8A manufactured by the optical waveguide mold 6A has a height of the convex portion of the grating pattern of the incident portion 2 of b１ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ , the height of the convex part of the grating pattern at the output part is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ , the height of the convex portion of the grating pattern of the enlarged portion 7 is b ３ , the fill factor of the convex part is ff ３ , the thickness of the remaining film is d ３ Then, the thickness t of the resin of the first transfer section 1A and the second transfer section 1B is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ ) 0.9 × (d ３ +b ３ ×ff ３ ) ≦t≦1.1 × (d ３ +b ３ ×ff ３ ) is satisfied.

[0090] As shown in FIG. 17(a), the optical waveguide mold 6A has the tops of the incident portion pattern 62A, the emission portion pattern 63A, and the expansion portion pattern 67 aligned with the flat surfaces of the first transfer portion pattern 61A and the second transfer portion pattern 61B (D １ =D ２ =D ３ ) but the positions of the bottoms of the incident portion pattern 62A, the exit portion pattern 63A, and the enlarged portion pattern 67 of the optical waveguide mold 6A can be different. Figure 17 is a schematic cross-sectional view showing the manufacturing process of an optical waveguide when imprint molding is performed using the optical waveguide mold 6A.

[0091] In this case, the manufactured optical waveguide 8A has the same thickness (d１ = d ２ = d ３ ), but the height b of the convex part of the grating pattern of the incident part 2 １ , the height b of the convex portion of the grating pattern of the emission section 3 ２ , the height b of the convex portion of the pattern of the enlarged portion 7 ３ will be different.

[0092] As shown in FIG. 18(a), the optical waveguide mold 6A has the bottoms of the incident portion pattern 62A, the emission portion pattern 63A, and the expansion portion pattern 67 aligned with the flat surfaces of the first transfer portion pattern 61A and the second transfer portion pattern 61B (B １ -D １ =B ２ -D ２ =B ３ -D ３ ) However, the positions of the apexes of the incident portion pattern 62A, the exit portion pattern 63A, and the expansion portion pattern 67 of the optical waveguide mold 6A may be different. Figure 18 is a schematic cross-sectional view showing the manufacturing process of an optical waveguide when imprint molding is performed using the optical waveguide mold 6A.

[0093] In this case, in the manufactured optical waveguide 8A, as shown in FIG. 18(d), the positions of the apexes of the patterns of the incident portion 2, the exit portion 3, and the expansion portion 7 are the same (b １ +d １ = b ２ +d ２ = b ３ +d ３ ), but the thickness of the remaining film of the pattern in the incident portion 2, the exit portion 3, and the expansion portion 7 will be different.

[0094] The optical waveguide mold 6A is １ =B １ × (1-FF １ ) D ２ =B ２ × (1-FF ２ ) D ３ =B ３ × (1-FF ３ ) is satisfied, the resin 5 is least likely to move laterally, which is preferable.

[0095] In this case, the manufactured optical waveguide has a thickness t of the resin 5 of the first transfer section 1A and the second transfer section 1B, which is expressed by the following formula: t=d １ +b １ ×ff １ = d ２ +b ２ ×ff ２ = d ３ +b ３ ×ff ３ It will satisfy the following.

[0096] The thickness d of the remaining film 51 of the grating patterns of the incident portion 2 and the exit portion 3 and the expansion pattern of the expansion portion 7 is １ , d ２ , d ３ , is preferably 100 nm or less, since this improves the diffraction efficiency on the wide-angle side. Here, the residual film 51 refers to the portion where the resin is thinnest for each of the grating pattern of the incident portion 2 formed by the incident portion pattern 62A, the grating pattern of the exit portion 3 formed by the exit portion pattern 63A, and the expansion pattern of the expansion portion 7 formed by the expansion portion pattern 67. １ , d ２ , d ３ It is preferable that at least one of the above, and preferably all of them, is 100 nm or less, and more preferably 30 nm or less.

[0097] REFERENCE SIGNS LIST 1 Transfer section 1A First transfer section 1B Second transfer section 2 Incident section 2A Incident section 3 Exit section 3A Exit section 4 Transparent substrate 5 Resin 6 Optical waveguide mold 6A Optical waveguide mold 7 Expanded section 8 Optical waveguide 8A Optical waveguide 9 Void 51 Residual film 61 Transfer section pattern 61A First transfer section pattern 61B Second transfer section pattern 62 Incident section pattern 62A Incident section pattern 63 Exit section pattern 63A Exit section pattern 67 Expanded section pattern

Claims

1. An optical waveguide mold for manufacturing an optical waveguide formed of a transparent substrate and a resin formed on the surface of the transparent substrate, the optical waveguide mold comprising a transfer section for transferring light, an incident section for making light incident on the transfer section, and an exit section for making the light exit from the transfer section, the optical waveguide mold having a flat transfer section pattern for forming the transfer section in the resin, and at least one or both of an incident section pattern for forming the incident section in the resin and an exit section pattern for forming the exit section in the resin, the optical waveguide mold satisfying the following formula: 0.9×B×(1-FF)≦D≦1.1×B×(1-FF), where B is the depth of the concaves in the incident section pattern or the exit section pattern, FF is the fill factor of the convex parts, and D is the difference in height between the incident section pattern or the exit section pattern and the transfer section pattern.

2. The optical waveguide mold according to claim 1, characterized in that the following relationship is satisfied: D=B×(1-FF).

3. A mold for an optical waveguide for manufacturing an optical waveguide, which is formed of a transparent substrate and a resin formed on a surface of the transparent substrate, and which comprises a transfer section for transferring light, an incident section for making light incident on the transfer section, and an exit section for making the light exit from the transfer section, the mold for an optical waveguide having a flat transfer section pattern for forming the transfer section in the resin, an incident section pattern for forming the incident section in the resin, and an exit section pattern for forming the exit section in the resin, the depth of a recess in the incident section pattern being set to B. １ , the fill factor of the convex part is FF １ The depth of the recess of the pattern for the emission part is B ２ , the fill factor of the convex part is FF ２ The difference between the height of the pattern for the incident portion and the height of the pattern for the transfer portion is D １ The difference between the height of the pattern for the emission part and the height of the pattern for the transfer part is D ２ Then, the following formula 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B １ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) A mold for an optical waveguide, 4. D １ =D ２ 4. The optical waveguide mold according to claim 3, wherein the above-mentioned satisfies the above.

5. B １ -D １ = B ２ -D ２ 4. The optical waveguide mold according to claim 3, wherein the above-mentioned satisfies the above.

6. D １ = B １ × (1-FF １ ) D ２ = B ２ × (1-FF ２ 4. The optical waveguide mold according to claim 3, wherein the above-mentioned condition is satisfied.

7. A mold for an optical waveguide for manufacturing an optical waveguide, the mold being formed of a transparent substrate and a resin formed on a surface of the transparent substrate, and comprising a first transfer section and a second transfer section for transferring light, an entrance section for making light incident on the first transfer section, an expansion section disposed between the first transfer section and the second transfer section for controlling the light incident from the first transfer section and outputting it to the second transfer section in order to expand an exit pupil, and an exit section for outputting the light from the second transfer section, the mold having a flat first transfer section pattern for forming the first transfer section in the resin, a flat second transfer section pattern for forming the second transfer section in the resin, an entrance section pattern for forming the entrance section in the resin, an output section pattern for forming the output section in the resin, and an expansion section pattern for forming the expansion section in the resin, the depth of a recess in the entrance section pattern being set to B. １ , the fill factor of the convex part is FF １ , the depth of the recess of the pattern for the emission part is B ２ , the fill factor of the convex part is FF ２ , the depth of the recess of the enlarged portion pattern is B ３ , the fill factor of the convex part is FF ３ , the difference D between the height of the pattern for the incident portion and the height of the pattern for the first transfer portion １ , the difference D between the height of the pattern for the emission part and the height of the pattern for the second transfer part ２ , the difference D between the height of the pattern for the enlarged portion and the height of the pattern for the first transfer portion or the pattern for the second transfer portion ３ is expressed by the following formula: 0.9 × B １ × (1-FF １ ) ≦D １ ≦1.1×B １ × (1-FF １ ) 0.9 x B ２ × (1-FF ２ ) ≦D ２ ≦1.1×B ２ × (1-FF ２ ) 0.9 x B ３ × (1-FF ３ ) ≦D ３ ≦1.1×B ３ × (1-FF ３ ) A mold for an optical waveguide, 8. D １ =D ２ =D ３ 8. The optical waveguide mold according to claim 7, wherein the above-mentioned satisfies the above.

9. B １ -D １ = B ２ -D ２ = B ３ -D ３ 8. The optical waveguide mold according to claim 7, wherein the above-mentioned satisfies the above.

10. D １ = B １ × (1-FF １ ) D ２ = B ２ × (1-FF ２ ) D ３ = B ３ × (1-FF ３ 8. The optical waveguide mold according to claim 7, wherein the above-mentioned condition is satisfied.

11. A method for manufacturing an optical waveguide, comprising imprint molding using the optical waveguide mold according to any one of claims 1 to 10.

12. The method for manufacturing an optical waveguide according to claim 11, wherein the refractive index of said resin is 1.8 or more.

13. A method for manufacturing an optical waveguide as described in claim 11, characterized in that the imprint molding is performed so that the thickness of the residual resin film formed by at least one of the pattern for the incident portion, the pattern for the exit portion, and the pattern for the enlarged portion is 100 nm or less.

14. An optical waveguide comprising a transparent substrate and a resin formed on a surface of the transparent substrate, comprising: a transfer section for transferring light, the transfer section being made of the transparent substrate and a resin formed flat on the surface of the transparent substrate; an entrance section for making light incident on the transfer section, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate; and an exit section for making the light exit from the transfer section, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate, the transfer section being made of a resin formed as a grating pattern on the surface of the transparent substrate, the transfer section being made of a resin formed as a grating pattern on the transfer section ... being made of a resin formed as a grating pattern on the transfer section, the transfer section being made of a resin formed as a grating pattern on the transfer section being made of a resin formed as a grating pattern on the transfer section being made of a resin formed as a grating pattern on the transfer section being made of a resin formed as a grating pattern on the transfer section being made of a resin formed as a grating pattern on the １ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ The height of the convex portion of the grating pattern of the emission portion is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ Then, the thickness t of the resin in the transfer portion is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ ) An optical waveguide characterized in that 15.d １ = d ２ 15. The optical waveguide according to claim 14, wherein the following is satisfied:

16. b １ +d １ = b ２ +d ２ 15. The optical waveguide according to claim 14, wherein the following is satisfied:

17. t=d １ +b １ ×ff １ = d ２ +b ２ ×ff ２ 15. The optical waveguide according to claim 14, wherein the following is satisfied:

18. An optical waveguide comprising a transparent substrate and a resin formed on a surface of the transparent substrate, comprising: a first transfer section and a second transfer section for transferring light, comprising the transparent substrate and a resin formed flat on the surface of the transparent substrate; an entrance section for making light incident on the first transfer section, comprising resin formed as a grating pattern on the surface of the transparent substrate; an enlargement section disposed between the first transfer section and the second transfer section, comprising resin formed as an enlargement pattern on the surface of the transparent substrate, controlling the light incident from the first transfer section to enlarge an exit pupil and outputting it to the second transfer section; and an exit section for outputting the light from the second transfer section, comprising resin formed as a grating pattern on the surface of the transparent substrate, wherein the height of the convex portion of the grating pattern of the entrance section is set to b １ , the fill factor of the convex part is ff １ , the thickness of the remaining film is d １ The height of the convex portion of the grating pattern of the emission portion is b ２ , the fill factor of the convex part is ff ２ , the thickness of the remaining film is d ２ The height of the convex portion of the enlargement pattern of the enlargement portion is b ３ , the fill factor of the convex part is ff ３ , the thickness of the remaining film is d ３ Then, the thickness t of the resin in the first transfer section and the second transfer section is calculated by the following formula: 0.9 × (d １ +b １ ×ff １ ) ≦t≦1.1 × (d １ +b １ ×ff １ ) 0.9 × (d ２ +b ２ ×ff ２ ) ≦t≦1.1 × (d ２ +b ２ ×ff ２ ) 0.9 × (d ３ +b ３ ×ff ３ ) ≦t≦1.1 × (d ３ +b ３ ×ff ３ ) An optical waveguide characterized in that 19.d １ = d ２ = d ３ 20. The optical waveguide according to claim 18, wherein the following is satisfied:

20. b １ +d １ = b ２ +d ２ = b ３ +d ３ 20. The optical waveguide according to claim 18, wherein the following is satisfied:

21. t=d １ +b １ ×ff １ = d ２ +b ２ ×ff ２ = d ３ +b ３ ×ff ３ 20. The optical waveguide according to claim 18, wherein the following is satisfied:

22. The optical waveguide according to any one of claims 14 to 21, characterized in that the refractive index of the resin is 1.8 or more.

23. An optical waveguide according to any one of claims 14 to 21, characterized in that the thickness of the residual film of at least one of the grating patterns in the incident portion and the exit portion and the expansion pattern in the expansion portion is 100 nm or less.

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