Projection device and projection method

Abstract

The objective is to increase the brightness of the projected light on the object being displayed and to make that brightness uniform. [Solution] The projection device comprises a light source unit 31, an optical system 32, a diffractive optical element 33, and a display element 34. The light source unit 31 has LDs 311 to 313 as light sources. The optical system 32 focuses the light incident from the LDs 311 to 313 onto the diffractive optical element 33. The diffractive optical element 33 diffracts the incident light. The display element 34 uses the diffracted light to generate light having an image of the projection target and projects it onto the display target object 2. The diffraction angle α of the diffractive optical element 33 and the focusing angle β of the optical system 32 satisfy α > β.

Description

Technical Field

[0001] The present invention relates to a projection device and a projection method.

Background Art

[0002] Conventionally, a projection device including an LD (LASER Diode) light source and a DOE (Diffractive Optical Element) is known. The projection device forms planar light composed of multiple bright spots by diffracted light multiple times based on the DOE. The projection device transmits the planar light through a display element such as an LCD (Liquid Crystal Display), and projects a pattern onto a display object using a projection system. The projection device has a feature that it can efficiently illuminate a predetermined surface.

[0003] Also, in order to improve the light output, an illumination device including a plurality of laser light source devices (LD light sources), a condensing optical system, a diffusing optical element (DOE), a collimating optical system, and a spatial light modulator (display element) is known (see Patent Document 1). The illumination device condenses the light emitted from the plurality of LD light sources and makes it incident on the DOE, collimates the diffracted light, transmits the image generated by the display element, and projects it onto a screen (display object) using a projection system.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above illumination device collimates the diffracted light and projects it onto a display object, and there is a possibility that the bright spots of the projection light projected onto the display object are not averaged and the brightness within the plane does not become uniform.

[0006] The object to be addressed by this invention is to increase the brightness of the projected light on the object to be displayed and to make that brightness uniform. [Means for solving the problem]

[0007] To solve the above problems, the projection device of the present invention comprises a light source unit having a plurality of light sources, a diffractive optical element that diffracts incident light, an optical system that focuses the light incident from the plurality of light sources onto the diffractive optical element, and a display element that generates light having an image of the projection target using the diffracted light and projects it onto the display target, wherein the diffraction angle α of the diffractive optical element and the focusing angle β of the optical system satisfy α > β. [Effects of the Invention]

[0008] The present invention makes it possible to increase the brightness of the projected light on the object to be displayed, and to make that brightness uniform. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows a projection device and a display object according to the first embodiment of the present invention. [Figure 2] This is a block diagram showing the functional configuration of a projection device. [Figure 3] This is a side view showing the image projection unit of the first embodiment. [Figure 4] This diagram shows the arrangement of the light source, diffractive optical element, display element, and display object in the first embodiment. [Figure 5] This is a diagram showing the projected light of the first embodiment. [Figure 6] This is a side view showing the image projection unit of the second embodiment. [Figure 7] This is a schematic diagram showing the light source unit of the second embodiment. [Figure 8] This figure shows the pitch of the light source in the second embodiment. [Figure 9] This is a schematic diagram showing the optical system of the second embodiment. [Figure 10] This figure shows the projected light of the second embodiment. [Figure 11] This is a side view showing the image projection unit of the third embodiment. [Figure 12] This figure shows the arrangement of the light source, diffractive optical element, display element, and display object in the third embodiment. [Figure 13] This figure shows the projected light of the third embodiment. [Figure 14] This figure shows the projected light of a modified example of the third embodiment. [Modes for carrying out the invention]

[0010] The first to third embodiments of the present invention will be described in detail below with reference to the drawings. However, the scope of the present invention is not limited to the illustrated examples.

[0011] A first embodiment of the present invention will be described with reference to Figures 1 to 5. As shown in Figure 1, the projection device 1 of this embodiment projects projection light L onto the display object 2 to display (project) various images onto the surface of the display object 2. The display object 2 may be, for example, a screen, the wall, floor or ceiling of a building, or the surface of any object. In this embodiment, the distance d from the projection device 1 to the display object 2 is, for example, about 1 m to 10 m, but is not limited thereto. The image projected onto the surface of the display object 2 is not particularly limited, but may be, for example, an image of a sign to guide people in the vicinity, or an image to decorate the surface of the display object 2.

[0012] As shown in Figure 2, the projection device 1 includes a CPU (Central Processing Unit) 11, RAM (Random Access Memory) 12, a storage unit 13, a communication unit 14, an operation unit 15, an image projection unit 30, and the like. The image projection unit 30 includes a light source unit 31, an optical system 32, a diffractive optical element 33, a display element 34, and the like. All parts of the projection device 1, except for the optical system 32 and the diffractive optical element 33, are connected via a bus 16. The projection device 1 may further include other components such as a display unit for displaying status information of the projection device 1, a speaker, etc.

[0013] The CPU 11 controls each part of the projection device 1. The CPU 11 reads out various programs stored in the storage unit 13, expands them in the RAM 12, and executes various processes in cooperation with the expanded programs. The RAM 12 is a volatile semiconductor memory that temporarily stores programs and data, and a work area is formed.

[0014] The storage unit 13 is composed of a flash memory or the like and is a non-volatile memory that can be read and written, and stores various programs and various data. Also, the storage unit 13 can store image data and the like received from an external device via the communication unit 14 according to an instruction from the CPU 11. The communication unit 14 is a communication module for performing wired communication with an external device such as a PC (Personal Computer) according to a communication standard such as USB (Universal Serial Bus). The CPU 11 transmits and receives information to and from an external device via the communication unit 14. The external device transmits image data for projection to the projection device 1. Also, the communication unit 14 may be a communication module for performing wireless communication with an external device according to a communication standard such as wireless LAN (Local Area Network). The operation unit 15 has buttons, a remote control, and its receiving unit, etc., accepts various operation inputs from the user, and outputs the operation information to the CPU 11.

[0015] The light source unit 31 is a MCM (Multi Chip Module) which is a module (package) with LDs as a plurality of light sources in order to increase the output of the emitted light. The light source unit 31 has, for example, three LDs 311, 312, and 313 (Fig. 3) arranged one-dimensionally as semiconductor chips so that the light emission directions are parallel. The LDs 311 to 313 are assumed to emit laser light of the same color (for example, green). The light source unit 31 emits laser light from the LDs 311, 312, and 313 according to the instruction of the CPU 11. However, the number of LDs in the light source unit 31 and the color of the emitted light are not limited to the above configuration. For example, a configuration may be adopted in which LDs such that the colors of the emitted light are R (red), G (green), and B (blue), respectively, are arranged in the light source unit 31 with one or more of each color. The optical system 32 is a condensing optical system that condenses the light emitted from the light source unit 31 onto the diffractive optical element 33. The optical system 32 has, for example, a spherical convex lens.

[0016] The diffractive optical element 33 is a diffractive grating (DOE) having a three-dimensional uneven structure in which a plurality of diffractive gratings with different grating periods are combined. The diffractive optical element 33 diffracts the incident laser light according to the pitches of a plurality of grating periods, and emits diffracted light of a higher order composed of a dot pattern of a plurality of bright spots where the diffracted light with a matrix (grating) pattern interferes and enhances each other. The display element 34 is a transmissive liquid crystal display element arranged perpendicular to the optical axes of the LDs 311 to 313. The display element 34 includes a dot matrix type liquid crystal panel in which pixels are arranged in a matrix, polarizing plates arranged on both sides so as to sandwich the liquid crystal panel, and a liquid crystal drive circuit that drives the liquid crystal panel. The liquid crystal drive circuit applies a drive voltage corresponding to the pixel value of the image to be projected (displayed) to each pixel based on the image data stored in the storage unit 13 under the control of the CPU 11, and controls the alignment state of the liquid crystal layer of each pixel. In response to the application of the drive voltage, each pixel switches between a state (on state) in which the light incident on the pixel passes through the polarizing plate on the emission side and a state (off state) in which the light incident on the pixel is absorbed by the polarizing plate on the emission side. The display element 34 distributes the on-state pixels based on the image data, transmits the image of the image data, and projects the transmitted light onto the display object 2 to display the image.

[0017] As shown in Figure 3, in the image projection unit 30, the optical system 32, diffractive optical elements 33, and display elements 34 are arranged in order along the optical axis L0 of the light source unit 31 to the display object 2. The optical axis L0 is taken in the horizontal direction. The Z axis is taken parallel to the optical axis L0, and is defined as the axis with the direction of light propagation of the optical axis L0 being the +Z direction. The X axis is defined as the axis with the zenith direction being the +X direction. Furthermore, the Y axis is the axis perpendicular to the X and Z axes. These three-dimensional XYZ axes are the same in other figures. As shown in Figure 4, the light source unit 31 is arranged so that the arrangement direction of LDs 311 to 313 is parallel to the X axis. The optical system 32 is arranged so that the optical axis L0 is parallel to the Z axis. The diffractive optical elements 33 are arranged so that the vertical direction of the rectangular plane of diffraction is parallel to the X axis. The display elements 34 are arranged so that the vertical direction of the rectangular plane of pixel arrangement is parallel to the X axis. The object to be displayed 2 is positioned such that the vertical direction of the projection rectangular plane is parallel to the X-axis. In particular, the display element 34 is positioned so that multiple pixels are arranged in a matrix on the XY plane. Thus, the angle between the X-axis and the arrangement direction of the light source 31 is 0°. The angle between the X-axis and the vertical direction of the diffractive optical element 33 is 0°.

[0018] As shown in Figure 3, the focusing angle of the optical system 32 is denoted as angle β. The diffraction angle of the diffractive optical element 33 is denoted as angle α. Angle α is the angle between the 0th-order light and the 1st-order light of one LD. In the emitted light of LD311, the 0th-order light after diffraction is denoted as light L10, and the 1st-order light is denoted as light L11. In the emitted light of LD312, the 0th-order light after diffraction is denoted as light L20, and the 1st-order light is denoted as light L21. In the emitted light of LD313, the 0th-order light after diffraction is denoted as light L30, and the 1st-order light is denoted as light L31. Angle α is, for example, the angle between light L20 and light L21 of LD312.

[0019] The diffraction angle (angle α) of the diffractive optical element 33 is predetermined by the design. Angle β is determined by the spacing between the light sources (chips) of the light source unit 31 and the optical system 32. In the case of a light source unit 31 in which three LDs 311 to 313 are arranged in the X-axis direction, it is preferable to set the optical system 32 such that angles α and β are related by the following equation (1). α > β …(1) More specifically, it is preferable to set the optical system 32 such that angles α and β are related by the following equation (2). β = (≒)(2 / 3)α …(2) Generalizing equation (2), we get equation (3). β = (≒)((N-1) / N)α …(3) However, N is the number of one-dimensional arrays of LDs in the light source section (3 in this case). In other words, the optical system 32 focuses the light from the light source 31 so as to satisfy the above equations (1) to (3).

[0020] The optical system 32 is arranged to focus the light emitted from the light source 31 onto the diffractive optical element 33, so that the image projection unit 30 (optical system 32) satisfies equation (1) (especially equation (2) or equation (3)). As a result, as shown in Figure 5, the dot pattern consisting of multiple dots D1 is evenly distributed in the projected light projected onto the display object 2. Therefore, regardless of the size of the projection onto the display object 2, the brightness of the projected light becomes uniform, and the brightness of the displayed image becomes appropriate.

[0021] In the projection device 1, when the CPU 11 receives an input from the user via the operation unit 15 for an image display instruction, it lights up the LDs 311 to 313 of the light source unit 31. The CPU 11 reads image data containing the image to be projected from the storage unit 13. The CPU 11 causes the display element 34 to generate an image corresponding to the read image data and projects (displays) the projection light L containing the image onto the display target object 2.

[0022] As described above, according to this embodiment, the projection device 1 comprises a light source unit 31, an optical system 32, a diffractive optical element 33, and a display element 34. The light source unit 31 has LDs 311 to 313 as light sources. The optical system 32 focuses the light incident from LDs 311 to 313 onto the diffractive optical element 33. The diffractive optical element 33 diffracts the incident light. The display element 34 uses the diffracted light to generate projection light L having an image of the object to be projected and projects it onto the object to be displayed 2. The diffraction angle α of the diffractive optical element 33 and the focusing angle β of the optical system 32 satisfy equation (1). Therefore, the brightness of the projection light on the object to be displayed 2 can be increased by LDs 311 to 313, and the brightness can be made uniform regardless of the projection size (the density of bright spots (dots D1) can be averaged).

[0023] In the light source unit 31, the LDs 311 to 313 are arranged in a one-dimensional arrangement direction (X-axis direction). Therefore, the area occupied by the LDs 311 to 313 in the light source unit 31 can be reduced.

[0024] The angles α and β satisfy equation (3) (equation (2)) using the number of light sources (LD311~313) constituting the light source unit 31, N (=3). Therefore, the brightness of the projected light on the display object 2 can be made uniform.

[0025] The optical system 32 has a spherical convex lens. Therefore, the optical system 32 can easily and reliably focus the light emitted from LDs 311 to 313 onto the diffractive optical element 33.

[0026] Next, a second embodiment of the present invention will be described with reference to Figures 6 to 10. This embodiment uses the projection device 1, similar to the first embodiment. However, the image projection unit 30 of the projection device 1 is replaced with an image projection unit 30a. For this reason, the same reference numerals are used for parts that are the same as those in the projection device 1, and their descriptions are omitted, while the different parts will be described primarily.

[0027] As shown in FIG. 6, the image projection unit 30a includes a light source unit 31a, an optical system 32a, a diffractive optical element 33, and a display element 34. As shown in FIG. 7, the light source unit 31a is a MCM on which LD314, 315, 316, and 317 are mounted. In the light source unit 31a, the four LDs 314, 315, 316, and 317 are arranged two-dimensionally (2×2) so that the light emission directions are parallel. LD315 and LD314 are arranged in order in the one-dimensional arrangement direction of the +X direction on the -Y direction side. LD317 and LD316 are arranged in order in the one-dimensional arrangement direction of the +X direction on the +Y direction side. That is, LD314 and LD316 are arranged in order in the one-dimensional arrangement direction of the +Y direction on the +X direction side. Similarly, LD315 and LD317 are arranged in order in the one-dimensional arrangement direction of the +Y direction on the -X direction side. LD314, 315, 316, and 317 are assumed to emit light of the same color (for example, green). However, the number of LDs in the light source unit 31 and the color of the emitted light are not limited to the above configuration.

[0028] As shown in FIG. 6, let the condensing angle of the optical system 32a be an angle β. Let the diffraction angle of the diffractive optical element 33 be an angle α. Let the 0th-order light after diffraction in the emitted light of LD314 and LD316 be light L40, and similarly, let the 1st-order light be light L41. Let the 0th-order light after diffraction in the emitted light of LD315 and LD317 be light L50, and similarly, let the 1st-order light be light L51. The angle α is, for example, the angle between the light L40 and the light L41 of LD314 and LD316.

[0029] As shown in FIG. 8, specifically, in the light source unit 31a, the LDs 314, 315, 316, and 317 are arranged with gaps therebetween. LD314 and LD315 are arranged with a pitch P1 therebetween. LD314 and LD316 are arranged with a pitch P2 therebetween. Here, P1 = P2 is assumed. However, it is not limited to this. In general, many MCMs have different pitches P1 and P2 (P1 < P2 or P1 > P2).

[0030] When the pitch P1 and the pitch P2 are the same, the optical system 32a is a condensing optical system having a spherical convex lens. As shown in FIG. 9, when the pitch P1 and the pitch P2 are different, the optical system 32a is a condensing optical system having a cylindrical lens 321a and a concave lens 322a. The cylindrical lens 321a is a cylindrical lens having convex lens surfaces in the cross section of the XZ plane and the cross section of the YZ plane, respectively. The cylindrical lens 321a refracts the laser light emitted from the light source unit 31a and emits it to the concave lens 322a. In the cylindrical lens 321a, the curvature of the convex lens surface in the cross section of the XZ plane is defined as the curvature R1, and the curvature of the convex lens surface in the cross section of the YZ plane is defined as the curvature R2. When P1 < P2, R1 > R2. When P1 > P2, R1 < R2. The concave lens 322a is a double-sided concave lens or a single-sided concave lens. The concave lens 322a refracts the light incident from the cylindrical lens 321a, emits it to the diffractive optical element 33, and condenses it. Note that even when the pitch P1 and the pitch P2 are the same, the optical system 32a may be configured to have a cylindrical lens 321a where P1 = P2 and R1 = R2, and a concave lens 322a.

[0031] The image projection unit 30a (optical system 32a) satisfies the condition of Equation (1). More specifically, the image projection unit 30a (optical system 32a) uses Equation (3) (the number N of LDs in the one-dimensional array direction = 2), and the condensing angle β by the optical system 32a is β = (≒)(1 / 2)α …(4) set to this. Thereby, as shown in FIG. 10, in the projection light projected onto the display object 2, a dot pattern composed of a plurality of dots D1 is evenly arranged. In particular, the projection light in FIG. 10 has a more evenly arranged dot pattern pitch of the dots D1 in the vertical direction (X-axis direction) and the horizontal direction (Y-axis direction) compared to the projection light in FIG. 5. For this reason, regardless of the size of the projection size onto the display object 2, the brightness of the projection light becomes more uniform, and the brightness of the displayed image also becomes more appropriate.

[0032] As described above, according to this embodiment, the light source unit 31a has multiple light sources (LD314~317) arranged in a two-dimensional first arrangement direction (X-axis direction) and a second arrangement direction (Y-axis direction). Therefore, the area occupied by the LD314~317 in the light source unit 31a can be made smaller.

[0033] The angles α and β satisfy equations (3) and (4) using the number of light sources N (=2) in the X-axis or Y-axis direction. Therefore, the brightness of the projected light on the display object 2 can be made more uniform.

[0034] The optical system 32a includes a cylindrical lens 321a and a concave lens 322a when pitches P1 and P2 are different. The cylindrical lens 321a has a curvature R1 corresponding to the pitch P1 of the light sources in the X-axis direction (LD314, 315) and a curvature R2 corresponding to the pitch P2 of the light sources in the Y-axis direction (LD314, 316). Therefore, the light emitted from LD314~317, which are arranged in two dimensions and have different pitches P1 and P2, can be reliably focused onto the diffractive optical element 33.

[0035] Next, a third embodiment of the present invention will be described with reference to Figures 11 to 14. This embodiment uses the projection device 1, similar to the first embodiment. However, the image projection unit 30 of the projection device 1 is replaced with an image projection unit 30b. For this reason, the same reference numerals are used for parts that are the same as those in the projection device 1, and their descriptions are omitted. The differences will be described primarily.

[0036] As shown in Figure 11, the image projection unit 30b includes a light source unit 31b, an optical system 32, a diffractive optical element 33, and a display element 34. The light source unit 31b, like the light source unit 31, is an MCM on which LD311, 312, and 313 are mounted. As shown in Figure 12, the three LD311, 312, and 313 in the light source unit 31b are arranged in a one-dimensional array direction so that the light emission directions are parallel. However, the light source unit 31b is arranged such that its array direction has an angle φ (≠0°) with the X axis. The diffractive optical element 33 is arranged such that the vertical direction of the rectangular plane of diffraction has an angle φ with the X axis. The display element 34 is arranged such that the vertical direction of the rectangular plane of pixel array is parallel to the X axis. The display object 2 is arranged such that the vertical direction of the rectangular plane is parallel to the X axis.

[0037] As shown in Figure 11, in the plane of the Z-axis relative to the alignment direction of LD311-313, the focusing angle of the optical system 32 is denoted as angle β. In the plane of the Z-axis relative to the alignment direction of LD311-313, the diffraction angle of the diffractive optical element 33 is denoted as angle α. The 0th order light after diffraction in the emitted light of LD311 is denoted as light L10, and the 1st order light as light L11. The 0th order light after diffraction in the emitted light of LD312 is denoted as light L20, and the 1st order light as light L21. The 0th order light after diffraction in the emitted light of LD313 is denoted as light L30, and the 1st order light as light L31. Angle α is, for example, the angle between light L20 and light L21 of LD312 in the plane of the Z-axis relative to the alignment direction of LD311-313. Figure 11 illustrates the diffracted light in the plane of the Z-axis relative to the alignment direction of LD311-313.

[0038] The image projection unit 30b (optical system 32) satisfies the condition of equation (1). More specifically, the image projection unit 30b (optical system 32) is configured to satisfy equation (3) (equation (2)). As a result, as shown in Figure 13, the dot pattern consisting of multiple dots D1 is evenly distributed in the projected light projected onto the display object 2. Therefore, regardless of the size of the projection onto the display object 2, the brightness of the projected light becomes uniform, and the brightness of the displayed image becomes appropriate.

[0039] Furthermore, multiple pixel regions 21 corresponding to multiple pixels of the display element 34 projected onto the display object 2 are arranged in a matrix. The arrangement direction of the LDs 311 to 313 of the light source unit 31b and the arrangement direction of the diffractive optical element 33 that determines the arrangement direction of the planar dots D1 consisting of multiple bright points are set to have an angle φ with respect to the vertical direction (X-axis direction) of the pixel region 21. The angle φ is a predetermined angle that is larger than the minute angle at which moiré may occur, for example, 15°. As a result, the arrangement direction of the dots D1 is tilted by 15° with respect to the vertical columns of the pixel region 21, reducing the occurrence of moiré of the projected light on the pixels of the display element 34, regardless of the size of the projection onto the display object 2.

[0040] As described above, according to this embodiment, the angle between the arrangement direction of the multiple light sources (LD311~313) in the light source unit 31b, the arrangement direction of the diffractive optical element 33, and the pixel arrangement direction of the display element 34 is a predetermined angle that is larger than the minute angle at which moiré occurs. Therefore, the occurrence of moiré of projected light on the pixels of the display element 34 can be reduced.

[0041] Furthermore, in the third embodiment, as shown in Figure 12, the light source unit 31b (the arrangement direction of the three LDs 311, 312, and 313) and the diffractive optical element 33 are arranged to have an angle φ (≠0°) with respect to the X axis, but the present invention is not limited thereto. Only the light source unit 31b (the arrangement direction of the three LDs 311, 312, and 313) may be arranged to have an angle φ (≠0°) with respect to the X axis. In this case, the angle φ is, for example, 45° (tilted 45° counterclockwise with respect to the X axis (not shown)). With such a configuration, the dots D1 projected onto the display object 2 will be as shown in Figure 14, and similarly the brightness of the projected light will be uniform, and the brightness of the displayed image will also be appropriate. Note that in Figure 14, the dots D1 corresponding to each of the LDs 311 to 313 are shown in different forms, but in reality, each dot D1 will have the same color and brightness. Also, Figure 14 shows the length corresponding to angle α and the length corresponding to angle β.

[0042] The above description of the embodiment is merely an example of the projection apparatus and projection method according to the present invention, and is not limited thereto. For example, the above embodiment describes a configuration in which a monochromatic image is projected using monochromatic laser light emitted from one light source unit 31, 31a, 31b, but is not limited thereto. For example, a color image may be projected using multiple light source units that emit laser light of different colors. In this case, the image projection unit has intersecting first and second dichroic mirrors, a blue light source unit that emits laser light in the blue wavelength band, a green light source unit that emits laser light in the green wavelength band, and a red light source unit that emits laser light in the red wavelength band. The first dichroic mirror reflects laser light in the blue wavelength band and transmits laser light in other wavelength bands. The second dichroic mirror reflects laser light in the red wavelength band and transmits laser light in other wavelength bands. The blue light source is positioned at an angle at which the emitted laser light is reflected by the first dichroic mirror and incident on the optical system. The green light source is positioned at an angle such that the emitted laser light passes through the first and second dichroic mirrors and enters the optical system. The red light source is positioned at an angle such that the emitted laser light is reflected by the second dichroic mirror and enters the optical system. In this configuration, the blue, green, and red light sources are emitted at exclusive timings, and during the emission period of each color, the display element is driven with image data corresponding to the color of the emitting light source. This allows for the superimposition of blue, green, and red images onto the display object to project a color image.

[0043] Furthermore, although the above embodiment described a display element 34 that can switch each pixel of the liquid crystal panel between two grayscale states (on and off), it is not limited to this. The display element may also be able to switch each pixel between three or more grayscale states (for example, 256 grayscale states). That is, the orientation state and transmittance of the liquid crystal of each pixel of the liquid crystal panel may be switchable between three or more steps (for example, 256 steps). In this case, the image data should be such that the pixel value of each pixel can take the value of the number of display grayscale levels of the liquid crystal panel.

[0044] Furthermore, although a liquid crystal display element having a liquid crystal panel was described as the display element 34 in the above embodiment, the invention is not limited to this. The display element may be, for example, a DMD (Digital Micromirror Device). A DMD has a plurality of micro-mirrors arranged in an array, and by switching the tilt angle of each micro-mirror according to the image data, it forms projected light having the image of the object to be projected onto using the reflected light from the plurality of micro-mirrors.

[0045] While embodiments of the present invention have been described, the scope of the present invention is not limited to the embodiments described above, but includes the scope of the invention as described in the claims and its equivalents. [Explanation of Symbols]

[0046] 1 Projection device, 31, 31a, 31b Light source unit, 32, 32a Optical system, 33 Diffractive optical element, 34 Display element

Claims

1. A light source unit having multiple light sources, A diffractive optical element that diffracts incident light, An optical system for focusing light incident from the plurality of light sources onto the diffractive optical element, The system includes a display element that generates light having an image of the object to be projected onto using the diffracted light and projects it onto the object to be displayed. The diffraction angle α of the diffractive optical element and the focusing angle β of the optical system are α＞β A projection device that satisfies the requirements.

2. The projection apparatus according to claim 1, wherein the light source unit comprises the plurality of light sources arranged in a one-dimensional arrangement direction.

3. The angles α and β are determined using the number N of light sources constituting the light source unit. β=((N-1) / N)α The projection apparatus according to claim 2, which satisfies the requirements.

4. The projection apparatus according to claim 1, wherein the optical system has a spherical convex lens.

5. The projection apparatus according to claim 1, wherein the light source unit comprises the plurality of light sources arranged in a two-dimensional first arrangement direction and a second arrangement direction.

6. The angles α and β are determined using the number N of light sources in the first or second array direction. β=((N-1) / N)α The projection apparatus according to claim 5, which satisfies the requirements.

7. The pitch of the light sources arranged in the first arrangement direction is different from the pitch of the light sources arranged in the second arrangement direction, The optical system described above is A cylindrical lens having a convex lens surface having a curvature corresponding to the pitch of the light sources in the first arrangement direction and a curvature corresponding to the pitch of the light sources in the second arrangement direction, The projection apparatus according to claim 5, comprising a concave lens.

8. The projection apparatus according to any one of claims 1 to 7, wherein the arrangement direction of the plurality of light sources in the light source unit, or the angle between the arrangement direction of the plurality of light sources and the arrangement direction of the diffractive optical elements and the pixel arrangement direction of the display elements, is a predetermined angle that is greater than the minute angle at which moiré occurs.

9. The optical system comprises the process of focusing light incident from multiple light sources in a light source section having multiple light sources onto a diffractive optical element, The diffractive optical element performs the step of diffracting the focused light, The display element includes the step of generating light having an image of the object to be projected onto using the diffracted light and projecting it onto the object to be displayed, The diffraction angle α of the diffractive optical element and the focusing angle β of the optical system are α＞β A projection method that satisfies the following conditions.

Images