Multiple projection device using a microprism array

Abstract

This invention provides a multiple projection device using a microprism array that can improve the visibility of projected images with a simple configuration and can produce a variety of projected images. [Solution] The multiple projection device 1 using a microprism array comprises a microprism array 10, which is made up of multiple irregularly shaped cells 11, each constituting a discontinuous microprism, arranged in a two-dimensional array corresponding to a target projection pattern P, and a light source unit 20, which is made up of multiple light-emitting elements 21a to 21c arranged opposite the incident surface of the microprism array 10 and arranged so as not to overlap with each other when viewed in the direction of the optical axis Lm perpendicular to the incident surface. When light is projected from the light-emitting elements 21a to 21c toward the incident surface 10a of the microprism array 10, a multiple projection image Pm is projected onto the projection surface S, which is obtained by multiple projection of three single projection images Pa to Pc, the same number as the light-emitting elements 21a to 21c.

Description

Technical Field

[0001] The present invention relates to a multiple projection apparatus using a micro prism array.

Background Art

[0002] Conventionally, an optical element called a micro prism array has been proposed. The micro prism array is an optical element formed by arranging fine prisms in a two-dimensional array, and can project a desired graphic pattern by projecting light from a light source unit (see, for example, Non-Patent Documents 1, 2, etc.).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional technology, the projection devices using a micro prism array reported so far form a single projected image on a projection surface by projecting light from one location with respect to one micro prism array. In this configuration, there are problems that the visibility is low because the projected image is single, and that the obtained projected image is limited to a relatively simple figure because it is difficult to form a fine drawing pattern with a micro prism array.

[0005] This invention has been made in view of the above-mentioned problems, and aims to provide a multiple projection device using a microprism array that can improve the visibility of projected images with a simple configuration and can obtain a variety of projected images. [Means for solving the problem]

[0006] The present invention provides a multiple projection device using a microprism array, comprising: a microprism array comprising a plurality of irregularly shaped cells, each constituting a discontinuous microprism, arranged in a two-dimensional array corresponding to a target projection pattern; and a light source unit comprising a plurality of light-emitting units arranged opposite the incident surface of the microprism array and such that they do not overlap when viewed in the direction of the optical axis perpendicular to the incident surface.

[0007] In this configuration, when light is projected from multiple light-emitting units in the light source towards the incident surface of the microprism array, a multiple projection image is projected onto the projection surface on the opposite side of the light source from the microprism array. This image consists of multiple single projection images of the same number of target projection patterns as the number of light-emitting units. Therefore, since the multiple projection image is projected while maintaining the clarity of each single projection image, visibility can be reliably improved. Thus, this configuration provides a multiple projection device using a microprism array that can improve the visibility of projected images with a simple configuration and can produce a variety of projected images.

[0008] Furthermore, the plurality of light-emitting units are arranged along at least one direction in a plane intersecting the optical axis direction.

[0009] In this configuration, when light is projected from multiple light-emitting units, which are arranged along at least one direction in a plane intersecting the optical axis, toward the incident surface of the microprism array, a multiple projection image is projected onto the projection surface located on the opposite side of the light source unit across the microprism array. This image is created by multiple projections of single projection images of the same number of target projection patterns as the number of light-emitting units.

[0010] Furthermore, the plurality of light-emitting units are arranged along at least one direction in a plane parallel to the incident surface.

[0011] In this configuration, when light is projected from multiple light-emitting units, which are arranged along at least one direction in a plane parallel to the incident surface, toward the incident surface of the microprism array, a multiple projection image is projected onto the projection surface located on the opposite side of the light source unit across the microprism array. This image is created by multiple projections of single projection images of the same number of target projection patterns as the number of light-emitting units.

[0012] Furthermore, the microprism array has directionality in at least one predetermined direction within a plane intersecting the optical axis direction in relation to the directionality of the target projection pattern, and the plurality of light-emitting units are arranged in one dimension along one direction parallel to the at least one predetermined direction.

[0013] With this configuration, by projecting light from multiple light-emitting units toward the incident surface of the microprism array, multiple single projection images are superimposed on the projection surface, aligned in one direction related to their orientation. This effectively improves the overall visibility of the superimposed image.

[0014] Furthermore, the microprism array has directionality in two predetermined directions that intersect each other in a plane that intersects with the optical axis direction in relation to the directionality of the target projection pattern, and the plurality of light-emitting units are arranged in two dimensions along two directions that are parallel to the two predetermined directions.

[0015] With this configuration, by projecting light from multiple light-emitting units arranged in two dimensions toward the incident surface of a microprism array, each single projection image is superimposed in two dimensions onto the projection surface, thereby improving decorative properties and effectively enhancing visibility across the entire superimposed image.

[0016] Furthermore, the plurality of light-emitting units are formed by arranging the plurality of light-emitting elements.

[0017] In this configuration, when multiple arranged light-emitting elements emit light and project it onto the incident surface of the microprism array, the same number of single projection images of the target projection pattern are projected onto the projection surface located on the opposite side of the light source across the microprism array. Therefore, multiple projection images can be reliably projected with a simple configuration of multiple arranged light-emitting elements.

[0018] Furthermore, the plurality of light-emitting elements include two or more light-emitting colors.

[0019] This configuration allows for improved visibility by overlaying multiple single projection images using two or more colors.

[0020] Furthermore, the system includes a light emission control unit that controls at least one of the plurality of light-emitting elements to emit light at a different timing from the others.

[0021] This configuration allows for improved visibility through a visual effect achieved by overlapping projections of at least one of several single projection images with staggered timings.

[0022] Furthermore, the light source is configured to include at least one light-emitting element and a light-shielding plate disposed between the microprism array and the at least one light-emitting element, and the plurality of light-emitting units consist of the plurality of light-transmitting windows arranged in the light-shielding plate.

[0023] In this configuration, when at least one light-emitting element emits light and projects it onto the incident surface of a microprism array through multiple windows of a light-shielding plate acting as multiple light-emitting elements, the same number of single projection images as the number of windows are superimposed onto the projection surface located on the opposite side of the microprism array from the light source. Therefore, multiple projection images can be reliably projected with a simple configuration comprising at least one light-emitting element and a light-shielding plate.

[0024] Also, when the distance between the microprism array and the light projecting unit is d, the distance between the microprism array and the projection surface is L, the interval between single projected images projected onto the projection surface is D, and the maximum width of the single projected image in the one predetermined direction related to the directionality of the target projection pattern is w, the interval δ between adjacent light projecting units is represented by δ = d × D / L (where D > w).

[0025] According to this configuration, it is possible to effectively avoid the situation where single projected images appear overlapping in the multiple projected image.

Brief Description of the Drawings

[0026] [Figure 1] It is an overall configuration diagram schematically showing a multiple projection device using a microprism array according to the first embodiment of the present invention. [Figure 2] It is a perspective view showing an example of a microprism array. [Figure 3] It is a plan view showing the whole microprism array. [Figure 4] It is a plan view showing a partially enlarged microprism array. [Figure 5] It is an explanatory diagram schematically showing a state where a target projection pattern is formed on a microprism array. [Figure 6] It is an explanatory diagram showing the positional relationship of each part in the multiple projection device according to the first embodiment. [Figure 7] It is a schematic diagram showing a state of multiple projection by controlling three light emitting elements to start and stop emitting light one by one in order in the multiple projection device according to the first embodiment. [Figure 8] It is a photograph taken of a state of multiple projection onto a projection surface using a prototype of the multiple projection device according to the first embodiment. [Figure 9] It is an overall configuration diagram schematically showing a multiple projection device according to the first modification of the first embodiment. [Figure 10] It is an overall configuration diagram schematically showing a multiple projection device according to the second modification of the first embodiment. [Figure 11]This is a schematic overall diagram showing a multiplex projection device according to a third modified example of the first embodiment. [Figure 12] This is a schematic overall diagram showing a multiplex projection device according to a fourth modified example of the first embodiment. [Figure 13] This is a schematic overall diagram showing a multiple projection device using a microprism array according to a second embodiment of the present invention. [Figure 14] This is a schematic overall diagram showing a multiple projection device using a microprism array according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0027] Hereinafter, various embodiments of the multiple projection device using a microprism array according to an embodiment of the present invention will be described with reference to the drawings.

[0028] <Configuration of the first embodiment> First, a multiple projection device 1 (hereinafter simply referred to as "multiple projection device 1") using a microprism array according to the first embodiment of the present invention will be described with reference to Figures 1 to 6. Figure 1 is a schematic overall configuration diagram showing the overall configuration of the multiple projection device 1. Figure 2 is a perspective view showing an example of the microprism array 10. Figure 3 is a plan view showing the entire microprism array 10. Figure 4 is a plan view showing an enlarged part of the microprism array 10. Figure 5 is a schematic explanatory diagram showing how the target projection pattern P is formed on the microprism array 10. Figure 6 is an explanatory diagram showing the positional relationship of each part in the multiple projection device 1. In Figures 1, 6, etc., a single projection image in red is shown with vertical hatching, a single projection image in white is shown without hatching, and a single projection image in blue is shown with horizontal hatching. In this specification, the line passing through the center of the microprism array and perpendicular to the incident plane is defined as the "optical axis of the microprism array," and in each figure, the optical axis Lm of the microprism array 10 is shown by a dashed line. Furthermore, the "optical axis direction perpendicular to the incident plane" in this invention refers to the axis direction of the optical axis Lm of the microprism array 10, and is the same as the Z direction in Figures 1 and 6.

[0029] The multiple projection device 1 is a device for projecting a target projection pattern P onto a projection surface S, and comprises a microprism array 10 and a light source unit 20.

[0030] The microprism array 10 is formed by arranging multiple microprisms in a two-dimensional pattern corresponding to the target projection pattern P. More specifically, the microprism array 10 is made of a transparent resin material and is an optical component formed by arranging multiple irregularly shaped cells 11, each constituting a discontinuous microprism, in a two-dimensional array, as shown in Figure 2. Specifically, PMMA (polymethyl methacrylate), PC (polycarbonate), etc., can be suitably used as the resin material constituting the microprism array 10. In this specification, "each a discontinuous prism" means that the boundaries between adjacent prisms are discontinuous.

[0031] The microprism array 10 is formed by arranging multiple cells (b x c) in a two-dimensional array, each cell 11 being a square in plan view with side length a, as shown in Figures 3 and 4, so that the entire microprism array 10, consisting of b x c cells, is rectangular (including square) in shape, with one side being a x b = B and the other side being a x c = C. Each cell 11 can be set to any size depending on the application; for example, it may be a tiny prism with side length a of less than 1.0 mm, or it may be a prism with a length a of several mm or more. In this specification, when each cell 11 consists of tiny prisms, it is called a microprism array. Furthermore, each cell 11 is not limited to a square in plan view with the same length for both vertical and horizontal sides, but may also be a rectangular in plan view with different lengths for vertical and horizontal sides.

[0032] The microprism array 10 is designed to project a target projection pattern P, such as a predetermined figure or character, onto a projection surface S using multiple discontinuous prism cells 11. Each cell 11 has an irregular uneven shape with different prism thicknesses, inclination angles and orientations of the output surfaces. In this embodiment, as shown in Figure 5, the target projection pattern P is a ">" shape indicating the direction of travel. The target projection pattern P indicates the X direction as the direction of travel and has directionality in the X direction.

[0033] Furthermore, the above-described microprism array 10 is preferably manufactured by a manufacturing method that includes: a mold design step of designing a mold model having an inverted shape of a molded product model of a pre-designed microprism array 10; a mold processing step of manufacturing a mold having an uneven structure by machining a mold base material based on the mold model designed in the mold design step; and a molding step of molding a molding material into a microprism array 10 using a mold apparatus having the mold. This manufacturing method has the effect of efficiently mass-producing high-quality microprism arrays 10 because a mold is manufactured by forming an irregular uneven structure by machining a mold base material in the mold processing step, and a molding material is molded into a microprism array 10 using a mold apparatus equipped with the mold in the molding step.

[0034] The light source unit 20 is configured to include three light-emitting elements 21a to 21c, which serve as multiple light-emitting units, and a light emission control unit 25.

[0035] The light-emitting elements 21a to 21c are arranged in this order along one direction (the X direction in Figure 1) in a plane that is opposite to and parallel to the incident surface 10a of the microprism array 10. Preferably, the normal to the center in the XY direction on the incident surface 10a of the microprism array 10 is arranged to pass through the center in the XY direction of the array consisting of the light-emitting elements 21a to 21c. The light-emitting elements 21a to 21c are composed of, for example, LEDs (light-emitting diodes). Figure 1 shows an example in which the light-emitting element 21a is a red LED that emits red light, the light-emitting element 21b is a white LED that emits white light, and the light-emitting element 21c is a blue LED that emits blue light.

[0036] The light emission control unit 25 is a control circuit that controls the timing of the start and stop of light emission of the light-emitting elements 21a to 21c based on settings stored in a memory unit (not shown). The light emission control unit 25 may control the light-emitting elements 21a to 21c to start and stop emitting light at the same timing. Alternatively, the light emission control unit 25 may control at least one of the multiple light-emitting elements 21a to 21c to emit light at a different timing than the others. For example, the light-emitting elements 21a to 21c may be controlled to start and stop emitting light one by one in any order.

[0037] Next, the positional relationships of the various parts of the multiple projection device 1 will be explained with reference to Figure 6. In the multiple projection device 1, the spacing between adjacent single projection images Pa to Pc in the multiple projection image Pm (hereinafter referred to as "spacing of the multiple projection image Pm") can be changed by the positional relationship between the microprism array 10 and the multiple light-emitting units (in this embodiment, light-emitting elements 21a to 21c).

[0038] The spacing D of the multiple projection images Pm depends on the distance d between the microprism array 10 and the light-emitting units (light-emitting elements 21a to 21c), the spacing δ between adjacent light-emitting units (light-emitting elements 21a to 21c), and the distance L between the microprism array 10 and the projection surface S, and is defined by the following equation 1. D=L×δ / d <Formula 1>

[0039] The spacing D of these multiple projection images Pm needs to be optimized according to the size of the projection images, especially the line width. However, when applying the present invention for directional indication purposes, it is preferable to set the spacing D to be greater than the maximum line width w in the arrangement direction of the single projection images Pa~Pc (in this embodiment, the X direction), that is, satisfying D>w ···<Equation 2>.

[0040] This is to avoid the overlapping appearance of single projection images Pa to Pc in the multiple projection image Pm, due to the degree of blurring of the outlines of single projection images Pa, etc., from the microprism array 10.

[0041] Furthermore, from the above, the distance δ between adjacent light-emitting units (light-emitting elements 21a to 21c) can be expressed as δ = d × D / L (where D > w) ... <Equation 3>.

[0042] Furthermore, in order to more clearly separate the single projection images, it is preferable that D > 1.5w ···<Equation 4> is satisfied.

[0043] <Operation of each part in the first embodiment> Next, the operation of each part of the multiple projection device 1 using the microprism array according to this embodiment having the above-described configuration will be explained when a multiple projection image Pm is projected onto the projection surface S.

[0044] When the light emission control unit 25 controls the light-emitting elements 21a to 21c to emit light, light-emitting element 21a emits blue light, light-emitting element 21b emits white light, and light-emitting element 21c emits red light.

[0045] Then, when light is projected from the light-emitting elements 21a to 21c toward the incident surface 10a of the microprism array 10, a single blue projection image Pa is projected onto the optical axis La of the light-emitting element 21a, a single projection image Pb is projected onto the optical axis Lb of the light-emitting element 21b, and a single projection image Pc is projected onto the optical axis Lc of the light-emitting element 21c on the projection surface S located on the opposite side of the light source 20 across the microprism array 10. As a result, a multiple projection image Pm is projected, in which three single projection images Pa to Pc, equal to the number of light-emitting elements (the number of light-emitting elements 21a to 21c), are arranged at equal intervals D in the X direction. In this embodiment, the optical axis Lb of the light-emitting element 21b coincides with the optical axis Lm of the microprism array 10.

[0046] Furthermore, in this embodiment, the target projection pattern P is a ">" shaped figure indicating the direction of travel, and has directionality in the X direction. Therefore, the single projection images Pa, Pb, and Pc corresponding to the target projection pattern P are projected in multiples at equal intervals in the same X direction as the directionality of the figure, thereby effectively improving overall visibility.

[0047] For example, if the light emission control unit 25 controls the light-emitting elements 21a to 21c to start and stop emitting light one by one in the order of light-emitting element 21c, light-emitting element 21b, and light-emitting element 21a, then, as shown in Figure 7, a multiple projection image Pm will be projected, in which a single red projection image Pc, a single white projection image Pb, and a single blue projection image Pa are projected one by one in sequence. In this way, the single projection images Pc, Pb, and Pa are projected sequentially in the direction of travel indicated by ">", which has the effect of more clearly indicating the direction of travel.

[0048] Figure 8 shows a photograph taken using the prototype of the multiple projection device 1 to project multiple images onto the projection surface S. In the prototype, six light-emitting elements are arranged in a row, and the six light-emitting elements are emitted simultaneously to project six ">" shaped figures multiple times.

[0049] <Summary of the First Embodiment> As is clear from the above detailed description, the multiple projection device 1 using a microprism array according to the first embodiment comprises a microprism array 10 formed by arranging a plurality of irregularly shaped cells 11, each constituting a discontinuous microprism, in a two-dimensional array corresponding to a target projection pattern P, and a light source unit 20 formed by arranging a plurality of light-emitting elements 21a to 21c as light-emitting units opposite the incident surface of the microprism array 10 and such that they do not overlap when viewed in the direction of the optical axis Lm perpendicular to the incident surface.

[0050] With this configuration, when light is projected from multiple light-emitting elements 21a to 21c provided in the light source unit 20 toward the incident surface 10a of the microprism array 10, a multiple projection image Pm is projected onto the projection surface S provided on the opposite side of the light source unit 20 across the microprism array 10. This multiple projection image Pm is formed by multiple (three) single projection images Pa, Pb, and Pc, the same number as the number of light-emitting elements 21a to 21c. Therefore, since the multiple projection image Pm is projected while maintaining the clarity of each single projection image Pa, etc., visibility can be reliably improved. Thus, this embodiment provides a multiple projection device 1 using a microprism array that can improve the visibility of projection images with a simple configuration and can obtain a variety of projection images.

[0051] Furthermore, the multiple light-emitting elements 21a to 21c are arranged along at least one direction in a plane that intersects the optical axis Lm direction.

[0052] In this configuration, when light is projected from the light-emitting elements 21a to 21c, which are arranged along at least one direction in a plane intersecting the optical axis Lm direction, toward the incident surface of the microprism array 10, a multiple projection image Pm is projected onto the projection surface S provided on the opposite side of the light source unit 20 across the microprism array 10. This multiple projection image Pm is created by multiple projections of single projection images Pa, Pb, and Pc of the same number (3) target projection patterns P as the light-emitting elements 21a to 21c.

[0053] Furthermore, the multiple light-emitting elements 21a to 21c are arranged along at least one direction in a plane parallel to the incident surface.

[0054] In this configuration, when light is projected from the light-emitting elements 21a to 21c, which are arranged along at least one direction in a plane parallel to the incident surface, toward the incident surface of the microprism array 10, a multiple projection image Pm is projected onto the projection surface S provided on the opposite side of the light source unit 20 across the microprism array 10. This multiple projection image Pm is created by multiple projections of single projection images Pa, Pb, and Pc of the same number (3) of target projection patterns P as the light-emitting elements 21a to 21c.

[0055] Furthermore, the microprism array 10 has a directionality in at least one predetermined direction (X direction) in a plane intersecting the optical axis Lm direction in relation to the directionality of the target projection pattern P, and the multiple light-emitting elements 21a to 21c are arranged in one dimension along one direction (X direction) parallel to at least one predetermined direction (X direction).

[0056] With this configuration, by projecting light from multiple light-emitting elements 21a to 21c toward the incident surface 10a of the microprism array 10, multiple single projection images Pa, Pb, and Pc are superimposed on the projection surface S, aligned in one direction (X direction) related to their orientation, thereby effectively improving overall visibility.

[0057] Furthermore, the multiple light-emitting units of the present invention are arranged by arranging a plurality (3) of light-emitting elements 21a to 21c.

[0058] With this configuration, when the multiple (3) arranged light-emitting elements 21a to 21c emit light and project it onto the incident surface 10a of the microprism array 10, three single projection images Pa, Pb, and Pc are projected onto the projection surface S located on the opposite side of the light source 20 across the microprism array 10, the same number as the light-emitting elements (light-emitting elements 21a to 21c). Therefore, a simple configuration with multiple light-emitting elements 21a to 21c can reliably project a multiple projection image Pm.

[0059] Furthermore, the multiple light-emitting elements 21a to 21c each contain two or more emission colors. In other words, in this embodiment, the three light-emitting elements 21a to 21c each contain three emission colors: red, white, and blue. Therefore, the single projected images Pa, Pb, and Pc are superimposed with two or more colors, thereby improving visibility.

[0060] Furthermore, when the light emission control unit 25 controls at least one of the multiple light-emitting elements 21a to 21c to emit light at a different timing than the others, visibility can be improved through a visual effect caused by the overlapping projection of at least one of the multiple single projection images Pa, Pb, and Pc at different timings.

[0061] Furthermore, when d is the distance between the microprism array 10 and the light-emitting elements 21a to 21c as light-emitting units, L is the distance between the microprism array 10 and the projection surface S, D is the interval between single projection images Pa to Pc, and w is the maximum width of single projection images Pa to Pc in a predetermined direction (X direction) related to the directionality of the target projection pattern P, the interval δ between adjacent light-emitting units (light-emitting elements 21a to 21c) is expressed as δ = d × D / L (where D > w).

[0062] This configuration effectively avoids the overlapping of single projection images in the multiple projection image Pm.

[0063] <First modified example of the first embodiment> Next, a multiplex projection device 1A according to a first modification of the first embodiment will be described with reference to Figure 9. Figure 9 is a schematic overall configuration diagram showing a multiplex projection device 1A according to a first modification of the first embodiment.

[0064] In the first embodiment described above, an example was shown in which three light-emitting elements 21a to 21c, which serve as multiple light-emitting units, are arranged in the X direction. However, in this modified example, they are arranged in one dimension along the Y direction, which is a direction that intersects the X direction (specifically, an orthogonal direction) within a plane that intersects the optical axis Lm direction. According to this modified example, on the projection surface S provided on the opposite side of the light source unit 20 across the microprism array 10, three single projection images Pa to Pc, the same number as the light-emitting elements 21a to 21c, are multiple-projected in the Y direction.

[0065] Here, the target projection pattern P in this embodiment is a ">" shape indicating the direction of travel, similar to the first embodiment, and has directionality in the X direction. In this embodiment, the single projection images Pa, Pb, and Pc are multiple projections arranged in the width direction (Y direction) perpendicular to the direction of travel (X direction), thereby effectively improving overall visibility.

[0066] In this modified example, if the light-emitting elements 21a to 21c are illuminated simultaneously, parts of the single projection images Pa, Pb, and Pc of the directional indicator figures aligned in the Y direction will overlap. Therefore, by controlling the light emission control unit 25 to illuminate at least one of the multiple light-emitting elements 21a to 21c at a different timing than the others, it is possible to avoid the overlapping projection of parts of the single projection images simultaneously. For example, the light emission control unit 25 may illuminate only one of the light-emitting elements 21a to 21c and turn off the other two, and sequentially change the target of illumination among the three light-emitting elements 21a to 21c.

[0067] <Second variation of the first embodiment> The "light source unit comprising a plurality of light-emitting units arranged along at least one direction in a plane intersecting the optical axis direction" of the present invention is not limited to a configuration in which the light-emitting elements 21a to 21c are arranged on the same straight line along the X direction, as in the first embodiment described above, but also includes configurations in which they are arranged on a curve or a broken line extending along the X direction. In the multiple projection device 1B according to the second modification of the first embodiment, as shown in Figure 10, an example is shown in which the light-emitting elements 21a to 21c are arranged on the same circular arc AR that extends along one direction (the X direction) and curves in the Z direction. This modification also produces the same effects as the first embodiment described above. In Figure 10, the Z direction is the optical axis direction of the microprism array 10, and corresponds to the "optical axis direction perpendicular to the incident plane (of the microprism array)" of the present invention.

[0068] <Third Modification of the First Embodiment> In the third modified example of the first embodiment, the multiple projection device 1C shows an example in which three light-emitting elements 21a to 21c are arranged in the W direction, which intersects the Z direction at an angle other than perpendicular, as shown in Figure 11. In Figure 11, the projected images 21a' to 21c' of the light-emitting elements 21a to 21c in the Z direction are shown by dashed lines. In this modified example as well, the light-emitting elements 21a to 21c are arranged so as not to overlap with each other when viewed in the optical axis Lm direction (Z direction) perpendicular to the incident plane of the microprism array 10. Therefore, this modified example has the same effect as the first embodiment. Furthermore, even if the light-emitting elements 21a to 21c are offset from each other (i.e., moved by a slight distance) in the optical axis direction (Z direction) of the microprism array 10, the effect on the multiple projection image Pm on the projection plane S is small.

[0069] <Fourth variation of the first embodiment> In the fourth modification of the first embodiment, the multiple projection device 1D, as shown in Figure 12, is an example in which the light-emitting element 21a is shifted toward the microprism array 10 in the Z direction compared to the third modification. In this modification as well, the light-emitting elements 21a to 21c are arranged so as not to overlap with each other when viewed in the optical axis Lm direction (Z direction) perpendicular to the incident plane of the microprism array 10. Therefore, this modification produces the same effects as the first embodiment. Furthermore, even if the light-emitting elements 21a to 21c are moved by a small distance in the optical axis direction (Z direction) of the microprism array 10, the effect on the multiple projection image Pm on the projection plane S is small.

[0070] <Second Embodiment> Next, the multiplex projection device 2 according to the second embodiment will be described with reference to Figure 13. Figure 11 is a schematic overall configuration diagram showing the multiplex projection device 2 according to the second embodiment.

[0071] In the first embodiment described above, an example was shown in which three light-emitting elements 21a to 21c, which serve as multiple light-emitting units, are arranged only in the X direction, which is one direction within a plane intersecting the optical axis Lm direction (Z direction) of the microprism array 10. However, in this embodiment, the light-emitting elements 21a, etc., which serve as multiple light-emitting units, are arranged two-dimensionally along two predetermined directions: the X direction and the Y direction, which intersects the X direction. Specifically, light-emitting elements 21a1 to 21a3 are arranged in the X direction in the first row in the Y direction, light-emitting elements 21b1 to 21b3 are arranged in the X direction in the second row in the Y direction, and light-emitting elements 21c1 to 21c3 are arranged in the X direction in the third row in the Y direction, so that the light source unit 20 is composed of a total of nine light-emitting elements 21a1 to 21c3.

[0072] When the light emission control unit 25 controls the light-emitting elements 21a1 to 21c3 to emit light, the light-emitting elements 21a1 to 21a3 emit blue light, the light-emitting elements 21b1 to 21b3 emit white light, and the light-emitting elements 21c1 to 21c3 emit red light.

[0073] Then, when light is projected from the light-emitting elements 21a1 to 21c3 toward the incident surface 10a of the microprism array 10, single blue projection images Pa1 to Pa3 are projected onto the projection surface S located on the opposite side of the light source 20 across the microprism array 10. These images are projected onto the optical axes La1 to La3 of the light-emitting elements 21a1 to 21a3, onto the optical axes Lb1 to Lb3 of the light-emitting elements 21b1 to 21b3, and onto the optical axes Lc1 to Lc3 of the light-emitting elements 21c1 to 21c3. As a result, nine single projection images Pa1 to Pc3, the same number as the number of light-emitting elements (the number of light-emitting elements 21a to 21c), are superimposed and arranged in two dimensions at equal intervals D in the X and Y directions.

[0074] In other words, with this configuration, by projecting light from each of the multiple light-emitting elements 21a1 to 21c3 arranged in two dimensions toward the incident surface 10a of the microprism array 10, each single projection image Pa1 to Pc3 is superimposed in two dimensions on the projection surface S, thereby improving decorative properties and effectively improving visibility of the entire superimposed projection image Pm.

[0075] <Third Embodiment> Next, the multiplex projection device 3 according to the third embodiment will be described with reference to Figure 14. Figure 14 is a schematic overall configuration diagram showing the multiplex projection device 3 according to the third embodiment.

[0076] In the first and second embodiments described above, examples were shown in which multiple light-emitting units were composed of multiple light-emitting elements 21a, etc. However, in this embodiment, the light source unit 20 is composed of at least one light-emitting element 21 and a light-shielding plate 22 disposed between the microprism array 10 and at least one light-emitting element 21. The light-emitting element 21 is assumed to be composed of a white LED that emits white light. Multiple (three) light-emitting units are formed by arranging multiple window portions 22a to 22c along the X direction in the light-shielding plate 22. The light-shielding plate 22 is transparent only in the window portions 22a to 22c and is light-shielding in other parts.

[0077] When the light emission control unit 25 controls the light-emitting element 21 to emit light, the light-emitting element 21 emits white light. The white light emitted from the light-emitting element 21 passes through a plurality (3) of windows 22a, 22b, and 22c arranged in the light-shielding plate 22, forming three optical axes La, Lb, and Lc.

[0078] Then, when light passes through the windows 22a to 22c and is projected toward the incident surface 10a of the microprism array 10, a single blue projection image Pa is projected on the optical axis La of window 22a, a single projection image Pb is projected on the optical axis Lb of window 22b, and a single projection image Pc is projected on the optical axis Lc of window 22c on the projection surface S located on the opposite side of the light source 20 across the microprism array 10. As a result, three single projection images Pa to Pc, equal to the number of light-emitting sections (the number of windows 22a to 22c), are superimposed and arranged at equal intervals D in the X direction.

[0079] In other words, with this configuration, when at least one light-emitting element 21 emits light and projects it onto the incident surface of the microprism array 10 through the three windows 22a to 22c of the light-shielding plate 22 which acts as multiple light-emitting elements, three single projection images Pa to Pc, the same number as the windows 22a to 22c, are superimposed on the projection surface S provided on the opposite side of the light source 20 across the microprism array 10. Therefore, a superimposed projection image Pm can be reliably projected with a simple configuration consisting of at least one light-emitting element 21 and a light-shielding plate 22.

[0080] <Other variations> The present invention is not limited to the embodiments and modifications described above, and various modifications can be made without departing from the spirit of the invention. For example, the number of light-emitting elements 21a etc. set to three in the first embodiment is merely an example and is not limited thereto. There may be multiple light-emitting elements 21a etc., such as two or four or more. The light-emitting elements 21a etc. may consist only of LEDs of the same light-emitting color, or they may include LEDs of different light-emitting colors.

[0081] Furthermore, the light emission control unit 25 may also perform control to increase or decrease the brightness in addition to controlling the timing of light emission from the light-emitting elements 21a to 21c. [Industrial applicability]

[0082] The multi-projection device using the microprism array according to the present invention is envisioned to be incorporated into the turn signals of automobiles to create a variety of drawings on the road surface to alert pedestrians, or to be used as an effective guide light by creating a variety of drawings on pathway guidance lights inside buildings. [Explanation of Symbols]

[0083] 1. Multiplex projection device using a microprism array <First embodiment> 1A Multiple projection device using a microprism array <First modification of the first embodiment> 1B Multiple projection device using a microprism array <Second modification of the first embodiment> 1C Multiple projection device using a microprism array <Third modification of the first embodiment> Multiple projection device using a 1D microprism array <Fourth modification of the first embodiment> 2. Multiple projection device using a microprism array <Second embodiment> 3. Multiplex projection device using a microprism array <Third embodiment> 10 Prism Arrays 10a Incidence plane 11 cells 20 Light source section 21a, 21b, 21c Light-emitting element (light-emitting section <first and second embodiments>) 22 Light-shielding plate 22a, 22b, 22c Window section (light-emitting section <Third embodiment>) P Target projection pattern Pa~Pc Single Projection Image <First Embodiment, Modified Example of First Embodiment, Third Embodiment> Pa1~Pc3 Single projection image <Second embodiment> Pm multiple projection image Lm Microprism Array Optical Axis

Claims

1. A microprism array is formed by arranging multiple irregularly shaped cells, each constituting a discontinuous microprism, in a two-dimensional array corresponding to the target projection pattern, A multiple projection device using a microprism array, comprising: a light source unit arranged opposite the incident surface of the microprism array and having multiple light-emitting units arranged so as not to overlap when viewed in the optical axis direction perpendicular to the incident surface.

2. The multiple projection device using a microprism array according to claim 1, wherein the plurality of light-emitting units are arranged along at least one direction in a plane intersecting the optical axis direction.

3. The multiple projection apparatus using a microprism array according to claim 2, wherein the plurality of light-emitting units are arranged along at least one direction in a plane parallel to the incident surface.

4. The microprism array has directionality in at least one predetermined direction within a plane intersecting the optical axis direction in relation to the directionality of the target projection pattern, The multiple projection apparatus using a microprism array according to claim 2 or 3, wherein the plurality of light-emitting units are arranged in one dimension along one direction parallel to at least one predetermined direction.

5. The microprism array has directionality in two predetermined directions that intersect each other in a plane that intersects with the optical axis in relation to the directionality of the target projection pattern, The multiple projection device using a microprism array according to claim 4, wherein the plurality of light-emitting units are arranged in two dimensions along two directions parallel to the two predetermined directions.

6. The plurality of light-emitting units are arranged by a plurality of light-emitting elements, and the multiple projection device uses a microprism array according to any one of claims 1 to 3.

7. The multiple light-emitting elements include two or more light-emitting colors, and the multiple projection apparatus using the microprism array according to claim 6 is also described.

8. A multiple projection apparatus using a microprism array according to claim 6, comprising a light emission control unit that controls the emission of light from at least one of the plurality of light-emitting elements at a different timing from the others.

9. The light source is configured to include at least one light-emitting element and a light-shielding plate disposed between the microprism array and the at least one light-emitting element. The plurality of light-emitting units consist of the plurality of light-transmitting window portions arranged in the light-shielding plate, wherein the multiple projection units use a microprism array according to any one of claims 1 to 3.

10. A multiple projection device using a microprism array according to claim 4, wherein the distance between the microprism array and the light-emitting unit is d, the distance between the microprism array and the projection surface is L, the interval between single projection images projected onto the projection surface is D, and the maximum width of the single projection image in one predetermined direction related to the directionality of the target projection pattern is w, and the interval between adjacent light-emitting units δ is expressed as δ = d × D / L (where D > w).

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