Polarization light irradiation device

Abstract

To provide a polarization light irradiation device capable of performing irradiation efficiently in oblique irradiation of polarization light.SOLUTION: A polarization light irradiation device for irradiating an object having a flat plate shape with light, includes a light source part, a light blocking plate, and a polarization element. The light source part has a plane arrangement surface, and a plurality of LEDs that are arranged on the arrangement surface and irradiate the object with light. The light blocking plate has a flat plate shape, has an opening, and is arranged in parallel with the object between the light source part and the object. The polarization element is disposed in parallel with the object. When a component perpendicular to the arrangement surface of the light emitted from the LEDs is represented as a main light ray, none of the main light rays of the plurality of LEDs are blocked by the light blocking plate.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a polarized light irradiation device. [Background technology]

[0002] Patent Document 1 describes a light irradiation device in which an irradiator (light source) having multiple LEDs is arranged at an angle to a work (object to be irradiated), and an optical component (polarizing element) is arranged between the irradiator and the work, parallel to the work. In this light irradiation device, half of the light distribution angle of each LED is set to be smaller than the angle of the optical axis with respect to the work. This makes it possible to irradiate light efficiently with a simple configuration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-152617 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such oblique irradiation with polarized light, a technique is required that enables efficient irradiation.

[0005] In view of the above circumstances, an object of the present invention is to provide a polarized light irradiation device that enables efficient irradiation in oblique irradiation of polarized light. [Means for solving the problem]

[0006] In order to achieve the above object, a polarized light irradiation device according to one embodiment of the present technology is a polarized light irradiation device that irradiates a target object having a flat plate shape with light, and includes a light source unit, a light shielding plate, and a polarizing element. The light source unit has a flat arrangement surface and a plurality of LEDs that are arranged on the arrangement surface and irradiate the object with light. The light blocking plate has a flat plate shape, has an opening, and is disposed between the light source unit and the object and parallel to the object. The polarizing element is arranged parallel to the object. When a component of the light emitted from the LEDs that is perpendicular to the arrangement surface is defined as a principal ray, none of the principal rays of the LEDs is blocked by the light blocking plate.

[0007] In this polarized light irradiation device, the main light emitted by multiple LEDs is polarized and is irradiated onto the target without being blocked by a light shielding plate. This makes it possible to efficiently irradiate the target with polarized light at an angle.

[0008] When the light source unit and the light shading plate are viewed along a cross section perpendicular to the light shading plate, a line passing through the center of the opening of the light shading plate and perpendicular to the light shading plate is defined as a first line, and a line passing through the center of the opening and the center of the placement surface is defined as a second line, in all of the cross sections, the placement surface is perpendicular to the second line, and the following formula may be satisfied.

number

[0009] The light shading plate is a member having a thickness, and the polarized light irradiation device may be configured such that, when the light source unit and the light shading plate are viewed along a cross section perpendicular to the light shading plate, a line passing through the center of the opening of the light shading plate and perpendicular to the light shading plate is defined as a first line, and a line passing through the center of the opening and the center of the placement surface is defined as a second line, in all of the cross sections, the placement surface is perpendicular to the second line, and the following formula is satisfied.

number

[0010] The polarizing element may be disposed between the light source unit and the light blocking plate.

[0011] The polarizing element may have the same shape as the opening of the light-shielding plate, and may be integrally formed with the light-shielding plate by being embedded in the opening.

[0012] The plurality of LEDs may be arranged in a grid pattern on the arrangement surface.

[0013] The opening of the light blocking plate may have a rectangular shape. Effect of the Invention

[0014] According to the present invention, it is possible to efficiently irradiate a polarized light obliquely. Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in the present disclosure. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram illustrating a configuration example of a polarized light irradiation device according to an embodiment of the present technology. [Diagram 2] FIG. 2 is a schematic diagram showing the direction of light irradiation by an LED. [Diagram 3] FIG. 3 is a cross-sectional view taken along plane A in FIG. 2. [Figure 4] 10A and 10B are schematic diagrams showing an example in which a chief ray is blocked. [Diagram 5] FIG. 11 is a schematic diagram showing a configuration example of a polarized light irradiation device according to a second embodiment. [Figure 6] FIG. 13 is a diagram used to consider conditional expressions. [Figure 7] FIG. 1 is a simulation diagram of Equation 1. [Figure 8] 1 is a graph of relative illuminance. [Figure 9] 13 is a graph showing relative integrated light quantities. [Figure 10] FIG. 13 is a schematic diagram showing a configuration example of a polarized light irradiation device according to a third embodiment. [Figure 11] FIG. 13 is a diagram used to consider conditional expressions. [Figure 12] FIG. 2 is a simulation diagram of Equation 2. [Figure 13] FIG. 1 is a schematic diagram showing an example of the configuration of a polarized light irradiation device that blocks main light rays using a polarizing plate frame. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0017] <First embodiment> [Polarized light irradiation device] FIG. 1 is a schematic diagram showing a configuration example of a polarized light irradiation device 1 according to an embodiment of the present technology. The polarized light irradiation device 1 is configured to irradiate light to a workpiece W transported along a predetermined direction. As shown in FIG. 1, in this embodiment, a long, strip-shaped workpiece W is pulled out from a feed roller 2 and taken up by a take-up roller 3. The polarized light irradiation device 1 irradiates light to the workpiece W transported from the feed roller 2 to the take-up roller 3. As indicated by an arrow T in the figure, the transport direction of the workpiece W is the direction from the feed roller 2 to the take-up roller 3.

[0018] For convenience, the following XYZ coordinates are defined for the drawing. X direction: The transport direction of the workpiece W (the direction in which the workpiece W moves is the positive direction) Y direction: Width direction of strip-shaped workpiece W Z direction: Normal direction of workpiece W Of course, the application of this technology is not limited to the direction in which the polarized light irradiation device 1 is used or the direction in which the workpiece W is transported.

[0019] The workpiece W has a flat plate shape. In this example, the workpiece W has a belt-like shape, but this shape is also included in the flat plate shape. It is not limited to this, and the workpiece W may have other flat plate shapes such as a flat rectangular shape or a circular shape. In addition, the present technology also includes a case where a thin workpiece W is placed on a flat plate-shaped base, and the base and the workpiece W as a whole have a flat plate shape. As the workpiece W, for example, a liquid crystal film is arranged. Of course, the type of the workpiece W is not limited, and the present technology can be applied to any irradiation target. The workpiece W corresponds to an embodiment of the target object according to the present technology.

[0020] The polarized light irradiation device 1 further includes a light source unit 4, a control unit 5, an aperture 6, and a polarizing element 7. Note that the polarizing element 7 is not shown in Figs. 1 and 2. The light source unit 4 irradiates light such as ultraviolet light onto the workpiece W. For example, a photo-alignment film is formed on the workpiece W in advance, and then the light source unit 4 irradiates polarized light of a predetermined wavelength. This technology can be used for such an alignment process. Of course, the application of this technology is not limited to alignment processes in which polarized light is irradiated onto a photo-alignment film. Furthermore, the light source unit 4 may be capable of emitting light of any wavelength, not limited to ultraviolet light.

[0021] The light source unit 4 has a housing unit 8 and multiple LEDs (Light Emitting Diodes) 9. The housing unit 8 has a rectangular parallelepiped shape. The multiple LEDs 9 are arranged on one of the six faces (arrangement surface 10) of the housing unit 8. The arrangement surface 10 is a rectangular flat surface, and the multiple LEDs 9 are arranged in a lattice pattern on the arrangement surface 10. In this example, three LEDs 9 are arranged along the X direction and six LEDs 9 are arranged along the Y direction, totaling 18 LEDs 9 arranged in a lattice pattern.

[0022] The arrangement of the LEDs 9 is not limited, and other lattice arrangements such as a triangular lattice, or other arrangements other than a lattice may be adopted. In this case, the housing 8 may have a shape that matches the arrangement of the LEDs 9, such as a disk shape, and the LEDs 9 may be arranged on an arrangement surface 10 that is circular or the like. The number of LEDs 9 to be arranged is also not limited. In this example, the LEDs 9 are illustrated typically as shaded circles, but the specific shape of the LEDs 9 is not limited.

[0023] In this embodiment, the light source unit 4 is disposed at an angle so that the placement surface 10 is parallel to the Y axis and forms a predetermined angle with the XY plane. That is, the light source unit 4 is disposed in a tilted state, rotated slightly about the Y axis from a state in which the placement surface 10 is parallel to the XY plane. Note that the light source unit 4 is tilted so as to rotate clockwise about the Y axis when viewed from the negative side in the Y direction (the lower left side of the figure). That is, it is tilted so that the positive side of the transport direction (the right side, the positive side of the X axis) is the lower side (the negative side of the Z axis) and the negative side is the upper side.

[0024] Fig. 2 is a schematic diagram showing the direction of light irradiation by the LEDs 9. Fig. 2 shows three LEDs 9 (9a, 9b, and 9c from the left) arranged in the second row from the front among the multiple LEDs 9. Also, the main rays 11 (11a, 11b, and 11c) emitted from the LEDs 9a to 9c are shown by arrows. Note that, to make the drawing easier to see, the other LEDs 9 and the housing unit 8 are not shown.

[0025] The light emitted from the LED 9 is diffused light, and the angle of diffusion varies depending on the type of LED 9, but chief ray 11 is emitted in a direction perpendicular to the arrangement surface 10. That is, in reality, diffuse light other than chief rays 11a to 11c is emitted in directions other than those indicated by the arrows in the figure, but only the components of chief rays 11a to 11c are shown by arrows. Chief rays 11a to 11c are each emitted in a direction from the upper right to the lower left of the figure.

[0026] The control unit 5 controls the operation of each mechanism of the polarized light irradiation device 1. For example, the control unit 5 controls the timing of emission from the LED 9, the emission intensity, etc. The conveying speed of the workpiece W may be controlled by controlling the rotation of the delivery roller 2 and the take-up roller 3. Any other control of the mechanism may be executed.

[0027] A PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array) or other device such as an ASIC (Application Specific Integrated Circuit) may be used as the control unit 5. In Figures 1 and 2, the control unit 5 is illustrated diagrammatically as a functional block, but the position where the control unit 5 is configured may be designed arbitrarily.

[0028] The aperture 6 is a member having a flat plate shape. The aperture 6 is composed of a left flat plate portion 12a, a right flat plate portion 12b, and an opening 13. Each of these has a rectangular shape, and is arranged between the light source unit 4 and the workpiece W, parallel to the XY plane, in the X direction, in the order of the left flat plate portion 12a, the opening 13, and the right flat plate portion 12b from the left. Since the workpiece W is also arranged parallel to the XY plane, the aperture 6 is arranged parallel to the workpiece W. In Figures 1 and 2, the left flat plate portion 12a and the right flat plate portion 12b are illustrated by dashed lines.

[0029] In this example, the left plate portion 12a and the right plate portion 12b are separated, but they may be connected. For example, the opening 13 may be circular, and the plate portion may be shaped by hollowing out a circle from a rectangle. The specific shape of the aperture 6 is not limited. In addition, the aperture 6 is made of, for example, a material having rigidity, but the specific material is not limited. The aperture 6 corresponds to an embodiment of the light blocking plate according to the present technology.

[0030] Fig. 3 is a cross-sectional view taken along plane A in Fig. 2. Plane A is parallel to the XZ plane, and its position in the Y direction is equal to the center position of LEDs 9a to 9c. Therefore, Fig. 3 shows a cross section at the position where LEDs 9a to 9c are located.

[0031] The polarizing element 7 has, for example, a flat plate shape, and is disposed between the light source unit 4 and the aperture 6, parallel to the XY plane. That is, as shown in Fig. 3, the light source unit 4, the polarizing element 7, the aperture 6, and the workpiece W are disposed in this order from the top, and among these, the polarizing element 7, the aperture 6, and the workpiece W are parallel to the XY plane. That is, it can be said that the polarizing element 7 is disposed parallel to the workpiece W.

[0032] The polarizing element 7 transmits and polarizes only the component of the light emitted from the LED 9 that vibrates in one direction. In this embodiment, the light emitted from the LED 9 is polarized into linearly polarized light by the polarizing element 7. Therefore, in FIG. 3, the portion of the principal rays 11a to 11c located above the polarizing element 7 is unpolarized light, and the portion located below is linearly polarized light. The linearly polarized light is irradiated onto the workpiece W. As the polarizing element 7, for example, a wire grid polarizing element is used, but the specific type is not limited. The polarizing element 7 may also be disposed between the aperture 6 and the workpiece W.

[0033] [Relationship between chief ray and aperture] In this embodiment, the polarized light irradiation device 1 is configured so that none of the chief rays 11 of the multiple LEDs 9 are blocked by the aperture 6. For example, as shown in Figures 2 and 3, the chief ray 11a emitted from the LED 9a passes through the vicinity of the left flat plate portion 12a of the opening 13 of the aperture 6 and reaches the workpiece W. In other words, it is not blocked by the aperture 6.

[0034] Similarly, the chief ray 11c of the LED 9c is not blocked by the right flat plate portion 12b of the aperture 6, and passes through the opening 13 to reach the workpiece W. Naturally, the central chief ray 11b is not blocked either. Furthermore, as is clear from the positional relationship of each mechanism, the chief rays 11 emitted from the other 15 LEDs 9 shown only in Figure 1 also reach the workpiece W without being blocked.

[0035] In this way, the polarized light irradiation device 1 is configured so as not to block any of the chief rays 11. Specifically, such a configuration is realized by adjusting the shape of the opening 13 of the aperture 6, the position and angle of the housing part 8, the arrangement of each LED 9, or their positions in the vertical direction, etc.

[0036] For example, the component of the diffused light emitted from the left LED 9a that is directed to the left of the principal ray 11a may be blocked by the left flat plate portion 12a of the aperture 6. Similarly, the component of the diffused light emitted from the right LED 9b that is directed to the right of the principal ray 11c may be blocked by the right flat plate portion 12b. However, such a case where the diffused light is blocked is also included in the scope of the present technology. In other words, it does not matter whether the diffused light is blocked or not, as long as each principal ray 11 is not blocked.

[0037] In addition, the blocking of the chief ray 11 by the aperture 6 includes both the blocking of the chief ray 11 by reflection by the upper surface of the left flat plate portion 12a or the right flat plate portion 12b, and the blocking of the chief ray 11 by reflection by the side surface of the left flat plate portion 12a (the surface parallel to the YZ direction that constitutes the opening 13).

[0038] Fig. 4 is a schematic diagram showing an example in which the chief ray 11 is blocked. In Fig. 4, the light source unit 4 is arranged at a further inclination compared to Fig. 3. The configuration of other mechanisms such as the aperture 6 is the same. In Fig. 4, the polarizing element 7 is omitted to make the drawing easier to see. In the subsequent drawings, the polarizing element 7 may also be omitted as necessary.

[0039] The left-side chief ray 11a is reflected by the side surface of the left flat plate portion 12a and travels in a direction to the lower right, which is not the direction originally expected. The right-side chief ray 11c is reflected by the surface of the right flat plate portion 12b and travels in an upper left direction. In other words, these chief rays 11a and 11c are blocked. The left and right chief rays 11 of the other five rows are also blocked in the same manner.

[0040] On the other hand, the central chief ray 11b is not blocked. Similarly, the central chief ray 11 of the other five rows is not blocked either. However, this example does not satisfy the condition that "none of the chief ray 11 is blocked." In other words, there is one or more chief ray 11 that is blocked. Therefore, a configuration such as this example is not included in the scope of the present technology.

[0041] In order to eliminate this state, the inclination of the light source unit 4 may be made shallower so that all of the chief rays 11 are contained within the opening 13. Alternatively, the shape of the opening 13 may be changed, for example by widening the opening 13. By adjusting the arrangement of various other mechanisms, it is possible to realize a configuration in which all of the chief rays 11 are not blocked.

[0042] As described above, in the polarized light irradiation device 1 according to this embodiment, the chief rays 11 emitted by the multiple LEDs 9 are polarized, and all of the rays are irradiated onto the workpiece W without being blocked by the aperture 6. This makes it possible to efficiently irradiate the polarized light obliquely.

[0043] In a polarized light irradiation device such as that of the present technology, light is irradiated obliquely onto the workpiece W in order to make the workpiece W have a desired orientation state. However, since the light emitted from the light source unit 4 in which a plurality of LEDs 9 are arranged in a matrix is ​​diffuse light, it is necessary to place an aperture 6 between the polarizing element 7 and the workpiece W to limit the angle of the light irradiated onto the workpiece W. However, depending on the arrangement angle when the light source unit 4 is arranged obliquely, the width of the opening 13 of the aperture 6 becomes limited, and part of the light from the light source unit 4 is blocked, resulting in a problem that the light at the desired angle does not sufficiently reach the workpiece W.

[0044] In this technology, the chief ray 11, which is light at a desired angle among the light emitted from each LED 9, is irradiated onto the workpiece W without being blocked. Furthermore, if the chief ray 11 hits the side surface of the left flat plate portion 12a, even if the chief ray 11 reaches the workpiece W by reflection, it is not light at a desired angle, which is undesirable. In this technology, the chief ray 11 is not reflected by the side surface, so this does not occur. In this way, efficient irradiation of polarized light is achieved.

[0045] In this embodiment, the LEDs 9 are arranged in a lattice pattern on the arrangement surface 10. This makes it possible to improve the uniformity of light irradiation.

[0046] In this embodiment, the opening 13 of the aperture 6 has a rectangular shape, which makes it possible to efficiently block diffused light.

[0047] <Second embodiment> A more detailed embodiment of the polarized light irradiation device 1 according to the present technology will be described as the second embodiment. In the following description, the description of the same configurations and functions as those described in the above embodiment will be omitted or simplified.

[0048] [Conditional formula when the aperture has no thickness] 5 is a schematic diagram showing a configuration example of a polarized light irradiation device 1 according to a second embodiment. In this embodiment, when the light source unit 4 and the aperture 6 are viewed along a cross section perpendicular to the aperture 6, if a line passing through the center of the opening 13 of the aperture 6 and perpendicular to the aperture 6 is defined as a first line, and a line passing through the center of the opening 13 and the center of the arrangement surface 10 is defined as a second line, the arrangement surface 10 is perpendicular to the second line in both cross sections, and the following formula is satisfied.

number

[0049] In this example, the aperture 6 is made of a thin, flat member. That is, as shown in Fig. 5, the aperture 6 appears to be substantially linear when viewed from the negative side in the Y direction. The configuration and arrangement of other mechanisms of the polarized light irradiation device 1 are the same as those in the example of Fig. 3.

[0050] 5 is a diagram of the light source unit 4 and the aperture 6 viewed along a cross section parallel to the XZ plane. Since the aperture 6 is parallel to the XY plane, FIG. 5 corresponds to a diagram viewed along a cross section perpendicular to the aperture 6.

[0051] Also, a straight line M1 that passes through the center of the opening 13 and is perpendicular to the aperture 6 is shown by a dashed line. The center of the opening 13 means the center in the left-right direction. Therefore, the straight line M1 can also be said to be the perpendicular bisector of the opening 13. The straight line M1 corresponds to an embodiment of the first straight line according to the present technology.

[0052] Furthermore, a straight line M2 passing through the center of the opening 13 and the center of the arrangement surface 10 is illustrated by a dashed line. The center of the arrangement surface 10 means the center in the direction of the arrangement surface 10 (diagonal direction). The arrangement surface 10 is also perpendicular to the straight line M2. Therefore, the straight line M2 can also be said to be the perpendicular bisector of the arrangement surface 10. The straight line M2 passes through the center of the central LED 9b and is a straight line that overlaps with the chief ray 11b. The straight line M2 corresponds to an embodiment of the second straight line according to the present technology.

[0053] Also, the distance L between two LEDs 9 located at the ends of the multiple LEDs 9 is shown. Here, the distance L means the distance between the centers of the two LEDs 9. In FIG. 5, the distance L is the distance between the center of the LED 9a located at the upper left end (the center in the direction of the arrangement surface 10) and the center of the LED 9c located at the lower right end. Also, the width X of the opening 13 of the aperture 6 is shown. The width X is the length along the left-right direction of the opening 13. Furthermore, the acute angle θ formed by the straight lines M1 and M2 is shown. The angles formed by the straight lines M1 and M2 include acute angles (upper right and lower left corners) and obtuse angles (lower right and upper left corners), and θ is defined as the acute angle side.

[0054] The inventors have studied what relationships hold between the parameters L, X, and θ when none of the principal rays 11a to 11c are blocked in this example. Fig. 6 is a diagram used to study the conditional expressions.

[0055] 6 shows a state in which the light source unit 4 is tilted so that the chief ray 11a exactly contacts the right end of the left flat plate portion 12a, and the chief ray 11c exactly contacts the left end of the right flat plate portion 12b. The contact position between the chief ray 11a and the left flat plate portion 12a is defined as point A, and the contact position between the chief ray 11b and the right flat plate portion 12b is defined as point B. Since the width of the opening 13 is X, the length of the side AB is also X.

[0056] The center of LED 9a (the upper right end of chief ray 11a) is defined as point C, and the center of LED 9c (the upper right end of chief ray 11c) is defined as point D. Since the distance between the center of LED 9a and the center of LED 9c is L, the length of side CD is also L.

[0057] Since the acute angle between the lines M1 and M2 is θ, the acute angle between the line M1 and the principal ray 11c is also θ. In other words, if the intersection point between the side AB and the line M1 is E and the intersection point between the line M1 and the principal ray 11c is F, then ∠EFB=θ. The angle θ is shown in Figure 6.

[0058] Now, consider translating side CD along the principal rays 11a and 11c until point C reaches the position of point A. Point D after the movement is designated as point G. In Figure 6, side AG after the movement is shown by a dashed line. The length of side AG is also L.

[0059] Then, ∠GAB=θ can be shown as follows. ∠GAB =180°-∠AGB-∠ABG (because the sum of the interior angles of triangle AGB is 180°) =180°-∠FEB-∠ABG (because ∠AGB=∠FEB=90°) =∠EFB (because the sum of the interior angles of triangle EFB is 180°) =θ

[0060] That is, in the triangle AGB, cosθ=cos∠GAB=AG / AB=L / X. Therefore, L=Xcosθ holds. If the inclination θ is increased even slightly (cosθ is decreased) from this state, the chief rays 11a and 11c will be blocked. Conversely, if the inclination θ is decreased even slightly (cosθ is increased), the rays will not be blocked. Therefore, the condition for preventing light blocking is L≦Xcosθ, as shown in formula 1.

[0061] Fig. 7 is a simulation diagram of formula 1. The inventors performed a simulation using a drawing as shown in Fig. 7 to determine the value of the distance L between the LEDs 9 at the ends when the angle θ is 30°, the width X of the opening 13 is 40, and the two chief rays 11 at the ends just touch the aperture 6. As a result, the value of L was approximately 34.641. Actually, when the values ​​of X and θ are substituted into the formula (L=Xcosθ), L = 40 × cos30° =40×√3 / 2 ≒40×0.8660254 ≒34.641 which is equal to the value of L obtained by simulation. Therefore, the validity of formula 1 has been confirmed. Note that L' in the figure represents the length (distance between the ends) of the images projected onto the aperture 6 by the two chief rays 11 at the ends. In the case of the figure, the projected image is exactly overlapped on the opening 13, so L' is equal to the width X of the opening 13.

[0062] From equation 1 (L≦Xcosθ), the following can be stated: If the distance L between the LEDs 9 is increased, the width X of the opening 13 must be increased accordingly. Alternatively, the inclination θ of the light source unit 4 must be made smaller. Conversely, if the distance L is reduced, the required width X will also be reduced. Or, the inclination θ can be increased. If the width X is large, the inclination θ can also be large. Conversely, if the width X is small, the inclination θ must be small. Since the slope θ is between 0° and 90°, cosθ is between 0 and 1. Therefore, if the distance L is greater than the width X, Equation 1 is not satisfied regardless of the value of θ.

[0063] This formula 1 holds true when viewed along any cross section perpendicular to the aperture 6. For example, formula 1 also holds true when the LEDs 9 in other rows, such as the third row, are cut along a plane parallel to the XZ plane. In this example, it is clear that the condition holds true when the LEDs 9 are cut along a plane parallel to the XZ plane at any position in the Y direction. However, for example, when the aperture 6 is circular, the width of the opening 13 narrows toward the front or back in the Y direction, so that formula 1 may hold true in some cross sections and formula 1 may not hold true in other cross sections. In such cases, there are cross sections where formula 1 does not hold true, in other words, there are some principal rays 11 that are blocked by the aperture 6.

[0064] Not only the XZ plane, but also the plane obtained by rotating the XZ plane about the Z axis is a plane perpendicular to the aperture 6. Therefore, the cross-sections by these planes are also cross-sections perpendicular to the aperture 6. In this example, since the light source unit 4 is inclined only in the direction parallel to the XZ plane, it is sufficient if Expression 1 is satisfied only in the cross-section parallel to any XZ plane (it can be said that none of the principal rays 11 are blocked). However, when the light source unit 4 is also inclined in the Y direction, it may be necessary to satisfy Expression 1 in all cross-sections perpendicular to the aperture 6, not just in the cross-sections parallel to any XZ plane.

[0065] FIG. 8 is a graph of relative illuminance. The horizontal axis represents the pretilt angle of the work W (liquid crystal). The pretilt angle is the angle formed by the long axis of the liquid crystal molecule and the alignment surface, which is different from θ in FIG. 5. The vertical axis represents the relative illuminance with respect to the work W.

[0066] The inventor performed a simulation on what values the relative illuminance takes at each incident angle. In the graph, the relationship between the pretilt angle and the relative illuminance when L < Xcosθ is shown by a solid line. The relationship when L = Xcosθ is shown by a fine dashed line, and the relationship when L > Xcosθ is shown by a thick dashed line. Note that the emission intensity of the LED 9 and the width X of the aperture 13 of the aperture 6 are fixed in each case. Also, in the cases of L < Xcosθ and L > Xcosθ, the value of the distance L is fixed to a predetermined value that satisfies the conditional expression.

[0067] For example, looking at the values of the respective relative illuminances at a pretilt angle of 30 degrees, the difference between the value of L<Xcosθ and the value of L=Xcosθ is a value slightly smaller than 0.1. On the other hand, the difference between the value of L>Xcosθ and the value of L=Xcosθ is a value slightly larger than 0.1. Thus, when considering around L=Xcosθ, the amount of change in the light quantity at a pretilt angle of 30 degrees is smaller for L<Xcosθ than for L>Xcosθ. The same relationship holds for other pretilt angles as well. Therefore, it can be said that when L<Xcosθ, light at a desired angle is efficiently transmitted with L=Xcosθ as the boundary.

[0068] Figure 9 is a graph of the relative integrated light quantity. The inventor performed a simulation on what values the relative integrated light quantity takes at each measurement position. In the graph, similar to the graph of FIG. 8, the relationship between the measurement position in the Y direction and the relative integrated light quantity in each case of L<Xcosθ, L=Xcosθ, and L>Xcosθ is shown. Also, similar to the simulation of FIG. 8, the values of the emission intensity, the value of the width X, and the value of the distance L are fixed.

[0069] For example, an illuminometer is installed on the extension line of the irradiation position (the × mark in FIG. 2) of the main light ray 11a by the LED 9a with respect to the work W, and scanning is performed in the direction toward the LED 9a by the illuminometer. Here, -90 mm to +90 mm of the measurement position corresponds to the width (180 mm) in the Y direction of the light source unit 4. For example, at L=cosθ, the value of the relative integrated light quantity is 1.1×10 -9 or more.

[0070] Also, for example, looking at the values of the respective relative integrated light amounts at measurement position 0, the difference between the value of L<Xcosθ and the value of L=Xcosθ is a value slightly smaller than 0.1. On the other hand, the difference between the value of L>Xcosθ and the value of L=Xcosθ is a value slightly larger than 0.1. Thus, when considering around L=Xcosθ, the amount of change in the light amount at measurement position 0 is smaller for L<Xcosθ than for L>Xcosθ. The same relationship also holds for other measurement positions. Therefore, it can be said that when L<Xcosθ, light at the desired angle is efficiently transmitted across the boundary of L=Xcosθ.

[0071] As can be seen from the simulation results in FIGS. 8 and 9, by setting L≦Xcosθ, none of the principal rays 11 are blocked, and the workpiece W is efficiently irradiated. In this embodiment, since the configuration and positional relationship of each member are defined by equations, it is possible to more accurately realize a configuration in which the principal ray 11 is not blocked.

[0072] <Third Embodiment> [Conditional Equation When the Aperture Has a Thickness] FIG. 10 is a schematic diagram showing a configuration example of the polarized light irradiation device 1 according to the third embodiment. In this embodiment, the aperture 6 is a member having a thickness. When the light source unit 4 and the aperture 6 are viewed along a cross section perpendicular to the aperture 6, a straight line passing through the center of the aperture 13 of the aperture 6 and perpendicular to the aperture 6 is defined as the first straight line, and a straight line passing through the center of the aperture 13 and the center of the placement surface 10 is defined as the second straight line. In any cross section, the placement surface 10 is perpendicular to the second straight line, and the following equation is satisfied. [Number] Here, L: Distance between two LEDs 9 located at the ends among a plurality of LEDs 9 X: Width of the aperture 13 of the aperture 6 θ: Acute angle formed by the first straight line and the second straight line d: Thickness of the aperture 6 That is.

[0073] The configuration of this embodiment differs from that of the second embodiment in that the aperture 6 has a thickness, but the other configurations are the same. As shown in FIG. 10, the aperture 6, i.e., the left flat plate portion 12a and the right flat plate portion 12b, each have a thickness in the vertical direction, and the thickness (length in the vertical direction) is d. In the second embodiment, the straight lines M1 and M2 pass through the center of the opening 13, i.e., the center in the horizontal direction, but in this embodiment, the center of the opening 13 means the center including not only the horizontal direction but also the vertical direction. Therefore, as shown in FIG. 10, the point that is the center of gravity of the rectangular opening 13 becomes the center, and the straight lines M1 and M2 intersect at that point.

[0074] The inventors have studied what relationships hold between the parameters L, X, θ, and d when none of the principal rays 11a to 11c are blocked in this example. Fig. 11 is a diagram used to study the conditional expressions.

[0075] 11 shows a state in which the light source unit 4 is tilted so that the chief ray 11a exactly contacts the lower right end of the left flat plate portion 12a, and the chief ray 11c exactly contacts the upper left end of the right flat plate portion 12b. Since the aperture 6 has a point-symmetrical configuration with respect to the center of the opening 13, when the chief ray 11a exactly contacts the lower right end of the left flat plate portion 12a, the chief ray 11c also exactly contacts the upper left end of the right flat plate portion 12b at the same time. The contact position between the chief ray 11a and the left flat plate portion 12a is defined as point A, and the contact position between the chief ray 11c and the right flat plate portion 12b is defined as point B. The upper right end of the left flat plate portion 12a is defined as point H.

[0076] The center of LED 9a (the upper right end of chief ray 11a) is defined as point C, and the center of LED 9c (the upper right end of chief ray 11c) is defined as point D. Since the distance between the center of LED 9a and the center of LED 9c is L, the length of side CD is also L.

[0077] Since the acute angle between the lines M1 and M2 is θ, the acute angle between the line M1 and the principal ray 11c is also θ. In other words, if the intersection point between the side HB and the line M1 is E and the intersection point between the line M1 and the principal ray 11c is F, then ∠EFB=θ. The angle θ is shown in Figure 11.

[0078] Now, consider translating side CD along the principal rays 11a and 11c until point C reaches side HB. Point C after the movement is designated as point I, and point D after the movement is designated as point G. In Fig. 11, side IG after the movement is shown by a dashed line.

[0079] Then, ∠GIB=θ can be shown as follows. ∠GIB =180°-∠IGB-∠IBG (because the sum of the interior angles of triangle IGB is 180°) =180°-∠FEB-∠IBG (because ∠IGB=∠FEB=90°) =∠EFB (because the sum of the interior angles of triangle EFB is 180°) =θ That is, in the triangle IGB, cosθ =cos∠GIB =IG / IB =L / IB Therefore, L = I B cos θ holds true. Furthermore, since IB=HB-HI=X-HI, L=(X-HI)cosθ.

[0080] On the other hand, since the straight line M1 and the side AH are parallel, ∠HAI=θ. That is, in the triangle AHI, tan θ =tan∠HAI =HI / AH =HI / d Therefore, HI=dtanθ holds. Substituting this into L=(X-HI)cosθ from earlier, we get L=(X-dtanθ)cosθ.

[0081] If the inclination θ is increased even slightly from this state (if tan θ is increased and cos θ is decreased), the principal rays 11a and 11c will be blocked. Conversely, if the distance L is reduced even slightly (if tan θ is reduced and cos θ is increased), the rays will not be blocked. Therefore, the condition for preventing light blocking is L≦(X-dtan θ)cos θ, as shown in Equation 2.

[0082] Fig. 12 is a simulation diagram of formula 2. The inventors performed a simulation using a drawing as shown in Fig. 12 to determine the value of the distance L between the LEDs 9 at the ends when the formed angle θ is 30°, the width X of the opening 13 is 40, the thickness of the aperture 6 is 20, and the two chief rays 11 at the ends just touch the lower right of the left flat plate portion 12a and the upper left of the right flat plate portion 12b. As a result, the value of L was approximately 24.641. Actually, when the values ​​of X, θ, and d are substituted into the formula (L=(X-dtanθ)cosθ), L = (40-20tan30°) × cos30° =(40-20×1 / √3)×√3 / 2 ≒28.4529946 × 0.8660254 ≒24.641 which is equal to the value of L obtained by simulation. Therefore, the validity of formula 2 has been confirmed. Note that X' in the figure is the passing width of chief ray 11 at opening 13, and coincides with the length L' of the projected image of the two chief rays 11 at the end onto aperture 6. Also, X'' is the dimension that becomes narrower due to the thickness of aperture 6, and is equal to the length of side HI in FIG. 11, i.e., dtan θ.

[0083] From equation 2 (L≦(X-dtanθ)cosθ), the following can be stated: As in the case of formula 1, the greater the distance L between the LEDs 9, the greater the required width X of the opening 13, etc. If the thickness d is large, it is necessary to make L smaller, X larger, or θ smaller. The opposite is also true. cosθ takes a value between 0 and 1. Therefore, if the distance L is greater than X-dtanθ, equation 2 is not satisfied. Since tanθ=sinθ / cosθ, the right-hand side of Equation 2 is equal to Xcosθ-dsinθ. Therefore, L≦Xcosθ-dsinθ (Equation 2') is equivalent to Equation 2 being true.

[0084] Equation 2 holds true when viewed along any cross section perpendicular to aperture 6. In this embodiment, when aperture 6 has a thickness, the configuration and positional relationship of each member is defined by an equation that includes thickness d, making it possible to realize with even greater precision a configuration in which chief ray 11 is not blocked.

[0085] <Other embodiments> The present technology is not limited to the above-described embodiment, and various other embodiments can be realized.

[0086] FIG. 13 is a schematic diagram showing a configuration example of a polarized light irradiation device 1 that blocks the principal ray 11 by a polarizing plate frame 16. As shown in the figure, in this embodiment, a polarizing plate 15 is disposed between the light source unit 4 and the workpiece W. The polarizing plate 15 is made up of a polarizing plate frame 16 and a polarizing element 7. The polarizing plate frame 16 is a flat plate-shaped member capable of blocking the principal ray 11, and has an opening 13 for holding the polarizing element 7. The polarizing element 7 has the same shape as the opening 13 (i.e., for example, a circular plate shape). Then, the polarizing element 7 is embedded in the opening 13, whereby the polarizing element 7 and the polarizing plate frame 16 are integrally configured as the polarizing plate 15.

[0087] As a result, none of the principal rays 11 are blocked by the polarizing plate frame 16, and furthermore, when passing through the opening 13, they are polarized by the polarizing element 7 embedded therein. Therefore, the same effects as those of the example shown in Fig. 3 etc. are achieved. In addition, in this embodiment, the polarizing element 7 and the polarizing plate frame 16 having a light blocking function are integrally configured, which makes it possible to miniaturize the device and reduce the manufacturing costs of the parts. In this embodiment, the polarizing plate frame 16 corresponds to one embodiment of the light blocking plate.

[0088] When the polarized light irradiation device 1 is used, the inclination of the light source unit 4 may be fixed at an angle that satisfies the condition that none of the principal rays 11 are blocked, or may be changeable within an angle range that satisfies the condition. For example, a mechanism for rotating the light source unit 4 may be provided, and the user may manually rotate the light source unit 4 to change the inclination. Alternatively, the control unit 5 may control the inclination of the light source unit 4 in response to an instruction using a user's device. Also, the irradiation state of the workpiece W may be detected, and the control unit 5 may automatically control the inclination in response to the detection result.

[0089] Specific values ​​of the thickness d of the aperture 6, the width X of the opening 13, and the inclination θ of the light source unit 4 are not limited and may be any values ​​that satisfy the conditions. As an example, a configuration in which the thickness d is 3 to 5 mm, the opening 13 is rectangular as shown in FIG. 1 and has a width X of about 100 mm, and the inclination θ is 50° to 60° can be adopted.

[0090] The configurations of the polarized light irradiation device, the light source unit, the aperture, the polarizing element, the LED, etc. described with reference to the drawings are merely one embodiment, and can be modified as desired without departing from the spirit of the present technology. In other words, any other configurations for implementing the present technology may be adopted.

[0091] In the present disclosure, when the term "approximately" is used, this is used only to facilitate understanding of the description, and there is no special meaning in whether or not the term "approximately" is used. That is, in the present disclosure, concepts that define the shape, size, positional relationship, state, etc., such as "center," "central," "uniform," "equal," "same," "orthogonal," "parallel," "symmetrical," "extended," "axial direction," "rectangular," "rectangular," "circular," "cuboid," "disk-shaped," "flat," "strip-shaped," and the like, include concepts such as "substantially center," "substantially central," "substantially uniform," "substantially equal," "substantially the same," "substantially orthogonal," "substantially parallel," "substantially symmetrical," "substantially extended," "substantially axial direction," "substantially rectangular," "substantially rectangular," "substantially circular," "substantially cuboid," "substantially disc-shaped," "substantially flat," and "substantially strip-shaped." For example, it also includes states that fall within a specified range (e.g., a range of ±10%) based on standards such as "perfectly centered," "perfectly central," "perfectly uniform," "perfectly equal," "perfectly the same," "perfectly orthogonal," "perfectly parallel," "perfectly symmetrical," "perfectly extended," "perfectly axial," "perfectly rectangular," "perfectly oblong," "perfectly circular," "perfectly cuboid," "perfectly disk-shaped," "perfectly flat," "perfectly strip-shaped," etc. Therefore, even if the word "approximately" is not added, it may include a concept expressed by adding "approximately." Conversely, a perfect state is not excluded when the word "approximately" is added.

[0092] In the present disclosure, expressions using "more than", such as "greater than A" and "smaller than A", are expressions that comprehensively include both concepts that include equivalent to A and concepts that do not include equivalent to A. For example, "greater than A" is not limited to cases that do not include equivalent to A, but also includes "A or greater". Furthermore, "smaller than A" is not limited to "less than A", but also includes "A or less". When implementing the present technology, specific settings, etc. may be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so that the effects described above are achieved.

[0093] It is also possible to combine at least two of the characteristic parts of the present technology described above. That is, the various characteristic parts described in each embodiment may be arbitrarily combined without distinction between the embodiments. In addition, the various effects described above are merely examples and are not limited thereto, and other effects may be exhibited. [Explanation of symbols]

[0094] 1...Polarized light irradiation device 4...Light source section 6…Aperture 7...Polarizing element 9, 9a~9c…LED 10...Placement surface 11, 11a~11c...chief ray 13...Aperture 15...Polarizing plate 16...Polarizing plate frame

Claims

1. A polarized light irradiation device that irradiates a flat-plate-shaped object with light, A light source unit including a flat arrangement surface and a plurality of LEDs arranged on the arrangement surface and configured to irradiate light onto the object; a light blocking plate having a flat shape, an opening, and disposed between the light source unit and the object and parallel to the object; A polarizing element arranged parallel to the object, When a component of the light emitted from the LED that is perpendicular to the arrangement surface is defined as a principal ray, none of the principal rays of the LEDs is blocked by the light blocking plate. Polarized light irradiation device.

2. The polarized light irradiation device according to claim 1, When the light source unit and the light blocking plate are viewed along a cross section perpendicular to the light blocking plate, a straight line passing through the center of the opening of the light blocking plate and perpendicular to the light blocking plate is defined as a first straight line, and a straight line passing through the center of the opening and the center of the arrangement surface is defined as a second straight line, In any of the cross sections, the arrangement surface is perpendicular to the second straight line and satisfies the following formula: Polarized light irradiation device. [0010] L: the distance between two of the LEDs located at the ends X: the width of the opening of the light shielding plate θ: acute angle between the first straight line and the second straight line

3. The polarized light irradiation device according to claim 1, The light shielding plate is a member having a thickness, When the light source unit and the light blocking plate are viewed along a cross section perpendicular to the light blocking plate, a straight line passing through the center of the opening of the light blocking plate and perpendicular to the light blocking plate is defined as a first straight line, and a straight line passing through the center of the opening and the center of the arrangement surface is defined as a second straight line, In any of the cross sections, the arrangement surface is perpendicular to the second straight line and satisfies the following formula: Polarized light irradiation device. [0025] L: the distance between two of the LEDs located at the ends X: the width of the opening of the light shielding plate θ: acute angle between the first straight line and the second straight line d: thickness of the light shielding plate

4. The polarized light irradiation device according to any one of claims 1 to 3, The polarizing element is disposed between the light source unit and the light blocking plate. Polarized light irradiation device.

5. The polarized light irradiation device according to any one of claims 1 to 3, The polarizing element has the same shape as the opening of the light-shielding plate, and is embedded in the opening to be integral with the light-shielding plate. Polarized light irradiation device.

6. The polarized light irradiation device according to any one of claims 1 to 3, The LEDs are arranged in a grid pattern on the arrangement surface. Polarized light irradiation device.

7. The polarized light irradiation device according to any one of claims 1 to 3, The opening of the light blocking plate has a rectangular shape. Polarized light irradiation device.

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