Optical member and dimming unit

Abstract

To provide an optical member with which cracks hardly occur.SOLUTION: In order to solve the above problem, an optical member according to the present invention comprises a light-shielding unit 15 and a dimming unit formed on a substrate 2. The dimming unit is composed of a pattern formed continuously from the light-shielding unit 15, the pattern having a transmissivity inclination film 4 whose transmissivity changes successively, and which has a transmissivity inflection point where a transmissivity change rate changes before and after it, and whose film thickness changes in succession. The transmissivity change rate in a direction from the transmissivity inflection point to the tip of the pattern is larger than a transmissivity change rate at the transmissivity inflection pint from the light-shielding unit. When it is assumed that a direction orthogonal to the film thickness direction of the transmissivity inclination film 4 is an axis X, the pattern has, at the same position as the transmissivity inflection point on the axis X, a pattern inflection point where the shape change rage of the pattern changes before and after it, and the shape change rate is contrary to the transmissivity change rate of the transmissivity inclination film.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an optical member and a light control unit used in projection technology. [Background technology]

[0002] Multi-projection technology is known, which projects multiple images using a projector to create one large image. In order to overlap the images seamlessly, the images are overlapped so that the edges of the projected images overlap, but this creates a problem in that the brightness of the overlapping projection area becomes high. As a means of adjusting the brightness of the overlapping projection area to be the same as the surrounding area, there are signal processing methods that adjust the image signal and optical methods that use light shielding plates, but the former has problems such as being expensive and prone to black floating, which is an insufficient black color to be projected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3737029 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a technology for adjusting the brightness of the overlap projection section by a light shielding plate in which multiple sawtooth filters are superimposed so that the transmittance changes stepwise. The light shielding plate of Patent Document 1 is made by superimposing sawtooth filters, so the transmittance changes stepwise, but by forming a film in a sawtooth shape whose transmittance changes continuously, the amount of light can be adjusted more effectively. However, a film whose transmittance changes continuously can be obtained by continuously changing its physical film thickness, but if the physical film thickness is changed suddenly, cracks are likely to occur. In particular, there is a problem that cracks are likely to occur in the area with the lowest transmittance close to the light shielding section, i.e., the area with the thickest film. [Means for solving the problem]

[0005] In order to solve the above problems, the optical element of the present invention comprises a light-shielding portion and a light-adjusting portion formed on a substrate, the light-adjusting portion comprising a pattern formed continuously from the light-shielding portion, in which the transmittance changes continuously and the transmittance change rate changes before and after the transmittance change pattern, the transmittance change rate from the transmittance inflection point toward the tip of the pattern is greater than the transmittance change rate from the light-shielding portion to the transmittance inflection point, the pattern has a pattern inflection point at which the shape change rate of the pattern changes before and after the pattern, at the same position on the X-axis as the transmittance inflection point, when the direction perpendicular to the thickness direction of the transmittance gradient film is taken as the X-axis, and the shape change rate is opposite to the transmittance change rate of the transmittance gradient film. Effect of the Invention

[0006] It is possible to provide an optical member that can adjust the amount of light continuously and linearly in the dimming section and that suppresses cracks in the dimming section. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 shows an optical member according to the present invention. [Diagram 2] FIG. 13 is a diagram showing the change in transmittance of the transmittance gradient film with respect to the X-axis of the optical member according to the present invention, the ratio of the film-formed area in the direction perpendicular to the X-axis on the film-formed surface of the transmittance gradient film, and the brightness of light transmitted through the optical member. [Diagram 3] Cross-sectional view of a transmittance gradient film according to the present invention. [Figure 4] FIG. 1 is a diagram showing a method for forming a film by a vacuum deposition method for the transmittance gradient film of the present invention. [Diagram 5] 1 is a cross-sectional view of an optical member according to a first embodiment, showing transmittance and pattern shape; [Figure 6] FIG. 1 shows a cross-sectional view, transmittance, and pattern shape of an optical member according to Example 2. [Figure 7] 1 is a cross-sectional view of an optical member according to a third embodiment, showing transmittance and pattern shape; [Figure 8] A diagram showing a multi-projection technology using the optical member of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the present invention will be described with reference to the drawings.

[0009] FIG. 1 shows an optical member according to the present invention. The optical member 1 of the present invention has a light-shielding portion and a light-adjusting portion, and the light-adjusting portion is formed continuously from the light-shielding portion. A gradient transmittance film whose transmittance changes continuously in a direction perpendicular to the thickness direction is formed in a pattern shape on at least one surface of the substrate. Specifically, the transmittance of the gradient transmittance film increases continuously with increasing distance from the light-shielding portion. Furthermore, the gradient transmittance film has a transmittance inflection point at which the rate of change in transmittance changes significantly before and after the inflection point, and the rate of change in transmittance from the inflection point to the pattern tip is greater than the rate of change in transmittance from the light-shielding portion to the inflection point. The change in transmittance is correlated with the film thickness of the gradient transmittance film, and the rate of change in film thickness from the inflection point to the pattern tip is greater than the rate of change in film thickness from the light-shielding portion to the inflection point. Here, the transmittance inflection point refers to a point at which the average rate of change in transmittance before and after the inflection point changes by about 1.5 to 5 times.

[0010] In addition, the pattern shape of the light control part also changes in a direction perpendicular to the film thickness direction of the transmittance gradient film so that the pattern area continuously narrows from the light shielding part to the pattern tip, and has a pattern inflection point where the shape change rate changes greatly before and after. Furthermore, the change rate of the pattern shape is set to be opposite to the change rate of the transmittance gradient film, and specifically, the shape change rate from the light shielding part to the pattern inflection point is formed to be larger than the shape change rate from the pattern inflection point to the pattern tip direction. Here, when the direction in which the transmittance of the transmittance gradient film continuously changes is taken as the X-axis, the transmittance inflection point and the pattern inflection point are located at substantially the same position on the X-axis. Here, the pattern inflection point refers to a point where the average shape change rate of the pattern before and after it changes by about 1.5 to 5 times.

[0011] FIG. 2 shows the transmittance change with respect to the X-axis of the transmittance gradient film of the optical member according to the present invention, the ratio of the film-formed area in the direction perpendicular to the X-axis on the transmittance gradient film formation surface, and the brightness of light transmitted through the optical member. Here, the ratio of the film-formed area indicates, for example, the ratio of the area on the AA′ line in FIG. 2 where the transmittance gradient film is formed, and the rate of change corresponds to the rate of change of the pattern shape. As shown in FIG. 2, in the optical member of the present invention, the transmittance gradient film does not have a constant rate of change in transmittance from the light-shielding part to the tip of the pattern, and the rate of change differs at the inflection point of the X-axis. Specifically, the transmittance changes gently from the light-shielding part to the transmittance inflection point, and the rate of change in transmittance from the transmittance inflection point to the tip of the pattern becomes large. On the other hand, the rate of change of the film-formed area also differs at the inflection point of the pattern, and the rate of change is opposite to that of the transmittance gradient film. Specifically, the rate of change is large from the light-shielding part to the inflection point of the pattern, and the rate of change is gentle from the inflection point of the pattern to the tip of the pattern. When the brightness of the image projected through the optical member according to the present invention is set to 1 in the region of the optical member where the transmittance gradient film is not formed, the brightness of the light control portion attenuates approximately linearly toward the light shielding portion. Note that, although there is only one pattern inflection point and one transmittance inflection point in FIG. 2, there may be a plurality of pattern inflection points and transmittance inflection points. However, when a plurality of transmittance inflection points and pattern inflection points are provided, when the transmittance inflection point and pattern inflection point closest to the light shielding portion are respectively the first transmittance inflection point and the first pattern inflection point, and the transmittance inflection point and pattern inflection point second closest to the light shielding portion are respectively the second transmittance inflection point and the second pattern inflection point, the film is formed so that the transmittance change rate at the first transmittance inflection point and the second transmittance inflection point is larger than the transmittance change rate at the light shielding portion and the first transmittance inflection point. Furthermore, the shape change rate from the light-shielding portion to the first pattern inflection point is formed to be larger than the shape change rates of the first pattern inflection point and the second pattern inflection point. In addition, in Fig. 2, the transmittance of the transmittance gradient film changes linearly from the light-shielding portion to the transmittance inflection point and from the transmittance inflection point to the pattern tip, respectively, but it does not necessarily have to change linearly.That is, the pattern formed by the transmittance gradient film does not necessarily need to have a shape change rate that changes linearly from the light blocking portion to the pattern inflection point, and from the pattern inflection point to the pattern tip.

[0012] ≪Base material≫ As the substrate 2 used in the present invention, any substrate can be used as long as it is transparent in the desired light wavelength region (transparent substrate). For example, substrates made of inorganic materials such as glass and quartz, and various synthetic resin substrates such as polyester, norbornene, polyether, acrylic, styrene, PET (polyethylene terephthalate), PES (polyethersulfone), polysulfone, PEN (polyethylene naphthalate), PC (polycarbonate), and polyimide can be used. Considering the use environment of the optical member, it is preferable that the heat resistance is high, and from this point of view, a glass substrate is preferably used. On the other hand, compared with inorganic substrates such as glass, synthetic resin substrates have the advantages of being flexible, light, and easy to process, but they are prone to deformation due to thermal stress and changes in characteristics due to moisture, and furthermore, depending on the manufacturing method, they may have polarization characteristics. For this reason, when using a synthetic resin substrate, it is desirable to use a material that has high heat resistance (high glass transition temperature Tg), low water absorption, and small birefringence. Examples of synthetic resins that satisfy these requirements include norbornene. If necessary, a substrate made of an organic-inorganic hybrid material, for example a substrate having a silsesquioxane skeleton, may be used.

[0013] The thickness of the substrate according to the present invention is preferably somewhat thick in order to improve rigidity and handling, and is more preferably about 0.5 to 20 mm, and more preferably about 1 to 10 mm. If the plate thickness is too thick, there is a risk that retardation due to birefringence will become large, particularly when a synthetic resin substrate is used.

[0014] ≪Transmittance gradient film≫ Fig. 3 shows a cross-sectional view of the transmittance gradient film according to the present invention. As shown in Fig. 3, the transmittance gradient film 4 is composed of a light absorption laminate 3 including a light absorption layer 11 and a dielectric layer 12. As the light absorption layer 11, for example, simple substances or alloys of Ti, Ni, Cr, Fe, Nb, Ta, or their oxides, nitrides, etc. can be preferably used, but it is mainly preferable to use metal oxides. Since metal oxides generally have a smaller light absorption rate (attenuation coefficient) than metal films and metal nitride films, the film thickness of the light absorption layer 11 can be made relatively thick, and control such as continuously changing the film thickness of the light absorption layer as described later becomes relatively easy. Specifically, TiOx (0 < x < 2) which is inexpensive and has a relatively linear transmittance in the visible wavelength region can be preferably used.

[0015] The oxidation number or nitrogenation number of the light absorption layer 11 may be substantially the same in all layers, or different layers may be provided. By having different oxidation numbers or nitrogenation numbers in the light absorption layer, optical properties such as refractive index and attenuation coefficient change, and the wavelength dependence of transmittance may show a different tendency. For example, in the case of titanium oxide (TiOx), when x = 1 (TiO), when the physical film thickness is 200 Å, the transmittance shows a gentle downward trend toward the short wavelength side (400 nm side) of the visible light wavelength. On the other hand, when x = 1.5 (Ti 2 O 3 ), when the physical film thickness is also 200 Å, the transmittance shows a downward trend toward the long wavelength (700 nm side) of the visible light wavelength. That is, TiO and Ti 2 O 3 have complementary optical properties in terms of the transmittance characteristics of visible light wavelengths. Thus, by using both a TiO layer and a Ti 2 O 3 layer in the light absorption layer 11, it is easy to reduce the wavelength dependence of transmittance at visible light wavelengths as the light absorption laminate 3, and the degree of freedom in film design for realizing low reflection in this wavelength region is increased. As a method for making the oxidation number or nitrogenation number different in the light absorption layer 11, a method of adjusting the oxidation number of the starting material for each layer, or a method of adjusting the ratio of air, oxygen, nitrogen, etc. introduced during film formation can be used.

[0016] When the oxidation number or nitridation number of each light absorbing layer 11 is approximately the same, a method for reducing the wavelength dependency of the transmittance of the light absorbing laminate 3 at visible light wavelengths is, for example, to form the light absorbing layer 11 into a layer of TiO and a layer of Ti 2 O 3 In this way, it is possible to reduce the wavelength dependency of the transmittance of each layer of the light absorbing layer 11 at visible light wavelengths. 2 O 3 In the case of a mixed layer of TiO and TiO2, the oxidation number of the starting material may be adjusted to any desired oxidation number, or the ratio of air, oxygen, nitrogen, etc. introduced during film formation may be adjusted. Alternatively, a two-source deposition method may be used to deposit, for example, TiO and TiO2. 2 O 3 may be formed simultaneously. When the oxidation number or nitridation number is made different for each layer of the light absorbing layer 11, it is preferable that the oxidation number or nitridation number of the light absorbing layer closest to the substrate 2 side is the smallest among the light absorbing layers. In general, the smaller the oxidation number or nitridation number, the higher the light absorption, while the reflectance is also likely to be high. For this reason, by arranging the light absorbing layer with a smaller oxidation number or nitridation number on the substrate 2 side and arranging the light absorbing layer with a larger oxidation number or nitridation number on the surface layer side, it is possible to effectively suppress the reflectance while maintaining the light absorption function. On the other hand, it is preferable that the oxidation number or nitridation number of the light absorbing layer closest to the surface layer among the light absorbing layers 11 forming the light absorbing laminate 3 is the largest. This is because the reflection of the light absorbing layer 11 tends to decrease as the oxidation number or nitridation number increases. In other words, by adopting such a configuration, it is possible to effectively suppress the reflection while maintaining the light blocking property. The light absorbing layers present between the light absorbing layer closest to the substrate 2 and the light absorbing layer closest to the surface layer may have substantially uniform oxidation numbers and nitridation numbers, or may have different oxidation numbers and nitridation numbers, or may have oxidation numbers and nitridation numbers that increase continuously toward the surface layer, for example. On the other hand, by making the oxidation numbers or nitridation numbers of the light absorbing layers 11 substantially the same, the optical constants of the light absorbing layers 11 can be made the same for each layer, which has the advantage of facilitating film design. Note that in this embodiment, TiO and Ti 2 O 3 However, the present invention is not limited to this and any material can be used.

[0017] Also, when forming a light absorption layer (TiOx: x < 1) with an oxygen ratio smaller than that of TiO in the light absorption layer, for example, Ti may be used as a starting material and film formation may be carried out while introducing air or oxygen. Alternatively, for example, TiO may be used as a starting material, and a method such as irradiating high-energy at a level where oxygen deviation occurs during film formation to intentionally obtain oxygen deficiency can be used. Conversely, for example, Ti 2 O 3 When forming a light absorption layer (TiOx: 1.5 < x) with an oxygen ratio larger than that of O, for example, Ti 4 O 7 etc. may be selected as the starting material, or for example, Ti 2 O 3 may be used as a starting material and film formation may be carried out while introducing air or oxygen.

[0018] As the dielectric layer 12, SiO 2 , MgF 2 , SiO 2 , SiO, Si 3 H 4 , Al 2 O 3 , MgO, LaTiO 3 , ZrO 2 , TiO 2 , Nb 2 O 5 , Ta 2 O 5 etc. can be used. As the dielectric layer 12, in order to suppress characteristic changes due to oxidation of the light absorption layer 11, it is preferably a layer with high gas barrier properties. From this point, Al 2 O 3 is particularly suitable.

[0019] It is preferable to provide a low refractive index material layer 13 on the surface layer of the light absorption laminate 2. For example, SiO 2 or MgF 2 is suitable. At this time, when the center wavelength is λ, it is preferable to adjust the optical film thickness to be about λ / 4, specifically about 0.7 to 1.3λ / 4. By doing so, it is possible to achieve low reflection for a desired wavelength.

[0020] Here, the light absorbing laminate 3 has a region where the film thickness changes continuously, that is, the transmittance gradient film 4, as shown in FIG. 3. It is sufficient that at least the light absorbing layer 11 forming the transmittance gradient film 4 changes in film thickness continuously, and the dielectric layer 12 may or may not change in film thickness, but it is more preferable that the film thickness of the low refractive index layer 13 of the outermost layer is approximately uniform in the film formation region. This is because the outermost layer has an anti-reflection function, and from this point of view, it is preferable that the film thickness is 0.7 to 1.3λ / 4. When it is desired to reduce the reflectance change in the pattern region, it is preferable that the film thickness of the dielectric layer forming the transmittance gradient film 4 is approximately uniform in the film formation region. This is because when comparing the light absorbing layer 11 and the dielectric layer 12 constituting the transmittance gradient film 4, the dielectric layer 12 has a thicker film thickness and has a larger effect on the reflectance characteristics. It is noted that in the optical member 1 of the present invention, the film thickness change of at least the light absorbing layer 11 forming the transmittance gradient film 4 is not uniform from the light shielding portion to the pattern tip, but has an inflection point, which corresponds to the transmittance inflection point 5. That is, there is a correlation between the film thickness and the transmittance of the light absorbing layer 11. Here, the average rate of change in the transmittance from the transmittance inflection point toward the pattern tip is preferably about 1.5 to 5 times the average rate of change in the transmittance from the light shielding part to the transmittance inflection point. If the difference in the rate of change is too small, the change in the film thickness of the light absorbing layer from the light shielding part to the transmittance inflection point is not sufficiently gentle. On the other hand, if the difference in the rate of change is too large, the change in the film thickness of the light absorbing layer from the transmittance inflection point toward the pattern tip becomes too large, and there is a risk of cracks occurring in this region.

[0021] In the present invention, the transmittance gradient film 4 is formed in a pattern shape. The pattern shape is formed so that it becomes continuously smaller from the light-shielding part toward the pattern tip. Furthermore, it has a pattern inflection point where the shape change rate is different before and after it. The pattern inflection point is located at approximately the same position as the transmittance inflection point 5 in the X-axis direction. The pattern shape change rate is formed so that the change rate from the light-shielding part to the pattern inflection point is about 1.5 to 5 times the change rate from the pattern inflection point toward the pattern tip. The pattern formed by the transmittance gradient film 4 is periodically formed in a direction perpendicular to the X-axis. At this time, the interval (pitch) between each pattern is about 0.05 to 1 mm, and more preferably about 0.05 to 0.3 mm. If the pitch is too small, it is difficult to form a pattern, while if the pitch is too large, it is difficult to average the light transmitted through the dimming part, and there is a risk of light and dark occurring in the image in the direction perpendicular to the X-axis. Furthermore, the length of the pattern in the X-axis direction depends on the specifications of the projector used and the position of the optical member 1, but is preferably about 1 to 20 mm, and more preferably about 2 to 10 mm. If the pattern is too short, it is necessary to suddenly change the film thickness of the transmittance gradient film 4. If the film thickness is suddenly changed, there is a risk that cracks will easily occur. On the other hand, if the pattern is too long, the distance from the projection unit of the projector becomes long when the optical member is placed, so that the length required for the optical member in the direction perpendicular to the X-axis direction becomes long, leading to an increase in the size of the optical member.

[0022] In the optical member 1 of the present invention, the light-shielding portion may be formed with a light-shielding film made of, for example, metal, dye, pigment, or the like, or may be formed with a light-shielding material such as a thin plate coated with a light-shielding coating on a resin substrate such as PET, but it is more preferable to form a light-absorbing laminate 3 similar to the transmittance gradient film 4. The film configuration of the light-absorbing laminate 3 may be the same as or different from that of the transmittance gradient film 4. When the light-absorbing laminate 3 identical to the transmittance gradient film 3 is formed in the light-shielding portion, the light-shielding property can be effectively increased by forming at least a part of the light-absorbing layer 11 of the light-absorbing laminate 3 as a metal film. In this case, it is preferable to arrange the metal film in a layer other than the layer closest to the surface of the light-absorbing layer 11. This is because the reflectance increases when the metal film is arranged near the surface. By providing at least one light-absorbing layer made of a metal oxide or metal nitride on the surface side of the metal film, the light reflected by the metal film can be effectively attenuated. For this reason, when a metal film is provided, it is preferable to form the metal film in a layer as close to the substrate as possible. The transmittance of the light-shielding part is preferably 1% or less (optical density OD=2 or more), and when the light-shielding part is formed by the light-absorbing laminate 3, the number of layers and the thickness of the light-absorbing layer 11 and the dielectric layer 12 are adjusted to satisfy this. For example, when only a metal oxide is used as the light-absorbing layer 11, the number of layers of the light-absorbing layer 11 is preferably about 5 to 12 layers, more preferably about 6 to 9 layers. If the number of layers of the light-absorbing layer 11 is too small, the thickness of each light-absorbing layer 11 must be limited in order to provide sufficient light absorption, making film design difficult. On the other hand, if the number of layers of the light-absorbing layer 11 is increased too much, the overall thickness of the light-absorbing laminate 3 becomes too thick, and cracks are likely to occur. Note that the light-absorbing layer 11 is preferably sandwiched between the dielectric layers 12 in order to stabilize its light absorption characteristics. In this case, when the light-absorbing layer 11 is about 5 to 12 layers, the light-absorbing laminate 3 has at least about 11 to 25 layers. Here, the optical density OD is expressed as OD=Log(1 / T) where T is the transmittance, and the higher the transmittance, the lower the optical density.

[0023] In addition, a functional film may be formed on the light shielding portion and the light control portion. Examples of the functional film include an anti-soiling film that prevents fingerprints and dirt from adhering due to its water and oil repellency, and a hard film that improves scratch resistance. As the anti-soiling film, a fluorine-containing compound such as fluoroalkyl ether can be suitably used. The fluorine-containing compound can be impregnated into a metal support such as steel wool to form a film by vapor deposition (resistance heating), and is suitable in that it can be formed in the same process as the light absorption laminate 3 of the present invention. It is known that a fluorine-containing compound such as fluoroalkyl ether reacts with Si-OH (silanol group) to form a strong film, and the fluorine-containing compound can be applied to a SiO 2 film as an adhesion layer before film formation. 2 It is more preferable to form the low refractive index layer 13 of the light absorbing laminate 3 using SiO 2 As the hard film, a resin hard coat film can be used, but a stronger inorganic film is preferable, such as a Si 3 N 4 Examples of the functional film include nitride films such as TiN and AlN, and DLC (diamond-like carbon) films. Of these, nitride films that can be formed by the same physical vapor deposition method as the transmittance gradient film 4 are more preferably used. Note that both an antifouling film and a hard film may be formed as the functional film. In this case, it is preferable to form the antifouling film on the hard film.

[0024] In the present invention, the light absorbing stack 3 and the gradient transmittance film 4 may be formed on only one surface of the substrate 2, or on both surfaces. When the light absorbing stack 3 and the gradient transmittance film 4 are formed on only one surface of the substrate 2, it is preferable to provide the above-mentioned functional film on the surface on which they are not formed. Furthermore, an anti-reflection film consisting of a single layer or multiple layers may be formed as necessary. When the light absorbing stack 3 and the gradient transmittance film 4 are formed on both surfaces of the substrate, the pattern shape and the rate of change in transmittance of the gradient transmittance film 4 may be the same or different on each surface.

[0025] ≪Manufacturing method≫ An example of a method for producing the optical member 1 of the present invention will be described below. Note that the production method described below is merely an example, and the present invention is not limited to this.

[0026] A positive photoresist (OFPR-5000LB: manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to the substrate 1 by spin coating, and exposure is performed using an exposure mask. The exposure was performed using g-line (light wavelength 436 nm). After exposure, the photoresist in the exposed area is removed with an alkaline developer (NMD-3: manufactured by Tokyo Ohka Kogyo Co., Ltd.) made of TMAH (tetramethylammonium hydroxide), and the substrate is rinsed and washed with pure water, followed by drying. In this way, the photoresist is formed in areas other than the area where the light absorbing laminate 3 is to be formed.

[0027] Next, the light absorbing laminate 3 is formed. The light absorbing laminate 3 is formed by a vacuum deposition method. FIG. 4a is a diagram showing a typical deposition apparatus. The substrate is attached to a deposition dome 22 provided in a vacuum chamber 21. A tilting jig 24 having a desired inclination with respect to the plane of the substrate 2 is attached between the substrate 2 and the evaporation source 23 as shown in FIG. 4b. During deposition, the substrate 2 also rotates in accordance with the rotation of the deposition dome 22. Depending on the positional relationship between the evaporation source 23, the substrate 2, and the tilting jig 24 at this time, the deposition material scattered from the evaporation source 23 can adhere to the substrate 2 or be blocked by the tilting jig 24, thereby providing a gradient in the thickness of the deposition film formed on the substrate 2. Since the positional relationship between the evaporation source 23 and the substrate 2 is substantially fixed by the apparatus, the length of the light control section and the inclination of the thickness of the deposition film can be adjusted to the desired value by adjusting the angle θ of the tilting jig 24 with respect to the substrate 2 and the distance G between the substrate 2 and the tilting jig 24. In addition, the angle θ with respect to the substrate 2 may be changed on the tilting jig 24 as necessary. The tilting jig 24 may be used at least when the light absorbing layer of the light absorbing laminate 3 is formed. For example, the tilting jig 24 may be driven and placed in a place that does not affect the formation of the light control section or the light blocking section when the dielectric layer is formed. After the light absorbing laminate 3 is formed on the substrate 2 in this manner, the substrate 2 is immersed in acetone and ultrasonic cleaning is performed. As a result, the photoresist is removed, and the light absorbing laminate 3 having a pattern shape is formed on the substrate 2. The optical member 1 is obtained by washing the substrate 2 with pure water and drying the substrate 2. In this example, the photoresist is used to form the pattern shape, but for example, a film formation mask having a pattern shape punched out thereon may be provided between the substrate 2 and the tilting jig 24 so that the light absorbing laminate 3 is formed in a pattern shape, or after the light absorbing laminate 3 is formed, the substrate may be cut into the pattern shape using a laser or a punching blade, or a pattern shape may be provided in advance on the base material before the light absorbing laminate 3 is formed.

[0028] Example 1 FIG. 5 shows a cross-sectional view, transmittance, and pattern shape of the optical member according to Example 1. In the optical member of this example, a light control portion, a light shielding portion, and a transparent portion are formed on a glass substrate with a thickness of 3 mm. The light control portion has a length (L) of 5 mm and a pitch (P) of 0.1 mm in a pattern shape with a pattern inflection point where the rate of change of the pattern shape changes in the length direction of the pattern, and a light absorption laminate 3 in which the transmittance continuously changes from the light shielding portion toward the pattern tip is formed. The light absorption laminate 3 formed in the light control portion is used as the transmittance gradient film 4. Note that the transmittance gradient film 4 has a transmittance inflection point 5 where the rate of change of the transmittance changes in a certain region. A light absorption laminate 3 having the same film configuration as the light control portion is formed on the light shielding portion with a substantially uniform film thickness. Here, the transmittance change from the light shielding portion to the transmittance inflection point 5 and the transmittance change from the transmittance inflection point 5 to the pattern tip of the transmittance gradient film of Example 1 are not uniform, but the average rate of change of the transmittance in each region is approximately 14.7% / mm and 22.8% / mm, respectively, and the average rate of change of the transmittance from the transmittance inflection point 5 to the pattern tip is about 1.55 times the average rate of change of the transmittance from the light shielding portion to the transmittance inflection point.

[0029] The light absorption laminate 3 of Example 1 has a structure in which a light absorption layer 11 made of TiOx (0 < x < 2) and a dielectric layer 12 made of Al 2 O 3 are alternately laminated. In the pattern region of the light control portion, both the TiOx layer and the Al 2 O 3 layer have a film thickness gradient. Further, SiO 2 which is a low refractive index layer 13 with a substantially uniform film thickness is formed on the entire surface including the light control portion, the light shielding portion, and the transparent portion to a thickness of approximately λ / 4 (λ = 550 nm). Further, a functional film 14 (antifouling film) mainly composed of fluoroalkyl ether is formed on SiO 2 . In this example, the light absorption laminate 3 has 6 layers of TiOx and Al 2 O 3The light-shielding portion has seven layers. The transmittance of the light-shielding portion in this embodiment is about 0.5% (optical density OD=about 2.3) at a light wavelength of 550 nm. The transmittance of the transparent portion is about 98.5% (optical density OD=about 0.0066) at a light wavelength of 550 nm, and the transmittance of the light-adjusting portion changes continuously from about 0.5% to 98.5% from the light-shielding portion side toward the pattern tip. When the direction perpendicular to the film thickness direction of the light-absorbing laminate 3 (transmittance gradient film 4) is taken as the X-axis, the pattern inflection point 6 is located at approximately the same position as the transmittance inflection point 5 on the X-axis. The pattern is formed so that the area where the transmittance gradient film 4 is formed continuously becomes smaller from the light-shielding portion, but the pattern shape change rate is opposite to the transmittance change rate of the transmittance gradient film 4. That is, in this embodiment, the shape change rate from the light-shielding portion to the pattern inflection point 6 is larger than the shape change rate from the pattern inflection point 6 to the pattern tip, and the magnification is about 1.55 times.

[0030] Example 2 FIG. 6 shows a cross-sectional view, transmittance, and pattern shape of the optical member according to Example 2. The optical member of this example has a light control portion, a light shielding portion, and a transparent portion formed on a glass substrate with a thickness of 3 mm. In this example, the light control portion has a pattern-shaped light absorption laminate 3 (transmittance gradient film 4) with a length (L) of 5 mm and a pitch (P) of 0.1 mm, having a pattern inflection point where the rate of change of the pattern shape changes in the length direction of the pattern, and the transmittance continuously changes from the light shielding portion toward the pattern tip. The light shielding portion has a light shielding film 15 made of Cr, and the light absorption laminate 3 is formed thereon. Here, the light absorption laminate 3 has the same film configuration as the transmittance gradient film 4. In this example, the light absorption laminate 3 formed in a pattern, that is, the transmittance gradient film 4, has a transmittance inflection point 5 where the transmittance continuously decreases from the light shielding portion to the pattern tip, but the rate of change of the transmittance changes, and the transmittance changes linearly from the light shielding portion to the transmittance inflection point 5 and from the transmittance inflection point to the pattern tip. The average rate of change of the transmittance in each region is approximately 10.0% / mm and 25.5% / mm, and the rate of change of the transmittance from the transmittance inflection point 5 to the pattern tip is about 2.55 times the rate of change of the transmittance from the light shielding portion to the transmittance inflection point.

[0031] The light absorption laminate 3 of Example 2 has a structure in which a light absorption layer 11 made of TiOx (0 < x < 2) and a dielectric layer 12 made of Al 2 O 3 are alternately laminated. In the pattern region of the light control portion, both the TiOx layer and the Al 2 O 3 layer have a film thickness gradient. Also, a low refractive index layer 13 of SiO 2 with a substantially uniform film thickness is formed on the entire surface including the light control portion, light shielding portion, and transparent portion to a thickness of approximately λ / 4 (λ = 550 nm). Further, a functional film 14 (antifouling film) mainly composed of fluoroalkyl ether is formed on the SiO 2 . In this example, the light absorption laminate 3 has 6 layers of TiOx and Al 2 O 3The light-shielding portion has seven layers. The transmittance of the light-shielding portion in this embodiment is about 0.05% (optical density OD=about 3.3) at a light wavelength of 550 nm. The transmittance of the transparent portion is about 98.5% (optical density OD=about 0.0066) at a light wavelength of 550 nm, and the transmittance of the light-adjusting portion changes continuously from about 2.0% to 98.5% from the light-shielding portion side toward the pattern tip. Here, when the direction perpendicular to the thickness direction of the light-absorbing laminate 3 (transmittance gradient film 4) is taken as the X-axis, the pattern inflection point 6 is located at approximately the same position as the transmittance inflection point 5 on the X-axis. The pattern is formed so that the area where the transmittance gradient film 4 is formed continuously becomes smaller from the light-shielding portion, but the pattern shape change rate is opposite to the transmittance change rate of the transmittance gradient film 4. That is, in this embodiment, the shape change rate from the light-shielding portion to the pattern inflection point 6 is larger than the transmittance change rate from the pattern inflection point 6 to the pattern tip, and the magnification is about 2.55 times.

[0032] Example 3 FIG. 7 shows a cross-sectional view, transmittance, and pattern shape of the optical member according to Example 3. In the optical member of this example, a light control portion and a light shielding portion are formed on a plastic substrate having a thickness of 1 mm. In the light control portion, the plastic substrate is punched out in a pattern shape. Here, the plastic substrate uses a norbornene-based resin manufactured by Nippon Zeon Co., Ltd. The pattern in this example is formed by punching, and the length (L) of the pattern is 5 mm and the pitch (P) is 0.3 mm. On this pattern, a transmittance gradient film 4 is formed so that the transmittance continuously decreases from the light shielding portion side toward the tip of the pattern. In this example, the pattern has two pattern inflection points where the shape change rate changes in the pattern length direction, and there are also two transmittance inflection points where the change rate of the transmittance of the transmittance gradient film changes accordingly. Here, at the pattern inflection point, they are called the first pattern inflection point 6 and the second pattern inflection point 6' in order from the light shielding portion side, and at the transmittance inflection point, they are called the first transmittance inflection point 5 and the second transmittance inflection point 5' in order from the light shielding portion side. At this time, when the vertical direction to the film thickness direction of the light absorption laminate 3 (transmittance gradient film 4) is taken as the X-axis, the first pattern inflection point 6 and the first transmittance inflection point 5, and the second pattern inflection point 6' and the second transmittance inflection point 5' exist at substantially the same positions on the X-axis, respectively. Here, the transmittance changes at the first transmittance inflection point 5 from the light shielding portion and at the second transmittance inflection point 5' from the first transmittance inflection point 5 of the transmittance gradient film 4 of this example are not uniform, but the average change rates of the transmittance in their respective regions are approximately 10.1% / mm and 26.2% / mm, respectively, and the average change rate of the transmittance at the second transmittance inflection point 5' from the first transmittance inflection point 5 is about 2.58 times the average change rate of the transmittance at the first transmittance inflection point 5 from the light shielding portion. The average change rate of the transmittance from the second transmittance inflection point 5' to the tip of the pattern is approximately 8.0% / mm, and the change rate is the smallest.

[0033] A light absorption laminate 3 having the same film configuration as the light control portion is formed substantially uniformly in the light shielding portion. The light absorption laminate 3 of Example 3 includes light absorption layers 11, 11' made of TiOx (0 < x < 2) and Ti, and Al 2 O 3In the pattern region of the dimming section, the TiOx layer 11, the Ti layer 11', the Al 2 O 3 The light-shielding and light-adjusting portions are provided with a low-refractive-index layer 13 of MgF 2 The film is formed at approximately λ / 4 (λ=550 nm).

[0034] In this embodiment, the light absorbing laminate is made up of three TiOx layers and one Ti layer, for a total of four layers, and Al 2 O 3 The structure has five layers. In this embodiment, Ti (metal) is provided in a part of the light absorbing layer in order to suppress the total film thickness so as to minimize the film stress, taking into consideration that a plastic substrate is used as the substrate. The transmittance of the light shielding portion in this embodiment is approximately 0.3% (optical density OD = approximately 2.52) at a light wavelength of 550 nm. The transmittance of the pattern tip is approximately 98.0% (optical density OD = approximately 0.0088) at a light wavelength of 550 nm, and in the light control portion, the transmittance changes continuously from approximately 0.7% to 98.0% from the light shielding portion side toward the pattern tip.

[0035] When the direction perpendicular to the film thickness direction of the light absorbing laminate 3 (transmittance gradient film 4) is taken as the X-axis, the first pattern inflection point 6 and the second pattern inflection point 6' are located at approximately the same position on the X-axis as the first transmittance inflection point 5 and the second transmittance inflection point 5'. The pattern is formed so that the area where the transmittance gradient film 4 is formed becomes smaller continuously from the light shielding part, but the pattern shape change rate is set to be opposite to the transmittance change rate of the transmittance gradient film 4. That is, the average shape change rate from the light shielding part to the first pattern inflection point 6 is larger than the average shape change rate from the first pattern inflection point 6 to the second pattern inflection point 6', and the magnification is about 2.58 times. The shape change rate from the second pattern inflection point 6' to the pattern tip is larger than the shape change rate from the first pattern inflection point 6 to the second pattern inflection point 6'. By providing such an inflection point, it is possible to give a rounded shape to the pattern tip. As in this embodiment, when a pattern is formed by punching or laser processing, the pattern tip is rounded to facilitate pattern creation and increase durability. Furthermore, when a pattern shape is formed by punching or the like, image defects such as high-brightness ghosts may occur due to light diffraction at the pattern tip. However, as in this embodiment, the pattern tip shape is rounded to reduce the directivity of diffracted light and prevent it from interfering with projection. In this embodiment, the light absorbing laminate is formed after the pattern is formed in advance, but the light absorbing laminate may be formed first and then punched into the pattern shape. At this time, the substrate may be punched together with the light absorbing laminate, or a cutting allowance where the light absorbing laminate is not formed may be provided and punched here. In this embodiment, the shape change rate from the second pattern inflection point 6' to the pattern tip is greater than the shape change rate from the light-shielding portion to the first pattern inflection point 6, but this is not necessarily required as long as the shape change rate from the second pattern inflection point 6' to the pattern tip is greater than the shape change rate from the first pattern inflection point 6 to the second pattern inflection point 6'.

[0036] The optical member of the present invention can be suitably used for multi-projection, for example, in which a large image is obtained by superimposing a plurality of projector images. In multi-projection, a boundary line is generated between adjacent images where no image is projected. As a countermeasure to this, there is a method of eliminating the boundary line by superimposing a part of the adjacent images, but since the brightness of the overlapping part is high, it is necessary to adjust it to the brightness of the surroundings. The optical member of the present invention is provided between the projection part 33 of the projector 31 and the screen 32 as shown in Fig. 8(a)(b), and is arranged so that the light corresponding to the area where the images overlap passes through the dimming part of the optical member 1. Here, the optical member of the present invention is arranged so that the amount of light passing through the dimming part changes approximately linearly, making it easy to determine the position of the optical member. In addition, the film thickness gradient in the area close to the light-shielding part where the film thickness is the thickest in the dimming part is gentle, so cracks are unlikely to occur. Fig. 8(a) shows the brightness on the screen when the optical member 1 of the present invention is used in the multi-projection technology. As shown in Fig. 8(a), the brightness of the image overlapping part can be effectively adjusted by using the optical member 1 of the present invention. The optical member 1 of the present invention may be fixed and installed in front of the light projecting unit 33, but may also be vibrated in a direction perpendicular to the transmittance gradient direction of the transmittance gradient film. In this way, it is possible to effectively average the brightness of the image in the vibration direction, making it possible to obtain a better image. The optical member 1 of the present invention may have an optical member driving means for moving the optical member 1 in the pattern direction by an actuator such as a motor. [Explanation of symbols]

[0037] 1 Optical components 2. Board 3 Light absorbing laminate 4 Transmittance gradient membrane 5, 5´ Transmittance inflection point 6, 6´ Pattern inflection point 11 Light absorbing layer 12 Dielectric layer 13 Low refractive index layer 14 Functional membrane 15 Light-shielding film 21 Vacuum Chamber 22 Evaporation Dome 23 Evaporation Source 24 Inclined Jig 31 Projector 32 screens 33 Light projector

Claims

1. It consists of a light-shielding part and a light-adjusting part formed on a substrate, The light control unit includes: A continuous layer formed from the light-shielding portion. The pattern has a transmittance gradient film having a transmittance inflection point, the transmittance of which changes continuously, and a transmittance change rate changes before and after the inflection point. a rate of change in transmittance from the transmittance inflection point toward the pattern tip is greater than a rate of change in transmittance from the light-shielding portion to the transmittance inflection point; The pattern is When the direction perpendicular to the thickness direction of the transmittance gradient film is taken as the X-axis, An optical member characterized in that a pattern inflection point, where a rate of change in shape of the pattern changes before and after the inflection point, is located at the same position on the X-axis as the inflection point of the transmittance, and the rate of change in shape is opposite to the rate of change in transmittance of the transmittance gradient film.

2. 2. The optical member according to claim 1, wherein the transmittance gradient film is formed by laminating a plurality of light absorbing layers and dielectric layers.

3. the transmittance gradient film and the pattern each have a plurality of transmittance inflection points and a pattern inflection point, When a first transmittance inflection point, a first pattern inflection point, a second transmittance inflection point, and a second pattern inflection point are respectively defined as a first transmittance inflection point, a first pattern inflection point, a second transmittance inflection point, and a second pattern inflection point from the light-shielding portion, The rate of change in transmittance from the first transmittance inflection point to the second transmittance inflection point is is greater than the rate of change in transmittance from the light-shielding portion to the first transmittance inflection point, and, A shape change rate from the light shielding portion to the first pattern inflection point is 2. The optical member according to claim 1, wherein the rate of change from the first pattern inflection point to the second pattern inflection point is greater than the rate of change from the first pattern inflection point to the second pattern inflection point.

4. The light-shielding portion is formed with a light-absorbing laminate having the same film configuration as the transmittance gradient film, 2. The optical member according to claim 1, wherein the light absorbing layer is formed to have a substantially uniform thickness.

5. The substrate is a transparent substrate, 2. The optical member according to claim 1, wherein the light control section has an area where the gradient film is not formed.

6. A light control unit comprising a driving means for driving the optical member according to any one of claims 1 to 5.

Images