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

Abstract

The purpose of the present invention is to provide: an optical waveguide in which the ripple of a transmission section is small and the residual film of an incident section or an exit section is small; an optical waveguide mold for manufacturing the optical waveguide; and a method for manufacturing the optical waveguide. An optical waveguide mold for manufacturing an optical waveguide which is formed from a transparent substrate (4) and a resin (5) and which comprises a transmission section (1), an incidence section (2), and an emission section (3), said optical waveguide mold being provided with: a flat transmission section pattern (61) for forming the transmission section (1) in the resin (5); and one or both of an incident portion pattern 62 for forming the incident portion 2 and an exit portion pattern 63 for forming the exit portion 3, where B is the depth of the concave portion of the incident portion pattern 62 or the exit portion pattern 63, and FF is the fill factor of the convex portion, B is the depth of the concave portion of the incident portion pattern 62 or the exit portion pattern 63, and FF is the fill factor of the convex portion of the exit portion pattern 63. If D is the difference between the height of the pattern (62) for the incidence section or the pattern (63) for the emission section and the height of the pattern (61) for the transmission section, the following expression is satisfied: 0.9 * B * (1-FF) < = D < = 1.1 * B * (1-FF).

Description

Technical Field

[0001] This invention relates to a mold for an optical waveguide, a method for manufacturing an optical waveguide, and an optical waveguide. Background Technology

[0002] In waveguides for augmented reality (AR) glasses, where the market outlook is promising, there is active development of structures for high-refractive-index resin materials to achieve high field-of-view performance, and various input / output couplers to achieve high transmission efficiency and uniform image output. Optical waveguides are used in various electronic devices due to their lightweight nature and ability to transmit signals at high speeds. In recent years, imprinting, a patterning technique that replaces photolithography, has gained attention in such optical waveguides (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-207717 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, when fabricating optical waveguides using the embossing method, if the gaps in the pattern of the transmission section of the mold are large, ripples or other defects will occur in the transmission section of the waveguide, leading to decreased efficiency or color shift. Therefore, if the resin film thickness is increased to fill these gaps, the residual film under the pattern in the incident or exit section will become larger, resulting in a decrease in efficiency on the wide-angle side.

[0008] Therefore, the object of the present invention is to provide an optical waveguide with small corrugation in the transmission section and small residual film in the incident or exit section, a mold for manufacturing the optical waveguide, and a method for manufacturing the optical waveguide.

[0009] Technical means to solve the problem

[0010] To achieve the above objectives, the optical waveguide mold of the present invention is a mold for manufacturing an optical waveguide, the optical waveguide being formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and comprising: a transmission portion for transmitting light; an incident portion for incident light onto the transmission portion; and an exit portion for exiting the light from the transmission portion. The optical waveguide mold is characterized by having: a transmission portion pattern for forming the transmission portion in the resin and being flat; and at least one or both of an incident portion pattern and an exit portion pattern, wherein the incident portion pattern is used to form the incident portion in the resin, and the exit portion pattern is used to form the exit portion in the resin. If the depth of the recess in the incident portion pattern or the exit portion pattern is set to B, the fill factor of the convex portion is set to FF, and the difference between the height of the incident portion pattern or the exit portion pattern and the height of the transmission portion pattern is set to D, then the optical waveguide mold satisfies the following formula:

[0011] 0.9×B×(1-FF)≦D≦1.1×B×(1-FF).

[0012] In this case, it is preferable to satisfy D=B×(1-FF).

[0013] Furthermore, the optical waveguide mold of the present invention is a mold for manufacturing an optical waveguide, the optical waveguide being formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and comprising: a transmission section for transmitting light; an incident section for incident light onto the transmission section; and an exiting section for exiting the light from the transmission section. The optical waveguide mold is characterized by having: a transmission section pattern for forming the transmission section on the resin and being flat; an incident section pattern for forming the incident section on the resin; and an exiting section pattern for forming the exiting section on the resin. If the depth of the recess in the incident section pattern is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the recess in the exiting section pattern is set to B2 and the fill factor of the convex portion is set to FF2, the difference between the height of the incident section pattern and the height of the transmission section pattern is set to D1, and the difference between the height of the exiting section pattern and the height of the transmission section pattern is set to D2, then the optical waveguide mold satisfies the following formula:

[0014] 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1)

[0015] 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2).

[0016] In this case, D1 = D2. Alternatively, B1 - D1 = B2 - D2.

[0017] In addition, it is preferable to satisfy:

[0018] D1 = B1 × (1 - FF1)

[0019] D2 = B2 × (1 - FF2).

[0020] Furthermore, the optical waveguide mold of the present invention is an optical waveguide mold for manufacturing optical waveguides. The optical waveguide is formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and includes: a first transmission portion and a second transmission portion for transmitting light; an incident portion for incident light onto the first transmission portion; an expanding portion disposed between the first transmission portion and the second transmission portion, and controlling the light incident from the first transmission portion to exit the second transmission portion to expand the exit pupil; and an exit portion for exiting the light from the second transmission portion. The optical waveguide mold is characterized by having: a pattern for the first transmission portion, used to form the first transmission portion in the resin and being flat; a pattern for the second transmission portion, used to form the second transmission portion in the resin and being flat; and a pattern for the incident portion, used to... The incident portion is formed in the resin; an exit portion pattern is used to form the exit portion in the resin; and an enlargement portion pattern is used to form the enlargement portion in the resin. If the depth of the concave portion of the incident portion pattern is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the concave portion of the exit portion pattern is set to B2 and the fill factor of the convex portion is set to FF2, and the depth of the concave portion of the enlargement portion pattern is set to B3 and the fill factor of the convex portion is set to FF3, then the difference D1 between the height of the incident portion pattern and the height of the first transmission portion pattern, the difference D2 between the height of the exit portion pattern and the height of the second transmission portion pattern, and the difference D3 between the height of the enlargement portion pattern and the height of either the first transmission portion pattern or the second transmission portion pattern satisfy the following formula:

[0021] 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1)

[0022] 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2)

[0023] 0.9×B3×(1-FF3)≦D3≦1.1×B3×(1-FF3).

[0024] In this case, D1=D2=D3. Alternatively, B1-D1=B2-D2=B3-D3.

[0025] In addition, it is preferable to satisfy:

[0026] D1 = B1 × (1 - FF1)

[0027] D² = B² × (1 - FF²)

[0028] D3 = B3 × (1 - FF3).

[0029] Furthermore, the manufacturing method of the optical waveguide of the present invention is characterized by using the above-described optical waveguide mold for imprinting.

[0030] In addition, the refractive index of the resin is preferably 1.8 or higher.

[0031] Furthermore, the embossing is preferably performed such that the thickness of the resin residual film formed by at least any one of the incident part pattern, the exit part pattern, and the enlarged part pattern is 100 nm or less.

[0032] Furthermore, the optical waveguide of the present invention comprises a transparent substrate and a resin formed on the surface of the transparent substrate. It is characterized by having: a transmission section comprising the transparent substrate and a resin formed planarly on the surface of the transparent substrate, for transmitting light; an incident section comprising a resin formed as a grating pattern on the surface of the transparent substrate, for incident light onto the transmission section; and an exiting section comprising a resin formed as a grating pattern on the surface of the transparent substrate, for exiting light from the transmission section. If the height of the protrusion of the grating pattern in the incident section is set to b1, the fill factor of the protrusion is set to ff1, and the thickness of the residual film is set to d1, and the height of the protrusion of the grating pattern in the exiting section is set to b2, the fill factor of the protrusion is set to ff2, and the thickness of the residual film is set to d2, then the thickness t of the resin in the transmission section satisfies the following formula:

[0033] 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1)

[0034] 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2).

[0035] In this case, d1 = d2. Alternatively, b1 + d1 = b2 + d2.

[0036] In addition, it is preferable to satisfy t=d1+b1×ff1=d2+b2×ff2.

[0037] Furthermore, the optical waveguide of the present invention comprises a transparent substrate and a resin formed on the surface of the transparent substrate, characterized by having: a first transmission section and a second transmission section comprising the transparent substrate and a resin formed planarly on the surface of the transparent substrate, and for transmitting light; an incident section comprising resin formed as a grating pattern on the surface of the transparent substrate, and for incident light onto the first transmission section; and an amplifying section disposed between the first transmission section and the second transmission section, comprising resin formed as an amplifying pattern on the surface of the transparent substrate, and for controlling the light incident from the first transmission section to exit into the second transmission section. The exit pupil is enlarged; and the exit portion includes resin formed as a grating pattern on the surface of the transparent substrate, and is used to allow light to exit from the second transmission portion. If the height of the convex portion of the grating pattern in the incident portion is set to b1, the fill factor of the convex portion is set to ff1, and the thickness of the residual film is set to d1; the height of the convex portion of the grating pattern in the exit portion is set to b2, the fill factor of the convex portion is set to ff2, and the thickness of the residual film is set to d2; and the height of the convex portion of the enlargement pattern in the enlarged portion is set to b3, the fill factor of the convex portion is set to ff3, and the thickness of the residual film is set to d3, then the thickness t of the resin in the first transmission portion and the second transmission portion satisfies the following formula:

[0038] 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1)

[0039] 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2)

[0040] 0.9×(d3+b3×ff3)≦t≦1.1×(d3+b3×ff3).

[0041] In this case, d1 = d2 = d3. Alternatively, b1 + d1 = b2 + d2 = b3 + d3.

[0042] In addition, it is preferable to satisfy t=d1+b1×ff1=d2+b2×ff2=d3+b3×ff3.

[0043] In addition, the refractive index of the resin is preferably 1.8 or higher.

[0044] In addition, it is preferable that the thickness of the residual film of at least any one of the grating patterns of the incident portion and the exit portion and the enlargement pattern of the enlarged portion is 100 nm or less.

[0045] The effects of the invention

[0046] A waveguide with small corrugations in the transmission section and small residual film in the incident or exit section can be provided, a mold for manufacturing the waveguide, and a method for manufacturing the waveguide. Attached Figure Description

[0047] [ Figure 1 [Illustration 1] is a schematic cross-sectional view showing the structure of an optical waveguide.

[0048] [ Figure 2 [1] is a graph showing the relationship between the refractive index of the substrate and the diffraction efficiency.

[0049] [ Figure 3 [1] is a graph showing the relationship between the thickness of the residual film and the diffraction efficiency.

[0050] [ Figure 4 [Illustration 1] is a diagram illustrating a method for manufacturing an optical waveguide based on an existing mold.

[0051] [ Figure 5 [Illustration 1] is a diagram illustrating another method for manufacturing an optical waveguide based on an existing mold.

[0052] [ Figure 6 [Image] is a diagram showing the state of the flat section of an optical waveguide manufactured using existing molds.

[0053] [ Figure 7 [Illustration 1] shows another method for manufacturing an optical waveguide based on an existing mold.

[0054] [ Figure 8 [Illustration 1] is a schematic cross-sectional view showing the manufacturing method of the optical waveguide of the present invention.

[0055] [ Figure 9 [ ] is a diagram used to illustrate resin filling through the flexing of a mold.

[0056] [ Figure 10 [ ] is a diagram illustrating the conditions under which voids are filled without residue through flexing.

[0057] [ Figure 11 [ ] is a diagram illustrating the limit value of mold deflection caused by applying pressure.

[0058] [ Figure 12 [ ] is a diagram showing the filling conditions in a mold when the length of the flat section is 3 mm.

[0059] [ Figure 13 [ ] is a diagram showing the filling conditions in a mold when the length of the flat section is 2 mm.

[0060] [ Figure 14 [Illustration 1] is a schematic cross-sectional view showing the manufacturing method of the optical waveguide of the present invention.

[0061] [ Figure 15 [Illustration 1] is a schematic cross-sectional view showing the manufacturing method of the optical waveguide of the present invention.

[0062] [ Figure 16[This is a schematic perspective view showing the optical waveguide with an enlarged portion according to the present invention.]

[0063] [ Figure 17 [Illustration 1] is a schematic cross-sectional view showing the manufacturing method of the optical waveguide of the present invention.

[0064] [ Figure 18 [Illustration 1] is a schematic cross-sectional view showing the manufacturing method of the optical waveguide of the present invention. Detailed Implementation

[0065] Optical waveguide, for example Figure 1 As shown, it includes a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4. In addition, the optical waveguide is mainly composed of a transmission section 1, an incident section 2, and an exit section 3.

[0066] The transmission section 1 includes a transparent substrate 4 and a resin 5 formed planarly on the surface of the transparent substrate 4, and is used to transmit light. Light incident from the incident section 2 is transmitted within the transmission section 1 while undergoing total internal reflection, and is emitted from the exit section 3.

[0067] The incident portion 2 contains 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 transmission portion 1. The grating pattern can be of any shape as long as it allows light to be incident on the transmission portion 1. For example, it can be a pattern that allows light to diffract so that it can travel within the transmission portion 1 while undergoing total internal reflection, and is a line and space with periodically arranged inclined protrusions.

[0068] The emitting section 3 contains resin 5 formed as a grating pattern on the surface of the transparent substrate 4 and is used to emit light from the transmission section 1. The grating pattern can be of any shape as long as it enables light to be emitted from the transmission section 1. For example, it can be a pattern that enables light to be diffracted and emitted from the transparent substrate 4, and is a line and space with periodically arranged inclined protrusions.

[0069] Simulations were performed for this type of optical waveguide. Furthermore, the pitch of the grating pattern in the incident section was set to 420 nm, the height of the tilted protrusion to 350 nm, the width to 210 nm, and the angle to 55 degrees. Additionally, the wavelength of the incident light was set to 630 nm. Figure 2 The relationship between the incident angle and the diffraction efficiency of the incident section 2 for each refractive index of the transparent substrate 4 is shown. For example... Figure 2 As shown, a higher refractive index results in higher diffraction efficiency over a wider range of incident angles. Therefore, optical waveguides require materials with high refractive indices. Specifically, the refractive index of the transparent substrate 4 or the resin 5 is preferably 1.8 or higher.

[0070] Furthermore, when the grating pattern is fabricated using an imprinting method, a residual film 51 is generated under the pattern. When there is no refractive index difference between the transparent substrate 4 and the resin 5, the residual film has no effect. However, currently, the refractive index of the substrate is higher than that of the resin 5; the refractive index of the substrate is 2.0, and the refractive index of the resin 5 is 1.9, a difference of approximately 0.1. Regarding this relationship between the refractive indices of the substrate and the resin 5, it is expected that even if the refractive index of the materials increases in the future, the trend of the substrate having a higher refractive index than the resin 5 will continue. Therefore, considering the presence of a residual film 51 in the grating pattern of the incident portion 2, a simulation was performed to investigate the effect of the thickness difference of the residual film 51 on the diffraction efficiency of the incident portion 2. Furthermore, the spacing of the grating pattern in the incident portion was set to 420 nm, the height of the inclined protrusion was set to 350 nm, the width was set to 210 nm, and the angle was set to 55 degrees. Additionally, the wavelength of the incident light was set to 630 nm. The refractive indices of the substrate, the refractive index of the resin 5, and the thickness of the residual film 51 used in the simulation are shown in Table 1 and... Figure 3 (a) in.

[0071] [Table 1]

[0072]

[0073] The results are shown in Figure 3 (b) in.

[0074] Simulation results show that an incident angle of ±30° was achieved when a grating pattern with a refractive index of 1.9 was configured on a substrate with a refractive index of 2.0. However, if the residual film 51 becomes thicker, the efficiency on the wide-angle side decreases; therefore, it was found that ideally, the residual film 51 should be kept below 30 nm. Furthermore, simulations also confirmed that if the refractive index of resin 5 is increased to 1.95, the efficiency on the wide-angle side can be maintained as long as the residual film 51 is below 100 nm.

[0075] Here, we discuss the molding of the grating pattern of the incident portion 2 or the exit portion 3 of the optical waveguide and the flat portion of the transmission portion 1 on the resin 5 of the transparent substrate 4 by an imprinting method. The optical waveguide mold 6 used in the imprinting method is as follows: Figure 4 As shown, it is mainly composed of at least one or both of the pattern 61 for the transmission section, the pattern 62 for the incident section, and the pattern 63 for the exit section. The material of the optical waveguide mold 6 can be any material as long as it can be used for the embossing method, such as glass or resin.

[0076] Pattern 61 for the transmission section is a flat pattern used to form the flat portion of the transmission section 1 in the resin 5.

[0077] The incident portion pattern 62 is used to form the incident portion 2 in the resin 5. The incident portion pattern 62 can be anything as long as the incident portion 2 can be formed in the resin 5. For example, it can be a pattern formed by inverting the grating pattern of the incident portion 2.

[0078] The pattern 63 for the ejector portion is used to form the ejector portion 3 in the resin 5. The pattern 63 for the ejector portion can be anything as long as the ejector portion 3 can be formed in the resin 5. For example, it can be a pattern formed by inverting the grating pattern of the ejector portion 3.

[0079] Figure 4 (a) is a diagram showing the state of resin 5 during molding when the resin 5 coated on the transparent substrate 4 before imprinting has a relatively thick film thickness. If the resin 5 has a relatively thick film thickness before molding, when the resin 5 is pressurized using the optical waveguide mold 6, as... Figure 4 As shown in (b) and (c), resin 5 easily moves laterally from the grating pattern side to the flat area side, therefore, although molding is possible, but as Figure 4 As shown in (d), the residual film 51 will become thicker.

[0080] on the contrary, Figure 5 (a) is a diagram showing the state of resin 5 when it is being molded with a thin film thickness on the transparent substrate 4 before imprinting. If the film thickness of resin 5 before molding is reduced, when pressure is applied to resin 5 using the optical waveguide mold 6, as... Figure 5 As shown in (b) and (c), the lateral movement of resin 5 from the grating pattern side to the flat portion side becomes difficult, as... Figure 5 (d) Figure 6 As shown, gaps 9 remain after molding, which is the reason for the ripples in the flat part.

[0081] in addition, Figure 7 (a) is a diagram showing the state of the resin 5 during molding after eliminating the gaps in the pattern 61 of the transmission section of the optical waveguide mold 6 to prevent residual gaps 9 after molding. If the gaps in the pattern 61 of the transmission section of the optical waveguide mold 6 are eliminated, then when the resin 5 is pressurized using the optical waveguide mold 6, as... Figure 7 As shown in (b) and (c), the resin 5 moves laterally from the side of the transfer section with pattern 61 to the side of the grating pattern, therefore, as Figure 7 As shown in (d), the residual film 51 of the grating pattern will become thicker after molding.

[0082] Therefore, based on the above, when it is desirable to thin the residual film 51 of the grating pattern, it is ideal to form the transmission section 1, the incident section 2, and the exit section 3 by minimizing lateral movement of the resin 5 when pressurizing the resin 5 with the waveguide mold 6.

[0083] Therefore, the optical waveguide mold 6 of the present invention will be described below, which makes it less likely for the resin 5 to move laterally when the resin 5 is pressurized using the optical waveguide mold 6. The optical waveguide mold 6 of the present invention is used to manufacture an optical waveguide formed of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and includes: a transmission section 1 for transmitting light; an incident section 2 for incident light onto the transmission section 1; and an exit section 3 for exiting the light from the transmission section 1. Furthermore, as described above, the optical waveguide mold 6 is mainly composed of at least one or both of the transmission section pattern 61, the incident section pattern 62, and the exit section pattern 63. As for the material of the optical waveguide mold 6, any material suitable for embossing can be used, such as known materials like glass.

[0084] Here, in order to prevent lateral movement of the resin 5 when pressurizing it with the optical waveguide mold 6, it is only necessary to balance the unit volume of the gap (recess) of the incident part pattern 62 or the exit part pattern 63 with the gap of the transmission part pattern 61 adjacent to the incident part pattern 62 or the exit part pattern 63. Specifically, as Figure 8 As shown in (a), if the spacing of the incident part pattern 62 or the exit part pattern 63 is set to P, the depth of the concave part is set to B, the fill factor of the convex part is set to FF, and the difference between the height of the incident part pattern 62 or the exit part pattern 63 and the height of the transmission part pattern 61 is set to D, then it is preferable that P×D=P×B×(1-FF), that is, D=B×(1-FF).

[0085] Here, the fill factor of the convex portion refers to the proportion of the convex portion's area relative to the area of ​​the patterned surface (hereinafter referred to as the patterned surface) when viewed from the side of the optical waveguide mold 6 having the incident portion pattern 62 or the exit portion pattern 63, etc. Figure 8 As shown in (a), the difference between the height of the incident part pattern 62 or the exit part pattern 63 and the height of the transmission part pattern 61 is, in other words, the height of the top of the protrusion of the incident part pattern 62 or the exit part pattern 63 relative to the flat surface of the transmission part pattern 61.

[0086] Furthermore, even if D=B×(1-FF) is not satisfied and the unit volume of the aforementioned gap is unbalanced, as long as the error is slight, it can be formed by flexing the optical waveguide mold 6 in a convex shape towards the resin 5 side or its opposite side. Specifically, such as Figure 9As shown in (a), the resin 5 at the bottom of the incident part pattern 62 and the exit part pattern 63 moves under pressure, the filling part expands near the pattern, and the gap 9 of the transport part pattern 61 narrows. If pressure is further applied, as... Figure 9 As shown in (b), the optical waveguide mold 6 flexes and pushes the resin 5 outwards. If the flexing of the optical waveguide mold 6 is small, gaps 9 will remain; however, if there is sufficient flexing, gaps will remain as shown in (b). Figure 9 As shown in (c), the resin 5 pushed in the center can fill the surrounding gaps.

[0087] Therefore, the error in unit volume between the gaps is preferably at least 10%. In this case, it is sufficient to satisfy the following formula:

[0088] 0.9×B×(1-FF)≦D≦1.1×B×(1-FF).

[0089] Of course, the error should be small, preferably below 5%, and more preferably below 3%.

[0090] Therefore, when the resin 5 is pressurized using the optical waveguide mold 6, such as Figure 8 As shown in (b) and (c), almost no lateral movement of resin 5 occurs. Therefore, as Figure 8 As shown in (d), the residual film 51 of the grating pattern after molding can be thinned, and the transmission section 1 can be made into a good shape without ripples or gaps 9.

[0091] Furthermore, the conditions under which molding can be performed without leaving gaps 9 by flexing the mold 6 used for the optical waveguide. First, as... Figure 10 As shown, the area of ​​the resin 5 pushed away by the flexing of the optical waveguide mold 6 is defined as Y, and the area of ​​the gap at the end of the optical waveguide mold 6 after flexing is defined as Z.

[0092] If we approximate the radius of curvature of the deflection as R, define the maximum depth at which resin 5 is pushed away as x, define the height of the void as s', define the angle from the vertical line to the intersection of resin 5 and the void as α, and define the angle from the vertical line to the point of maximum void height as θ, then:

[0093] Y=R 2 (α-cosαsinα)

[0094] ※The area αR of a sector with radius R and angle 2α 2 The area R of a triangle with height Rcosα and base length 2Rsinα. 2 The difference between cosα and sinα

[0095] ※cosα=cosθ+(s' / R)

[0096] Z≒s'(a-Rsinα) / 2

[0097] ※The area of ​​a triangle with a base of length a-Rsinα and a height of s'.

[0098] Here, the condition for the gap to be filled without residue by the deflection of the optical waveguide mold 6 is when Y=2Z, so the following equation (1) holds.

[0099] R 2 (α-cosαsinα)=s'(a-Rsinα)...Formula (1)

[0100] Additionally, regarding the limit value of bending the optical waveguide mold 6 by applying pressure, such as... Figure 11 As shown, based on the simply supported beam model subjected to uniform pressure p, if the radius of curvature is set as R', the length of the beam is set as L, and the magnitude of the vertical deflection is set as δ, then the following equation (2) holds.

[0101] R'=(L / 2) 2 / (2δ)…Equation (2)

[0102] ※δ=5pL 4 / (384EI)

[0103] I=g 3 / 12

[0104] E: Young's modulus of the mold used for optical waveguides

[0105] g: Thickness of the mold used for optical waveguides

[0106] Therefore, the mold can only flex to completely fill the voids when the radius of curvature R of the filling condition is greater than or equal to the radius of curvature R' of the deflection under pressure (R≧R'). However, if the coating thickness t is not greater than the indentation depth χ of the beam, filling is not possible.

[0107] Figure 12 This is a graph showing the relationship between the height s' of the gap 9 between the resin 5 and the optical waveguide mold 6, calculated according to equation (1), and the radius of curvature R generated by the deflection of the optical waveguide mold 6 required to fill the resin 5 without gaps. Additionally, Figure 12 The dashed lines (1) to (5) in the figure show the value of the radius of curvature R' calculated according to equation (2) and from the pressure difference applied to both sides of the optical waveguide mold 6 during the stamping process and the thickness of the optical waveguide mold 6. The thickness g and pressure p of the transmission section pattern 61 of the optical waveguide mold are as follows.

[0108] Dashed line (1) g: 0.7 mm, p: 0.25 MPa

[0109] Dashed line (2) g: 0.7 mm, p: 0.5 MPa

[0110] Dashed line (3) g: 0.7 mm, p: 0.75 MPa

[0111] Dashed line (4) g: 0.5 mm, p: 0.25 MPa

[0112] Dashed line (5) g: 0.5 mm, p: 0.5 MPa

[0113] Furthermore, the width L of the pattern 61 in the transmission section of the optical waveguide mold is set to 3 mm. In addition, the material of the optical waveguide mold is glass with a Young's modulus E of 73.6 GPa.

[0114] Since the radius of curvature R' is proportional to the cube of the thickness α of the transmission part pattern 61 of the waveguide mold, a curvature radius sufficient for filling can be achieved by applying pressure by changing the thickness α from 0.7 mm to 0.5 mm.

[0115] In addition, the case where the width L of the pattern 61 in the transmission section of the optical waveguide mold is set to 2 mm was also discussed. Figure 13 This is a graph showing the relationship between the height s' of the gap between the resin 5 and the optical waveguide mold 6, calculated according to equation (1), and the radius of curvature R generated by the deflection of the optical waveguide mold 6 required to fill the resin 5 without gaps. Additionally, Figure 13 The dashed lines (1) to (4) in the figure show the value of the radius of curvature R' calculated according to equation (2) and from the pressure difference applied to both sides of the optical waveguide mold 6 during the stamping process and the thickness of the optical waveguide mold 6. The thickness g and pressure p of the transmission section pattern 61 of the optical waveguide mold are as follows.

[0116] Dashed line (1) g: 0.7 mm, p: 0.75 MPa

[0117] Dashed line (2) g: 0.7 mm, p: 1.5 MPa

[0118] Dashed line (3) g: 0.7 mm, p: 2 MPa

[0119] Dashed line (4) g: 0.7 mm, p: 0.1 MPa

[0120] Furthermore, regarding the material of the mold for the optical waveguide, dashed lines (1) to (3) are set to glass with a Young's modulus E of 73.6 GPa. In addition, dashed line (4) is set to polyethylene terephthalate (PET) with a Young's modulus E of 4 GPa.

[0121] like Figure 13As shown, if the width L is set to 2 mm, the waveguide mold needs to be more flexed to achieve gapless filling, making filling more difficult. Even with a pressure of 2 MPa, filling is impossible if the gap is not below 50 nm; filling is almost impossible to achieve by flexing alone. Therefore, it is important to balance the unit volume of the gap (recess) in the incident pattern 62 or the exit pattern 63 with the gap in the transmission pattern 61 adjacent to the incident pattern 62 or the exit pattern 63. Furthermore, within the fillable range, the required coating thickness t is greater than 27 nm in the indentation depth x when the gap is 50 nm, so the influence of the coating thickness t is almost negligible.

[0122] Next, use Figure 8 The manufacturing method of the optical waveguide of the present invention will be described. The manufacturing method of the optical waveguide of the present invention is a method for manufacturing an optical waveguide as described above, and the optical waveguide mold 6 of the present invention is used for stamping. The optical waveguide is formed of a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and includes: a transmission section 1 for transmitting light; an incident section 2 for incident light onto the transmission section 1; and an exit section 3 for exiting light from the transmission section 1. The optical waveguide mold 6 uses the following mold: As described above, if the spacing of the incident part pattern 62 or the exit part pattern 63 is set to P, the depth of the concave part is set to B, the fill factor of the convex part is set to FF, and the depth of the transmission part pattern 61 adjacent to the incident part pattern 62 or the exit part pattern 63 is set to D, then the mold at least satisfies 0.9×B×(1-FF)≦D≦1.1×B×(1-FF), preferably 0.95×B×(1-FF)≦D≦1.05×B×(1-FF), more preferably 0.97×B×(1-FF)≦D≦1.03×B×(1-FF). Most preferably, a mold satisfying D=B×(1-FF) is used.

[0123] First, resin 5 is coated onto the surface of the transparent substrate 4. Resin 5 can be any transparent resin suitable for die-casting, such as photocurable resins, thermocurable resins, or thermoplastic resins. Specifically, an acrylic photocurable resin can be used. The coating of resin 5 onto the transparent substrate 4 can be performed using known methods such as spin coating. Furthermore, the refractive index of resin 5 is preferably 1.8 or higher.

[0124] Next, using an optical waveguide mold 6 and an imprinting method, at least one or both of the incident portion 2 or the exit portion 3 constituting the grating pattern, and the transmission portion 1 constituting the flat surface, are transferred to a photocurable resin. Specifically, as... Figure 8As shown in (b) and (c), a waveguide mold 6 is pressed onto a transparent substrate 4 to apply a fluid resin 5, causing the resin 5 to fill the transmission section pattern 61, the incident section pattern 62, and the exit section pattern 63. At this time, it is preferable to pressurize the waveguide mold 6 until the thickness d of the residual film 51 of the resin 5 becomes 100 nm or less, preferably 30 nm or less. Here, the residual film 51 refers to the thinnest portion of the resin for each of the grating patterns of the incident section 2 formed by the incident section pattern 62 or the exit section 3 formed by the exit section pattern 63.

[0125] Then, allow resin 5 to cure, and as follows Figure 8 The optical waveguide of the present invention can be manufactured by demolding as shown in (d).

[0126] Next, the optical waveguide of the present invention manufactured in this manner will be described. The optical waveguide of the present invention includes a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4. Furthermore, the optical waveguide is mainly composed of an incident section 2, an exit section 3, and a transmission section 1.

[0127] The transmission section 1 includes a transparent substrate 4 and a resin 5 formed planarly on the surface of the transparent substrate 4, and is used to transmit light. Light incident from the incident section 2 is transmitted within the transmission section 1 while undergoing total internal reflection, and is emitted from the exit section 3.

[0128] The incident portion 2 contains 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 transmission portion 1. The grating pattern can be of any shape as long as it allows light to be incident on the transmission portion 1. For example, it can be a pattern that allows light to be diffracted so that it can advance in the transmission portion 1 while undergoing total internal reflection, and is a space with periodically arranged inclined protrusions.

[0129] The emitting section 3 contains resin 5 formed as a grating pattern on the surface of the transparent substrate 4 and is used to emit light from the transmission section 1. The grating pattern can be of any shape as long as it enables light to be emitted from the transmission section 1. For example, it can be a pattern that enables light to be diffracted and emitted from the transparent substrate 4, and is a line and space with periodically arranged inclined protrusions.

[0130] The transparent substrate 4 is a base portion used to form patterns on the resin 5 of the flat portion of the transmission section 1, the incident portion 2, and the exit portion 3. Furthermore, it is used to transmit light incident from the incident portion 2 to the exit portion 3. Any material can be used as long as light can be transmitted from the incident portion 2 to the exit portion 3; for example, glass can be used. Additionally, based on the simulation results described above, the refractive index of the transparent substrate 4 is preferably 1.8 or higher, preferably 1.9 or higher, and more preferably 2.0 or higher.

[0131] Resin 5 is used to form the pattern of the incident section 2, the exit section 3, and the transmission section 1. Any material can be used as long as it can form the pattern of the transmission section 1, the incident section 2, and the exit section 3. In addition, based on the simulation results above, it is preferable that the refractive index of the transparent substrate 4 or the resin 5 is 1.8 or higher, preferably 1.9 or higher, and more preferably 1.95 or higher.

[0132] Furthermore, the optical waveguide of the present invention is preferably formed as follows: if the height of the convex portion of the grating pattern in the incident portion 2 or the exit portion 3 is set to b, the fill factor of the convex portion is set to ff, the thickness of the residual film 51 is set to d, and the thickness of the resin 5 adjacent to the transmission portion 1 of the grating pattern is set to t, then 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). In the most preferably case where t=d+b×ff, it becomes a good shape with fewer corrugations or gaps 9 in the transmission portion 1. In addition, the fill factor of the convex portion refers to the proportion of the area of ​​the convex portion relative to the area of ​​the pattern surface. The fill factor ff of the convex portion of the grating pattern in the incident portion 2 or the exit portion 3 of the optical waveguide is essentially the same as the fill factor (1-FF) of the concave portion of the pattern 62 for the incident portion or the pattern 63 for the exit portion. Furthermore, the depth D of the so-called transmission portion pattern 61, such as... Figure 8 As shown in (a), it refers to the difference between the height of the flat surface of the pattern 61 for the transmission section and the height of the apex of the protrusion of the pattern 62 for the incident section or the pattern 63 for the exit section.

[0133] Furthermore, when the thickness d of the residual film 51 of the grating pattern in the incident section 2 and the exit section 3 is 100 nm or less, preferably 30 nm or less, the diffraction efficiency on the wide-angle side is improved, and therefore it is preferred.

[0134] Furthermore, in the above description, the optical waveguide mold 6 was described with the same depth B for the incident pattern 62 and the exit pattern 63, and the difference D between the height of the incident pattern 62 or the exit pattern 63 and the height of the transmission pattern 61 was also the same. However, these can be different. In this case, the optical waveguide mold 6 is used to manufacture an optical waveguide formed from a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and includes: a transmission section 1 for transmitting light; an incident section 2 for incident light onto the transmission section 1; and an exit section 3 for exiting light from the transmission section 1. The optical waveguide mold 6 includes: a transmission section pattern for forming the transmission section 1 in the resin 5 and being flat; an incident section pattern for forming the incident section 2 in the resin 5; and an exit section pattern for forming the exit section 3 in the resin 5. Furthermore, if the depth of the concave portion of the pattern for the incident portion is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the concave portion of the pattern for the exit portion is set to B2 and the fill factor of the convex portion is set to FF2, the difference between the height of the pattern for the incident portion and the height of the pattern for the transmission portion is set to D1, and the difference between the height of the pattern for the exit portion and the height of the pattern for the transmission portion is set to D2, then the optical waveguide mold 6 only needs to satisfy the following formula:

[0135] 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1)

[0136] 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2).

[0137] Furthermore, while a tolerance of ±10% is permissible in the formula, the error should ideally be small, preferably 5% or less, and more preferably 3% or less.

[0138] When the optical waveguide mold 6 is used for die-printing, the manufactured optical waveguide includes a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and has: a transmission section 1, including the transparent substrate 4 and the resin 5 formed planarly on the surface of the transparent substrate 4, for transmitting light; an incident section 2, including the resin 5 formed as a grating pattern on the surface of the transparent substrate 4, for allowing light to be incident on the transmission section 1; and an exit section 3, including the resin 5 formed as a grating pattern on the surface of the transparent substrate 4, for allowing light to be emitted from the transmission section 1. Furthermore, if the height of the protrusion of the grating pattern in the incident section 2 is set to b1, the fill factor of the protrusion is set to ff1, and the thickness of the residual film is set to d1, and the height of the protrusion of the grating pattern in the exit section 3 is set to b2, the fill factor of the protrusion is set to ff2, and the thickness of the residual film is set to d2, then the thickness t of the resin 5 in the transmission section 1 satisfies the following formula:

[0139] 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1)

[0140] 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2).

[0141] Figure 14 This is a schematic cross-sectional view showing the manufacturing process of an optical waveguide under the following conditions: the top positions of the incident pattern 62 and the exit pattern 63 of the optical waveguide mold 6 relative to the flat surface of the transmission pattern 61 are the same (D1=D2), but the bottom positions of the incident pattern 62 and the exit pattern 63 of the optical waveguide mold 6 are different.

[0142] In this case, such as Figure 14 As shown in (d), in the manufactured optical waveguide, the thickness of the residual film of the grating pattern in the incident part 2 and the exit part 3 is the same (d1=d2), but the height b1 of the protrusion of the grating pattern in the incident part 2 is different from the height b2 of the protrusion of the grating pattern in the exit part 3.

[0143] in addition, Figure 15 This is a schematic cross-sectional view showing the manufacturing process of an optical waveguide under the following conditions: the bottom positions of the incident pattern 62 and the exit pattern 63 of the optical waveguide mold 6 relative to the flat surface of the transmission pattern 61 are the same (B1-D1=B2-D2), but the top positions of the incident pattern 62 and the exit pattern 63 of the optical waveguide mold 6 are different.

[0144] In this case, such as Figure 15 As shown in (d), in the manufactured optical waveguide, the top positions of the grating patterns of the incident part 2 and the exit part 3 are the same (b1+d1=b2+d2), but the thickness of the residual film of the grating patterns of the incident part 2 and the exit part 3 is different.

[0145] In addition, the optical waveguide mold 6 satisfies the following requirements:

[0146] D1 = B1 × (1 - FF1)

[0147] D² = B² × (1 - FF²)

[0148] When the resin 5 is in a position to move laterally, it is the least likely to cause lateral movement, and therefore is preferred.

[0149] In this case, the thickness t of the resin 5 in the transmission section 1 of the manufactured optical waveguide satisfies the following formula:

[0150] t=d1+b1×ff1=d2+b2×ff2=d3+b3×ff3.

[0151] Furthermore, when the thicknesses d1 and d2 of the grating patterns in the incident portion 2 and the exit portion 3 are 100 nm or less, the diffraction efficiency on the wide-angle side improves, which is therefore preferable. Here, the term "residual film 51" refers to the thinnest portion of the resin for each of the grating patterns in the incident portion 2 formed by the incident portion pattern 62 and the exit portion 3 formed by the exit portion pattern 63. Either the thickness d1 or the thickness d2, preferably both, is 100 nm or less, and more preferably 30 nm or less.

[0152] In addition, optical waveguides such as Figure 16 As shown, it sometimes also has an enlargement section 7 for expanding the exit pupil. In this case, the optical waveguide 8A is as follows: Figure 17 As shown in (d), it includes a transparent substrate 4 and a resin 5 formed on the surface of the transparent substrate 4, and is mainly composed of a first transmission section 1A, a second transmission section 1B, an incident section 2, an enlarged section 7 and an exit section 3.

[0153] The first transmission section 1A and the second transmission section 1B include a transparent substrate 4 and a resin 5 formed planarly on the surface of the transparent substrate 4, and are used for transmitting light. Light incident from the incident section 2 is transmitted to the amplification section 7 in the first transmission section 1A while undergoing total internal reflection. In addition, light incident from the amplification section 7 is transmitted in the second transmission section 1B while undergoing total internal reflection, and is emitted from the exit section 3.

[0154] The incident portion 2 contains 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 transmission portion 1A. The grating pattern can be of any shape as long as it allows light to be incident on the first transmission portion 1A. For example, it can be a pattern that allows light to be diffracted so that it can advance while undergoing total internal reflection within the first transmission portion 1A, and is a periodically arranged line and space with inclined protrusions.

[0155] The emitting section 3 contains resin 5 formed as a grating pattern on the surface of the transparent substrate 4 and is used to emit light from the second transmission section 1B. The grating pattern can be of any shape as long as it enables light to be emitted from the second transmission section 1B. For example, it can be a pattern that enables light to be diffracted and emitted from the transparent substrate 4, and is a line and space with periodically arranged inclined protrusions.

[0156] The enlarging section 7 is disposed between the first transmission section 1A and the second transmission section 1B, and contains resin 5 formed as an enlarging pattern on the surface of the transparent substrate 4. It is used to control the light incident from the first transmission section 1A and emanate it into the second transmission section 1B to enlarge the exit pupil. The enlarging pattern can be of any shape as long as it can control the light incident from the first transmission section 1A and emanate it into the second transmission section 1B to enlarge the exit pupil. For example, it can be a grating pattern capable of replicating the light incident from the first transmission section 1A and enlarging the exit pupil, and is a periodically arranged line and space with protrusions. In this case, the spacing of the protrusions in the enlarging pattern can be set to 1 / √2 times the spacing of the grating patterns in the incident section 2 or the exit section 3.

[0157] The transparent substrate 4 is a base portion used to form patterns on the resin 5 of the flat portion of the first transmission section 1A and the second transmission section 1B, the incident portion 2, and the exit portion 3. Furthermore, it is used to transmit light incident from the incident portion 2 to the exit portion 3. Any material can be used as long as light can be transmitted from the incident portion 2 to the exit portion 3; for example, glass can be used. Additionally, based on the simulation results described above, the refractive index of the transparent substrate 4 is preferably 1.8 or higher, preferably 1.9 or higher, and more preferably 2.0 or higher.

[0158] Resin 5 is used to form the pattern of the incident portion 2, the exit portion 3, the enlarged portion 7, the first transmission portion 1A, and the second transmission portion 1B. Any material can be used as long as it can form the pattern of the transmission portion 1, the incident portion 2, and the exit portion 3. In addition, based on the simulation results above, it is preferable that the refractive index of the transparent substrate 4 or the resin 5 is 1.8 or higher, preferably 1.9 or higher, and more preferably 1.95 or higher.

[0159] Mold 6A for manufacturing this optical waveguide with enlarged section 7, such as... Figure 17 As shown in (a), it is mainly composed of a first transmission section pattern 61A, a second transmission section pattern 61B, an incident section pattern 62A, an exit section pattern 63A, and an enlargement section pattern 67. The material of the optical waveguide mold 6A can be any material that can be used for embossing, such as known materials like glass.

[0160] Pattern 61A for the first transmission section is a flat pattern used to form the flat portion of the first transmission section 1A in the resin 5. Pattern 61B for the second transmission section is a flat pattern used to form the flat portion of the second transmission section 1B in the resin 5.

[0161] The incident portion pattern 62A is used to form the incident portion 2 in the resin 5. The incident portion pattern 62A can be anything as long as the incident portion 2 can be formed in the resin 5. For example, it can be a pattern formed by inverting the grating pattern of the incident portion 2.

[0162] The pattern 63A for the ejector portion is used to form the ejector portion 3 in the resin 5. The pattern 63A for the ejector portion can be anything as long as the ejector portion 3 can be formed in the resin 5. For example, it can be a pattern formed by inverting the grating pattern of the ejector portion 3.

[0163] The enlargement pattern 67 is used to form the enlargement 7 in the resin 5. The enlargement pattern 67 can be anything as long as the enlargement 7 can be formed in the resin 5. For example, it can be a pattern formed by inverting the enlargement pattern of the enlargement 3 described above.

[0164] Here, in order to prevent lateral movement of the resin 5 when pressurizing the resin 5 with the optical waveguide mold 6A, it is only necessary to balance the unit space volume of the gaps (recesses) of the incident part pattern 62A and the enlarged part pattern 67 with the gaps of the first transmission part pattern 61A adjacent to the incident part pattern 62A and the enlarged part pattern 67, and the gaps of the second transmission part pattern 61B adjacent to the exit part pattern 63A and the enlarged part pattern 67. Specifically, if the depth of the recess in pattern 62A for the incident portion is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the recess in pattern 63A for the exit portion is set to B2 and the fill factor of the convex portion is set to FF2, and the depth of the recess in pattern 67 for the enlarged portion is set to B3 and the fill factor of the convex portion is set to FF3, then the difference D1 between the height of pattern 62A for the incident portion and the height of pattern 61A for the first transmission portion, the difference D2 between the height of pattern 63A for the exit portion and the height of pattern 61B for the second transmission portion, and the difference D3 between the height of pattern 67 for the enlarged portion and the height of pattern 61A for the first transmission portion or pattern 61B for the second transmission portion can satisfy the following formula:

[0165] 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1)

[0166] 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2)

[0167] 0.9×B3×(1-FF3)≦D3≦1.1×B3×(1-FF3).

[0168] Furthermore, while a tolerance of ±10% is permissible in the formula, the error should ideally be small, preferably 5% or less, and more preferably 3% or less.

[0169] In this case, in the optical waveguide 8A manufactured using the optical waveguide mold 6A, if the height of the convex portion of the grating pattern in the incident portion 2 is set to b1, the fill factor of the convex portion is set to ff1, and the thickness of the residual film is set to d1; the height of the convex portion of the grating pattern in the exit portion is set to b2, the fill factor of the convex portion is set to ff2, and the thickness of the residual film is set to d2; and the height of the convex portion of the grating pattern in the enlarged portion 7 is set to b3, the fill factor of the convex portion is set to ff3, and the thickness of the residual film is set to d3, then the resin thickness t of the first transmission portion 1A and the second transmission portion 1B satisfies the following formula:

[0170] 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1)

[0171] 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2)

[0172] 0.9×(d3+b3×ff3)≦t≦1.1×(d3+b3×ff3).

[0173] In addition, optical waveguide mold 6A, such as Figure 17 As shown in (a), the top positions of the incident part pattern 62A, the exit part pattern 63A, and the enlargement part pattern 67 relative to the flat surfaces of the first transmission part pattern 61A and the second transmission part pattern 61B can be made the same (D1=D2=D3), but the bottom positions of the incident part pattern 62A, the exit part pattern 63A, and the enlargement part pattern 67 of the optical waveguide mold 6A are different. Figure 17 This is a schematic cross-sectional view showing the manufacturing process of an optical waveguide when it is stamped using the optical waveguide mold 6A.

[0174] In this case, such as Figure 17 As shown in (d), in the manufactured optical waveguide 8A, the residual film thickness of the patterns in the incident part 2, the exit part 3, and the enlarged part 7 is the same (d1=d2=d3), but the height b1 of the protrusion of the grating pattern in the incident part 2, the height b2 of the protrusion of the grating pattern in the exit part 3, and the height b3 of the protrusion of the pattern in the enlarged part 7 are different.

[0175] In addition, the optical waveguide mold 6A can also be used as follows: Figure 18 As shown in (a), the bottom positions of the incident part pattern 62A, the exit part pattern 63A, and the enlargement part pattern 67 relative to the flat surfaces of the first transmission part pattern 61A and the second transmission part pattern 61B are made the same (B1-D1=B2-D2=B3-D3), but the top positions of the incident part pattern 62A, the exit part pattern 63A, and the enlargement part pattern 67 of the optical waveguide mold 6A are different. Figure 18This is a schematic cross-sectional view showing the manufacturing process of an optical waveguide when it is stamped using the optical waveguide mold 6A.

[0176] In this case, such as Figure 18 As shown in (d), in the manufactured optical waveguide 8A, the top positions of the patterns of the incident part 2, the exit part 3, and the enlarged part 7 are the same (b1+d1=b2+d2=b3+d3), but the thickness of the residual film of the patterns of the incident part 2, the exit part 3, and the enlarged part 7 is different.

[0177] In addition, the optical waveguide mold 6A meets the following requirements:

[0178] D1 = B1 × (1 - FF1)

[0179] D² = B² × (1 - FF²)

[0180] D3 = B3 × (1 - FF3)

[0181] When the resin 5 is in a position to move laterally, it is the least likely to cause lateral movement, and therefore is preferred.

[0182] In this case, the thickness t of the resin 5 in the first transmission section 1A and the second transmission section 1B of the manufactured optical waveguide satisfies the following formula:

[0183] t=d1+b1×ff1=d2+b2×ff2=d3+b3×ff3.

[0184] Furthermore, when the thicknesses d1, d2, and d3 of the residual film 51 of the grating patterns of the incident portion 2 and the exit portion 3, and the enlarging pattern of the enlarging portion 7, are 100 nm or less, the diffraction efficiency on the wide-angle side improves, which is therefore preferable. Here, the residual film 51 refers to the thinnest part of the resin for each of the grating patterns of the incident portion 2 formed by the incident portion pattern 62A, the grating patterns of the exit portion 3 formed by the exit portion pattern 63A, and the enlarging pattern of the enlarging portion 7 formed by the enlarging portion pattern 67. It is preferable that any one or more of the thicknesses d1, d2, and d3 are 100 nm or less, and more preferably 30 nm or less.

[0185] Explanation of icon numbers

[0186] 1: Transmission Department

[0187] 1A: First Transmission Unit

[0188] 1B: Second Transmission Unit

[0189] 2: Entrance section

[0190] 2A: Entrance section

[0191] 3: Exit part

[0192] 3A: Launching section

[0193] 4: Transparent substrate

[0194] 5: Resin

[0195] 6: Molds for optical waveguides

[0196] 6A: Mold for optical waveguides

[0197] 7: Enlarged Section

[0198] 8: Optical waveguide

[0199] 8A: Optical waveguide

[0200] 9: Gap

[0201] 51: Residual film

[0202] 61: Pattern for transmission section

[0203] 61A: Pattern for the first transmission section

[0204] 61B: Pattern for the second transmission section

[0205] 62: Pattern for the incident section

[0206] 62A: Pattern for the incident section

[0207] 63: Pattern for the ejector section

[0208] 63A: Pattern for the ejector section

[0209] 67: Pattern used for enlarged parts

Claims

1. A mold for an optical waveguide, used to manufacture an optical waveguide, the optical waveguide being formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and comprising: The transmission unit is used to transmit light; An incident section is used to allow light to be incident on the transmission section; And an emission section for emitting light from the transmission section. The optical waveguide mold is characterized by having: A flat transport section pattern is used to form the transport section in the resin; and At least one or both of an incident portion pattern and an exit portion pattern, wherein the incident portion pattern is used to form the incident portion in the resin, and the exit portion pattern is used to form the exit portion in the resin. If the depth of the concave portion of the incident portion pattern or the exit portion pattern is set to B, the fill factor of the convex portion is set to FF, and the difference between the height of the incident portion pattern or the exit portion pattern and the height of the transmission portion pattern is set to D, then the optical waveguide mold satisfies the following formula: 0.9×B×(1-FF)≦D≦1.1×B×(1-FF).

2. The mold for optical waveguides according to claim 1, characterized in that, satisfy: D = B × (1 - FF).

3. A mold for an optical waveguide, used to manufacture an optical waveguide, the optical waveguide being formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and comprising: The transmission unit is used to transmit light; An incident section is used to allow light to be incident on the transmission section; And an emission section for emitting light from the transmission section. The optical waveguide mold is characterized by having: A flat transfer section pattern is used to form the transfer section in the resin; An incident portion pattern is used to form the incident portion in the resin; and A pattern is used to form the ejection portion in the resin. If the depth of the concave portion of the pattern for the incident portion is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the concave portion of the pattern for the exit portion is set to B2 and the fill factor of the convex portion is set to FF2, the difference between the height of the pattern for the incident portion and the height of the pattern for the transmission portion is set to D1, and the difference between the height of the pattern for the exit portion and the height of the pattern for the transmission portion is set to D2, then the optical waveguide mold satisfies the following formula: 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1) 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2).

4. The mold for optical waveguides according to claim 3, characterized in that, satisfy: D1=D2.

5. The mold for optical waveguides according to claim 3, characterized in that, satisfy: B1-D1=B2-D2.

6. The mold for optical waveguides according to claim 3, characterized in that, satisfy: D1 = B1 × (1 - FF1) D2 = B2 × (1 - FF2).

7. A mold for manufacturing an optical waveguide, the optical waveguide being formed from a transparent substrate and a resin formed on the surface of the transparent substrate, and comprising: The first and second transmission units are used to transmit light; An incident section is used to allow light to be incident on the first transmission section; An expanding section is disposed between the first transmission section and the second transmission section, and controls the light incident from the first transmission section to exit into the second transmission section to expand the exit pupil; and an exiting section is used to allow the light to exit from the second transmission section. The optical waveguide mold is characterized by having: A flat first transport portion is patterned for forming the first transport portion in the resin; A flat second transport portion is patterned for forming the second transport portion in the resin; An incident portion pattern is used to form the incident portion in the resin; A pattern for the ejector portion is used to form the ejector portion in the resin; as well as A pattern is used to form the enlarged portion in the resin. If the depth of the concave portion of the incident part pattern is set to B1 and the fill factor of the convex portion is set to FF1, the depth of the concave portion of the exit part pattern is set to B2 and the fill factor of the convex portion is set to FF2, and the depth of the concave portion of the enlarged part pattern is set to B3 and the fill factor of the convex portion is set to FF3, then the difference D1 between the height of the incident part pattern and the height of the first transmission part pattern, the difference D2 between the height of the exit part pattern and the height of the second transmission part pattern, and the difference D3 between the height of the enlarged part pattern and the height of either the first or second transmission part pattern satisfy the following formula: 0.9×B1×(1-FF1)≦D1≦1.1×B1×(1-FF1) 0.9×B2×(1-FF2)≦D2≦1.1×B2×(1-FF2) 0.9×B3×(1-FF3)≦D3≦1.1×B3×(1-FF3).

8. The mold for optical waveguides according to claim 7, characterized in that, satisfy: D1=D2=D3.

9. The mold for optical waveguides according to claim 7, characterized in that, satisfy: B1-D1=B2-D2=B3-D3.

10. The mold for optical waveguides according to claim 7, characterized in that, satisfy: D1 = B1 × (1 - FF1) D² = B² × (1 - FF²) D3 = B3 × (1 - FF3).

11. A method for manufacturing an optical waveguide, characterized in that, The optical waveguide is formed by stamping using a mold as described in any one of claims 1 to 10.

12. The method for manufacturing an optical waveguide according to claim 11, characterized in that, The resin has a refractive index of 1.8 or higher.

13. The method for manufacturing an optical waveguide according to claim 11, characterized in that, The embossing is performed in such a way that the thickness of the resin residual film formed by at least any one of the incident part pattern, the exit part pattern, and the enlarged part pattern is 100 nm or less.

14. An optical waveguide comprising a transparent substrate and a resin formed on the surface of the transparent substrate. The optical waveguide is characterized by having: The transmission section includes the transparent substrate and a resin formed planarly on the surface of the transparent substrate, and is used to transmit light; An incident portion comprising a resin formed as a grating pattern on the surface of the transparent substrate, and used to allow light to be incident on the transmission portion; and The emission section contains resin formed as a grating pattern on the surface of the transparent substrate and is used to emit light from the transmission section. If the height of the convex portion of the grating pattern in the incident section is set to b1, the fill factor of the convex portion to ff1, and the thickness of the residual film is set to d1, and the height of the convex portion of the grating pattern in the exit section is set to b2, the fill factor of the convex portion to ff2, and the thickness of the residual film is set to d2, then the thickness t of the resin in the transmission section satisfies the following formula: 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1) 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2).

15. The optical waveguide according to claim 14, characterized in that, satisfy: d1=d2.

16. The optical waveguide according to claim 14, characterized in that, satisfy: b1+d1=b2+d2.

17. The optical waveguide according to claim 14, characterized in that, satisfy: t = d1 + b1 × ff1 = d2 + b2 × ff2.

18. An optical waveguide comprising a transparent substrate and a resin formed on the surface of the transparent substrate. The optical waveguide is characterized by having: The first transmission section and the second transmission section include the transparent substrate and a resin formed planarly on the surface of the transparent substrate, and are used to transmit light; The incident portion includes resin formed as a grating pattern on the surface of the transparent substrate and is used to allow light to be incident on the first transmission portion; An enlarging portion, disposed between the first transmission portion and the second transmission portion, comprises resin formed as an enlarging pattern on the surface of the transparent substrate, and controls light incident from the first transmission portion to exit into the second transmission portion to enlarge the exit pupil; and The emission section contains resin formed as a grating pattern on the surface of the transparent substrate and is used to emit light from the second transmission section. If the height of the convex portion of the grating pattern in the incident section is set to b1, the fill factor of the convex portion to ff1, and the thickness of the residual film to d1; the height of the convex portion of the grating pattern in the exit section is set to b2, the fill factor of the convex portion to ff2, and the thickness of the residual film to d2; and the height of the convex portion of the enlargement pattern in the enlargement section is set to b3, the fill factor of the convex portion to ff3, and the thickness of the residual film to d3, then the resin thickness t of the first transmission section and the second transmission section satisfies the following formula: 0.9×(d1+b1×ff1)≦t≦1.1×(d1+b1×ff1) 0.9×(d2+b2×ff2)≦t≦1.1×(d2+b2×ff2) 0.9×(d3+b3×ff3)≦t≦1.1×(d3+b3×ff3).

19. The optical waveguide according to claim 18, characterized in that, satisfy: d1=d2=d3.

20. The optical waveguide according to claim 18, characterized in that, satisfy: b1+d1=b2+d2=b3+d3.

21. The optical waveguide according to claim 18, characterized in that, satisfy: t=d1+b1×ff1=d2+b2×ff2=d3+b3×ff3.

22. The optical waveguide according to any one of claims 14 to 21, characterized in that, The resin has a refractive index of 1.8 or higher.

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

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