projector

Abstract

This invention provides a projector that reduces EMI noise emitted to the outside of the projector. The projector includes: a first light modulation device that emits a first image light; a second light modulation device that emits a second image light; a prism that combines the first image light and the second image light; a first metal component that connects the first light modulation device and the prism; a lens that projects the light combined by the prism; a second metal component that supports the lens; and a third metal component that connects the prism and the second metal component. An air layer is provided in the opposing region between the first metal component and the prism.

Description

Technical Field

[0001] This invention relates to projectors. Background Technology

[0002] In recent years, high-brightness projectors with laser light sources have been used in facilities such as large conference rooms, halls, and event spaces. In these high-brightness projectors, a light modulation device comprising a liquid crystal panel, a light valve, and a prism that synthesizes the image light emitted from these light modulation devices—all of which generate the individual image lights of the three primary colors—is held in place by a metal component that is resistant to heat deformation. By using a metal component to hold the light modulation device and the prism, it is possible to suppress any shift in the relative position of the prism to the light modulation device due to heat generated from components containing the laser light source and the power supply.

[0003] For example, in the projection-type display device disclosed in Patent Document 1, a reflective light valve that generates modulated light of the three primary colors is embedded in an opening formed in a first mounting member that is a metal plate component. The first mounting member with the reflective light valve embedded is bonded to the prism via a second mounting member using an adhesive material.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2004-354795

[0005] However, in a projector incorporating the projection-type display device disclosed in Patent Document 1, when EMI (Electromagnetic Interference) noise is generated from a light modulation device containing a reflective light valve or an integrated circuit connected to the light modulation device, the EMI noise is transmitted from the first mounting component and the second mounting component to the prism. Since the prism is formed of glass with a specified dielectric constant, it acts as a dielectric of a capacitor for EMI noise. The EMI noise transmitted in the prism is emitted to the outside of the projector from the metal component supporting the prism and the metal component connected to it. The EMI noise emitted to the outside of the projector affects the operation of electronic devices located outside the projector. Summary of the Invention

[0006] The projector disclosed herein comprises: a first light modulation device that emits a first image light; a second light modulation device that emits a second image light; a prism that combines the first image light and the second image light; a first metal component that connects the first light modulation device and the prism; a lens that projects the light combined by the prism; a second metal component that supports the lens; and a third metal component that connects the prism and the second metal component. An air layer is provided in the opposing region between the first metal component and the prism. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the projector according to the first embodiment.

[0008] Figure 2 yes Figure 1 A schematic diagram of the lighting device of the projector.

[0009] Figure 3 yes Figure 1 A three-dimensional diagram of the image forming apparatus of a projector.

[0010] Figure 4 It is Figure 3 A stereoscopic image of a portion of the image forming apparatus after disassembly.

[0011] Figure 5 yes Figure 3 A cross-sectional view of a portion of an image forming apparatus.

[0012] Figure 6 yes Figure 3 The front view of a part of the image forming apparatus.

[0013] Figure 7 Is Figure 6 A cross-sectional view of the image forming apparatus as seen along the arrow at line C1-C1.

[0014] Figure 8 Is Figure 6 A cross-sectional view of the image forming apparatus as seen along the arrow at line C2-C2.

[0015] Figure 9 It means from Figure 1 A graph showing an example of EMI noise measurement from a projector.

[0016] Figure 10 It means from Figure 1 A chart illustrating the calculation of EMI noise emitted by a projector.

[0017] Figure 11 This is a front view of a conventional image forming apparatus.

[0018] Figure 12 This is a front view of a portion of the image forming apparatus according to the second embodiment.

[0019] Figure 13 Is Figure 12 A cross-sectional view of the image forming apparatus as seen along the arrow at line C3-C3.

[0020] Figure 14 This is a cross-sectional view of a portion of the image forming apparatus according to the third embodiment.

[0021] Figure 15This is a graph showing a calculation example of EMI noise emitted from the projector in the third embodiment.

[0022] Figure 16 This is a cross-sectional view of the image forming apparatus of the first variation of the third embodiment.

[0023] Figure 17 This is a cross-sectional view of the image forming apparatus of the second variation of the third embodiment.

[0024] Figure 18 This is a front view of the image forming apparatus of the third modification of the projector disclosed herein.

[0025] Label Explanation

[0026] 1: Projector; 4B, 4G, 4R: Light modulation device; 6: Projection optical system (lens); 55: Metal component (first metal component); 420: Cross-shaped dichroic prism (prism); 430, 440: Metal component (third metal component); 480: Metal component (second metal component); 500: Opposite area; 500p: Inner perimeter (perimeter); 500q: Outer perimeter (perimeter); 501, 502, 503: Area; 520: Air layer; 530: Recess; IB: Image light; IG: Image light; IR: Image light; LF: Full-color image light. Detailed Implementation

[0027] [First Implementation]

[0028] The following uses Figures 1 to 11 The first embodiment of this disclosure will be described. In the following figures, the scale of the dimensions varies depending on the constituent elements in order to facilitate observation of each constituent element.

[0029] (Projector)

[0030] Figure 1 This is a schematic diagram showing the structure of the projector 1 according to the first embodiment. The projector 1 is a projection-type image display device that displays images on a screen (not shown), and it is a projector that has a liquid crystal panel as a light modulation device for generating image light. Figure 1 As shown, the projector 1 includes an outer casing 600, an illumination device 2, a color separation optical system 3, light modulation devices 4R, 4G, and 4B, field lenses 10R, 10G, and 10B, a cross-shaped color separation prism (prism) 420, and a projection optical system (lens) 6.

[0031] The outer casing 600 is formed of moldable resin. The illumination device 2, color separation optical system 3, light modulation devices 4R, 4G, 4B, field lenses 10R, 10G, 10B, and cross-shaped dichroic prism 420 are housed inside the outer casing 600. The side of the portion of the outer casing 600 that emits the image light LF, which is the object to be displayed, protrudes along the emission direction of the image light LF compared to the surrounding portion. An opening for emitting the image light is formed at the end of the protruding portion of the outer casing 600. The front end portion of the projection optical system 6 in the emission direction protrudes from the opening for emitting the image light. The remaining portion of the projection optical system 6, excluding the end portion, is housed inside the outer casing 600.

[0032] In addition to the aforementioned components, the projector 1 also includes (but not shown) components that support or fix each component, and a cooling device or cooling structure for cooling the component that generates the most heat. On the outer casing 600, in addition to the aforementioned opening for emitting image light, there is also an opening (but not shown) for intake or exhaust.

[0033] The lighting device 2 emits white illumination light WL along the optical axis AX2. The structure of the lighting device 2 will be explained later.

[0034] The color-separating optical system 3 separates the illumination light WL incident from the illumination device 2 into red light LR, green light LG, and blue light LB. The color-separating optical system 3 includes dichroic mirrors 7A and 7B, total reflection mirrors 8A, 8B, and 8C, and relay lenses 9A and 9B.

[0035] Dichroic mirror 7A allows blue light LB to pass through the illumination light WL incident from the illumination device 2, while reflecting green light LG and red light LR, thereby separating the illumination light WL into blue light LB, green light LG, and red light LR. Dichroic mirror 7B reflects green light LG incident from dichroic mirror 7A, while allowing red light LR to pass through, thus separating green light LG from red light LR.

[0036] Total internal reflection mirror 8A is positioned in the optical path of blue light LB, reflecting the blue light LB that has passed through dichroic mirror 7A toward optical modulation device 4B. Total internal reflection mirrors 8B and 8C are positioned in the optical path of red light LR, guiding the red light LR that has passed through dichroic mirror 7B to optical modulation device 4R. Green light LG is reflected from dichroic mirror 7B toward optical modulation device 4G.

[0037] Relay lens 9A is positioned in the optical path of the red light LR between dichroic mirror 7B and total reflection mirror 8B. Relay lens 9B is positioned in the optical path of the red light LR between total reflection mirrors 8B and 8C. The optical path length of the red light LR from dichroic mirror 7A to cross-shaped dichroic prism 420 is longer than the optical path lengths of the blue light LB and green light LG of the same range. By positioning relay lenses 9A and 9B in the optical path of the red light LR from dichroic mirror 7A to cross-shaped dichroic prism 420, the light loss of the red light LR caused by its longer optical path compared to the blue light LB and green light LG is compensated.

[0038] Optical modulation device 4B modulates the incident blue light LB according to the image information to form the blue image light IB. Optical modulation device 4G modulates the incident green light LG according to the image information to form the green image light IG. Optical modulation device 4R modulates the incident red light LR according to the image information to form the red image light IR.

[0039] Field lens 10B is positioned in the optical path of the blue light LB between the total reflection mirror 8A and the light modulation device 4B, parallelizing the blue light LB incident on the light modulation device 4B. Field lens 10G is positioned in the optical path of the green light LG between the dichroic mirror 7B and the light modulation device 4G, parallelizing the green light LG incident on the light modulation device 4G. Field lens 10R is positioned in the optical path of the red light LR between the total reflection mirror 8C and the light modulation device 4R, parallelizing the red light LR incident on the light modulation device 4R.

[0040] Image lights IR, IG, and IB generated by the various light modulation devices 4R, 4G, and 4B are incident on the cross-shaped dichroic prism 420. The cross-shaped dichroic prism 420 combines the red image light IR, the green image light IG, and the blue image light IB, and emits the combined full-color image light LF toward the projection optical system 6.

[0041] The cross-shaped dichroic prism 420 consists of four right-angled prisms. Figure 1 In the top view shown, four right-angle prisms are arranged such that their respective apexes converge at the center of the surface of the cross-shaped dichroic prism 420. A reflective surface 421 is formed at the interface between two adjacent right-angle prisms, which are aligned with each other on a straight line. This reflective surface 421 reflects the blue image light IB while allowing the green image light IG and the red image light IR to pass through. At the interface between two adjacent right-angle prisms, which is perpendicular to the reflective surface 421 and aligned with each other on a straight line, a reflective surface 422 is formed that reflects the red image light IR while allowing the green image light IG and the blue image light IB to pass through. The cross-shaped dichroic prism 420 functions as a light combining component in the projector 1 to combine image lights IR, IG, and IB of different colors.

[0042] The light modulation devices 4R, 4G, and 4B, and the cross-shaped dichroic prism 420 constitute the image forming apparatus 400 of the projector 1. In the image forming apparatus 400, red image light IR, green image light IG, and blue image light IB, which are the three primary colors of light, are generated. The red image light IR, green image light IG, and blue image light IB are combined to generate full-color image light LF. The structure of the image forming apparatus 400 will be described later.

[0043] The projection optical system 6 has a projection lens group comprising multiple refracting lenses. The projection optical system 6 projects the full-color image light LF synthesized by the cross dichroic prism 420 towards a screen (not shown) for magnification. Thus, the magnified image is displayed on the screen.

[0044] (lighting device)

[0045] Figure 2 This is a schematic diagram showing the structure of lighting device 2. (For example...) Figure 2 As shown, the lighting device 2 has light emitting devices 11 and 12 and a uniform illumination optical system 13.

[0046] The light emitting device 11 includes a light source 20, a collimating optical system 21, a dichroic mirror 22, a focusing optical system 23, and a phosphor wheel 25. The light source 20 is composed of a semiconductor laser (LD) that emits blue light E. The peak wavelength of the blue light E emitted from the LD is, for example, 445 nm, which is set to a wavelength that can excite the phosphor layer 27 (described later) to generate yellow light LY. The light source 20 can be composed of one LD or multiple LDs. The number of LDs constituting the light source 20 is appropriately determined based on the relationship between the amount of blue light E required to generate yellow light LY with a specified refractive power according to the performance assumptions of the projector 1 and the amount of blue light E emitted from one LD.

[0047] The optical axis AX1 of the blue light E emitted from the light source 20 is perpendicular to the optical axis AX2 of the projector 1. The collimating optical system 21 consists of one or more convex lenses, which parallelize the blue light E emitted from the light source 20 and direct it toward the dichroic mirror 22.

[0048] Dichroic mirror 22 is positioned in the optical path of blue light E from collimating optical system 21 to focusing optical system 23. Dichroic mirror 22 is plate-shaped and has a reflective surface. The reflective surface of dichroic mirror 22 is arranged at an angle of 45 degrees relative to the optical axes AX1 and AX2, respectively. The reflective surface of dichroic mirror 22 reflects blue light E, while allowing yellow light LY, which contains red and green light, to pass through.

[0049] The focusing optical system 23 consists of one or more convex lenses. The focusing optical system 23 focuses the blue light E reflected from the dichroic mirror 22 and traveling in a direction parallel to the optical axis AX2, so that it is incident on the phosphor wheel 25, and picks up the yellow light LY emitted from the phosphor wheel 25 and parallelizes it.

[0050] The fluorescent wheel 25 is a rotating fluorescent plate that uses blue light E as excitation light to generate yellow light LY. It is a reflective fluorescent plate that emits yellow light LY in a direction parallel to and opposite to the incident direction of blue light E. The fluorescent wheel 25 includes a motor 24, a substrate 26, a fluorescent layer 27, and a reflective layer 28.

[0051] The substrate 26 is a circular plate driven by the motor 24 to rotate circumferentially along the rotation axis O and centered on the rotation axis O. The substrate 26 is formed of a metal material with excellent heat dissipation. The fluorescent layer 27 is disposed on the plate surface of the substrate 26 that is irradiated with blue light E, and is formed in a ring shape centered on the rotation axis O. The fluorescent layer 27 has a certain dimension in the radial direction centered on the rotation axis O. The fluorescent layer 27 uses the incident blue light E as excitation light to generate yellow light LY as fluorescence. The fluorescent layer 27 is a wavelength conversion layer that converts the incident blue light E into yellow light LY with a wavelength band different from that of blue light.

[0052] When the projector 1 is used, the substrate 26 rotates at a predetermined speed by the operation of the motor 24. In the lighting device 2, the blue light E reflected by the dichroic mirror 22 is used as an excitation light with high light intensity and intermittently illuminates the phosphor layer 27, thus enabling the phosphor layer 27 to have a long lifetime.

[0053] A reflective layer 28 is disposed between the fluorescent layer 27 and the substrate 26. An adhesive layer (not shown) is disposed between the fluorescent layer 27 and the reflective layer 28. An adhesive layer (not shown) is also disposed between the reflective layer 28 and the substrate 26. The reflective layer 28 has the same radial dimension as the fluorescent layer 27 about the rotation axis O. The reflective layer 28 reflects the yellow light LY generated by the fluorescent layer 27 that is incident on the reflective layer 28 in a direction opposite to the incident direction of the blue light E towards the fluorescent layer 27.

[0054] The light emitting device 12 includes a light source 30, a focusing optical system 31, a diffuser 32, and a collimating optical system 33. The light source 30 is composed of an LD that emits blue light B. The peak wavelength of the blue light B emitted from the LD is, for example, 445 nm, and is set according to the wavelength range of blue light B determined based on the performance of the projector 1, including color balance. The light source 30 can be composed of one LD or multiple LDs. The number of LDs constituting the light source 30 is appropriately determined based on the relationship between the amount of blue light B and the amount of blue light B emitted from one LD, as envisioned based on the performance requirements of the projector 1.

[0055] The optical axis AX3 of the blue light B emitted from the light source 30 is perpendicular to the optical axis AX2 of the projector 1 and parallel to the optical axis AX1. The focusing optical system 31, composed of one or more convex lenses, converges the blue light B emitted from the light source 30 to the vicinity of the diffuser plate 32. The diffuser plate 32 diffuses the incident blue light B, forming a blue light B with a light distribution similar to that of the yellow light LY emitted from the phosphor wheel 25. For example, frosted glass is used as the diffuser plate 32. The collimating optical system 33, composed of one or more convex lenses, parallelizes the blue light B emitted from the diffuser plate 32.

[0056] Blue light B emitted from light emitting device 12 is reflected by dichroic mirror 22 and combined with yellow light LY emitted from phosphor wheel 25 and passed through dichroic mirror 22. By combining blue light B and yellow light LY, white illumination light WL is generated. Illumination light WL travels along optical axis AX2 and is incident on uniform illumination optical system 13.

[0057] The uniform illumination optical system 13 includes an integrating optical system 34, a polarization conversion component 35, and an overlapping lens 36. The integrating optical system 34 splits the illumination light WL incident from the dichroic mirror 22 into multiple beams. The integrating optical system 34 includes lens arrays 41 and 42. Lens arrays 41 and 42 are each composed of multiple microlenses arranged in an array along a direction perpendicular to the optical axis AX2.

[0058] The polarization conversion component 35 converts the illumination light WL, which is emitted from the integrating optical system 34 and consists of multiple small beams, into linearly polarized light. The polarization conversion component 35 has a polarization separation film, a phase difference plate, and a mirror. The illumination light WL, converted into linearly polarized light by the integrating optical system 34, is incident on the overlapping lens 36. The overlapping lens 36 causes the illumination light WL incident from the polarization conversion component 35 to be emitted along the optical axis AX2, and overlaps with each other on the screen, which serves as the illumination object of the projector 1.

[0059] Figure 3 This is a perspective view showing the structure of the image forming apparatus 400. For example... Figure 3 As shown, the image forming apparatus 400 includes a liquid crystal panel 132R of the light modulation apparatus 4R, a liquid crystal panel 132G of the light modulation apparatus 4G, a liquid crystal panel 132B of the light modulation apparatus 4B, and a cross-shaped dichroic prism 420. Figure 3 In the middle, the LCD panel 132R is obscured by the cross-shaped dichroic prism 420 and is not shown.

[0060] The dichroic cross prism 420 has a surface 420a, a bottom surface 420b, and side surfaces 420R, 420G, 420B, and 420S. Hereinafter, the direction parallel to the height direction of the dichroic cross prism 420 and extending from the bottom surface 420b toward the surface 420a is defined as the Z direction. The direction perpendicular to the Z direction and extending from the side surface 420R toward the side surface 420B is defined as the X direction. The direction perpendicular to both the X and Z directions and extending from the side surface 420G toward the side surface 420S is defined as the Y direction.

[0061] The sides 420R, 420G, and 420B of the dichroic cross prism 420 are respectively opposite to the liquid crystal panels 132R, 132G, and 132B. In order to suppress the loss of the full-color image light LF synthesized by the dichroic cross prism 420, an optical glass with a higher refractive index than that of a general optical lens is used as the material of the dichroic cross prism 420.

[0062] The optical modulation device 4G includes a liquid crystal panel 132G, a flexible substrate 45, an integrated circuit (IC) 402G, a metal component (first metal component) 55, and a metal component 82.

[0063] The liquid crystal panel 132G converts the green light LG incident on the light modulation device 4G into green image light IG. The liquid crystal panel 132G is composed of a liquid crystal layer (not shown) of a predetermined size on a ZX plane parallel to the Z and X directions, and substrates 46 and 47 that clamp and hold the liquid crystal layer in the Y direction. The substrates 46 and 47 may also include vapor chambers that serve a cooling function.

[0064] On the rear side of substrate 46 in the Y direction, a number of switching elements (not shown) and pixel electrodes, the same number as the number of pixels in liquid crystal panel 132G, are disposed. Substrate 47 is disposed rearward in the Y direction than substrate 46. On the front side of substrate 47 in the Y direction, counter electrodes (not shown) corresponding to the plurality of pixel electrodes formed on substrate 46 are disposed. In liquid crystal panel 132G, a green image display area AG is formed in the region where substrate 47, liquid crystal layer, and substrate 46 are sequentially stacked in the Y direction. When viewed from the Y direction, image display area AG overlaps with the reflective surfaces 421, 422 and side surface 420S of cross-shaped dichroic prism 420. On the opposite side of the surfaces of the two substrates 46 and 47 that are in contact with the liquid crystal layer in the Y direction, dustproof components (not shown) are provided.

[0065] The flexible substrate 45 of the optical modulation device 4G is flexible and can be bent freely. In the flexible substrate 45, a circuit pattern (not shown) is printed on the front side of the plate in the Y direction, that is, the plate facing the cross dichroic prism 420.

[0066] The Z-direction end of substrate 46 protrudes further forward in the Z-direction than the Z-direction end of substrate 47. Hybrid IC 402G is disposed on the rear side of substrate 46 in the Y-direction, in a region further forward in the Z-direction than the region overlapping with the image display area AG, and is sandwiched between flexible substrate 45 and substrate 46 in the Y-direction. Hybrid IC 402G is electrically connected to the circuit pattern formed on flexible substrate 45. If substrate 46 has a vapor chamber as described above, heat from the switching elements and hybrid IC 402G in contact with substrate 46 is absorbed by substrate 46, thus making it difficult for heat from the switching elements and hybrid IC 402G to be transferred to metal component 55.

[0067] The front end of the flexible substrate 45 in the Z direction is connected to a driving power supply (not shown). Based on the aforementioned structure, a predetermined voltage is applied to each of the multiple pixels formed in the image display area AG of the liquid crystal panel 132G to modulate the green light LG incident on each pixel.

[0068] Substrates 46 and 47 that are in contact with each other in the Y direction without passing through the liquid crystal layer, flexible substrate 45, and hybrid IC 402G are bonded to each other, for example, by a photocurable adhesive material made of ultraviolet-curable resin.

[0069] The metal component 82 of the optical modulation device 4G is disposed on the substrate 47 in a region forward of the image display area AG in the Z direction and rearward in the Y direction. The metal component 82 is composed of a plurality of blades that protrude further rearward in the Y direction from the rearward side of the substrate 47 and have a predetermined length in the Z direction. The metal component 82 absorbs heat from the flexible substrate 45 and from the switching element and the hybrid IC 402G.

[0070] The metal component 55 of the light modulation device 4G holds the liquid crystal panel 132G and is bonded to the side 420G of the cross dichroic prism 420 by a photocurable adhesive.

[0071] The liquid crystal panel 132R of the light modulation device 4R converts the red light LR incident on the light modulation device 4R into red image light IR. The liquid crystal panel 132R consists of a liquid crystal layer (not shown) of a predetermined size on a YZ plane including the Y and Z directions, and substrates 46 and 47 that clamp and hold the liquid crystal layer in the X direction. A number of switching elements (not shown) and pixel electrodes, the same number as the pixels of the liquid crystal panel 132R, are disposed on the rear surface of substrate 46 in the X direction. On the front surface of substrate 47, disposed further rearward in the X direction than substrate 46, counter electrodes (not shown) corresponding to the plurality of pixel electrodes are disposed. A red image display area AR is formed in the area of ​​the liquid crystal panel 132R where substrate 47, the liquid crystal layer, and substrate 46 are sequentially stacked in the X direction. Figure 3In the image display area AR, which is not shown as it is obscured by the cross-shaped dichroic prism 420, it overlaps with the reflective surfaces 421 and 422 and the side surfaces 420R and 420B of the cross-shaped dichroic prism 420 when viewed from the X direction. On the opposite side of the surfaces of the two substrates 46 and 47 that are in contact with the liquid crystal layer in the X direction, dustproof components (not shown) are provided.

[0072] In the optical modulation device 4R, a circuit pattern (not shown) is printed on the front side of the flexible substrate 45 in the X direction, i.e., the side facing the cross-shaped dichroic prism 420. The hybrid IC 402R is disposed on the rear side of the substrate 46 in the X direction, in a region further forward in the Z direction than the region overlapping with the image display area AR, and is sandwiched between the flexible substrate 45 and the substrate 46 in the X direction. The hybrid IC 402R... Figure 3 The light is obscured by the flexible substrate 45 of the light modulation device 4G and is not shown. The hybrid IC 402R is electrically connected to the circuit pattern formed on the flexible substrate 45 of the light modulation device 4R. The front end of the flexible substrate 45 in the Z direction of the light modulation device 4R is connected to a driving power supply (not shown). Similar to the liquid crystal panel 132G, a predetermined voltage is applied to each of the multiple pixels formed in the image display area AR of the liquid crystal panel 132R to modulate the red light LR incident on each pixel.

[0073] In the light modulation device 4R, substrates 46 and 47, which are in contact with each other in the X direction without passing through the liquid crystal layer, flexible substrate 45, and hybrid IC 402R, are bonded to each other by a photocurable adhesive. The metal component 55 of the light modulation device 4R holds the liquid crystal panel 132R and is bonded to the side surface 420R of the cross dichroic prism 420 by a photocurable adhesive.

[0074] The liquid crystal panel 132B of the light modulation device 4B converts the blue light LB incident on the light modulation device 4B into blue image light IB. The liquid crystal panel 132B consists of a liquid crystal layer (not shown) of a predetermined size in the YZ plane and substrates 46 and 47 that clamp and hold the liquid crystal layer in the X direction. A number of switching elements (not shown) and pixel electrodes, the same number as the number of pixels in the liquid crystal panel 132B, are disposed on the front surface of substrate 46 in the X direction. On the rear surface of substrate 47, which is disposed further forward in the X direction than substrate 46, counter electrodes (not shown) corresponding to the multiple pixel electrodes are disposed. A blue image display area AB is formed in the liquid crystal panel 132B where substrate 47, the liquid crystal layer, and substrate 46 are sequentially stacked in the direction opposite to the X direction. When viewed from the X direction, the image display area AB overlaps with the reflective surfaces 421 and 422 and the side surfaces 420B and 420R of the cross-shaped dichroic prism 420. On the opposite side of the surface of each of the two substrates 46 and 47 that is in contact with the liquid crystal layer in the X direction, a dustproof component (not shown) is provided.

[0075] In the light modulation apparatus 4B, a circuit pattern (not shown) is printed on the rear side of the flexible substrate 45 in the X direction, i.e., the side facing the cross-shaped dichroic prism 420. A hybrid IC 402B is disposed on the front side of the substrate 46 in the X direction, in a region further forward in the Z direction than the region overlapping with the image display area AB, and is sandwiched between the flexible substrate 45 and the substrate 46 in the X direction. The hybrid IC 402B is electrically connected to the circuit pattern formed on the flexible substrate 45 of the light modulation apparatus 4B. The front end of the flexible substrate 45 of the light modulation apparatus 4B in the Z direction is connected to a driving power supply (not shown). Similar to the liquid crystal panel 132G, a predetermined voltage is applied to each of the plurality of pixels formed in the image display area AB in the liquid crystal panel 132B to modulate the blue light LB incident on each pixel.

[0076] In the light modulation device 4B, substrates 46 and 47, which are in contact with each other in the X direction without passing through the liquid crystal layer, flexible substrate 45, and hybrid IC 402B, are bonded to each other by a photocurable adhesive. The metal component 55 of the light modulation device 4B holds the liquid crystal panel 132B and is bonded to the side surface 420B of the cross dichroic prism 420 by a photocurable adhesive.

[0077] In the image forming apparatus 400, blue image light IB is emitted from the liquid crystal panel 132B of the light modulation apparatus 4B and incident on the cross dichroic prism 420 from a direction opposite to the X direction. It passes through the front region of the reflective surface 422 in the Y direction and is reflected in the Y direction by the reflective surface 421. Red image light IR is emitted from the liquid crystal panel 132R of the light modulation apparatus 4R and incident on the cross dichroic prism 420 from the X direction. It passes through the front region of the reflective surface 421 in the Y direction and is reflected in the Y direction by the reflective surface 422. Green image light IG is emitted from the liquid crystal panel 132G of the light modulation apparatus 4G and incident on the cross dichroic prism 420 from the Y direction, passing through the reflective surfaces 421 and 422. The blue image light IB reflected by the reflective surface 421, the red image light IR reflected by the reflective surface 422, and the green image light IG transmitted through the reflective surfaces 421 and 422 overlap and combine on the side surface 420S of the cross dichroic prism 420. The side 420S is equivalent to the light-combining surface in the cross dichroic prism 420.

[0078] The metal components 55 of the light modulation devices 4R, 4G, and 4B determine the positions of the liquid crystal panels 132R, 132G, and 132B, as well as the positions of the image lights IR, IG, and IB incident on the cross-shaped dichroic prism 420 and synthesized together. The alignment of the image lights IR, IG, and IB requires a high precision equivalent to that of the pixel size. For example, if the position of one color image light in the image lights IR, IG, and IB deviates from the positions of the other two colors by more than one pixel, color bleeding occurs in the full-color image light LF emitted from the side 420S of the cross-shaped dichroic prism 420, reducing the clarity and color balance of the image displayed by the projector 1.

[0079] Relative to the cross-shaped dichroic prism 420, the liquid crystal panels 132R, 132G, and 132B of the light modulation devices 4R, 4G, and 4B are each held by a metal component 55. This suppresses the shift in the relative positions of the liquid crystal panels 132R, 132G, and 132B relative to the cross-shaped dichroic prism 420 due to heat generated from heat sources including the light sources 20 and 30 of the projector 1 and the driving power supply. This prevents the leakage of full-color image light LF and a reduction in image clarity. The material of the metal component 55 is, for example, aluminum (Al) or stainless steel (SUS).

[0080] Although not illustrated, each pixel of the liquid crystal panels 132R, 132G, and 132B has a pixel circuit including the aforementioned switching elements, pixel electrodes, liquid crystal layer, and counter electrode. The image display areas AR, AG, and AB of the liquid crystal panels 132R, 132G, and 132B each include multiple data lines and multiple scan lines. The multiple scan lines are arranged parallel to each other. The multiple data lines are arranged parallel to each other in a manner perpendicular to the multiple scan lines. For each of the liquid crystal panels 132R, 132G, and 132B, the product of the total number of data lines and the total number of scan lines is equal to the number of pixels. Pixel circuits for each of the liquid crystal panels 132R, 132G, and 132B are located at the intersections of the multiple scan lines and multiple data lines. In each of the LCD panels 132R, 132G, and 132B, when viewed from the incident directions of red light LR, green light LG, and blue light LB, there are multiple pixel circuits arranged in a two-dimensional pattern corresponding to the same number of intersections as the product of the total number of scan lines and the total number of data lines.

[0081] Multiple scan lines are connected to a scan line driving circuit (not shown). Multiple data lines are connected to a data line driving circuit (not shown). The data line driving circuit drives the multiple data lines according to an image signal (not shown) supplied from outside the projector 1 via the flexible substrate 45. The data line driving circuit is connected to the scan line driving circuit.

[0082] In the pixel circuits of LCD panels 132R, 132G, and 132B, the switching elements are composed of TFTs (Thin Film Transistors) not shown. The gate terminal of the TFT is connected to the scan line, the source terminal of the TFT is connected to the data line, and the drain terminal of the TFT is connected to the pixel electrode. The liquid crystal layer is disposed between the pixel electrode and the counter electrode. The counter electrode converges at the common electrode and auxiliary line. The TFT is switched to an on or off state by applying a voltage, thus functioning as a switch.

[0083] In the pixel circuits of LCD panels 132R, 132G, and 132B, multiple line periods are included within one frame. During each line period, one scan line is selected from multiple scan lines, and a predetermined voltage is applied to multiple scan lines containing the selected scan line. A lower voltage than the predetermined value is applied to the remaining scan lines. In the pixel circuit connected to the scan line to which the predetermined voltage is applied, the TFT is in the on state. During each line period, the data line driving circuit applies a voltage corresponding to each data line to multiple data lines according to the image signal. Before the end of the line period, the scan line driving circuit causes the voltage applied to the selected scan line to decrease from the predetermined value. As the voltage decreases through the scan line selected by the scan line driving circuit, the TFT of the pixel circuit connected to the selected scan line switches to the off state, and the data voltage is written to the pixel circuit connected to the selected scan line. The brightness of the pixel corresponding to the pixel circuit varies according to the data voltage written to the pixel circuit.

[0084] By using a scan line driving circuit and a data line driving circuit to write independent data voltages to multiple pixel circuits, the red light LR, green light LG, and blue light LB incident on each of the liquid crystal panels 132R, 132G, and 132B are modulated into the desired image, generating red image light IR, green image light IG, and blue image light IB that are endowed with the desired image information.

[0085] Figure 4 This is a perspective view showing the LCD panel 132G and metal component 55 disassembled along the Y direction. (Example) Figure 4 As shown, the metal component 55 has a mounting plate 65 and two connecting plates 66. The mounting plate 65, like the side surface 420G of the dichroic prism 420, is rectangular and has a surface parallel to the side surface 420G. The size of the mounting plate 65 in the X direction is slightly smaller than that of the side surface 420G. The size of the mounting plate 65 in the Z direction is larger than that of the side surface 420G. The mounting plate 65 is bonded to the side surface 420G using a light-curing adhesive, as described later.

[0086] An opening 351 is formed on the mounting plate 65. When viewed from the Y direction, the opening 351 includes the image display area AG of the liquid crystal panel 132G. A mounting member 62 is provided on the rear side of the mounting plate 65 in the Y direction around the opening 351. A polarizer 355 is mounted to the opening 351 using the mounting member 62.

[0087] The connecting plate 66 protrudes from both ends of the mounting plate 65 in the X direction in a direction opposite to the Y direction. Protrusions 69 are formed at both ends of the connecting plate 66 in the Z direction, further protruding from the connecting plate 66 in a direction opposite to the Y direction. A protrusion 68 is formed at the center of the connecting plate 66 in the Z direction, further protruding from the connecting plate 66 in a direction opposite to the Y direction.

[0088] Through-holes 83 and grooves 84 are formed on the substrate 47 of the liquid crystal panel 132G. The through-hole 83 is formed in the substrate 47 at a position where a protrusion 69 can be inserted from a direction opposite to the Y direction, and is a hole penetrating the substrate 47 along the Y direction. The groove 84 is formed on the substrate 47 at a position where a protrusion 68 can be inserted from a direction opposite to the Y direction, and is a groove recessed from a side end parallel to the Z direction toward the center in the X direction. With each protrusion 68 inserted into its corresponding groove 84 from a direction opposite to the Y direction, and each protrusion 69 inserted into its corresponding through-hole 83 from a direction opposite to the Y direction, the protrusions 68 and 69 are bonded to the substrate 47 using a photocurable adhesive.

[0089] Here, return to Figure 3 The description is as follows. The metal components 55 of each of the light modulation devices 4R and 4B, like those of the light modulation device 4G, have a mounting plate 65 and two connecting plates 66. In the light modulation devices 4R and 4B, similar to the light modulation device 4G, protrusions 68 and 69 are provided on the connecting plates 66. Through holes 83 and slots 84 are formed on the substrates 47 of each of the liquid crystal panels 132R and 132B. In the light modulation device 4R, with each protrusion 68 inserted into its corresponding slot 84 from the opposite direction to the X direction and each protrusion 69 inserted into its corresponding through hole 83 from the opposite direction to the X direction, the protrusions 68 and 69 are bonded to the substrate 47 using a photocurable adhesive. In the light modulation device 4B, with each protrusion 68 inserted into its corresponding slot 84 along the X direction and each protrusion 69 inserted into its corresponding through hole 83 along the X direction, the protrusions 68 and 69 are bonded to the substrate 47 using a photocurable adhesive. In the liquid crystal panels 132R, 132G, and 132B, the through hole 83 and the groove 84 may be formed on the substrate 46 instead of on the substrate 47.

[0090] Figure 5 This is a cross-sectional view of the image forming apparatus 400, obtained by cutting through the image display area AG parallel to the YZ plane. For example... Figure 5 As shown, the metal component 55 holding the liquid crystal panel 132G is bonded to the side surface 420G of the cross-shaped dichroic prism 420. Thus, the flexible substrate 45 of the light modulation device 4G, the hybrid IC 402G, the metal substrate 46 of the liquid crystal panel 132G, the metal component 55, and the cross-shaped dichroic prism 420 are sequentially adjacent along the Y direction. The structure between the front side surface 55G of the metal component 55 in the Y direction and the side surface 420G opposite to the side surface 55G of the metal component 55 in the cross-shaped dichroic prism 420 will be explained later.

[0091] The cross-shaped dichroic prism 420 is supported in a Z-direction by metal parts (third metal parts) 430 and 440, and is fixed to metal part (second metal part) 480 via metal parts 430 and 440. Metal part 480 supports the multiple refractive lenses of the projection lens group of the projection optical system 6 of the projector 1.

[0092] Metal component 430 has an end face 430b parallel to the XY plane and an end face 430x parallel to the XZ plane. Metal component 430 extends from end face 430b in the Z direction and is bent or folded in the Y direction. End face 430b of metal component 430 faces surface 420a of dichroic prism 420 via a photocurable adhesive (not shown). Metal component 430 is bonded to dichroic prism 420 by the photocurable adhesive. When viewed in the direction opposite to the Z direction, end face 430b is smaller than surface 420a, thus preventing contact between metal component 430 and the metal components 55 of the light modulation devices 4R, 4G, and 4B. End face 430x of metal component 430 contacts the rear side 480d of metal component 480 in the Y direction. Metal component 430 is fixed to metal component 480 by a fastener containing a screw (not shown).

[0093] Metal component 440 has an end face 440a parallel to the XY plane and an end face 440x parallel to the XZ plane. Metal component 440 extends from end face 440a in a direction opposite to the Z direction and is bent or folded in the Y direction. End face 440a of metal component 440 faces the bottom surface 420b of dichroic prism 420 via a photocurable adhesive (not shown). Metal component 440 is bonded to dichroic prism 420 by the photocurable adhesive. When viewed along the Z direction, end face 440a is smaller than bottom surface 420b, thus preventing contact between metal component 440 and the metal components 55 of the light modulation devices 4R, 4G, and 4B. End face 440x of metal component 440 contacts the side surface 480d of metal component 480. Metal component 440 is fixed to metal component 480 by a fastener containing a screw (not shown).

[0094] The dichroic prism 420 is supported by metal components 430 and 440 and fixed to metal component 480 by the same components. This suppresses any shift in the relative position of the dichroic prism 420 with respect to the projection lens group of the projection optical system 6 due to heat generated from the heat source, including the light sources 20 and 30 of the projector 1 and the power supply. As a result, it prevents the leakage of full-color image light LF and a reduction in image sharpness. The materials of the metal components 430, 440, and 480 are, for example, Al or SUS.

[0095] Green image light IG, modulated by the liquid crystal panel 132G of the light modulation device 4G, is emitted from the liquid crystal panel 132G in the Y direction, passes through the polarizer 355 and the opening 351 in sequence, and enters the cross dichroic prism 420 from the side 420G. Although not shown, similarly to the light modulation device 4G, red image light IR, modulated by the liquid crystal panel 132R of the light modulation device 4R, is emitted from the liquid crystal panel 132R in the X direction, passes through the polarizer 355 and the opening 351 in sequence, and enters the cross dichroic prism 420 from the side 420R. Blue image light IB, modulated by the liquid crystal panel 132B of the light modulation device 4B, is emitted from the liquid crystal panel 132B in the direction opposite to the X direction, passes through the polarizer 355 and the opening 351 in sequence, and enters the cross dichroic prism 420 from the side 420B.

[0096] Figure 6 This is a diagram viewed from the Y direction illustrating the bonding state between the metal component 55 of the light modulation device 4G in the image forming apparatus 400 and the cross-shaped dichroic prism 420. (See diagram for example.) Figure 6 As shown, in the X direction, the length of the side surface 55G of the metal component 55 is less than the length of the side surface 420G of the dichroic prism 420. In the Z direction, the length of the side surface 55G is greater than the length of the side surface 420G. The opening 351 through which the green image light IG passes is smaller than the side surface 420G of the dichroic prism 420. Based on the aforementioned size relationship, the opposing region (area) 500 of the metal component 55 and the dichroic prism 420 is rectangular when viewed along the Y direction. The inner periphery (periphery) 500p of the opposing region 500 is formed by the periphery of the opening 351. The outer periphery (periphery) 500q of the opposing region 500 is formed by the periphery of the side surface 55G of the metal component 55 that is parallel to the Z direction and the periphery of the side surface 420G of the dichroic prism 420 that is parallel to the X direction.

[0097] Figure 7 Is Figure 6 A cross-sectional view of the image forming apparatus 400 as seen along the arrow at line C1-C1. Figure 8 Is Figure 6A cross-sectional view of the image forming apparatus 400 as seen along the arrow at line C2-C2. Figures 6 to 8 As shown, an adhesive material layer 510 and an air layer 520 are provided in the opposing region 500. The dielectric constant of the air layer 520 is 1.0 [F·m]. -1 The adhesive material layer 510 and the air layer 520 are alternately arranged along the periphery of the opposing region 500. The adhesive material layer 510 bonds the side surface 420G of the cross-shaped dichroic prism 420 to the side surface 55G of the metal component 55, thereby aligning the photosynthetic surface in the cross-shaped dichroic prism 420 with the image display area AG of the liquid crystal panel 132G and maintaining the relative positional relationship between the metal component 55 and the cross-shaped dichroic prism 420. The adhesive material layer 510 is, for example, a UV-curable resin, and is composed of a photocurable adhesive material. The adhesive material layer 510 is not composed of a thermocurable adhesive material, but rather a photocurable adhesive material. Therefore, even when heat is transferred to the metal component 55 during the operation of the projector 1, the adhesive material layer 510 will not melt or deteriorate, thus maintaining the relative positional relationship between the metal component 55 and the cross-shaped dichroic prism 420.

[0098] like Figure 5 As shown, when the projector 1 is operating and displaying an image, the hybrid ICs 402R, 402G, and 402B of the light modulation devices 4R, 4G, and 4B, respectively, and the driving power supply (not shown) that drives these hybrid ICs, become noise sources, generating EMI noise N from these hybrid ICs and the driving power supply. The EMI noise N is transmitted through the flexible substrate 45 to the metal substrate 46 and the metal component 55. The adhesive layer 510 has a dielectric constant corresponding to the type of adhesive material constituting the adhesive layer 510, and transmits the EMI noise N reaching the metal component 55 to the dichroic prism 420.

[0099] As described above, the dichroic prism 420 is formed of optical glass with a higher refractive index than that of general optical lenses, and therefore has a high dielectric constant corresponding to the refractive index. The dielectric constant of prisms formed of general optical glass is 3.7–10 [F·m]. -1 In contrast, the dielectric constant of the cross-shaped dichroic prism 420 is, for example, 8.0–10.0 [F·m]. -1 The dichroic prism 420 acts as a dielectric for EMI noise N, performing a stronger effect than prisms made of general-purpose optical glass. EMI noise N is capacitively coupled through the dichroic prism 420 and transmitted to metal components 430 and 440. The EMI noise N transmitted to metal components 430 and 440 is then transmitted from metal component 480 to the metal components or housing of the projector 1, ultimately being emitted to the outside of the projector 1.

[0100] Figure 9 This is a graph representing an example of the measurement results of EMI noise N emitted to the outside of projector 1. Figure 9 In the chart, EMI noise NH represents the horizontal component of EMI noise N. Figure 9 In the graph, EMI noise NV represents the vertical component of EMI noise N. For example... Figure 9 As shown, resonance peaks of EMI noise NH and NV are generated at a frequency of 220MHz. If the EMI noise N, which is similar to the EMI noise NH and NV in the resonance peaks, is emitted to the outside of the projector 1 at a value exceeding a specified limit, it may affect the operation and performance of electronic devices other than the projector 1.

[0101] The proportion of the multiple adhesive material layers 510 in the opposing region 500 is represented by the ratio [%] of the total area of ​​the multiple adhesive material layers 510 on the XZ plane to the total area of ​​the opposing region 500 in a plane parallel to the XZ plane, hereinafter referred to as the ratio P. If the adhesive material layers 510 are made of the same material, the higher the ratio P, the stronger the bond between the metal component 55 and the dichroic prism 420. On the other hand, the higher the ratio P, the wider the channel of EMI noise N reaching the metal component 55 to the dichroic prism 420, and the greater the EMI noise N emitted from the projector 1. The lower the ratio P, the weaker the bond between the metal component 55 and the dichroic prism 420. On the other hand, the lower the ratio P, the narrower the channel of EMI noise N reaching the metal component 55 to the dichroic prism 420, and the smaller the EMI noise N emitted from the projector 1.

[0102] Figure 10 This is a graph showing the simulation results regarding the relationship between the ratio P and the EMI noise N. In this simulation, the dielectric constant of the adhesive layer 510 is set to 5.0, and the distance s between the metal part 55 and the cross dichroic prism 420 in the Y direction, i.e., the thickness of the adhesive layer 510, is set to 1 mm. Figure 10 The vertical axis of the graph, “EMI noise attenuation rate”, represents the attenuation rate with the initial value of the EMI noise N generated in the hypothetical initial model. In the hypothetical initial model, the metal part 55 of a specified size and shape is in direct contact with the opposing area 500 of the cross-shaped dichroic prism 420 without being separated by either the adhesive layer 510 or the air layer 520. Figure 10The horizontal axis of the graph, "Ratio P," represents the percentage of the adhesive material layer 510 in the opposing region 500, assuming that the metal component 55 and the cross-shaped dichroic prism 420 have the same specified size and shape as the initial model. A ratio P = 0% represents a hypothetical state where the opposing region 500 has no adhesive material layer 510 and consists only of an air layer 520. A ratio P = 100% represents a conventional state where the opposing region 500 is entirely equipped with an adhesive material layer 510 and has no air layer 520 at all.

[0103] By setting the interval s to 1 mm and sandwiching a 1 mm thick adhesive material layer with a dielectric constant of 5.0 between the metal component 55 and the cross-shaped dichroic prism 420, such as Figure 10 As shown, within the range of ratio P from 100% to approximately 73%, the EMI noise N attenuates by approximately 3 dB relative to the initial model. Within the range where ratio P is less than 73%, the attenuation rate of EMI noise N increases as ratio P decreases. Under the conditions of this simulation, by setting the air layer 520 in the opposing region 500 at a ratio P less than approximately 73%, the EMI noise N emitted from the projector 1 can be reduced compared to the state where ratio P is 100%. Hereinafter, the minimum ratio P within the range of a certain amount of ratio P determined by the interval s is recorded as the reference ratio P0. In the results of this simulation, the reference ratio P0 is approximately 73%.

[0104] As described above, the attenuation rate of EMI noise N is in a trade-off relationship with the bonding strength between the metal component 55 and the dichroic prism 420, relative to the change in ratio P which is less than the reference ratio P0 = 73%. In this simulation, within the range of ratio P smaller than the reference ratio P0 = 73%, the lower the ratio P, the greater the attenuation rate of EMI noise N, but the lower the bonding strength between the metal component 55 and the dichroic prism 420. When the bonding strength between the metal component 55 and the dichroic prism 420 decreases excessively, the metal component 55 detaches from the dichroic prism 420, resulting in malfunction of the projector 1. Therefore, the preferred ratio P is a ratio within a range that is smaller than the reference ratio P0 and larger than the minimum ratio P that effectively ensures the bonding strength between the metal component 55 and the dichroic prism 420. Hereinafter, the minimum ratio P that effectively ensures the bonding strength between the metal component 55 and the dichroic prism 420 will be referred to as the minimum ratio P1.

[0105] The baseline ratio P0 and the minimum ratio P1 vary depending on the type, properties, and spacing s of the adhesive constituting the adhesive layer 510. Therefore, when actually determining the ratio P, the physical properties of the metal component 55, the dichroic prism 420, and the opening 351 are set to be identical to those of the actual object. Following the same process as in this simulation, the relationship between the ratio P and the attenuation rate of the EMI noise N relative to the initial model is graphically plotted to determine the baseline ratio P0. Regarding adhesive strength, the minimum ratio P1 is determined by calculating or measuring the relationship between the ratio P and the adhesive strength of the metal component 55 and the dichroic prism 420 when the area occupied by the adhesive material changes in a bonding area with the same shape as the opposing region 500, through simulation or experimentation. Within the determined baseline ratio P0 and minimum ratio P1, a ratio P close to the minimum ratio P1 is adopted.

[0106] Although not illustrated, the opposing regions between the sides 55R and 55B of the metal components 55 of the light modulation devices 4R and 4B in the image forming apparatus 400 and the sides 420R and 420B of the cross-shaped dichroic prism 420 are also frame-shaped, similar to the aforementioned opposing region 500. An adhesive material layer and an air layer are provided in the opposing regions between the sides 55R and 55B and the sides 420R and 420B. The ratio of the adhesive material layer in the opposing regions between the sides 55R and 55B and the sides 420R and 420B is appropriately determined in the same way as the ratio P in the opposing region 500.

[0107] The projector 1 of the first embodiment described above includes: a light modulation device (first light modulation device) 4G, which emits image light (first image light) IG; light modulation devices (second light modulation devices) 4R and 4B, which emit image light (second image light) IR and IB; a cross-shaped dichroic prism 420; a metal component (first metal component) 55; a lens of a projection optical system 6; a metal component (second metal component) 480; and metal components (third metal components) 430 and 440. The cross-shaped dichroic prism 420 combines the image light IG and the image light IR and IB. The metal component 55 connects the light modulation device 4R to the cross-shaped dichroic prism 420. The lens of the projection optical system 6 projects the full-color image light LF combined by the cross-shaped dichroic prism 420. The metal component 480 supports the lens of the projection optical system 6. The metal components 430 and 440 connect the cross-shaped dichroic prism 420 to the metal component 480. In the projector 1, an air layer 520 is provided in the opposing area 500 where the metal part 55 is opposite to the cross dichroic prism 420.

[0108] Figure 11This is a front view of a conventional image forming apparatus in which an adhesive material layer 510 is provided in the opposing region 500 at a ratio P = 100 [%). In the projector 1 of the first embodiment, if increasing the bonding strength between the metal component 55 and the cross-shaped dichroic prism 420 is emphasized as in the past, then... Figure 11 As shown, an adhesive material layer 510 is provided in the opposing region 500 with the ratio P set to 100%. According to the projector 1 of the first embodiment, by providing an air layer 520 in the opposing region 500, the channel through which EMI noise N reaches the metal component 55 and is transmitted to the cross dichroic prism 420 is narrowed, which can suppress the conduction of noise current, i.e., EMI noise N, emitted from the noise source of the light modulation devices 4R, 4G, 4B, which include the hybrid ICs 402R, 402G, 402B and the driving power supply of these hybrid ICs, to the cross dichroic prism 420 and the metal components 430, 440, 480. As a result, the EMI noise N emitted from the projector 1 can be reduced.

[0109] According to the projector 1 of the first embodiment, by setting the ratio P in the opposing region 500 within a range of a minimum ratio P1 and a reference ratio P0, the bonding strength between the metal component 55 and the dichroic prism 420 can be well ensured to the extent that the metal component 55 will not detach from the dichroic prism 420, and the EMI noise N transmitted from the metal component 55 to the dichroic prism 420 and the metal components 430, 440, and 480 can be reduced. Within the range of a minimum ratio P1 and a reference ratio P0, the closer the ratio P is to the minimum ratio P1, the more the EMI noise N is minimized while ensuring the bonding strength between the metal component 55 and the dichroic prism 420 as described above.

[0110] In the projector 1 of the first embodiment, the opposing region 500 is a frame-shaped structure surrounding the opening 351 of the light modulation device 4G through which the image light IG emitted from the liquid crystal panel 132G passes. The adhesive layer 510 and the air layer 520, which bond the metal component 55 and the dichroic prism 420, are alternately arranged adjacent to each other in the direction along the inner periphery 500p and outer periphery 500q of the opposing region 500, i.e., the periphery 351p of the opening 351. According to the projector 1 of the first embodiment, by adjusting the size and number of the air layer 520 in the direction along the inner periphery 500p and outer periphery 500q, the transmission amount of the ratio P and EMI noise N from the metal component 55 to the dichroic prism 420 can be easily adjusted.

[0111] Furthermore, the first image light in this invention is designated as image light IG, but it can also be image light IR or image light IB. When the first image light is image light IR, the first optical modulation device is optical modulation device 4R, the second image light is image light IG or IB, and the second optical modulation device is optical modulation device 4G or 4B. When the first image light is image light IB, the first optical modulation device is optical modulation device 4B, the second image light is image light IR or IG, and the second optical modulation device is optical modulation device 4R or 4G.

[0112] [Second Implementation]

[0113] Next, use Figure 12 and Figure 13 The second embodiment of this disclosure will be described.

[0114] Furthermore, in subsequent embodiments, structures common to the first embodiment are labeled with the same reference numerals, and their descriptions are omitted. In subsequent embodiments, structures and contents different from those in the first embodiment are mainly described.

[0115] The projector of the second embodiment has the same structure as the projector 1 of the first embodiment. However, in the image forming apparatus of the projector of the second embodiment, the arrangement of the metal component 55 of the liquid crystal panel of the light modulation device and the air layer 520 in the opposing region 500 of the cross dichroic prism 420 is different from that of the first embodiment.

[0116] Figure 12 This is a diagram viewed from the Y direction illustrating the bonding state between the metal component 55 of the light modulation device 4G in the image forming apparatus of the projector of the second embodiment and the cross-shaped dichroic prism 420. (See diagram below.) Figure 12 As shown, the opposing region 500 in the second embodiment is rectangular when viewed along the Y direction, just like in the first embodiment. Figure 13 Is Figure 12 A cross-sectional view of the image forming apparatus of the second embodiment, as seen along the arrow at line C3-C3. (See figure) Figure 12 and Figure 13 As shown, in the opposing region 500 of the image forming apparatus of the second embodiment, an air layer 520 is provided in the inner region 501 near the center of the opposing region 500 when viewed from a direction parallel to the Y direction in a main view. An adhesive material layer 510 is provided in the opposing region 500 in a region 502 that is outside the air layer 520.

[0117] When determining the ratio P of the adhesive material layer 510 in the opposing region 500, similarly to the first embodiment, the physical properties of the metal component 55, the dichroic prism 420, and the opening 351 are set to be identical to those of the actual object. The relationship between the ratio P and the attenuation rate of EMI noise relative to the initial model as described in the first embodiment is plotted to determine the reference ratio P0. Regarding the adhesive strength, the relationship between the ratio P and the adhesive strength of the metal component 55 and the dichroic prism 420 is calculated or measured through simulation or experiment when the area occupied by the adhesive material changes in an adhesive region with the same shape as the opposing region 500, and the minimum ratio P1 is determined. Within the range of the determined reference ratio P0 and the minimum ratio P1, a ratio P close to the minimum ratio P1 is adopted.

[0118] The projector of the second embodiment described above has the same constituent elements as the projector 1 of the first embodiment, and an air layer 520 is provided in the opposing region 500. According to the projector of the second embodiment, compared to the state where an adhesive material layer 510 is provided throughout the opposing region 500, the path of EMI noise N reaching the metal component 55 between the metal component 55 and the cross-shaped dichroic prism 420 can be narrowed, thereby reducing the EMI noise N transmitted from the cross-shaped dichroic prism 420 to the metal components 430, 440, and 480. Therefore, the EMI noise N emitted from the projector can be reduced.

[0119] In the projector of the second embodiment, the opposing region 500 is a frame-shaped structure surrounding the opening 351 of the light modulation device 4G through which the image light IG passes. An adhesive material layer 510 is provided in the region 502 of the opposing region 500, which is located outside the opening 351, compared to the region 501 where the air layer 520 is provided. According to the projector of the second embodiment, by adjusting the area ratio of the inner region to the outer region in the opposing region 500, the ratio P and the amount of EMI noise N transmitted from the metal component 55 to the cross-shaped dichroic prism 420 can be easily adjusted. According to the projector of the second embodiment, since an air layer 520 is provided inside the opposing region 500, leakage of the adhesive material layer 510 from the opposing region 500 to the opening 351 can be reliably prevented compared to the projector 1 of the first embodiment.

[0120] [Third Implementation]

[0121] Next, use Figures 14 to 17 The third embodiment of this disclosure will be described.

[0122] The projector of the third embodiment has the same structure as the projector 1 of the first embodiment. In the image forming apparatus of the projector of the third embodiment, the arrangement of the metal component 55 holding the liquid crystal panel of the light modulation device and the air layer 520 in the opposing region 500 of the cross-shaped dichroic prism 420 is the same as in the first embodiment. However, the spacing s between the side surface 55G of the metal component 55 in the region where the air layer 520 is provided and the side surface 420G of the cross-shaped dichroic prism 420 in the opposing region 500 differs from that in the first embodiment.

[0123] Figure 14 This is a cross-sectional view of the image forming apparatus according to the third embodiment, and is consistent with... Figure 6 The diagram showing the observation along the arrow at line C2-C2. (See figure below.) Figure 14 As shown, a recess 530 is formed on the side 55G of the metal component 55 in region 503, where an air layer 520 is provided in the opposing region 500. The recess 530 is recessed in the opposite direction to the Y direction compared to the surrounding side 55G. By forming the recess 530 in region 503, the distance t between the metal component 55 and the dichroic prism 420 in the Y direction in region 503 is larger than the distance s. The longer the distance t, the more difficult it is for the EMI noise N reaching the metal component 55 to be transmitted to the dichroic prism 420, and the smaller the EMI noise N emitted from the projector.

[0124] Figure 15 This is a graph showing the simulation results regarding the relationship between the interval t and the EMI noise N. Figure 15 The vertical axis of the graph, "EMI noise attenuation rate," is consistent with that described in the first embodiment. Figure 10 The vertical axis is the same, representing the attenuation rate with the initial value of EMI noise N generated in the hypothetical initial model. In the hypothetical initial model, the metal component 55 of a specified size and shape is in direct contact with the opposing region 500 of the dichroic prism 420 without being separated by either the adhesive layer 510 or the air layer 520. In this simulation, the interval t is varied to 1.0 [mm], 0.5 [mm], 0.25 [mm], and 0.1 [mm], and all conditions related to the metal component 55, the dichroic prism 420, and the opposing region 500, except for the interval t, are fixed. Figure 15 As shown, the attenuation rate of EMI noise N increases as the interval t decreases from 1.0 mm to 0.1 mm. If the interval s between the side surface 55G of the metal component 55 and the side surface 420G of the dichroic prism 420 in the region where the adhesive material layer 510 is provided in the ratio P and the opposing region 500 is constant, then the larger the interval s, the less EMI noise N is transmitted from the metal component 55 to the dichroic prism 420.

[0125] The projector of the third embodiment described above has the same constituent elements as the projector 1 of the first embodiment, and an air layer 520 is provided in the opposing region 500. According to the projector of the third embodiment, compared to the state where an adhesive material layer 510 is provided throughout the opposing region 500, the path of EMI noise N reaching the metal component 55 between the metal component 55 and the cross-shaped dichroic prism 420 can be narrowed, thereby reducing the EMI noise N transmitted from the cross-shaped dichroic prism 420 to the metal components 430, 440, and 480. Therefore, the EMI noise N emitted from the projector can be reduced.

[0126] In the projector of the third embodiment, a recess 530 is formed on the side surface 55G of metal components 55 facing each other with air layers 520 in the opposing region 500. According to the projector of the third embodiment, compared with the structure in which the recess 530 is not formed on the side surface 55G of the metal components 55, the amount of EMI noise N transmitted from the metal components 55 to the cross dichroic prism 420 can be reduced.

[0127] Figure 16 This is a cross-sectional view of the image forming apparatus of the first variation of the third embodiment. Figure 17 This is a cross-sectional view of the image forming apparatus of the second modification of the third embodiment. Figure 14 In the structure shown, a recess 530 is formed on the side 55G of the metal component 55. However, as a first variation of the image forming apparatus of the projector in the third embodiment, such as Figure 16 As shown, a recess 530 can also be formed on the side 420G of the cross-shaped dichroic prism 420 in region 503. As a second variation of the image forming apparatus of the projector in the third embodiment, such as... Figure 17 As shown, recesses 530 can also be formed on the side 55G of the metal component 55 in region 503 and on the side 420G of the cross dichroic prism 420. According to the first and second modifications of the image forming apparatus of the projector according to the third embodiment, similar to the image forming apparatus of the projector described above, compared with the structure without recesses 530, the amount of EMI noise N transmitted from the metal component 55 to the cross dichroic prism 420 can be reduced.

[0128] In the projector of the third embodiment, or in the first and second modifications of the third embodiment, the amount of EMI noise N transmitted from the metal component 55 to the cross-shaped dichroic prism 420 can be easily adjusted by adjusting the interval t. To obtain a good bonding strength between the metal component 55 and the cross-shaped dichroic prism 420, the interval s of the region in the opposing region 500 where the adhesive material layer 510 is provided is limited to a predetermined range based on the type or properties of the adhesive material constituting the adhesive material layer 510. In the projector 1 of the first embodiment, when the interval s is set within a predetermined range, if the range between the minimum ratio P1 and the reference ratio P0 is so narrow that it is difficult to determine the ratio P, the structure of the projector of the third embodiment is adopted. By setting the ratio P to be equal to the minimum ratio P1 based on the interval s, the interval t can be appropriately set wider so that the attenuation of EMI noise N converges within the predetermined range required by the projector 1, or in a manner that satisfies predetermined conditions.

[0129] Furthermore, in the projector of the second embodiment, a recess 530 may be formed on at least one of the side surfaces of region 501 in the opposing region 500, the side surface 55G of the metal component 55, and the side surface 420G of the dichroic prism 420. In the projector of the second embodiment, by forming a recess 530 on at least one of the side surfaces 55G and 420G of region 501, the amount of EMI noise N transmitted from the metal component 55 to the dichroic prism 420 can be reduced compared to a structure without a recess 530.

[0130] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above, and various modifications and alterations can be made within the scope of the spirit of the present invention as described in the technical solution of the present invention. In addition, the constituent elements of multiple embodiments can be appropriately combined. Regarding the above embodiments, the effects that should be particularly explained have been described, but even without detailed explanation, the effects of other embodiments suitable for the structure of the light source device can be obtained.

[0131] In the projector 1 of the first embodiment, or the projectors of the second and third embodiments, the shape of the metal component 55 is appropriately modified according to the structure of each of the light modulation devices 4R, 4G, and 4B and the conditions inside the projector's outer casing 600, and is not limited to... Figure 3 and Figure 4 The shape is illustrated. Depending on the shapes of the metal component 55 and the cross-shaped dichroic prism 420, the shape of the opposing region 500 is not limited to a frame shape; for example, it can be changed to any shape containing multiple rectangles.

[0132] In the projector 1 of the first embodiment, or the projectors of the second and third embodiments, the relative arrangement of the adhesive material layer 510 and the air layer 520 in the opposing region 500 is not limited to the arrangement divided by the inner and outer regions relative to the circumference and center of the opposing region 500, and may not be regular and may be appropriately changed.

[0133] Figure 18 This is a diagram viewed from the Y direction, illustrating a third modified example of the bonding state between the metal component 55 of the light modulation device 4G in the image forming apparatus 400 and the cross dichroic prism 420. (See diagram for reference.) Figure 18 As shown, for example, the adhesive material layer 510 can also be provided in the front and rear regions of the opposing region 500 in the Z direction. In the structure of the third modification, the ratio P is also determined in the same way as the ratio P described with respect to the projector 1 of the first embodiment. According to the structure of the third modification, similar to the projector 1 of the first embodiment, the EMI noise N transmitted from the metal part 55 to the cross dichroic prism 420 can be reduced, and the amount of EMI noise N emitted to the outside of the projector can be reduced. Furthermore, according to the structure of the third modification, the adhesive material layer 510 is provided in the outer region of the relatively large region between the inner periphery 500p and the outer periphery 500q in the opposing region 500. As a result, it is possible to prevent the adhesive material from intruding into the relatively small region between the inner periphery 500p and the outer periphery 500q and from leaking into the opening 351.

[0134] In the structure of the third variation, as described in the third embodiment, a recess 530 may be formed on any one of the sides 55R, 55G, 55B of the metal component 55 in the region 503 where the air layer 520 is provided, and the sides 420R, 420G, 420B of the cross dichroic prism 420.

[0135] Furthermore, in the opposing region of the projector disclosed herein, by distributing a substance or medium having a dielectric constant lower than that of the prism and the adhesive material in the region where the air layer is provided, the amount of EMI noise transmitted from the first metal component to the prism and the amount of EMI noise emitted to the outside of the projector can be reduced.

[0136] The projector according to the present invention may also have the following structure.

[0137] One aspect of the present invention provides a projector comprising: a first light modulation device that emits a first image light; a second light modulation device that emits a second image light; a prism that combines the first image light and the second image light; a first metal component that connects the first light modulation device and the prism; a lens that projects the light combined by the prism; a second metal component that supports the lens; and a third metal component that connects the prism and the second metal component, wherein an air layer is provided in the opposing region of the first metal component and the prism.

[0138] In one embodiment of the projector of the present invention, the opposing region may be a frame-shaped area surrounding the opening of the first light modulation device through which the first image light passes, wherein in the opposing region, the adhesive material layer for bonding the first metal component and the prism and the air layer are arranged adjacent to each other in a direction along the periphery of the opening.

[0139] In one embodiment of the projector of the present invention, the opposing region may be a frame-shaped area surrounding the opening of the first light modulation device through which the first image light passes, and an adhesive material layer for bonding the first metal component and the prism may be provided in the area of ​​the opposing region that is further outward from the opening than in the area where the air layer is provided.

[0140] In one embodiment of the projector of the present invention, at least one of the first metal component and the prism, which are opposed to each other by the air layer, may have a recess formed.

Claims

1. A projector characterized by comprising: The projector has: a first light modulating device that emits first image light; a second light modulating device that emits second image light; a prism that combines the first image light and the second image light; a first metal member that connects the first light modulating device and the prism; a lens that projects light combined by the prism; a second metal member that supports the lens; and a third metal member that connects the prism and the second metal member, an air layer is provided in an opposing region where the first metal member and the prism face each other, the first metal member has an opening through which the first image light passes, when viewed in an opposing direction along which the first metal member and the prism face each other, the opposing region is in a frame shape that surrounds the opening, in the opposing region, an adhesive layer that adheres the first metal member and the prism is provided, the adhesive layer and the air layer are alternately arranged adjacent to each other in a direction along a periphery of the opening.

2. The projector according to claim 1, wherein at least one of the first metal member and the prism that face each other across the air layer is formed with a recess. ​

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