JP4544495B2 - Volume hologram replication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a volume hologram duplicating method, and more particularly, to a volume hologram duplicating method for correcting that the diffraction characteristics of a volume hologram after duplication are different from those of an original.
[0002]
[Prior art]
Conventionally, a hologram replication method is used to produce a hologram having the same diffraction characteristics from an original hologram. When the hologram to be produced is a volume-type transmission hologram, as shown in FIG. 4A, a volume-type transmission hologram, a relief-type hologram, or an electron beam drawing hologram in which interference fringes are drawn by electron beam drawing A volume type hologram photosensitive material 11 such as a photopolymer is brought into close contact with the original plate 10 made of or made in close contact with the refractive index matching liquid, and the reproduction illumination light 12 is incident at a predetermined angle θ from the original plate 10 side. The 0th-order transmitted light 13 and the 1st-order diffracted light 14 that have passed through the original 10 are simultaneously incident on the hologram photosensitive material 11 and caused to interfere therewith, thereby replicating the original 10 on the hologram photosensitive material 11.
[0003]
When the hologram to be produced is a volume type reflection hologram, as shown in FIG. 4B, is the volume type hologram photosensitive material 21 such as a photopolymer adhered to the original plate 20 made of the volume type reflection hologram? Alternatively, they are brought into close contact with each other through a refractive index matching liquid, and the reproduction illumination light 22 is incident on the original 20 from the hologram photosensitive material 21 side at a predetermined angle θ, and the incident light 22 incident on the hologram photosensitive material 21 and the original 20 The original 20 is replicated on the hologram photosensitive material 21 by causing the first-order diffracted light 24 to interfere with the hologram photosensitive material 11 (in FIG. 4B, reference numeral 23 is the 0th-order transmitted light).
[0004]
[Problems to be solved by the invention]
When the hologram duplication method as described above is used, a hologram having the same diffraction angle characteristic as that of the original plates 10 and 20 should be obtained. In practice, however, in particular, a photopolymer is used as the hologram photosensitive materials 11 and 21. In this case, the peak diffraction angle characteristics of the duplicated hologram may deviate from those of the original plates 10 and 20. Although the cause is not necessarily clear, it is considered that the phenomenon is caused by a change in the inclination angle of the interference fringes in the sensitization process of the photosensitive material.
[0005]
Although it is conceivable to prepare the original plates 10 and 20 in consideration of such changes, the hologram original plates 10 and 20 are expensive and require a long time for preparation because high accuracy such as in-plane uniformity is required. Since this is necessary, it is not easy in practice, and the characteristic change due to the above-mentioned duplication varies depending on the lot of the hologram photosensitive material. Therefore, it is difficult to solve this problem by remanufacturing the masters 10 and 20.
[0006]
The present invention has been made in view of the above-described problems, and its object is to correct the difference in diffraction characteristics of the volume hologram after replication from the diffraction characteristics of the original plate or the angle of the two light beams during replication. To provide a volume hologram replication method.
[0007]
[Means for Solving the Problems]
The volume hologram replication method of the present invention that achieves the above object is a volume hologram replication method for replicating a volume hologram from a hologram master into a volume hologram photosensitive material,
In order to correct that the angle showing the diffraction efficiency peak of the replicated volume hologram is different from the incident angle of the two light beams that interfere with each other at the time of replication, an angle for compensating in advance the shift amount of the angle showing the diffraction efficiency peak In this state, the hologram master and the volume hologram photosensitive material are arranged so as to form an angle with each other. In this state, the hologram master is irradiated with duplication illumination light, and incident light incident on the hologram master or transmitted zero-order transmission is transmitted. In this method, light and first-order diffracted light are caused to interfere in a volume hologram photosensitive material.
[0008]
In this case, replication may be performed by interposing a wedge prism having a predetermined apex angle between the hologram master and the volume hologram photosensitive material so that an angle is formed between them, or refraction between the two. Replication may be performed with a rate matching liquid or air interposed.
[0009]
In this method, a volume hologram photosensitive material is arranged on the transmission side of a hologram master, and irradiation light for duplication is irradiated from the hologram master side, and the 0th order transmitted light and the 1st order diffracted light transmitted through the hologram master are converted into a volume hologram photosensitive material. Even when a volume-type transmission hologram is duplicated by interference, a volume-type hologram photosensitive material is arranged on the incident side of the hologram master, and the illumination light for duplication is irradiated from the volume-type hologram photosensitive material side to enter the hologram master. The present invention can also be applied to a case where a volume reflection hologram is replicated by causing incident light and first-order diffracted light to interfere in the volume hologram photosensitive material.
[0010]
The replication method of the present invention is a suitable method when a photopolymer is used as the volume hologram photosensitive material.
[0011]
In the present invention, in order to correct that the angle indicating the diffraction efficiency peak of the replicated volume hologram is different from the incident angle of the two interfering light beams at the time of replication, the angle shift indicating the diffraction efficiency peak in advance is corrected. The hologram master and the volume hologram photosensitive material are arranged so as to form an angle with each other by an angle that compensates for the quantity. In this state, the hologram master is irradiated with duplication illumination light, and incident light incident on the hologram master or Since the transmitted 0th-order transmitted light and 1st-order diffracted light interfere with each other in the volume hologram photosensitive material, the angle showing the peak of diffraction efficiency of the volume hologram replicated only by a simple replication arrangement change is interfered 2 The angle of the light beam with respect to the hologram original plate can be made substantially the same, and the same diffraction characteristic can be stably and easily produced by a replication method.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the volume hologram replication method of the present invention will be described based on examples.
[0013]
FIG. 1 is a diagram showing the characteristics of a specific volume-type transmission hologram master 1 and a volume-type transmission hologram 5 replicated therefrom. As shown in FIG. 1A, the hologram master 1 has an incident angle of 0 °. The incident light 2 having a wavelength of 532 nm is diffracted as a diffracted light 4 at a diffraction angle of 38 ° (an angle in the medium), and has a characteristic of having diffraction peaks at an incident angle of 0 ° and a diffraction angle of 38 °. ing. Note that the zero-order transmitted light is denoted by reference numeral 3.
[0014]
When such a hologram original plate 1 is used and a hologram duplication is made in a close contact arrangement as shown in FIG. 4A by using Omnidex 801 manufactured by DuPont as a volume hologram photosensitive material, as shown in FIG. When the incident light 6 having an incident angle of −6.2 ° (angle in the medium) is incident on the volume-type transmission hologram 5 having a wavelength of 532 nm, the diffraction angle is 32.1 ° (the angle in the medium). ) Is diffracted as diffracted light 8 and has characteristics of having diffraction peaks at an incident angle of −6.2 ° and a diffraction angle of 32.1 °. Zero-order transmitted light is indicated by 7.
[0015]
Therefore, when the volume transmission hologram is replicated in the close contact arrangement as shown in FIG. 4A, in this example, the angle indicating the diffraction peak is changed from 0 ° to −6.2 °. The diffraction angle is shifted from 38 ° to 32.1 °. The average of the incident angle shift amount -6.2 ° and the diffraction angle shift amount -5.9 ° is -6.1 °.
[0016]
Therefore, in the present invention, as shown in FIG. 2 (a), the angle between the volume-type transmission hologram master 1 and the volume-type hologram photosensitive material 11 that duplicates the average shift from 0 ° in the case of close contact. The refractive index at an apex angle of 6.1 ° is approximately the same as that of the original plate 1 and the photosensitive material 11 through the refractive index matching liquid 32 so as to be an angle that complements the angle, specifically 6.1 °. A wedge prism 31 is interposed between the two. With this arrangement, when incident light 2 having a wavelength of 532 nm is incident on the hologram master 1 at an incident angle of 0 °, the 0th-order transmitted light 3 has an incident angle of 6.1 ° (an angle in the medium), and the diffracted light. 4 is incident on the hologram photosensitive material 11 at an incident angle of 44.1 ° (an angle in the medium) and interferes with each other.
[0017]
Thereafter, when the exposed hologram photosensitive material 11 is subjected to predetermined ultraviolet irradiation and baking, as shown in FIG. 2B, the incident angle is 0.1 ° (angle in the medium) with respect to light having a wavelength of 532 nm. When the incident light 6 is incident, the volume transmission hologram 5 is diffracted while showing the efficiency peak at a diffraction angle of 38.2 ° (angle in the medium) as the diffracted light 8, and the hologram master 1 shown in FIG. Thus, a volume transmission hologram 5 having substantially the same diffraction angle characteristics is obtained.
[0018]
In the case of FIG. 2 (a), the wedge prism 31 is interposed between the volume transmission hologram master 1 and the volume hologram photosensitive material 11, but only the refractive index matching liquid 32 may be used instead. The air spacing may be such that the refractive index does not match the two. In that case, the hologram master 1 and the hologram photosensitive material 11 are set so that the incident angle of the zero-order transmitted light 3 in the hologram photosensitive material 11 is 6.1 ° and the incident angle of the diffracted light 4 is 44.1 °. Adjust the angle between.
[0019]
As described above, when replicating a volume transmission hologram from an original, the incident angle of incident light showing a diffraction peak and the diffraction angle of the diffracted light are shifted. Although it was a case where it compensates by arrange | positioning at an angle between, it is applicable similarly when replicating a volume type reflection hologram from an original. FIG. 3A shows the incident angle θ ₁ of the incident light 42 indicating the diffraction peak of the volume type reflection hologram master 41 and the diffraction angle θ ₂ of the diffracted light 44 (reference numeral 43 is the 0th order transmitted light). .), When this hologram master 41 is used to replicate a hologram in a close-contact arrangement as shown in FIG. 4B using the same volume hologram photosensitive material as in FIG. 1, the replicated volume transmission hologram 45 is For light of the same wavelength, a diffraction peak appears when the incident angle is Δθ ₁ larger than the incident angle θ _{1 at} the time of replication, and Δθ _{2 is} smaller than the incident angle θ ₂ of the diffracted light 44 at the time of replication. As shown. That is, the shift amount of the incident angle of the incident light 42 is −Δθ ₁ , the shift amount of the diffraction angle of the diffracted light is −Δθ ₂ , and the average shift angle −Δθ = − (Δθ ₁ + Δθ ₂ ) / 2.
[0020]
Therefore, also in this case, as shown in FIG. 3 (b), the angle between the volume type reflection hologram master 41 and the volume type hologram photosensitive material 21 that duplicates the average shift from 0 ° in the case of the close contact. A wedge prism 31 having a refractive index of apex angle Δθ of approximately the same refractive index as that of the original 41 and the photosensitive material 21 is interposed between the two through the refractive index matching liquid 32 so that the angle Δθ complements the angle −Δθ. Let In this arrangement, when the incident light 42 is incident on the hologram master 41 at an incident angle θ ₁ , the incident light 42 is incident on the hologram photosensitive material 21 at θ ₁ −Δθ (an angle in the medium) and the diffracted light 44. Is incident at an incident angle θ ₂ + Δθ (angle in the medium) and interferes with each other.
[0021]
Thereafter, when the exposed hologram photosensitive material 21 is subjected to predetermined ultraviolet irradiation and baking treatment, as shown in FIG. 3A, the incident angle is approximately θ ₁ (angle in the medium) with respect to light of the same wavelength. When the incident light 42 is incident, the volumetric reflection hologram 45 diffracts while showing the peak of efficiency as the diffraction light 44 having a diffraction angle of approximately θ ₂ (angle in the medium). Thus, a volume transmission hologram 45 having the same diffraction angle characteristic is obtained.
[0022]
In this case as well, the wedge prism 31 is interposed between the volume hologram photosensitive material 21 and the volume reflection hologram master 41. Instead, only the refractive index matching liquid 32 may be used, and the refractive index is Air intervals that do not match may be used. In that case, between the hologram photosensitive material 21 and the hologram original plate 41 so that the incident angle of the incident light 42 in the hologram photosensitive material 21 is θ ₁ −Δθ and the incident angle of the diffracted light 44 is θ ₂ + Δθ. Adjust the angle.
[0023]
The volume hologram replication method of the present invention described above can be applied to any hologram replication method as long as it is a volume hologram, but as an example, a volume transmission hologram is used for a hologram color filter or the like. The uniform volume diffraction grating, transmission hologram diffusion plate, and volume reflection hologram can be applied to reflection hologram diffusion plates, reflection hologram color filters, and reflection holograms for graphic arts.
[0024]
As mentioned above, although the volume type hologram replication method of the present invention has been described based on the embodiments, the present invention is not limited to these embodiments and can be variously modified.
[0025]
【The invention's effect】
As is apparent from the above description, according to the volume hologram duplication method of the present invention, it is corrected that the angle indicating the peak of diffraction efficiency of the duplicated volume hologram is different from the incident angle of the two interfering beams at the time of duplication. In order to achieve this, the hologram master and the volume hologram photosensitive material are arranged so as to form an angle with each other by an angle that compensates for the shift amount of the angle showing the peak of the diffraction efficiency, and the hologram master is copied in that state. Volume light that is replicated by simply changing the replication arrangement, because the illumination light is irradiated and the incident light incident on the hologram master or the transmitted 0th-order transmitted light and 1st-order diffracted light interfere with each other in the volume-type hologram photosensitive material. The angle that shows the peak of diffraction efficiency of the hologram can be made approximately the same as the angle of the two light beams that interfere during replication with the hologram master, and have the same diffraction characteristics It can be produced by stably easily duplicated method.
[Brief description of the drawings]
FIG. 1 is a diagram showing the characteristics of a volume-type transmission hologram master according to one specific example and a volume-type transmission hologram obtained therefrom by a contact replication method.
FIG. 2 is a diagram showing a hologram replication arrangement applied to the example of FIG. 1 according to the present invention and the characteristics of a volume type transmission hologram obtained thereby.
FIG. 3 is a diagram showing characteristics of a volume type reflection hologram master and a volume type transmission hologram obtained therefrom by a contact replication method, and a diagram showing a hologram replication arrangement to which the present invention is applied in that case.
FIG. 4 is a diagram for explaining a conventional volume hologram replicating method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Volume type transmission hologram master 2 ... Incident light 3 ... 0th order transmitted light 4 ... Diffraction light 5 ... Volume type transmission hologram 6 ... Incident light 7 ... 0th order transmission light 8 ... Diffraction light 10 ... Transmission hologram original plate 11 ... Volume type Holographic photosensitive material 12 ... Reproduction illumination light 13 ... 0th order transmitted light 14 ... 1st order diffracted light 20 ... Volume type reflection hologram master 21 ... Volume type hologram photosensitive material 22 ... Reproduction illumination light 23 ... 0th order transmitted light 24 ... 1st order diffracted light 31 ... Wedge prism 32 ... Refractive index matching liquid 41 ... Volume type reflection hologram master 42 ... Incident light 43 ... 0th order transmitted light 44 ... Diffracted light 45 ... Volume type transmission hologram

Claims (6)

In a volume hologram replication method for replicating a volume hologram from a hologram master into a volume hologram photosensitive material,
When the hologram master and the volume hologram photosensitive material are replicated in close contact, the incident angle of the incident light showing the peak of diffraction efficiency of the replicated volume hologram and the incidence of the incident light on the hologram master of the diffraction angle of the diffracted light, respectively. The average value of the difference between the angle and the diffraction angle of the diffracted light is calculated to calculate the amount of shift of the angle showing the peak of diffraction efficiency, and the hologram master and volume are compensated for the amount of shift of the angle showing the peak of diffraction efficiency. The hologram hologram photosensitive material is arranged so as to form an angle with each other, and in this state, the hologram master is irradiated with replication illumination light, incident light incident on the hologram master or transmitted zero-order transmitted light and first-order diffracted light In a volume hologram photosensitive material, and a volume hologram replication method.   2. The volume hologram duplication according to claim 1, wherein the hologram master and the volume hologram photosensitive material are duplicated by interposing a wedge prism having a predetermined apex angle between the hologram master and the volume hologram photosensitive material. Method.   2. The volume hologram replicating method according to claim 1, wherein the hologram master and the volume hologram photosensitive material are duplicated by interposing a refractive index matching liquid or air between the hologram master and the volume hologram photosensitive material. .   A volume hologram photosensitive material is disposed on the transmission side of the hologram master, and irradiation light for duplication is irradiated from the hologram master side, so that the 0th-order transmitted light and the first-order diffracted light transmitted through the hologram master interfere with each other in the volume hologram photosensitive material. 4. The volume hologram reproduction method according to claim 1, wherein the volume transmission hologram is duplicated.   A volume type hologram photosensitive material is arranged on the incident side of the hologram master, irradiation light for duplication is irradiated from the volume type hologram photosensitive material side, and the incident light incident on the hologram master and the first-order diffracted light interfere in the volume hologram photosensitive material. 4. The volume hologram reproduction method according to claim 1, wherein the volume reflection hologram is duplicated.   6. The volume hologram replication method according to claim 1, wherein the volume hologram photosensitive material is made of a photopolymer.

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