A projection display device

Abstract

A high-quality, small-sized, low-cost projection display device includes a dichroic mirror that divides light from a light source into first color light first illumination light and second color light second illumination light; a first illumination optical system that guides the first illumination light to a first reflective light modulation device; a second illumination optical system that guides the second illumination light to a second reflective light modulation device; a combining prism that transmits first image light output from the first reflective light modulation device through a dielectric multilayer film and changes the optical path of second image light output from the second reflective light modulation device by reflecting the second image light off the dielectric multilayer film to emit combined light in which the first image light and the second image light are combined; a first rear group lens; a second rear group lens; and a front group lens disposed closer to the magnification side than the combining prism and acting on the combined light, the first image light and the second image light having substantially equal angles of incidence on the dielectric multilayer film of 10 degrees or more and 27 degrees or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a dual-plate type projection display device provided with two reflective light modulating devices. BACKGROUND

[0002] Conventionally, a projection display device provided with a light modulating device such as a digital micromirror device (DMD) and a liquid crystal device and a projection optical system, which enlargingly projects a color image onto a screen or the like to display it, has been known.

[0003] For example, a single-plate type projection display device, which irradiates a light modulating device of a single plate with illumination light of different colors while switching it at high speed, has been known, which time-division projects images of different colors. Since the light modulating device can perform color display although it is a single plate, it has advantages in cost reduction and device miniaturization, but since it displays while time-division switching images of different display colors, it is difficult to achieve high luminance. In addition, in the case where a switching color filter is used in combination with a white light source in order to generate illumination light of which colors are time-division switched, only a part of the white light is used, and there is a problem that power consumption increases due to low light utilization efficiency.

[0004] As a different mode from the single-plate type, a three-plate type projection display device, which is provided with three light modulating devices, has been known, which irradiates each light modulating device with illumination light of different colors (for example, red (R), green (G), and blue (b)), and uses a cross dichroic prism or the like to synthesize and project display images of different colors output from each light modulating device. Since it can achieve high luminance compared to the aforementioned single-plate type, it is suitable for large screen uses such as movies, but since the structure of the optical system is complicated and the number of components is large, it is difficult to achieve cost reduction and device miniaturization, and the use is limited.

[0005] Therefore, in order to achieve a device which is excellent in balance among high luminance, miniaturization, and cost reduction, and which is highly versatile, a dual-plate type projection display device provided with two light modulating devices has been attempted.

[0006] For example, in Patent Literature 1, a projection display device provided with a light source section, a dichroic mirror which separates emergent light from the light source section into first color light and second color light, a first light modulating device which modulates the first color light, a second light modulating device which modulates the second color light, and a color synthesizing prism which performs color synthesis on the first color light modulated by the first light modulating device and the second color light modulated by the second light modulating device, is described. The device is further provided with a projection assembly which projects the synthesized light emitted from the color synthesizing prism.

[0007] Patent Document 2 describes a projection display device comprising: a polarizing cross dichroic prism for separating light from a light source; a first light modulator; and a second light modulator; and a polarizing cross dichroic prism for combining the output lights of the first and second light modulators. The light source assembly of this device is configured to illuminate the first and second light modulators with blue light during a first display period, and illuminate the first light modulator with green light and the second light modulator with red light during a second display period.

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-146951

[0009] Patent Document 2: International Publication No. 2018 / 073893

[0010] In the method described in Patent Document 1, when the incident angle to the dichroic mirror is set to θ1 and the incident angle to the color synthesis prism is set to θ2, the angles are set to θ1 = 55 degrees and θ2 = 35 degrees and the optical components are arranged. Figure 1 As shown, the prism assembly in which the total internal reflection (TIR) ​​prism and the color synthesis prism are integrated is arranged between the light modulator and the projection lens, and the incident angle θ2 for the color synthesis prism is set to 35 degrees, so that the back focal length of the projection lens becomes larger than that of the three-plate type. In this sense, the miniaturization of the device may not be sufficient.

[0011] In Patent Document 1, the device is miniaturized by arranging the light modulator symmetrically with respect to the color synthesis plane of the color synthesis prism. However, since θ2 is set to 35 degrees as described above, it is difficult to apply the most popular and cost-effective type of reflective light modulator. Figure 15 As shown, the most popular and cost-effective reflective light modulator is a type that arranges multiple micromirrors two-dimensionally on a screen, with each micromirror driven so that its reflective surface tilts ±12 degrees when turned on or off. In this device, as shown in the enlarged upper left corner of the figure, the on light to be displayed and the off light not to be displayed are reflected in different directions. However, in the device of Patent Document 1, the θ2 = 35 degrees and the symmetrical arrangement of the light modulators result in a geometric configuration that reflects the on light toward the projection lens and the off light away from the projection lens. Therefore, when implementing the method described in Patent Document 1, a cost-effective reflective light modulator cannot be used. Instead, a reflective light modulator in which the micromirrors are angled horizontally (H) or vertically (V) relative to the screen must be used.

[0012] Further, in the method described in Patent Literature 2, a polarizing cross dichroic prism is used as a means for color-combining the output light of the two light modulation devices, but the polarizing characteristics of the cross dichroic prism vary greatly depending on the incident angle. Therefore, for example, in an actual optical system in which the F value is about 2.5 and the in-plane incident angle deviation is ±12 degrees, a problem occurs in that color unevenness (color spots) significantly occurs within the display screen, and the display quality is reduced.

[0013] Therefore, a dual-panel type projection display device that achieves a good balance between high display quality with uniform color depth (few color spots) and miniaturization and low cost, and that is highly versatile, is sought. SUMMARY

[0014] One aspect of the present application is a projection display device characterized by comprising: a light source; a light channel that makes light from the light source propagate along an optical axis arranged in a first plane; a dichroic mirror that divides light from the light source that has entered via the light channel into first illumination light of a first color and second illumination light of a second color; a first illumination optical system that guides the first illumination light reflected by the dichroic mirror to a first reflective light modulation device; a second illumination optical system that guides the second illumination light transmitted through the dichroic mirror to a second reflective light modulation device; a combining prism that makes first image light output from the first reflective light modulation device transmit through a dielectric multilayer film, and makes second image light output from the second reflective light modulation device change the optical path by being reflected by the dielectric multilayer film, and emits combined light that combines the first image light and the second image light; a first rear group lens arranged between the combining prism and the first reflective light modulation device, and acting on the first image light; a second rear group lens arranged between the combining prism and the second reflective light modulation device, and acting on the second image light; and a front group lens arranged closer to the magnification side than the combining prism, and acting on the combined light, the incident angle of the first image light and the second image light to the dielectric multilayer film being substantially equal, and being 10 degrees or more and 27 degrees or less.

[0015] According to the present application, a dual-panel type projection display device that achieves a good balance between high display quality with uniform color depth (few color spots) and miniaturization and low cost, and that is highly versatile, can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a typical view showing the optical structure of the projection display device according to Embodiment 1.

[0017] Figure 2 is a view showing a part of the illumination optical system in Embodiment 1.

[0018] Figure 3 This is a diagram showing the projection optical system in Embodiment 1.

[0019] Figure 4 (a) is a diagram showing the structure of the synthetic prism 400; Figure 4 (b) is a graph showing the characteristics of the dielectric multilayer film 405 .

[0020] Figure 5 is a graph showing the characteristics of the dichroic mirror 180 .

[0021] Figure 6 This is a diagram showing the arrangement of the optical devices when the reflective light modulation device 200 b is viewed from the back side in the first embodiment.

[0022] Figure 7 (a) is a diagram typically showing an illumination optical system from the optical channel 140 to the reflective light modulation device 200a; Figure 7 (b) is a diagram typically showing an illumination optical system from the optical channel 140 to the reflective light modulation device 200b.

[0023] Figure 8 (a) is a diagram showing the structure of the light source device 110 used in Embodiment 1; Figure 8 (b) is a diagram showing the structure of the light source device 110 used in the second embodiment.

[0024] Figure 9 (a) is a graph showing the transmission characteristics of the cyan filter CF; Figure 9 (b) is a graph showing the transmission characteristics of the red filter RF.

[0025] Figure 10 This is a typical diagram showing the optical structure of the projection display device according to the second embodiment.

[0026] Figure 11 This is a diagram showing a portion of the illumination optical system in the second embodiment extracted.

[0027] Figure 12 This is a diagram showing a projection optical system in Embodiment 2.

[0028] Figure 13 (a) is a diagram showing the structure of the synthetic prism 410; Figure 13 (b) is a graph showing the characteristics of the dielectric multilayer film 415 .

[0029] Figure 14 1 is a diagram showing the arrangement of the optical devices when the reflective light modulation device 200 b is viewed from the back side in the second embodiment.

[0030] Figure 15 is a diagram for explaining a structure of a reflective light modulating device.

[0031] Figure 16 is a plan view of a rotating body.

[0032] Figure 17 is a diagram showing a light emitting property of a phosphor (fluorescent material).

[0033] Figure 18 (a) of FIG. 10 is a timing chart showing a color light of the illumination light IL output from the light source device 110 related to Embodiment 1; Figure 18 (b) of FIG. 10 is a timing chart showing a color light of the first illumination light related to Embodiment 1; Figure 18 (c) of FIG. 10 is a timing chart showing an image light output from the reflective light modulating device 200a related to Embodiment 1; Figure 18 (d) of FIG. 10 is a timing chart showing a color light of the second illumination light related to Embodiment 1; Figure 18 (e) of FIG. 10 is a timing chart showing an image light output from the reflective light modulating device 200b related to Embodiment 1.

[0034] Figure 19 (a) of FIG. 11 is a timing chart showing a color light of the illumination light IL output from the light source device 110 related to Embodiment 2; Figure 19 (b) of FIG. 11 is a timing chart showing a color light of the first illumination light related to Embodiment 2; Figure 19 (c) of FIG. 11 is a timing chart showing an image light output from the reflective light modulating device 200a related to Embodiment 2; Figure 19 (d) of FIG. 11 is a timing chart showing a color light of the second illumination light related to Embodiment 2; Figure 19 (e) of FIG. 11 is a timing chart showing an image light output from the reflective light modulating device 200b related to Embodiment 2.

[0035] Figure 20 (a) of FIG. 12 is a timing chart showing a color light of the illumination light IL output from the light source device 110 related to Embodiment 2; Figure 20 (b) of FIG. 12 is a timing chart showing a color light of the first illumination light related to Embodiment 2; Figure 20 (c) of FIG. 12 is a timing chart showing an image light output from the reflective light modulating device 200a related to Embodiment 2; Figure 20 (d) of FIG. 12 is a timing chart showing a color light of the second illumination light related to Embodiment 2; Figure 20 (e) of FIG. 12 is a timing chart showing an image light output from the reflective light modulating device 200b related to Embodiment 2.

[0036] BRIEF DESCRIPTION OF REFERENCE NUMERALS

[0037] 1 … … projection display device

[0038] 110 … … light source device

[0039] 105 … … dichroic mirror

[0040] 107 … … 1 / 4 wave plate

[0041] 109 … … condenser lens

[0042] 111R … … solid light source emitting red light

[0043] 112B … … solid light source emitting blue light

[0044] 113G … … solid light source emitting green light

[0045] 121 … … motor

[0046] 122 … … rotating body

[0047] 123 … … phosphor

[0048] 123Y … … yellow phosphor

[0049] 124 … … reflection portion

[0050] 140 … … light path

[0051] 150 … … light path side condenser lens

[0052] 151 … … intermediate image side condenser lens

[0053] 155 … … enlarged intermediate image

[0054] 160 … … intermediate image side condenser lens

[0055] 161 … … intermediate image side condenser lens

[0056] 162 … … relay lens

[0057] 163 … … modulator device side condenser lens

[0058] 170a, 170b … … TIR prism

[0059] 180 … … dichroic mirror

[0060] 181 … … light path changing mirror

[0061] 182a, 182b … … turning mirror

[0062] 200a, 200b … … reflection type light modulator device

[0063] 210 … … excitation light source assembly

[0064] 400 synthetic prism

[0065] 401, 402, 403 prism

[0066] 405 dielectric multilayer film

[0067] 410 synthetic prism

[0068] 411, 412 prism

[0069] 415 dielectric multilayer film

[0070] 601a first rear group lens

[0071] 601b second rear group lens

[0072] 602 front group lens

[0073] 610 projection optical system

[0074] 611a first relay lens

[0075] 611b second relay lens

[0076] 60 projection optical system

[0077] 612 third relay lens

[0078] 613 intermediate image

[0079] 614 projection lens

[0080] 700 projection surface

[0081] AG1, AG2, AG3 air gap

[0082] Ex excitation light

[0083] IL illumination light

[0084] LX optical axis of front group lens DETAILED DESCRIPTION

[0085] A projection display device according to an embodiment will be described below with reference to the accompanying drawings.

[0086] [Embodiment 1]

[0087] Figure 1is a typical view showing an optical structure of a projection display device according to Embodiment 1. The projection display device 1 is provided with a reflective light modulating device 200a (first reflective light modulating device) and a reflective light modulating device 200b (second reflective light modulating device). In the present embodiment, as the reflective light modulating devices 200a and 200b, a DMD in which a micromirror device is provided in an array is used. As described in reference to Figure 15

[0088] The projection display device 1 is provided with a light source device 110. The light source device 110 is a light source for illuminating the reflective light modulating devices 200a and 200b. Figure 8 (a) of FIG. 1 shows a structure of the light source device 110 used in the present embodiment. The light source device 110 is provided with an excitation light source assembly 210, which is an assembly in which a plurality of light emitting devices (for example, semiconductor lasers that emit blue light) are arranged two-dimensionally and a collimating lens is provided corresponding to each light emitting device. In addition, the light source device 110 is provided with a rotating body 122 that is rotatable by a motor 121, and a phosphor (fluorescent material) 123 is provided on a main surface of the rotating body 122. Further, a dichroic mirror 105, a ¼ wavelength plate 107, and a condensing lens are disposed between the excitation light source assembly 210 and the phosphor 123.

[0089] In the light source device of the present embodiment, the rotating body 122 is rotatable by the motor 121, and the phosphor 123 is provided on a main surface of the rotating body 122. Figure 16 A plan view of the rotating body 122 is shown. On the main surface of the rotating body 122, a yellow phosphor 123Y is applied on a part of a ring-shaped region centered on a rotation axis RA, and a reflection portion 124 for reflecting excitation light Ex is provided on the remaining part of the ring-shaped region without the phosphor. The reflection portion 124 is preferably mirror-finished in advance to efficiently reflect blue laser light. On the base of the region in which the yellow phosphor 123Y is provided, a reflection surface for reflecting fluorescent light radiated toward the rotating body 122 to the lens side is provided to improve the emission efficiency of the fluorescent light.

[0090] Figure 17 ​An example of a spectrum obtained from the yellow phosphor 123Y when the excitation light Ex is irradiated to the yellow phosphor 123Y is shown. The graph 32 shown by a single-dot chain line in the figure is a luminescence spectrum of the yellow phosphor 123Y. For reference, a luminescence spectrum of a general green phosphor is shown by a broken line graph 31, and a luminescence spectrum of a general red phosphor is shown by a solid line graph 33. In addition, a peak observed around a wavelength of 450 nm is not light emitted by the phosphor, but light after a portion of the excitation light Ex is not absorbed by the phosphor and is reflected. In addition, Figure 17 The graph 32 shown is an example, and the luminescence characteristics of the phosphor that can be used in the present embodiment are not necessarily identical thereto.

[0091] By rotating such a rotating body 122, the excitation light Ex is irradiated to either the yellow phosphor 123Y or the reflecting portion 124. In order to prevent the phosphor from overheating, the base material of the rotating body 122 preferably uses a metal having a high thermal conductivity, and a concave-convex portion or a hole is sometimes provided in the base material in order to improve the air cooling efficiency.

[0092] Next, the functions of each portion of the light source device 110 are described with reference to Figure 8 (a).

[0093] The collimated S-polarized blue light (excitation light Ex) emitted from the excitation light source assembly 210 is incident to the dichroic mirror 105. The S-polarized blue light (excitation light Ex) is reflected by the dichroic mirror 105 toward the rotating body 122. The excitation light passing through the 1 / 4 wavelength plate 107 is condensed by the condenser lens onto the rotating body 122.

[0094] During the rotation period in which the yellow phosphor 123Y is present at the position at which the excitation light Ex is condensed, yellow fluorescent light is emitted. In addition, during the rotation period in which the reflecting portion 124 is present at the position at which the excitation light Ex is condensed, the excitation light Ex (blue light) is reflected.

[0095] Among the yellow fluorescent light incident to the dichroic mirror 105, the P-polarized component is almost entirely transmitted, and the S-polarized component is mostly transmitted at a wavelength of about 490 nm or more. In addition, the blue light converted to P-polarization is almost entirely transmitted. That is, these lights are efficiently transmitted from the dichroic mirror 105, are emitted as output light of the light source device, and are appropriately condensed by the condenser lens 109.

[0096] The condenser lens 109 is set to a predetermined NA in order to match the F value of the projection optical system 610, which condenses the illumination light IL to the entrance of the light tunnel 140. As Figure 1As shown, the output light of the light source device is used as the illumination light IL of the projection display device. In addition, depending on the situation, in order to exclude unnecessary spectral components from the illumination light IL, a switching color filter (color wheel) can also be provided between the condenser lens 109 and the light tunnel 140, for example.

[0097] Next, the illumination optical system that distributes the illumination light IL provided by the light source device 110 to the reflective light modulation device 200a (first reflective light modulation device) and the reflective light modulation device 200b (second reflective light modulation device) will be described.

[0098] Figure 2 is a view that extracts a part of the illumination optical system of Embodiment 1. The illumination light IL that propagates via the light tunnel 140 is shaped into a light beam suitable for illuminating the reflective light modulation device 200a and the reflective light modulation device 200b by the light tunnel side condenser lens 150. The light tunnel side condenser lens 150 is composed of a single or multiple lenses.

[0099] The illumination light IL that passes through the light tunnel side condenser lens 150 further passes through the intermediate image side condenser lens 151 to form an enlarged intermediate image 155. However, a dichroic mirror 180 is disposed near the imaging position of the enlarged intermediate image 155, and the incident angle η1 of the illumination light IL is set to 27.5 degrees. The red light R included in the illumination light IL is transmitted through the dichroic mirror 180, and the green light G and the blue light B are reflected by the dichroic mirror 180. In addition, the incident angle η1 of the illumination light IL is not necessarily 27.5 degrees, and it is preferable to satisfy the following condition:

[0100] 25 degrees < η1 < 32 degrees... (Condition 1)

[0101] Figure 5 The wavelength dependency of the transmittance of the dichroic mirror 180 is shown. Compared to a cross dichroic prism, the plate-shaped dichroic mirror 180 has the advantage of a small PS separation width and angle shift (incident angle dependency). As shown in Figure 5 Even if the incident angle changes by ±10 degrees from 28 degrees, the angle shift exists, but the shift amount is small. In addition, the rising edge of the curve is steep, and is almost step-like, and it can be seen that the separation ability of the red light is excellent.

[0102] The red light R transmitted through the dichroic mirror 180 is used to illuminate the reflective light modulator 200b, while the green light G and blue light B reflected by the dichroic mirror 180 are used to illuminate the reflective light modulator 200a. In other words, the first color component of the enlarged intermediate image 155 of the illumination light is transferred to the first reflective light modulator, and the second color component is transferred to the second reflective light modulator. In the following description, the green light G and blue light B used to illuminate the reflective light modulator 200a are sometimes referred to as the first illumination light (G+B), and the red light R used to illuminate the reflective light modulator 200b is sometimes referred to as the second illumination light (R). Furthermore, the optical path of the first illumination light from the dichroic mirror 180 to the reflective light modulator 200a is referred to as the first illumination optical system, and the optical path of the second illumination light from the dichroic mirror 180 to the reflective light modulator 200b is referred to as the second illumination optical system.

[0103] As from Figure 1 and Figure 2 As can be understood from the figure, in the first illumination optical system, the first illumination light (G+B) reflected by the dichroic mirror 180 passes through the intermediate image-side condenser lens 160 (first lens), the folding reflector 182a (first reflector), the modulator-side condenser lens 163, and the TIR prism 170a, and is then focused onto the reflective light modulator 200a. In the first illumination optical system, the first illumination light is reflected at the dichroic mirror 180, the folding reflector 182a, and the TIR prism 170a between the light source device 110 and the reflective light modulator 200a. Therefore, the first illumination light is folded three times.

[0104] Furthermore, the optical axis of the illumination light IL from the optical channel 140 to the dichroic mirror 180 lies parallel to the Y-axis, that is, within a first plane parallel to the XY plane. The optical axis of the first illumination light lies within the first plane parallel to the XY plane after being reflected by the dichroic mirror 180 until it reaches the folding mirror 182a. On the other hand, after being reflected by the folding mirror 182a, the optical axis of the first illumination light deviates from the XY plane and has a Z-direction component. Specifically, the optical axis of the first illumination light is deflected in a direction intersecting the first plane by the folding mirror 182a in front of the reflective light modulator 200a.

[0105] The TIR prism 170 a is a total internal reflection prism formed by combining two prisms, for example, and causes the first illumination light to be totally internally reflected and enter the reflective light modulation device 200 a at a predetermined angle.

[0106] Incident angle η1 of illumination light IL incident on dichroic mirror 180 is set to 27.5 degrees, for example, as described above, and angle difference β between incidence and reflection at folding mirror 182 a (sum of incident angle and reflection angle) is set to 59.3 degrees, for example.

[0107] Meanwhile, the second illumination light (R) transmitted through the dichroic mirror 180 is focused onto the reflective light modulator 200b via the intermediate image-side condenser lens 161, the optical path changing reflector 181, the relay lens 162 (second lens), the folding reflector 182b (second reflector), the modulator-side condenser lens 163, and the TIR prism 170b. In the second illumination optical system, the second illumination light is reflected three times between the light source device 110 and the reflective light modulator 200b: the optical path changing reflector 181, the folding reflector 182b, and the TIR prism 170b. This means that the first illumination light is folded back the same number of times as the second illumination light, ensuring that each reflective light modulator is illuminated with homogeneous illumination light, thus minimizing unevenness in depth.

[0108] The optical axis of the second illumination light, after passing through the dichroic mirror 180 and being reflected by the optical path changing mirror 181, lies within a first plane parallel to the XY plane until it reaches the folding mirror 182b. However, after being reflected by the folding mirror 182b, the optical axis deviates from the XY plane and acquires a Z-direction component. In other words, the optical axis of the second illumination light is deflected in a direction intersecting the first plane by the folding mirror 182b in front of the reflective light modulator 200b.

[0109] The TIR prism 170 b is a total internal reflection prism formed by, for example, pasting two prisms together, and causes the second illumination light to be totally internally reflected and enter the reflective light modulation device 200 b at a predetermined angle.

[0110] In addition, the incident angle η2 ( Figure 2 ) is set to, for example, 64 degrees. The angle difference between the incident and reflected angles (the sum of the incident and reflected angles) β at the folding reflector 182b is the same as that of the first illumination light and is set to, for example, 59.3 degrees. Furthermore, the angle of incidence η1 of the illumination light IL incident on the dichroic mirror 180 and the angle of incidence η2 of the second illumination light incident on the optical path changing reflector 181 are set so that the following relationship holds.

[0111] η2≥η1……(Condition 2)

[0112] In the illumination optical system for the first illumination light and the illumination optical system for the second illumination light, the folding reflectors 182a and 182b, the modulator-side condenser lens 163, and the TIR prisms 170a and 170b can each use components of the same specifications. In both illumination optical systems, these optical components are arranged so that their relative positions relative to the reflective light modulator are identical.

[0113] Figure 7 (a) typically shows an illumination optical system from the optical channel 140 to the reflective light modulation device 200a, Figure 7 (b) shows a typical illumination optical system from the optical channel 140 to the reflective optical modulation device 200b. Figure 7 In (a), the change in the direction of the optical path caused by the dichroic mirror 180, the folding mirror 182a, and the TIR prism 170a is omitted in the figure, and the optical axis is shown as a straight line. Figure 7 In (b), the change in the direction of the optical path due to the optical path changing mirror 181, the folding mirror 182b, and the TIR prism 170b is omitted from the illustration, and the optical axis is shown as a straight line.

[0114] in addition, Figure 6 The configuration of each optical device when the reflective optical modulation device 200b is viewed from the back side is typically shown. Figure 6 In the figure, a part of the illumination optical system is omitted. The illumination light from the reflection point P of the folding reflector 182b toward the TIR prism 170b is incident on the reflective light modulator 200b at an incident angle of 45°. In addition, the DMD device used as the reflective light modulator 200b (and the reflective light modulator 200a) is as described in the reference. Figure 15 As described, a device is used in which the reflective surface of the micromirror of each pixel is tilted 45° relative to the screen frame when the screen is viewed from above, and the reflective surface is driven according to the image signal to change the reflection direction of the illumination light.

[0115] like Figure 7 As shown in (a), the intersection of the optical axis of the first illumination light and the dichroic mirror 180 is set to S, the intersection of the optical axis of the first illumination light and the folding reflector 182a is set to Pa, and the distance between S and Pa is set to La. Figure 7 As shown in (b), the intersection of the optical axis of the second illumination light and the dichroic mirror 180 is set to S, the intersection of the optical axis of the second illumination light and the folding reflective mirror 182b is set to Pb, and the distance between S and Pb is set to Lb.

[0116] like Figure 7 (a) and Figure 7As illustrated in (b), in this embodiment, the folding reflector 182a for the first illumination light and the folding reflector 182b for the second illumination light are arranged so that La and Lb are not necessarily equal, that is, La / Lb is not necessarily 1.

[0117] Since the optical path lengths from the folding reflector 182a (folding reflector 182b) to the reflective light modulator 200a (reflective light modulator 200b) are set equal for both the first illumination light and the second illumination light, a difference of La-Lb=ΔL occurs between the optical path length of the first illumination light from the optical channel 140 to the reflective light modulator 200a and the optical path length of the second illumination light from the optical channel 140 to the reflective light modulator 200b. Furthermore, as a configuration in which La / Lb is not 1, except for Figure 7 (a) and Figure 7 In addition to the structure of La>Lb shown in (b), the folding reflector 182a for the first illumination light and the folding reflector 182b for the second illumination light may be arranged in a manner of La<Lb.

[0118] In this embodiment, to maximize the consistency of the conditions under which the first illumination light illuminates the reflective light modulator 200a and the second illumination light illuminates the reflective light modulator 200b, an intermediate image-side condenser lens 160 is positioned between the dichroic mirror 180 and the folding mirror 182a in the optical path of the first illumination light. Furthermore, an intermediate image-side condenser lens 161 is positioned between the dichroic mirror 180 and the optical path changing mirror 181 in the optical path of the second illumination light. Furthermore, a relay lens 162 is positioned between the optical path changing mirror 181 and the folding mirror 182b. By appropriately setting the positions and focal lengths of these lenses, the influence of the optical path length difference ΔL can be reduced, allowing the illumination conditions of the two reflective light modulators to be consistent.

[0119] In addition, in this embodiment, as described above, the light source device 110 including the yellow phosphor outputs Figure 17 The fluorescence having the spectral characteristics shown is separated into different colors by a dichroic mirror 180. To improve the color purity of the illumination light, it is preferable to set a cyan filter CF in the first illumination optical system and a red filter RF in the second illumination optical system. Although the position of the filter is arbitrary, in this embodiment, considering the symmetry of the optical system, a dichroic filter (multilayer film filter) is set on the exit surface of the condenser lens 163 on the modulator side of each optical system. That is, as shown in FIG. Figure 7 As shown in (a), a lens having a Figure 9 (a) shows the characteristics of the cyan filter CF, as shown in Figure 7As shown in (b), a lens having a Figure 9 (b) shows the characteristics of the red filter RF.

[0120] Thus, the reflective light modulation device 200a and the reflective light modulation device 200b are illuminated by the first illumination light and the second illumination light, respectively.

[0121] Furthermore, when the optical path length from the dichroic mirror 180 to the reflective light modulator 200 a is defined as LDA, and the optical path length from the dichroic mirror 180 to the reflective light modulator 200 b is defined as LDB, the following conditions are preferably satisfied:

[0122] 0.9<LDA / LDB<1.1……(Condition 3)

[0123] The reflective light modulation device 200 a and the reflective light modulation device 200 b have a plurality of micro mirrors arranged in an array, and both modulate the illumination light IL emitted from the light source device 110 in synchronization with the color switching timing.

[0124] Figure 18 (a)~ Figure 18 (e) is a timing diagram for explaining the driving timing of the light source device 110 and each reflective light modulator, with time t representing the horizontal axis. Figure 8 (a) Figure 16 、 Figure 17 As described above, the light source device 110 rotates the rotating body 122, and alternately outputs yellow fluorescence emitted by the yellow fluorescent body 123Y and blue light reflected by the reflecting portion 124. If the rotating body 122 is controlled so as to rotate once in synchronization with one frame period of the image signal, then Figure 18 As shown in (a) of FIG. 1 , Y light and B light are alternately output from the light source device 110 .

[0125] Since the dichroic mirror 180 has Figure 5 The transmission characteristics shown in FIG. 1 , therefore, the first illumination light reflected by the dichroic mirror 180 is as shown in FIG. Figure 18 As shown in (b), the G light and the B light are alternately irradiated, and the second illumination light transmitted from the dichroic mirror 180 is as shown in FIG. Figure 18 (d) shows a method of intermittent irradiation of R light.

[0126] By inputting the G component and the B component of the image signal in synchronization with the color switching timing of the first illumination light, the reflective light modulation device 200a outputs the image signal. Figure 18 In addition, by inputting the R component of the image signal in synchronization with the timing of lighting of the R light of the second illumination light, the reflective light modulation device 200b outputs the image light G+B. Figure 18The image light R shown in (e) is output from the reflective light modulating device 200b. The image light of each color is pulse width modulated by the reflective light modulating device in accordance with the luminance of the color component in the image signal. In a case where it is necessary to make the pulse width (length of time) corresponding to one gradation different for each color, the clock frequency for driving the reflective light modulating device can be adjusted in coordination with the color of the image light.

[0127] Next, the projection optical system that synthesizes and projects the image light output from the reflective light modulating device 200a and the reflective light modulating device 200b will be described.

[0128] Figure 3 is extracted from the overall structure of the projection display apparatus 1 shown in Figure 1 is extracted from the overall structure of the projection display apparatus 1 shown in

[0129] As described above, the reflective light modulating device 200a drives the micro-mirror device in accordance with the signal component of the G color or the B color in the image signal, and causes the first illumination light to be reflected at a predetermined angle, outputting the image light G+B shown in (c). The image light G+B is transmitted from the TIR prism 170a to be incident on the first rear group lens 601a, and further transmitted from the synthesis prism 400 to be incident on the front group lens 602, and is enlarged and projected onto the projection surface 700 (e.g., a projection screen). Figure 18

[0130] In addition, the reflective light modulating device 200b drives the micro-mirror device in accordance with the signal component of the R color in the image signal, and causes the second illumination light to be reflected at a predetermined angle, outputting the image light R shown in (e). The image light R is transmitted from the TIR prism 170b to be incident on the second rear group lens 601b, and further undergoes internal reflection in the synthesis prism 400 to change the optical path to be incident on the front group lens 602, and is enlarged and projected onto the projection surface 700 (e.g., a projection screen). Further, in Figure 18 Figures 1-3

[0131] ​​​The front lens group 602 and the first rear lens group 601a together function as a projection lens for the image light G+B. Similarly, the front lens group 602 and the second rear lens group 601b together function as a projection lens for the image light R. Here, the TIR prism 170a and the TIR prism 170b use devices of the same structure, and the first rear lens group 601a and the second rear lens group 601b use lenses of the same structure. In addition, as described later, within the synthetic prism 400, the optical path length of the image light R and the optical path length of the image light G+B are configured to be equal. Therefore, in the projection lens system constituted by this embodiment, adjustment of the image on the projection surface 700 (for example, focus adjustment) can be simply performed by operating the front lens group 602.

[0132] The combining prism 400 changes the optical path of the image light R so as to overlap the optical path of the image light G+B, and guides the image light R and the image light G+B toward the front lens group 602 .

[0133] like Figure 4 As shown in (a), the composite prism 400 is composed of three prisms: prism 401, prism 402, and prism 403. Prisms 401 and 402 face each other with a small air gap AG1 between them, and prisms 402 and 403 face each other with a small air gap AG2 between them. A dielectric multilayer film 405 is provided on the optical surface of prism 402 that faces prism 401 across air gap AG1.

[0134] After the image light R enters the prism 402, it is totally internally reflected on the optical surface on the air gap AG2 side toward the dielectric multilayer film 405. In this embodiment, the incident angle ω of the image light R with respect to the dielectric multilayer film 405 is configured to be ω = 12 degrees. The dielectric multilayer film 405 is provided with Figure 4 In the film with the transmission / reflection characteristics shown in (b), image light R is almost entirely reflected. Furthermore, dielectric multilayer film 405 is not seamlessly sandwiched (bonded) between prisms 401 and 402, but rather separated from prism 401 by an air gap. Therefore, compared to bonded cross prisms, the PS separation width and angular offset are smaller, resulting in a steeper, almost step-like rise in the curve. Image light R reflected by dielectric multilayer film 405 passes through air gap AG2 and prism 403 before entering front lens group 602.

[0135] On the other hand, the image light G+B passes through the prism 401 and the air gap AG1, and is incident on the dielectric multilayer film 405 at an incident angle of 12 degrees. Figure 4 As is clear from the transmission / reflection characteristics of (b), the image light G+B is transmitted through the dielectric multilayer film 405. The image light G+B is further transmitted through the prism 402, the air gap AG2, and the prism 403, and enters the front lens group 602.

[0136] Further, the incident angle with respect to the dielectric multilayer film 405 is configured to be substantially equal between the image light R and the image light G+B, except for manufacturing errors. In addition, the shapes of the prism 402 and the prism 401 are set so that the optical path length from the incidence of the image light R into the prism 402 until reaching the dielectric multilayer film 405 is equal to the optical path length from the incidence of the image light G+B into the prism 401 until the emission.

[0137] According to the present embodiment described above, for example, compared with the dual-panel display device disclosed in Patent Literature 1, it is possible to reduce the back focal length of the projection lens, and thus it is possible to downsize the device. Further, since the reflective light modulation device of the type in which the micromirrors are arranged at 45 degrees with respect to the vertical direction (V direction) of the screen is used, it is advantageous in terms of cost. In addition, compared with the dual-panel display device disclosed in Patent Literature 2, since the optical system using the cross dichroic prism whose polarization characteristics greatly change depending on the incident angle is not used, it is possible to display an image of high quality with uniform color depth. That is, according to the present embodiment, it is possible to realize a dual-panel projection display device of high versatility which achieves a good balance among high quality, downsizing, and low cost.

[0138] [Embodiment 2]

[0139] Next, the projection display device according to Embodiment 2 will be described. For portions common or similar to those of Embodiment 1, the description will be simplified or omitted.

[0140] Figure 10 is a schematic view showing an optical structure of the projection display device according to Embodiment 2. The projection display device 2 is provided with a reflective light modulation device 200a (first reflective light modulation device) and a reflective light modulation device 200b (second reflective light modulation device). In the present embodiment, as with Embodiment 1, as the reflective light modulation device 200a and the reflective light modulation device 200b, a DMD in which micromirror devices are arranged in an array is used. In addition, as described in Reference Example 1, as the DMD, a device in which the reflecting surface of each pixel of the micromirror is inclined at 45° with respect to the screen frame when viewed from the screen, and the reflecting direction of the illumination light is changed by driving the reflecting surface according to the image signal is used. The micromirror corresponding to each pixel is driven according to the luminance level of the image signal so that the reflecting direction is changed by pulse width modulation. Figure 15

[0141] The projection display device 2 is provided with a light source device 110. The light source device 110 is a light source for illuminating the reflective light modulation device 200a and the reflective light modulation device 200b.

[0142] Figure 8 ​(b) shows the structure of the light source device 110 used in this embodiment. The light source device 110 of this embodiment does not excite a phosphor to emit light as in the light source device of Embodiment 1, but synthesizes the output light of solid light sources (for example, semiconductor lasers or LEDs of R, G, B) that can be independently driven and that are different in color light to output as illumination light IL. That is, the light source device 110 is provided with a solid light source 111R that emits red light, a solid light source 112B that emits blue light, a solid light source 113G that emits green light, and a lens 115 that condenses the light of each light source, uses a dichroic mirror 807 that reflects blue light and a dichroic mirror 808 that reflects red light to make the optical paths of each color light overlap, and emits the illumination light IL to the optical path 140 via the condensing lens 109. By using a solid light source (for example, a semiconductor laser or an LED), in this embodiment, it is possible to emit the illumination light IL with high color purity to the optical path 140 as compared with a phosphor.

[0143] Figure 11 is a view that extracts a part of the illumination optical system of Embodiment 2 to show, and corresponds to Figure 2 the view of Embodiment 1. The basic structure of the illumination optical system in this embodiment is similar to that of Embodiment 1, but the setting angles and positions of each optical device are different as shown in the table in the view. In this embodiment, in order to make the conditions of illumination of the first illumination light to the reflective light modulation device 200a and the conditions of illumination of the second illumination light to the reflective light modulation device 200b as uniform as possible, an intermediate image side condensing lens 160 is arranged between the dichroic mirror 180 and the fold mirror 182a in the optical path of the first illumination light, an intermediate image side condensing lens 161 is arranged between the dichroic mirror 180 and the optical path changing mirror 181 in the optical path of the second illumination light, and a relay lens 162 is arranged between the optical path changing mirror 181 and the fold mirror 182b. By appropriately setting the positions and focal lengths of these lenses, it is possible to reduce the influence of the difference ΔL in the optical path lengths and make the illumination conditions of the two reflective light modulation devices uniform.

[0144] In addition, Figure 14 typically shows the arrangement of each optical device when the reflective light modulation device 200b is viewed from the back side. Furthermore, in Figure 14 , a part of the illumination optical system is omitted from the view. The illumination light from the reflection point P of the fold mirror 182b to the TIR prism 170b is incident to the reflective light modulation device 200b at an incident angle of 45°. In addition, the DMD device used as the reflective light modulation device 200b (and the reflective light modulation device 200a) is a device that uses the reflecting surface of the micromirror of each pixel to be inclined at 45° with respect to the picture frame when viewed from the top view, and changes the reflection direction of the illumination light by driving the reflecting surface according to the image signal, as has been described with reference to Figure 15 .

[0145] The reflective light modulation device 200 a and the reflective light modulation device 200 b have a plurality of micro mirrors arranged in an array, and both modulate the illumination light IL emitted from the light source device 110 in synchronization with the color switching timing.

[0146] Figure 19 (a)~ Figure 19 (e) is a timing diagram for explaining the driving timing of the light source device 110 and each reflective light modulator, with time t representing the horizontal axis. Figure 8 As described in (b), the light source device 110 includes a solid light source 111R emitting red light, a solid light source 112B emitting blue light, and a solid light source 113G emitting green light, as solid light sources of different colors that can be driven independently. Figure 19 As shown in (a), during a period corresponding to one frame of the image signal, for example, about 2 / 3 the solid light source 111R and the solid light source 113G emitting green light are simultaneously lit to output R light and G light, and the remaining about 1 / 3 the solid light source 112B is lit to output B light.

[0147] Since the dichroic mirror 180 has Figure 5 The transmission characteristics shown in FIG. 1 , therefore, the first illumination light reflected by the dichroic mirror 180 is as shown in FIG. Figure 19 As shown in (b), the G light and the B light are alternately irradiated, and the second illumination light transmitted from the dichroic mirror 180 is as shown in FIG. Figure 19 (d) shows a method of intermittent irradiation of R light.

[0148] By inputting the G component and the B component of the image signal in synchronization with the color switching timing of the first illumination light, the reflective light modulation device 200a outputs the image signal. Figure 19 In addition, by inputting the R component of the image signal in synchronization with the timing of lighting of the R light of the second illumination light, the reflective light modulation device 200b outputs the image light G+B. Figure 19 (e) shows the image light R. Each color of image light is pulse-width modulated by the reflective light modulator according to the brightness of the color components in the image signal. If it is necessary to vary the pulse width (duration) corresponding to one level for each color, the clock frequency driving the reflective light modulator can be adjusted according to the color of the image light.

[0149] In addition, the drive timing is not limited to Figure 19 (a)~ Figure 19 An example of (e) may be Figure 20 (a)~ Figure 20 As shown in (e). Figure 20As shown in (a), the solid light source 111R is lit to output R light in the entire range of the period corresponding to one frame of the image signal, while the solid light source 113G emitting green light is lit to output G light in, for example, about 2 / 3 of the period corresponding to one frame of the image signal, and the solid light source 112B is lit to output B light in the remaining about 1 / 3.

[0150] Since the dichroic mirror 180 has Figure 5 the transmission characteristics shown in (b), the first illumination light reflected by the dichroic mirror 180 becomes a manner in which G light and B light are alternately irradiated, and the second illumination light transmitted through the dichroic mirror 180 becomes a manner in which R light is continuously irradiated. Figure 20 Figure 20 The G component and the B component of the image signal are input in synchronization with the color switching timing of the first illumination light, whereby the image light G+B shown in (c) of FIG. 6 is output from the reflective light modulating device 200a. In addition, the R component of the image signal is input in synchronization with the switching timing of the frame, whereby the image light R shown in (e) of FIG. 6 is output from the reflective light modulating device 200b. The image light of each color is pulse width modulated by the reflective light modulating device in accordance with the luminance of each color component in the image signal. In a case where it is necessary to make the pulse width (length of time) corresponding to one gradation different for each color, the clock frequency for driving the reflective light modulating device can be adjusted in coordination with the color of the image light.

[0151] Next, a projection optical system that synthesizes and projects the image light output from the reflective light modulating device 200a and the reflective light modulating device 200b will be described. Figure 20 Figure 20 is a diagram extracted from the overall structure of the projection display apparatus 2 shown in (a) in order to describe the projection optical system 610.

[0152]

[0153] Figure 12 is a diagram extracted from the overall structure of the projection display apparatus 2 shown in (a) in order to describe the projection optical system 610. Figure 10 As described above, the reflective light modulating device 200a drives the micro-mirror device in accordance with the signal components of the G color or the B color in the image signal, and causes the first illumination light to be reflected at a predetermined angle, thereby outputting the image light G+B shown in (c) of FIG. 6 or (c) of FIG. 7. The image light G+B is transmitted from the TIR prism 170a to be incident on the first relay lens 611a, and further transmitted from the synthesis prism 410 to form an intermediate image 613 via the third relay lens 612. The intermediate image 613 is magnified and projected onto a projection surface 700 (for example, a projection screen) by the projection lens 614 disposed on the magnification side.

[0154] Figure 19 Figure 20 ​​​​​​

[0155] In addition, the reflective light modulator 200b drives the micromirror device according to the R color signal component in the image signal, so that the second illumination light is reflected at a predetermined angle and outputted. Figure 19 (e) or Figure 20 The image light R shown in (e) is transmitted through the TIR prism 170b and enters the second relay lens 611b. The image light R is then internally reflected in the synthesizing prism 410, changing its optical path. The image light R then passes through the third relay lens 612 to form an intermediate image 613. The intermediate image 613 is magnified and projected onto a projection surface 700 (e.g., a projection screen) by a projection lens 614.

[0156] Thus, this embodiment differs from Embodiment 1 in that a relay lens is used to temporarily form an intermediate image of the display image in front of the projection lens 614. In this embodiment, the diameter of the light near the relay lens aperture can be reduced, thereby miniaturizing the synthesizing prism 410.

[0157] The combining prism 410 changes the optical path of the image light R so as to overlap the optical path of the image light G+B, and guides the image light R and the image light G+B toward the front lens group 602 .

[0158] like Figure 13 As shown in (a), the composite prism 410 is composed of two prisms, prism 411 and prism 412. Prism 411 and prism 412 are opposed to each other with a small gap, air gap AG3, between them. A dielectric multilayer film 415 is provided on the optical surface of prism 411, on the surface facing prism 412 across air gap AG3.

[0159] After the image light R enters the prism 411, it is totally internally reflected on the optical surface of the third relay lens 612 toward the dielectric multilayer film 415. In this embodiment, the incident angle ω of the image light R with respect to the dielectric multilayer film 415 is configured to be ω = 26.5 degrees. The dielectric multilayer film 415 is provided with Figure 13 The film, with its transmission / reflection characteristics shown in (b), reflects almost all of the image light R modulated by the highly monochromatic illumination light from the solid-state light source. Furthermore, the dielectric multilayer film 415 is not seamlessly sandwiched (bonded) between prisms 411 and 412, but rather separated by an air gap from prism 412. Therefore, compared to bonded cross prisms, the PS separation width and angular offset are smaller, resulting in a steeper, almost step-like rise in the curve in the graph. Image light R reflected by the dielectric multilayer film 415 passes through prism 411 and enters the third relay lens 612.

[0160] On the other hand, the image light G+B passes through the prism 412 and the air gap AG3, and is incident on the dielectric multilayer film 415 at an incident angle of 26.5 degrees.Figure 13 The transmittance / reflectance characteristics of (b) are such that the image light G+B modulated from the illumination light of which the monochromaticity is good for the solid light source is transmitted from the dielectric multilayer film 415. The image light G+B is further transmitted from the prism 411 to be incident on the third relay lens 612.

[0161] Further, the incident angle with respect to the dielectric multilayer film 415 is configured to be equal between the image light R and the image light G+B. In addition, the shapes of the prisms 411 and 412 are set so that the optical path length from the incidence of the image light R in the prism 411 until the incidence on the dielectric multilayer film 415 is equal to the optical path length from the incidence of the image light G+B in the prism 412 until the emission.

[0162] According to the present embodiment described above, for example, compared with the dual-panel display device disclosed in Patent Literature 1, it is possible to reduce the back focal length of the projection lens, and thus it is possible to downsize the device. Further, since the reflection-type light modulating device of the type in which the micromirrors are arranged at an angle of 45 degrees with respect to the vertical direction (V direction) of the screen is used, it is advantageous in terms of cost. In addition, compared with the dual-panel display device disclosed in Patent Literature 2, since the optical system is not using the cross dichroic prism whose polarization characteristics greatly change depending on the incident angle, it is possible to display an image of high quality in which the color depth is uniform. That is, according to the present embodiment, it is possible to realize a dual-panel projection display device of high versatility in which a good balance is achieved among high quality, downsizing, and low cost.

[0163] [Other Embodiments]

[0164] The present application is not limited to the embodiments or specific examples described above, but can be variously modified within the technical scope of the present application.

[0165] For example, the light source device used in Embodiment 1 can be combined with the projection optical system that forms the intermediate image used in Embodiment 2. Alternatively, the light source device used in Embodiment 2 can be combined with the projection optical system that does not form the intermediate image used in Embodiment 1.

[0166] In Embodiment 1, the incident angles ω of the first image light (R+G) and the second image light (R) incident on the dielectric multilayer film 405 of the composite prism 400 are set to be substantially equal in size except for a manufacturing error, and are set to ω = 12 degrees. In addition, in Embodiment 2, the incident angles ω of the first image light (R+G) and the second image light (R) incident on the dielectric multilayer film 415 of the composite prism 410 are set to be substantially equal in size except for a manufacturing error, and are set to ω = 26.5 degrees. In implementing the present application, the incident angles ω are not limited to 12 degrees or 26.5 degrees, and the incident angles ω are set in a range of 10 degrees or more and 27 degrees or less.

[0167] For example, the screen can be often used in conjunction with the projection display apparatus as a constituent element of a projection display system, but the embodiments of the present application are not limited thereto. As described above, the projection display apparatus according to the embodiments is simple in operation when optically adjusting a display image, and thus is also suitable for a portable use, for example, a display image can be easily projected on an arbitrary surface at an arbitrary place such as a wall of a building where no screen is provided.

Claims

1. A projection display device, characterized by comprising: Possessing: a light source; a light path that makes light from the light source propagate along an optical axis arranged in a first plane; a dichroic mirror that splits light from the light source that is incident via the light path into first illumination light of a first color and second illumination light of a second color; a first illumination optical system that guides the first illumination light reflected by the dichroic mirror to a first reflective light modulation device; a second illumination optical system that guides the second illumination light transmitted from the dichroic mirror to a second reflective light modulation device; a combining prism that makes first image light output from the first reflective light modulation device transmitted from a dielectric multilayer film and makes second image light output from the second reflective light modulation device reflected by the dielectric multilayer film to change an optical path, and emits combined light that combines the first image light and the second image light; a first rear group lens arranged between the combining prism and the first reflective light modulation device and acting on the first image light; a second rear group lens arranged between the combining prism and the second reflective light modulation device and acting on the second image light; and a front group lens arranged closer to a magnification side than the combining prism and acting on the combined light, the first image light and the second image light have an equal magnitude of an incident angle with respect to the dielectric multilayer film, and the magnitude is 10 degrees or more and 27 degrees or less.

2. The projection display device according to claim 1, wherein a projection lens system is constituted by the first rear group lens, the second rear group lens, and the front group lens, the first image light is magnification-projected by the first rear group lens and the front group lens, and the second image light is magnification-projected by the second rear group lens and the front group lens.

3. The projection display device according to claim 1, wherein the first rear group lens constitutes a first relay lens, the second rear group lens constitutes a second relay lens, the front group lens includes a third relay lens arranged on the combining prism side and a projection lens arranged on a magnification side, the first image light forms an intermediate image between the third relay lens and the projection lens by the first relay lens and the third relay lens, the second image light forms an intermediate image between the third relay lens and the projection lens by the second relay lens and the third relay lens, the intermediate images of the first image light and the second image light are magnification-projected by the projection lens.

4. The projection display device according to any one of claims 1 to 3, wherein the first illumination optical system includes a first mirror that deflects an optical axis of the first illumination light in a direction intersecting the first plane in front of the first reflective light modulation device, the second illumination optical system includes an optical path changing mirror that deflects an optical axis of the second illumination light in the first plane, and a second mirror that deflects an optical axis of the second illumination light in a direction intersecting the first plane in front of the second reflective light modulation device, ​ When a light path length from the dichroic mirror to the first reflective light modulating device is set as LDA, and a light path length from the dichroic mirror to the second reflective light modulating device is set as LDB, 0.9 < LDA / LDB < 1.1 is satisfied.

5. The projection display apparatus according to claim 4, wherein when an incident angle at which light from the light source is incident on the dichroic mirror is set as ηl, 25 degrees < ηl < 32 degrees is satisfied.

6. The projection display apparatus according to claim 5, wherein when an incident angle at which the second illumination light is incident on the light path changing mirror is set as η2, η2 ≥ ηl is satisfied.

7. The projection display apparatus according to any one of claims 1 to 6, wherein a condenser lens is provided between the light passage and the dichroic mirror, the condenser lens forms an intermediate image of light from the light source, the first illumination optical system transfers a first color light component of the intermediate image to the first reflective light modulating device, and the second illumination optical system transfers a second color light component of the intermediate image to the second reflective light modulating device. ​

Images