Image display device and control method

Abstract

To provide an image display device capable of detecting the state of light with high precision. [Solution] An image display device according to one embodiment of this technology comprises a light modulation element, an optical element, and a sensor unit. The optical element separates the modulated light modulated by the light modulation element into a first separated light and a second separated light that travel in different directions from each other, and restricts light that travels in the opposite direction along the optical path of the first separated light to travel along the optical path of the second separated light. The sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light.

Description

Technical Field

[0001] This technology relates to an image display device such as a projector.

Background Art

[0002] Conventionally, image display devices such as projectors have been widely used. For example, light from a light source is modulated by a light modulation element such as a liquid crystal element, and the modulated light is projected onto a screen or the like to display an image. As the light source, a mercury lamp, a xenon lamp, an LED (Light Emitting Diode), an LD (Laser Diode), or the like is used. Among these, solid light sources such as LEDs and LDs have a long lifespan and do not require lamp replacement as in the conventional case, and also have advantages such as lighting up immediately when the power is turned on.

[0003] Patent Document 1 describes an image projection device that displays a 3D (stereoscopic) video by applying the difference in polarization characteristics. In this image projection device, a video for the right eye is incident on a prism-type beam splitter so as to be P-polarized, and a video for the left eye is incident so as to be S-polarized. The video for the right eye and the video for the left eye are combined by the prism-type beam splitter and projected onto a screen through a projection lens (paragraphs

[0040]

[0049]

[0051] of the specification of Patent Document 1, FIG. 3, etc.).

[0004] Patent Document 2 describes a projection-type display device including a polarization beam splitter that reflects each of RGB lights to a reflective light valve and transmits the light modulated by the reflective light valve toward a projection lens. In this projection-type display device, an area sensor is disposed on the side of the surface of the polarization beam splitter that faces the surface on which each of the RGB lights is incident. The area sensor detects the state of leakage light that is transmitted through the polarization beam splitter without being reflected. Based on the detection result of the area sensor, it becomes possible to easily adjust the positions of each component, and it also becomes possible to grasp the deterioration state of each component (paragraphs

[0044] ~

[0058]

[0083] of the specification of Patent Document 2, FIG. 3, etc.).

Prior Art Documents

[0005] [Patent Document 1] International Publication No. 2014 / 132675 [Patent Document 2] Japanese Patent Publication No. 2008-129261 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the future, it is expected that various types of projectors will become widespread, including large projectors for digital cinema using laser light sources and projectors configured for 3D images. Such image display devices, including projectors, require technologies capable of detecting light conditions with high precision.

[0007] In light of the above circumstances, the objective of this technology is to provide an image display device capable of detecting the state of light with high precision. [Means for solving the problem]

[0008] To achieve the above objective, an image display device according to one embodiment of this technology comprises a light modulation element, an optical element, and a sensor unit. The optical element separates the modulated light modulated by the optical modulation element into a first separated light and a second separated light that travel in different directions from each other, and restricts the light incident by traveling in the opposite direction along the optical path of the first separated light from traveling along the optical path of the second separated light. The sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light.

[0009] In this image display device, modulated light is separated into first and second separated light by an optical element. Furthermore, the optical element restricts light traveling in the opposite direction along the optical path of the first separated light from traveling along the optical path of the second separated light. Therefore, by placing a sensor in the optical path of the second separated light, it becomes possible to detect the state of the modulated light with high precision.

[0010] The optical element may be arranged on the main optical path of the modulated light, emit the first separated light along the main optical path, and emit the second separated light along the other optical path.

[0011] The optical element may have a first emission surface for emitting the first separated light and a second emission surface for emitting a second separated light different from the first emission surface. In this case, the sensor portion may be arranged on the side of the second emission surface.

[0012] The optical element may have an optical separation surface that is positioned obliquely to the incident direction of the modulated light incident on the optical element.

[0013] The light separation surface may transmit a portion of the modulated light incident on the light separation surface as the first separated light, and reflect the other portion of the modulated light as the second separated light. In this case, the sensor unit may be positioned on the side of the light separation surface that reflects the second separated light.

[0014] The light separation surface may reflect a portion of the modulated light incident on the light separation surface as the first separated light, and transmit the other portion of the modulated light as the second separated light. In this case, the sensor unit may be positioned on the side opposite to the light separation surface.

[0015] The optical element may separate the modulated light such that the amount of light in the first separated light is greater than the amount of light in the second separated light.

[0016] The image display device may further include a combining unit that combines a plurality of modulated lights to generate a combined modulated light, and a projection unit that projects the combined modulated light generated by the combining unit. In this case, the optical element may be placed between the combining unit and the projection unit, and the combined modulated light may be separated into a first separated light and a second separated light.

[0017] The optical element may be an optical separation prism having a first surface to which the modulated light is incident, an optical separation surface that separates the modulated light incident on the first surface, and a second surface from which the second separated light separated by the optical separation surface is emitted. In this case, the sensor unit may be positioned in close proximity to the second surface of the optical separation prism.

[0018] The optical element may be a polarizing beam splitter, a half mirror, or a glass plate.

[0019] The image display device may further include a first emission unit that emits first image light in a first polarization state along a first direction. In this case, the optical element may have a light separation surface arranged obliquely to the first direction. The light separation surface may transmit a portion of the first image light onto a first optical path along the first direction and reflect the other portion of the first image light onto a second optical path along a second direction substantially perpendicular to the first direction. The sensor unit may also be arranged on the second optical path.

[0020] The image display device may further include a second emission unit that emits a second image light in a second polarization state along the second direction. In this case, the light separation surface may be positioned obliquely to the second direction, reflecting a portion of the second image light onto the first optical path and transmitting another portion of the second image light onto the second optical path.

[0021] The sensor unit may include a first filter that extracts light in the first polarization state, a first sensor that detects the state of the light extracted by the first filter, a second filter that extracts light in the second polarization state, and a second sensor that detects the state of the light extracted by the second filter.

[0022] The sensor unit may detect at least one of the intensity, chromaticity, and beam shape of the second separated light.

[0023] The optical element is configured to impart a predetermined action to incident light, and may separate the modulated light incident on the optical element into the first separated light to which the predetermined action is imparted and the second separated light to which the predetermined action is not imparted.

Advantages of the Invention

[0024] As described above, according to the present technology, it is possible to detect the state of light with high precision. Note that the effects described here are not necessarily limited, and any effect described in the present disclosure may be applicable.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic diagram showing a configuration example of an image display device according to an embodiment of the present technology. [Figure 2] It is a schematic diagram showing a configuration example of an image generation unit. [Figure 3] It is an enlarged view showing an enlarged portion of an image composition unit. [Figure 4] It is an enlarged view showing an enlarged portion of an image composition unit. [Figure 5] It is a schematic diagram showing a configuration example of a sensor unit. [Figure 6] It is a schematic diagram showing a configuration example of a sensor unit. [Figure 7] It is a schematic diagram showing another configuration example of a sensor unit. [Figure 8] It is a schematic diagram showing a configuration example of an image display device cited as a comparative example. [Figure 9] This is a schematic diagram showing another example configuration of the image generation unit. [Figure 10] This is a schematic diagram showing another example configuration of the image generation unit. [Figure 11] This is a schematic diagram showing another example configuration of the image generation unit. [Modes for carrying out the invention]

[0026] The embodiments of this technology will be described below with reference to the drawings.

[0027] [Image display device] Figure 1 is a schematic diagram showing an example configuration of an image display device according to one embodiment of this technology. The image display device 500 is a cinema projector using a laser light source and is capable of displaying 3D (stereoscopic) images by utilizing the polarization characteristics of light.

[0028] For convenience, in the following explanation, we will assume that the image display device 500 is viewed from above, with the X direction representing the left-right direction, the Y direction representing the depth direction, and the Z direction representing the height direction. Of course, the XYZ directions are not limited to these directions, and the image display device 500 can be used in any direction and orientation.

[0029] The image display device 500 includes a first image generation unit 100, a second image generation unit 200, an image synthesis unit 50, a half-wave plate 60, a projection optical system 70, a sensor unit 80, and a control unit 90.

[0030] The first image generation unit 100 generates and emits a first image light 10 that constitutes the right eye image in the 3D image. The first image generation unit 100 modulates light for each of the following colors (red, green, and blue light) and generates the first image light 10 by synthesizing the modulated light for each color. Note that the modulated light for each color is also a concept included in the image light.

[0031] As shown in Figure 1, the first image generation unit 100 emits the first image light 10 in a leftward direction along the X direction. The first image generation unit 100 also emits the first image light 10 so that it is P-polarized with respect to the bonding surface 51 of the image synthesis unit 50.

[0032] In this embodiment, the first image generation unit 100 corresponds to the first emission unit. The X direction corresponds to the first direction. The state in which the image is P-polarized with respect to the bonding surface 51 corresponds to the first polarization state.

[0033] The second image generation unit 200 emits a second image light 20 that constitutes the left eye image in the 3D image. The second image generation unit 200 modulates light for each of the RGB colors and generates the second image light 20 by synthesizing the modulated light for each color.

[0034] As shown in Figure 1, the second image generation unit 200 emits the second image light 20 in the direction towards the viewer (downward in the figure) along the Y direction. The second image generation unit 200 also emits the second image light 20 so that it is P-polarized with respect to the bonding surface 51 of the image synthesis unit 50.

[0035] The first and second image generation units 100 and 200 have substantially identical configurations. Figure 1 schematically illustrates some of the components of each of the first and second image generation units 100 and 200. Each of the first and second image generation units 100 and 200 will be described in detail later.

[0036] The half-wave plate 60 is positioned between the second image generation unit 200 and the image synthesis unit 50. The half-wave plate 60 has the function of rotating the polarization direction by 90° across the entire wavelength band of the three primary colors of light used. The specific configuration of the half-wave plate 60 is not limited and may be designed arbitrarily.

[0037] The half-wave plate 60 rotates the polarization direction of the second image light 20 emitted from the second image generation unit 200 by 90°. Consequently, the second image light 20, which is S-polarized with respect to the bonding surface 51, is emitted to the image synthesis unit 50.

[0038] In this embodiment, the second image generation unit 200 and the half-wave plate 60 correspond to the second emission unit. The Y direction corresponds to a second direction substantially perpendicular to the first direction. The state in which the light is S-polarized with respect to the bonding surface 51 corresponds to a second polarization state.

[0039] The image synthesis unit 50 is a prism-type beam splitter. The image synthesis unit 50 has the characteristics of a polarizing beam splitter, having high reflectivity for S-polarization and high transmittance for P-polarization across the entire wavelength band of the three primary colors of light used.

[0040] In this embodiment, two substantially identical right-angled isosceles prisms are joined together, and a polarizing film having predetermined optical properties is formed on the joined surface 51. The joined surface 51 is positioned at an angle of 45° with respect to the respective propagation directions of the first image light 10 and the second image light 20, and S-polarization and P-polarization are defined with respect to this joined surface 51.

[0041] The bonding surface 51 transmits the first image light 10, which is P-polarized, and reflects the second image light 20, which is S-polarized. As a result, the first and second image lights 10 and 20 are combined and emitted toward the projection optical system 70. Therefore, in this embodiment, the right eye image is displayed by the first image light 10, which is P-polarized, toward the bonding surface 51, and the left eye image is displayed by the second image light 20, which is S-polarized.

[0042] In this embodiment, the image synthesis unit 50 corresponds to an optical element. This point will be explained in detail later.

[0043] The projection optical system 70 is positioned on the output side of the image synthesis unit 50 and magnifies the first and second image lights 10 and 20 synthesized by the image synthesis unit 50 to a predetermined magnification and projects them onto a projection object such as a screen. This displays the right eye image and the left side image. The projection optical system 70 includes, for example, multiple projection lenses, and its specific configuration may be designed as appropriate.

[0044] The sensor unit 80 has a light-receiving sensor 81 and is capable of detecting the state of light. The state of light includes, for example, luminance (intensity), chromaticity, and the shape of the light beam. The shape of the light beam is a concept that includes the size (cross-sectional area) of the light beam.

[0045] Any luminance sensor, chromaticity sensor, or the like may be used as sensor 81. Alternatively, an array sensor composed of multiple sensors, or an image sensor such as a CMOS sensor or CCD sensor may be used as sensor 81.

[0046] As shown in Figure 1, the sensor 81 is positioned close to the front (lower in the figure) surface of the image synthesis unit 50. The sensor 81 can detect the states of the first and second image lights 10 and 20 with high accuracy. This point will be explained in detail later.

[0047] The control unit 90 controls the operation of each mechanism within the image display device 500. The control unit 90 is electrically connected to the first and second image generation units 100 and 200, the projection optical system 70, and other mechanisms, and outputs control signals to each mechanism. For example, it can control the operation of the light source unit and optical modulation element included in the first and second image generation units 100 and 200.

[0048] The control unit 90 includes, for example, a CPU, RAM, and ROM. The CPU loads a control program pre-recorded in the ROM into the RAM and executes it, thereby controlling each mechanism. The configuration of the control unit 90 is not limited, and any hardware and software may be used. For example, a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), or other devices such as an ASIC (Application Specific Integrated Circuit) may be used. In Figure 1, the control unit 90 is shown with a dashed line, but the location where the control unit 90 is placed is not limited and may be set as appropriate.

[0049] [Image generation unit] Figure 2 is a schematic diagram showing an example of the configuration of the image generation unit. Figure 2 illustrates an example of the configuration of the first image generation unit 100 when the image display device 500 shown in Figure 1 is viewed from the front along the Y direction. The half-wave plate 60 and the second image generation unit 200 shown in Figure 1 are located behind the image synthesis unit 50 shown in Figure 2, and are therefore not shown.

[0050] The first image generation unit 100 includes a light source unit 101, an illumination optical system 110, and an image modulation unit 130. The light source unit 101 generates white light W and emits it to the illumination optical system 110. The light source unit 101 may be a solid-state light source such as an LED (Light Emitting Diode) or an LD (Laser Diode), or a mercury lamp or a xenon lamp.

[0051] For example, a solid-state light source capable of emitting light of each of the RGB colors may be used, and these emitted lights may be combined to produce white light W. Alternatively, a solid-state light source emitting light in the blue wavelength range and a phosphor that emits yellow fluorescence when excited by blue light may be arranged. In this case, the blue light and yellow light are combined to emit white light W.

[0052] The illumination optical system 110 includes an integrator element 111, polarization conversion elements 112, 113 and 114, a focusing lens 115, a cross dichroic mirror 116, reflective mirrors 117 and 118, a dichroic mirror 119, and relay lenses 120, 121 and 122.

[0053] The integrator element 111 has first and second fly-eye lenses 111a and 111b. When white light W is transmitted through these first and second fly-eye lenses 111a and 111b, the brightness unevenness of the white light W is reduced.

[0054] The polarization conversion element 112 has the function of aligning the polarization state of the white light W incident via the integrator element 111. Any optical element such as a polarizer or a polarizing beam splitter may be used as the polarization conversion element 112. The white light W that has passed through the polarization conversion element 112 is emitted to the cross dichroic mirror 116 via the focusing lens 115.

[0055] The cross dichroic mirror 116 spectrally separates the white light W emitted from the focusing lens 115 into red light R on the long-wavelength side and green light G and blue light B on the short-wavelength side. The red light R spectrally separated by the cross dichroic mirror 116 is reflected by the reflection mirror 117 and incident on the polarization conversion element 113. The red light R, whose polarization state has been aligned by the polarization conversion element 113, is emitted to the image modulation unit 130 via the relay lens 120.

[0056] The green light G and blue light B, spectrally separated by the cross-dichroic mirror 116, are reflected by the reflection mirror 118 and incident on the polarization conversion element 114. The polarization states of the green light G and blue light B, aligned by the polarization conversion element 114, are spectrally separated by the dichroic mirror 119 into green light G on the longer wavelength side and blue light B on the shorter wavelength side.

[0057] The green light G, spectrally separated by the dichroic mirror 119, is emitted to the image modulation unit 130 via the relay lens 121. The blue light B, spectrally separated by the dichroic mirror 119, is emitted to the image modulation unit 130 via the relay lens 122.

[0058] The image modulation unit 130 includes reflective polarizing elements 131 (131R, 131G, 131B) arranged for each of the RGB colors, reflective optical modulation elements 132 (132R, 132G, 132B), wave plates 133 (133R, 133G, 133B), polarizing beam splitters 134 (134R, 134G, 134B), and half-wave plates 135 (135R, 135G, 135B). The image modulation unit 130 also includes a color blending prism 136 and polarizing plates 137 for generating the first image light 10.

[0059] The reflective polarizing element 131 is a prism-type beam splitter. From each of the relay lenses 120 to 122 shown in Figure 2, RGB light is emitted so that it is S-polarized with respect to the junction surface of the reflective polarizing element 131.

[0060] The reflective polarizing element 131R reflects the S-polarized component of red light R toward the waveplate 133R. The waveplate 133R functions as a compensating plate to compensate for the lifting of black brightness, rotating the polarization direction of the incident red light R before emitting it toward the reflective optical modulation element 132R. The rotation angle of the polarization direction is set appropriately so that a high-precision image is projected.

[0061] The reflective optical modulator 132R modulates and reflects the incident red light R based on an image signal corresponding to the red light R supplied from an external source. Typically, a reflective liquid crystal panel is used as the reflective optical modulator 132R, but it is not limited to this.

[0062] The red light R modulated by the reflective optical modulation element 132R (referred to as modulated light R using the same sign) is incident on the reflective polarizing element 131R via the waveplate 133R. The P-polarized component of the modulated light R passes through the junction surface and is incident on the polarizing beam splitter 134R.

[0063] The polarizing beam splitter 134R functions as a polarization conversion element, aligning the polarization state of the modulated light R and cutting out unwanted light. The modulated light R emitted from the polarizing beam splitter 134R has its polarization direction rotated by 90° by the half-wave plate 135R and is emitted to the color synthesis prism 136.

[0064] Green light G and blue light B are similarly modulated by reflective optical modulation elements 132G and 132B, and emitted from reflective polarizing elements 131G and 131B through half-wave plates 135G and 135B to the color synthesis prism 136.

[0065] The color-combining prism 136 is constructed, for example, by joining multiple glass prisms (four roughly identical right-angled isosceles prisms). Two interference films having predetermined optical properties are formed on the joining surface of each glass prism.

[0066] The first interference film reflects blue light B and transmits red light R and green light G. The second interference film reflects red light R and transmits blue light B and green light G. The first and second interference films have the characteristic of having high reflectivity for S-polarized light and low reflectivity for P-polarized light.

[0067] In this embodiment, the polarization direction of each of the modulated RGB light is rotated by 90° by the half-wave plate 135. As a result, each of the modulated RGB light is incident on the junction surface of the color synthesis prism 136 with S polarization. This makes it possible to project a high-brightness image.

[0068] Modulated light R and B are reflected by the junction surface, while modulated light G is transmitted through the junction surface. As a result, the modulated RGB are combined on the same optical path, and the first image light 10 is generated. The polarization direction of the first image light 10 is aligned by the polarizing plate 137 and emitted to the image synthesis unit 50.

[0069] In this embodiment, the orientation of the first image generation unit 100 is appropriately set so that the light that is S-polarized with respect to the bonding surface of the color synthesis prism 136 is P-polarized with respect to the bonding surface 51 of the image synthesis unit 50. Therefore, the first image light 10 that is P-polarized with respect to the bonding surface 51 of the image synthesis unit 50 is emitted from the first image generation unit 100.

[0070] As described above, the second image generation unit 200 has substantially the same configuration as the first image generation unit 100. The second image generation unit 200 emits a second image light 20 that is P-polarized to the bonding surface 51 of the image synthesis unit 50. The half-wave plate 60 rotates the polarization direction of the second image light 20 by 90°. As a result, the image synthesis unit 50 emits a second image light 20 that is S-polarized to the bonding surface 51.

[0071] Figure 1 shows the components of the first image generation unit 100, including the reflective polarizing element 131R, the reflective optical modulation element 132G, the waveplate 133G, the polarizing beam splitter 134G, the half-wave plate 135G, the color synthesis prism 136, and the polarizing plate 137.

[0072] The diagram also shows the components of the second image generation unit 200, including a reflective polarizing element 231R, a reflective optical modulation element 232G, a waveplate 233G, a polarizing beam splitter 234G, a half-wave plate 235G, a color synthesis prism 236, and a polarizing plate 237.

[0073] Figures 3 and 4 are enlarged views showing a magnified portion of the image synthesis unit 50. Figure 3 schematically illustrates the behavior of the first image light 10 emitted from the first image generation unit 100. Figure 4 schematically illustrates the behavior of the second image light 20 emitted from the second image generation unit 200 via the half-wave plate 60.

[0074] As shown in Figure 3, most of the P-polarized first image light 10A emitted from the first image generation unit 100 passes through the junction surface 51 and travels toward the projection optical system 70. The optical path of the first image light 10A incident on the junction surface 51 along the X direction, and the optical path of the first image light 10B that passes through the junction surface 51 and travels toward the projection optical system 70 along the X direction, becomes the main optical path OP1.

[0075] The main optical path OP1 is the optical path of the image light (modulated light) from the time the image light (modulated light) is generated until it is projected onto a screen or the like by the projection optical system 70. Therefore, the image synthesis unit 50 is located in the main optical path OP1 of the image light (modulated light).

[0076] On the other hand, among the first image light 10 emitted from the first image generation unit 100, there is also first image light 10C that is reflected by the junction surface 51 in the direction towards the viewer (downward in the figure) along the Y direction. The first image light 10C becomes so-called stray light and travels along another optical path OP2 that is different from the main optical path OP1.

[0077] In this embodiment, the image synthesis unit 50 functions as an optical element that separates the first image light 10A emitted from the first image generation unit 100 into a first image light 10B and a first image light 10C that travel in different directions. That is, the image synthesis unit 50 is positioned on the main optical path OP1 of the first image light 10, emits the first image light 10B along the main optical path OP1, and emits the first image light 10C along the other optical path OP2.

[0078] The bonding surface 51 of the image synthesis unit 50 functions as an optical separation surface positioned obliquely to the incident direction (X direction) of the first image light 10 incident on the image synthesis unit 50. More specifically, the side of the bonding surface 51 on which the first image light 10 is incident corresponds to the optical separation surface.

[0079] In this embodiment, the bonding surface 51 (light separation surface) is positioned at an angle of 45° with respect to the incident direction (X direction) of the first image light 10. The bonding surface 51 transmits the first image light 10B, which is a part of the first image light 10A incident on the bonding surface 51, and reflects the first image light 10C, which is another part of the first image light 10A.

[0080] The first image light 10B traveling toward the projection optical system 70 is projected onto a screen or the like by the projection optical system 70. In this case, a portion of the first image light 10B may be reflected by the projection lens or the like within the projection optical system 70.

[0081] The reflected light, reflected by the projection lens or the like, travels in the reverse direction along the main optical path OP1, which is the optical path of the first image light 10B, and is incident on the bonding surface 51 again. The reflected light that is incident on the bonding surface 51 again is either transmitted towards the first image generation unit 100 or reflected towards the second image generation unit 200. In either case, it does not travel along the other optical path OP2, which is the optical path of the first image light 10C.

[0082] In other words, the image synthesis unit 50 and the bonding surface 51 also have the function of restricting reflected light that travels in the opposite direction along the main optical path OP1 from traveling along the other optical path OP2. In this embodiment, the first image light 10B corresponds to the first separation light, and the first image light 10C corresponds to the second separation light. The main optical path OP1 corresponds to the first optical path, and the other optical path OP2 corresponds to the second optical path.

[0083] Furthermore, the color synthesis prism 136 of the first image generation unit 100 corresponds to a synthesis unit that synthesizes multiple modulated lights to generate a combined modulated light (first image light 10). The projection optical system 70 corresponds to a projection unit that projects the combined modulated light synthesized by the color synthesis unit. The image synthesis unit 50 is positioned between the color synthesis prism 136 and the projection optical system 70 and separates the combined modulated light (first image light 10A) into the first image light 10B and the first image light 10C.

[0084] As shown in Figure 3, the sensor unit 80 (sensor 81) is positioned on another optical path OP2, which is the optical path of the first image light 10C, and detects the state of the first image light 10C. The bonding surface 51 of the image synthesis unit 50 restricts the reflected light from the projection optical system 70 from traveling along the other optical path OP2. Therefore, reflected light from the projection optical system 70 does not enter the sensor 81, and the generation of noise components due to reflected light can be sufficiently suppressed. This makes it possible to detect the state of the first image light 10C with high accuracy, and to detect the state of the first image light 10A emitted from the first image generation unit 100 with high accuracy.

[0085] The position where the sensor 81 is placed can also be described as the position on the light separation surface side that reflects the first image light 10C along the other optical path OP2. By placing the sensor 81 on the light separation surface side on which the first image light 10A is incident, it is possible to restrict the reflected light incident on the surface opposite to the light separation surface (the surface from which the first image light 10B is emitted) from traveling along the other optical path OP2.

[0086] In this embodiment, two substantially identical right-angled isosceles prisms are joined together to form the image synthesis unit 50. Such a prism-type configuration is included in the optical separation prisms related to this technology.

[0087] As shown in Figure 3, the four sides of the image synthesis unit 50 that are parallel to the Z direction are designated as the first to fourth sides 52a to 52d.

[0088] The first side surface 52a is positioned opposite the first image generation unit 100 and is the surface onto which the first image light 10 is incident. The second side surface 52b is positioned opposite the second image generation unit 200 and is the surface onto which the second image light 20 is incident. The third side surface 52c is the surface from which the first image light 10B is emitted along the main optical path OP1. The fourth side surface 52d is the surface from which the first image light 10C is emitted along the other optical path OP2.

[0089] The sensor 81 is positioned on the fourth side surface 52d side from which the first image light 10C is emitted. Specifically, it is positioned in close proximity to the fourth side surface 52d. The sensor 81 may be in contact with the fourth side surface 52d, or it may be positioned with a gap between it and the surface.

[0090] By adopting a prism-type configuration for the image synthesis unit 50, the sensor 81 can be easily attached. In this embodiment, the first side surface 52a corresponds to the first surface. The fourth side surface 52d corresponds to the second surface and the second emission surface. The third side surface 52c corresponds to the first emission surface.

[0091] Furthermore, much of the first image light 10A incident on the bonding surface 51 travels along the main optical path OP1 as the first image light 10B. The remaining portion, the first image light 10C, travels along another optical path OP2. In other words, the bonding surface 51 of the image synthesis unit 50 separates the first image light 10B and 10C such that the amount of light in the first image light 10B is greater than the amount of light in the first image light 10C. This makes it possible to sense the first image light 10 while sufficiently suppressing the loss of light intensity of the projected image. Moreover, since leaked light is used as the target of sensing, there is almost no loss of light intensity compared to conventional methods.

[0092] As shown in Figure 4, much of the S-polarized second image light 20 emitted from the second image generation unit 200 through the half-wave plate 60 is reflected by the junction surface 51 and travels toward the projection optical system 70. The optical paths of the second image light 20A incident on the junction surface 51 along the Y direction, and the second image light 20B reflected in the X direction by the junction surface 51 and traveling toward the projection optical system 70, form the main optical path OP1.

[0093] In this embodiment, the optical path of the second image light 20B substantially coincides with the optical path of the first image light 10B shown in Figure 3. Therefore, from the junction surface 51 onward, the first image light 10B and the second image light 20B travel along the same main optical path OP1.

[0094] On the other hand, among the second image light 20 emitted from the second image generation unit 200, there is also a second image light 20C that passes through the junction surface 51 along the Y direction. The second image light 20C becomes so-called stray light and travels along another optical path OP2 that is different from the main optical path OP1.

[0095] In this embodiment, the optical path of the second image light 20C substantially coincides with the optical path of the first image light 10C shown in Figure 3. Therefore, the first image light 10C and the second image light 20C travel along the same other optical path OP2.

[0096] The image synthesis unit 50 also functions as an optical element that separates the second image light 20A emitted from the second image generation unit 200 into a second image light 20B and a second image light 20C that travel in different directions. That is, the image synthesis unit 50 is positioned on the main optical path OP1 of the second image light 20, emits the second image light 20B along the main optical path OP1, and emits the second image light 20B along the other optical path OP2.

[0097] The bonding surface 51 of the image synthesis unit 50 also functions as an optical separation surface positioned obliquely to the incident direction (Y direction) of the second image light 20 incident on the image synthesis unit 50. More specifically, the side of the bonding surface 51 on which the second image light 20 is incident corresponds to the optical separation surface. In other words, the optical separation surface for the first image light 10 and the optical separation surface for the second image light 20 are opposite sides of each other.

[0098] In this embodiment, the bonding surface 51 (light separation surface) is positioned at an angle of 45° with respect to the incident direction (Y direction) of the second image light 20. The bonding surface 51 reflects the first image light 20B, which is a part of the second image light 20A incident on the bonding surface 51, and reflects the second image light 20C, which is the other part of the second image light 20A.

[0099] Furthermore, the image synthesis unit 50 and the bonding surface 51 restrict reflected light incident by traveling in the reverse direction along the main optical path OP1 from traveling along the other optical path OP2. That is, even with respect to the second image light 20, reflected light reflected by the projection optical system 70 is restricted from traveling along the other optical path OP2. The second image light 20B corresponds to the first separation light, and the second image light 20C corresponds to the second separation light. The main optical path OP1 corresponds to the first optical path, and the other optical path OP2 corresponds to the second optical path.

[0100] Furthermore, the color synthesis prism 236 of the second image generation unit 200 corresponds to a synthesis unit that synthesizes multiple modulated lights to generate a combined modulated light (second image light 20). The image synthesis unit 50 is positioned between the color synthesis prism 236 and the projection optical system 70, and separates the combined modulated light (second image light 20A) into a second image light 10B and a second image light 10C.

[0101] As shown in Figure 4, the sensor unit 80 (sensor 81) is positioned on another optical path OP2, which is the optical path of the second image light 20C, and detects the state of the second image light 10C. The bonding surface 51 of the image synthesis unit 50 restricts the reflected light from the projection optical system 70 from traveling along the other optical path OP2. Therefore, reflected light from the projection optical system 70 does not enter the sensor 81, and the generation of noise components due to reflected light can be sufficiently suppressed. This makes it possible to detect the second image light 20C with high accuracy, and to detect the second image light 20A emitted from the second image generation unit 200 with high accuracy.

[0102] In other words, in this embodiment, the sensor 81 is positioned on the other optical path OP2, which is configured on the opposite side of the main optical path OP1 from the bonding surface 51 of the image synthesis unit 50. This makes it possible to sense the first image light 10 in a P-polarized state and the second image light 20 in an S-polarized state with high precision.

[0103] The position where the sensor 81 is placed can also be described as the side on which the second image light 20C is emitted along the other optical path OP2, that is, the side opposite to the optical separation surface. By placing the sensor 81 on the side opposite to the optical separation surface, it is possible to restrict the reflected light incident on the optical separation surface on the side where the second image light 20B is reflected from traveling along the other optical path OP2.

[0104] Similar to Figure 3, the four sides of the image synthesis unit 50 that are parallel to the Z direction are designated as the first to fourth sides 52a to 52d. The sensor 81 is positioned on the fourth side 52d side from which the second image light 20C is emitted. Specifically, it is positioned in close proximity to the fourth side 52d. In this embodiment, the second side 52b corresponds to the first surface. The fourth side 52d corresponds to the second surface and the second emission surface. The third side 52c corresponds to the first emission surface.

[0105] Furthermore, much of the second image light 20A incident on the bonding surface 51 is reflected as the second image light 20B and travels along the main optical path OP1. The remaining portion, the second image light 20C, is transmitted along the other optical path OP2. In other words, the bonding surface 51 of the image synthesis unit 50 separates the second image light 20B and 20C such that the amount of light in the second image light 20B is greater than the amount of light in the second image light 20C. This makes it possible to sense the second image light 20 while sufficiently suppressing the loss of light in the projected image. Moreover, since leaked light is used as the target of sensing, there is almost no loss of light compared to conventional methods.

[0106] Figures 5 and 6 are schematic diagrams showing an example configuration of the sensor unit 80. The sensor unit 80 illustrated in Figures 5 and 6 includes a circuit board 83 connected to a flexible circuit board 82 and a sensor 81 mounted on the circuit board 83. The light intensity signal measured by the sensor 81 is output to the control unit 90 in Figure 1, etc., via the circuit board 83 and the flexible circuit board 82. Control signals and driving power are also supplied to the sensor 81 and the circuit board 83.

[0107] The sensor 81 has a light-receiving surface 84, and a portion of the light-receiving surface 84 is set as a measurement area 85 (Active Area). Figure 6 is a schematic diagram showing the measurement area 85 of the sensor 81. The sensor 81 has a plurality of measuring units 86 capable of measuring the intensity of incident light. That is, a plurality of measuring units 86 are arranged in the measurement area 85. The plurality of measuring units 86 are arranged in a two-dimensional manner along mutually orthogonal directions. In this embodiment, a total of 40 measuring units 86, 4 in the horizontal direction and 10 in the vertical direction, are arranged in a matrix.

[0108] The sensor 81 also has a plurality of filters 87 that transmit light in a predetermined wavelength band, each of which is arranged in a plurality of measuring units 86. That is, a filter 87 is arranged corresponding to each of the 40 measuring units 86. In this embodiment, the plurality of filters 87 are of three types: a red filter 87R that transmits light in the red wavelength band, a green filter 87G that transmits light in the green wavelength band, and a blue filter 87B that transmits light in the blue wavelength band.

[0109] When the first and second image lights 10C and 20C are incident on the measurement area 85, the intensity of the red modulated light R is measured by a measurement unit 86 equipped with a red filter 87R. Similarly, the intensity of the green modulated light G is measured by a measurement unit 86 equipped with a green filter 87G, and the intensity of the blue modulated light B is measured by a measurement unit 86 equipped with a blue filter 87B. For example, the average value of the intensities measured by multiple measurement units 86 equipped with filters 87 of the same color is used.

[0110] As shown in Figure 6, the multiple filters 87 are arranged such that the filter group 88 aligned along the x-direction includes three types of filters 87R, 87G, and 87B: red, green, and blue. Furthermore, the multiple filters 87 are arranged so that no two filters of the same type 87 are adjacent along the second direction. This makes it possible to distribute the three types of filters 87R, 87G, and 87B evenly within the measurement area 85. As a result, it becomes possible to accurately measure the intensity of the modulated light of each RGB color. Note that the arrangement of the three types of filters 87R, 87G, and 87B is not limited to that shown in Figure 6 and may be set as appropriate.

[0111] In this embodiment, the multiple filters 87 also include a noise filter 87N. The noise filter 87N transmits the noise component light transmitted by the three types of filters 87R, 87G, and 87B, which are red, green, and blue, respectively. That is, the noise filter 87N transmits the noise component light that passes through the red filter 87R, the noise component light that passes through the green filter 87G, and the noise component light that passes through the blue filter 87B.

[0112] The noise filter 87N detects light in the wavelength range of approximately 200 nm to 660 nm with a low sensitivity of approximately 1-5%. Therefore, the measurement unit 86 (hereinafter referred to as the noise measurement unit) on which the noise filter 87N is located can measure the intensity of the light detected as noise component by the measurement units 86 of each color. By subtracting the intensity of the noise component light measured by the noise measurement unit 86 from the intensity of each RGB light measured by the measurement units 86R, 86G, and 86B of each color, it becomes possible to measure the intensity of the modulated light of each color with high accuracy.

[0113] As shown in Figure 6, the noise filter 87N is arranged so that at least one is included in the filter group 88 arranged along the horizontal direction. The noise filters 87N are also arranged so that they are not adjacent to each other along the vertical direction. This makes it possible to arrange the noise filters 87N without bias in the measurement area 85, and enables accurate measurement of the intensity of the modulated light of each RGB color.

[0114] In this embodiment, noise components caused by reflected light from the projection optical system 70 are sufficiently suppressed. Therefore, it is possible to project a high-precision image even without using the noise filter 87N. Of course, an even higher-precision image may be projected by using the noise filter 87N.

[0115] In this embodiment, when the measurement modes for the first and second image light 10 and 20 are selected, the control unit 90 shown in Figure 1 appropriately switches between the emission of the first image light 10 by the first image generation unit 100 and the emission of the second image light 20 by the second image generation unit 200.

[0116] For example, with the output operation of the second image generation unit 200 turned OFF, the first image generation unit 100 emits measurement image light (a concept included in the first image light 10). The measurement image light is, for example, image light for projecting a white image, a black image, or any other arbitrary image. Note that the operation to restrict the projection of image light when displaying a black image, etc., is also included in the operation to project image light. Image light of the content image to be viewed may also be emitted. The sensor unit 80 detects the state of the measurement image light, and the detection result is output to the control unit 90.

[0117] Subsequently, with the output operation of the first image generation unit 100 turned OFF, the second image generation unit 200 emits a measurement image (a concept included in the second image light 20). The sensor unit 80 detects the state of the measurement image, and the detection result is output to the control unit 90.

[0118] The timing of the selection of the measurement mode is not limited. For example, the measurement mode may be automatically selected in accordance with the timing when the user starts up the image display device 500 or when an instruction is given to stop the operation of the image display device 500. Examples include performing the measurement in accordance with the timing when the manufacturer's logo is displayed upon startup, or performing the measurement while displaying a black screen during the waiting period until the operation has finished stopping. Of course, the user may also input an instruction to perform a measurement, and the measurement mode may be selected in accordance with that instruction.

[0119] The control unit 90 detects the brightness (intensity), chromaticity, and shape of the light beam of the first and second image lights 10 and 20 based on the state of the measurement image light emitted from the first and second image generation units 100 and 200, respectively. In other words, in this embodiment, the control unit 90 also functions as part of the sensor unit 80.

[0120] For example, calibration is performed based on the state of the image light used for each measurement. Calibration enables highly accurate measurement and correction of, for example, white balance (white chromaticity), color space, i.e., RGB monochromaticity. It also enables various other processes, such as gamma measurement and correction. For example, if the image display device 500 has a brightness sensor that adjusts the brightness of the image according to the ambient light, it also becomes possible to correct the brightness adjustment function of that brightness sensor.

[0121] Furthermore, it is possible to adjust the balance of brightness, chromaticity, and other properties of the right-eye image and the left-side image. Other processing based on the detection results of the sensor unit 80 will be explained later, along with the effects of the image display device 500 according to this embodiment.

[0122] Figure 7 is a schematic diagram showing another configuration example of the sensor unit 80. The sensor unit 80 shown in Figure 7 includes a first polarizing plate 89a that transmits P-polarized light to the bonding surface 51 of the image synthesis unit 50 and restricts the propagation of light in other polarization states, and a first sensor 81a that detects the state of P-polarized light transmitted through the first polarizing plate 89a.

[0123] The sensor unit 80 also includes a second polarizing plate 89b that transmits S-polarized light to the bonding surface 51 of the image synthesis unit 50 and restricts the propagation of light in other polarization states, and a second sensor 81b that detects the state of S-polarized light transmitted through the second polarizing plate 89b.

[0124] The first image light 10C emitted from the first image generation unit 100 is incident on the first sensor 81a via the first polarizing plate 89a. The second image light 20C emitted from the second image generation unit 200 is incident on the second sensor 81b via the second polarizing plate 89b. Therefore, in the sensor unit 80 shown in Figure 7, it is possible to simultaneously detect the states of the first and second image lights 10 and 20 without switching the emission operations of the first and second image generation units 100 and 200.

[0125] This makes it possible to constantly detect the states of the first and second image lights 10 and 20, even when projecting content images, without having to set a measurement mode. As a result, by continuously feeding back the detection results, it becomes possible to project images with extremely high accuracy.

[0126] In the example shown in Figure 7, the first polarizer 89a corresponds to a first filter that extracts light in a first polarization state, and the second polarizer 89b corresponds to a second filter that extracts light in a second polarization state. Of course, other optical components besides waveplates may be used.

[0127] Another possible configuration involves placing a single sensor and rotatably positioning a polarizing element, such as a polarizing plate, in front of it. By appropriately controlling the rotation angle of the polarizing element, it is possible to appropriately switch between the first and second image lights 10 and 20 and have them incident on the sensor. By associating the detection result from the sensor with the rotation angle of the polarizing element and outputting it to the control unit 90, it is possible to easily determine whether the detection result is from the first or second image light 10 or 20. In this configuration as well, it is possible to always detect the state of the first and second image lights 10 and 20, even when projecting content images, without setting a measurement mode.

[0128] Figure 8 is a schematic diagram showing an example configuration of an image display device 900, which is given as a comparative example. In the comparative example image display device 900, sensors 981 (981R, 981G, 981B) are arranged near the reflective polarizing elements 931 (931R, 931G, 931B) (prism-type beam splitter) for each of the RGB colors, which are included in the first image generation unit 901.

[0129] Specifically, the sensor 981 is positioned close to the surface of the reflective polarizing element 931 that is opposite to the surface into which each of the RGB lights is incident. The sensors 981 for each of the RGB colors detect the state of leakage light of each color that is transmitted through the reflective polarizing element 931 without being reflected.

[0130] The following describes the effects of the image display device 500 according to this embodiment, in comparison to the configuration of the image display device 900 shown in Figure 8.

[0131] (Sensing accuracy) As shown in Figure 8, in the image display device 900, the reflected light 905 reflected by the projection optical system 970 travels in the opposite direction along the main optical paths of the first and second image lights 10 and 20 and is incident on the reflective polarizing element 931. As a result, the reflected light 905 is reflected by the reflective polarizing element 931 toward the sensor 981 and incident on the sensor 981. In other words, in the image display device 900, the interfacial reflection of the projected light (image light) from the projection lens, etc., is directly incident on the sensor 981, resulting in a very large noise component. Consequently, the sensing accuracy of the sensor 981 becomes very low.

[0132] In contrast, in the image display device 500 according to this embodiment, reflected light from the projection optical system 70 does not enter the sensor 81, making it possible to sufficiently suppress the generation of noise components due to reflected light. This makes it possible to achieve high sensing accuracy.

[0133] (Correlation with projected light) In the image display device 900 shown in Figure 8, it is possible to sense only the light before it is modulated by the reflective light modulation element 932. In other words, light different from the image light projected by the projection optical system 70 is sensed at a position very far from the projection optical system 70. Consequently, light with low correlation to the projected light (image light) is sensed, resulting in low sensing accuracy.

[0134] In contrast, in the image display device 500 according to this embodiment, the sensor unit 80 is positioned near the image synthesis unit 50, which is located directly in front of the projection optical system 70. The first and second image lights 10 and 20 generated by the first and second image generation units 100 and 200 are then sensed. Therefore, it becomes possible to sense highly correlated light from the projection light (image light) projected by the projection optical system 70, enabling high sensing accuracy. Furthermore, even when sensing diffracted light from the projection light, extremely high sensing accuracy is achieved.

[0135] (Detection of deterioration of optical components) In the image display device 900 shown in Figure 8, the light is sensed before it enters the reflective light modulation element 932. Therefore, it is not possible to detect the deterioration of optical components included in the image modulation unit 930, such as the reflective light modulation element 932, based on the sensing results.

[0136] In contrast, in the image display device 500 according to this embodiment, the first and second image light 10 and 20 emitted from the first and second image generation units 100 and 200 are sensed. That is, the light that has passed through the reflective polarizing element 131, reflective light modulation element 132, wave plate 133, polarizing beam splitter 134, half-wave plate 135, color synthesis prism 136 and polarizing plate 137 included in the image modulation unit 130 illustrated in Figure 2 is sensed.

[0137] Therefore, based on the sensing results of the sensor unit 80, it becomes possible to detect the deterioration of these optical components. Of course, deterioration of coatings formed on optical components and adhesives used for bonding optical components can also be detected. For example, based on detection results such as increased black brightness or decreased white brightness, it is possible to appropriately detect deterioration of the reflective optical modulation element 132, the waveplate 133 which functions as a compensating plate, or the polarizing beam splitter 134 which aligns the polarization state.

[0138] As a result, for example, optical components can be replaced at the appropriate time, which can reduce maintenance costs. Furthermore, it becomes possible to prepare replacement optical components in advance, before they completely fail. In other words, by anticipating failures and preparing replacement parts beforehand, the repair period can be shortened.

[0139] (Adjustment of the compensation plate using black luminance feedback) The image display device 500 according to this embodiment may also be equipped with a mechanism that allows the axis of the waveplate 133, which functions as a compensation plate, to be rotated using a motor or the like. In this case, the black brightness detected by the sensor unit 80 can be fed back (FB) to rotate the axis of the waveplate 133. This makes it possible to prevent deterioration of contrast due to misalignment of the compensation plate. Alternatively, it can also compensate for a decrease in contrast caused by deterioration of other optical components. The adjustment of the compensation plate may be performed automatically or by user operation via a remote control or the like.

[0140] Based on the sensing results of the sensor unit 80, the position and angle of other optical components may be changed. By appropriately configuring adjustment mechanisms, etc., within the image display device 500, high-precision image display based on the sensing results becomes possible.

[0141] (Prism sensing) The output operation of the first and second image generation units 100 and 200 is switched, or the sensor unit 80 shown in Figure 7 is configured. This makes it possible to measure the white brightness of the color synthesis prisms 136 and 236 included in the first and second image generation units 100 and 200, respectively. By controlling the operation of, for example, the light source unit 101 based on the white brightness measurement result, high-precision image display can be achieved.

[0142] (Number of sensors) In the image display device 900 shown in Figure 8, a sensor for each of the RGB colors is required in each of the first and second image generation units. In other words, a total of six sensors are required, increasing the component cost. In the image display device 500 according to this embodiment, it is possible to detect the state of the first and second image lights 10 and 20 with one or two sensors, thus reducing the component cost.

[0143] (No moving mechanism required) In the image display device 900 shown in Figure 8, it is conceivable to move the sensor as needed in the optical path between the image synthesis unit 950 and the projection optical system 970 in order to sense the first and second image lights. That is, the sensor is moved onto the optical path when sensing and moved outside the optical path during normal operation.

[0144] In this case, a movement mechanism to move the sensor is required, complicating the device. Additionally, space is needed to accommodate the sensor, increasing the device's size. For example, if the distance from the first and second image generation units to the image synthesis unit 950 increases, the back focus lengthens, leading to a larger projection optical system and more difficult design. Furthermore, concerns arise regarding reduced reliability of sensing results, increased operating time, and increased costs due to sensor movement.

[0145] In the image display device 500 according to this embodiment, the sensor unit 80 is fixed to the back side of the image synthesis unit 50, so the above-mentioned problems do not occur.

[0146] <Other Embodiments> This technology is not limited to the embodiments described above, and various other embodiments can be realized.

[0147] Figures 9 to 11 are schematic diagrams showing other configuration examples of the image generation unit. As shown in Figure 9, other polarizing elements such as wire grid polarizers may be used instead of prism-type beam splitters as reflective polarizing elements 631 (631R, 631G, 631B). The orientation in which the reflective optical modulation elements 632 (632R, 632G, 632B) are arranged is not limited and may be designed as appropriate. Similar to the above embodiment, by arranging the sensor unit 680 on the back side of the image synthesis unit 650 located directly in front of the projection optical system 670, it is possible to detect the state of the first and second image light with high accuracy.

[0148] As shown in Figure 10, transmissive optical modulation elements 732 (732R, 732G, 732B) may be used. For example, polarizers and compensating plates are arranged so as to sandwich the transmissive optical modulation elements 732. Other arbitrary configurations may be adopted. Similar to the above embodiment, by arranging the sensor unit 780 on the back side of the image synthesis unit 750 located directly in front of the projection optical system 770, it is possible to detect the state of the first and second image light with high accuracy.

[0149] Figure 11 is a schematic diagram showing an example configuration of an image display device equipped with a single image generation unit. That is, instead of generating and combining multiple images such as a right eye image and a left eye image, a single image generated by a single image generation unit 801 is projected via the projection optical system 870.

[0150] In the image generation unit 801 shown in Figure 11, a green modulated light G modulated by a reflective optical modulator 832G is incident on the color synthesis prism 836. A red modulated light R modulated by a reflective optical modulator 832R and a blue modulated light B modulated by a reflective optical modulator 832B are emitted along the same optical path by a reflective polarizer 831RB and incident on the color synthesis prism 836.

[0151] The color-combining prism 836 functions as one embodiment of the optical element according to this technology. Specifically, the color-combining prism 836 reflects a portion of the green modulated light G as a first separated light toward the projection optical system 870. The other portion of the green modulated light G is transmitted as a second separated light.

[0152] The color-combining prism 836 also transmits a portion of the red modulated light R and a portion of the blue modulated light B as first separated light toward the projection optical system 870. The remaining portion of the red modulated light R and a portion of the blue modulated light B are reflected as second separated light toward the optical path of the remaining portion of the green modulated light G.

[0153] The sensor unit 880 is positioned on the optical path of the other portion (second separated light) of each RGB color. The color synthesis prism 836 restricts the reflected light from the projection optical system 870 from entering the sensor unit 880, making it possible to detect the state of each modulated RGB light with high precision.

[0154] Thus, this technology is not limited to an image display device that generates two images using six optical modulation elements and combines them, but can be applied to any image display device. For example, as illustrated in Figures 2, 9, and 10, the image generation unit may be arranged independently, and a prism-type beam splitter arranged as an image synthesis unit may be arranged as an optical element related to this technology. For example, instead of the polarizing plate 137 shown in Figure 2, a prism-type polarizing beam splitter such as the image synthesis unit 50 may be arranged as an optical component to align the polarization state. By arranging a sensor unit on the back side of it, it becomes possible to detect the correspondence of image light emitted from the image generation unit with high precision.

[0155] Furthermore, the optical elements related to this technology can be placed at any position on the main optical path. For example, the polarizing beam splitter 134 shown in Figure 2 may be used as one embodiment of the optical elements related to this technology, with the sensor unit placed on its back side. Even in this case, it is possible to detect the state of the image light with high accuracy.

[0156] The optical elements related to this technology are not limited to polarizing beam splitters; half mirrors, glass plates, etc., can also be used. Any optical component capable of separating light into first and second separated light, and restricting light traveling in the opposite direction to the optical path of the first separated light from traveling along the optical path of the second separated light, may be used. When a plate-shaped optical component other than a prism type is used, the side that emits the first separated light becomes the first emission surface, and the side that emits the second separated light becomes the second emission surface.

[0157] Furthermore, the angle at which the light separation surface intersects the incident light is not limited to 45 degrees and can be designed arbitrarily.

[0158] In an image display device using six liquid crystal panels, the first and second image lights are not limited to the case where they represent the right eye image and the left eye image. The same image light generated based on the same image signal may be projected as the first and second image lights, respectively. For example, reducing the amount of light incident on the liquid crystal panels can extend their lifespan. Furthermore, by combining and projecting the same image, it is possible to suppress the decrease in brightness and achieve higher brightness. Of course, it is also possible to intentionally combine and project different images to produce interesting viewing effects.

[0159] The above example illustrates the case of sensing the leakage light from the first and second image beams. Specifically, using an optical component configured to impart a predetermined effect to the incident light, the incident light is separated into a first separated beam to which the predetermined effect has been applied and a second separated beam to which the predetermined effect has not been applied. For example, in the image synthesis unit described above, the application of the predetermined effect is transmission / reflection for a predetermined polarization state. The first separated beam to which the transmission / reflection effect for the predetermined polarization state has been applied and the second separated beam to which this effect has not been applied are then separated.

[0160] The invention is not limited to this, and the first and second separated light may be emitted by applying a predetermined action to either of them. For example, this includes cases where the half-mirror exemplified above is used.

[0161] It is also possible to combine at least two of the feature features of the present technology described above. In other words, the various feature features described in each embodiment may be combined arbitrarily, regardless of the specific embodiment. Furthermore, the various effects described above are merely examples and not limiting, and other effects may also be exhibited.

[0162] Furthermore, this technology can also be configured as follows. (1) Optical modulation element and An optical element that separates the modulated light modulated by the optical modulation element into a first separated light and a second separated light traveling in different directions from each other, and restricts the light incident by traveling in the opposite direction along the optical path of the first separated light from traveling along the optical path of the second separated light, A sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light. An image display device equipped with the following: (2) An image display device as described in (1), The optical element is arranged on the main optical path of the modulated light, emits the first separated light along the main optical path, and emits the second separated light along the other optical path. The sensor unit is arranged on the other optical path. Image display device. (3) An image display device as described in (1) or (2), The optical element has a first emission surface that emits the first separation light and a second emission surface that emits a second separation light different from the first emission surface. The sensor unit is positioned on the second emission surface side. Image display device. (4) An image display device described in any one of (1) to (3), The optical element has a light separation surface that is positioned obliquely to the incident direction of the modulated light incident on the optical element. Image display device. (5)(4) The image display device described above, The light separation surface transmits a portion of the modulated light incident on the light separation surface as the first separated light, and reflects the other portion of the modulated light as the second separated light. The sensor unit is positioned on the side of the light separation surface that reflects the second separated light. Image display device. (6)(4) The image display device described above, The light separation surface reflects a portion of the modulated light incident on the light separation surface as the first separated light, and transmits the other portion of the modulated light as the second separated light. The sensor unit is positioned on the side opposite to the light separation surface. Image display device. (7) An image display device described in any one of (1) to (6), The optical element separates the modulated light such that the amount of light in the first separated light is greater than the amount of light in the second separated light. Image display device. (8) An image display device described in any one of (1) to (7), further, The system comprises a synthesis unit that synthesizes multiple modulated lights to generate a combined modulated light, and a projection unit that projects the combined modulated light generated by the synthesis unit. The optical element is positioned between the synthesis unit and the projection unit, and separates the synthesized modulated light into the first separated light and the second separated light. Image display device. (9) An image display device described in any one of (1) to (8), The optical element is an optical separation prism having a first surface into which the modulated light is incident, an optical separation surface that separates the modulated light incident on the first surface, and a second surface from which the second separated light separated by the optical separation surface is emitted. The sensor unit is positioned in close proximity to the second surface of the light separation prism. Image display device. (10) An image display device described in any one of (1) to (9), The optical element is a polarizing beam splitter, a half mirror, or a glass plate. Image display device. (11) An image display device described in any one of (1) to (10), further, It comprises a first emission unit that emits a first image light in a first polarization state along a first direction, The optical element has an optical separation surface that is positioned obliquely to the first direction, The light separation surface transmits a portion of the first image light onto a first optical path along the first direction, and reflects the other portion of the first image light onto a second optical path along a second direction substantially perpendicular to the first direction. The sensor unit is arranged on the second optical path. Image display device. (12)(11) The image display device described above, further, It comprises a second emission unit that emits a second image light in a second polarization state along the second direction, The light separation surface is positioned obliquely to the second direction, reflecting a portion of the second image light onto the first optical path and transmitting the other portion of the second image light onto the second optical path. Image display device. (13)(12) The image display device described above, The sensor unit includes a first filter for extracting light in the first polarization state, a first sensor for detecting the state of the light extracted by the first filter, a second filter for extracting light in the second polarization state, and a second sensor for detecting the state of the light extracted by the second filter. Image display device. (14) An image display device described in any one of (1) to (13), The sensor unit detects at least one of the intensity, chromaticity, and shape of the second separated light. Image display device. (15) An image display device described in any one of (1) to (14), The optical element is configured for the purpose of imparting a predetermined effect to incident light, and separates the modulated light incident on the optical element into a first separated light to which the predetermined effect is applied and a second separated light to which the predetermined effect is not applied. Image display device. [Explanation of symbols]

[0163] OP1…main optical path OP2...Other optical paths 10, 10A, 10B, 10C…First image light 20, 20A, 20B, 20C… Second image light 50, 650, 750... Image synthesis unit 51…Joint surface 70, 670, 770, 870...Projection optical system 80, 680, 780, 880… Sensor section 81...Sensor 81a...First sensor 81b...Second sensor 89a...First polarizing plate 89b...Second polarizing plate 100...First image generation unit 110...Illumination optical system 130...Image Modulation Unit 132 (132R, 132G, 132B), 232G, 632, 832R, 832G, 832B... Reflective optical modulation elements 200...Second image generation unit 500…Image display device 732...Transmissive optical modulation element 801...Image generation unit 836...Color Combination Prism

Claims

1. A light source unit comprising a light source member that emits light corresponding to a predetermined color, and a fluorescent member that emits fluorescence based on the light emitted from the light source member, wherein white light is generated by combining the light emitted from the light source member and the fluorescence emitted from the fluorescent member, A first optical element separates the white light emitted from the light source into a first light corresponding to a first color which is one of red, green, or blue, and a second light corresponding to a color different from the first color. A second optical element that separates the first light into a first separated light and a second separated light that travel in different directions from each other, A third optical element that separates the second light into a third light corresponding to a second color different from the first color among red, green, and blue, and a fourth light corresponding to a third color different from the first and second colors among red, green, and blue, A sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light. It is equipped with, The sensor unit includes a first optical filter that transmits light in a predetermined wavelength band corresponding to the first color, a second optical filter having a transmission wavelength band that includes at least a part of the predetermined wavelength band, a third optical filter that transmits light in a predetermined wavelength band corresponding to the second color, and a fourth optical filter that transmits light in a predetermined wavelength band corresponding to the third color. The transmission wavelength band of the second optical filter includes at least a portion of the transmission wavelength band of the first optical filter, the transmission wavelength band of the third optical filter, and the transmission wavelength band of the fourth optical filter. The first to fourth optical filters are arranged in a two-dimensional manner. An image display device, A first optical modulation element that modulates the first light, A color synthesis unit that synthesizes the first light modulated by the first light modulation element and the modulated light based on the second light. Furthermore, it is equipped with, The first optical modulation element is arranged on the optical path of the first light, along the first surface of the color synthesis unit. Image display device.

2. The image display device according to claim 1, further, The third optical modulation element modulates the light, The fourth optical modulation element and It is equipped with, The second optical modulation element is arranged on the optical path of the third light, along the second surface of the color synthesis unit. The third optical modulation element is arranged on the optical path of the fourth light, along the third surface of the color synthesis unit. The color synthesis unit synthesizes the first light modulated by the first optical modulation element, the third light modulated by the second optical modulation element, and the fourth light modulated by the third optical modulation element. Image display device.

3. An image display device according to claim 2, The first color is red, The second color is green, The color of XL3 is blue. Image display device.

4. A light source unit comprising a solid-state light source that emits light in the blue wavelength band, and a phosphor that is excited by the blue wavelength band light emitted from the solid-state light source and emits fluorescence in the yellow wavelength band, wherein white light is generated by combining the blue wavelength band light emitted from the solid-state light source and the yellow wavelength band fluorescence emitted from the phosphor, A first optical element that reflects a first light corresponding to the red wavelength band from the white light emitted from the light source and transmits a second light including light corresponding to the green and blue wavelength bands, A second optical element that separates the first light into a first separated light and a second separated light that travel in different directions from each other, A sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light. It is equipped with, The sensor unit includes a first optical filter that transmits light in a predetermined wavelength band corresponding to red, a second optical filter that has a wavelength band that includes at least a part of the predetermined wavelength band and has a transmission wavelength band different from the predetermined wavelength band, a third optical filter that transmits light in a wavelength band corresponding to green, and a fourth optical filter that transmits light in a wavelength band corresponding to blue. The transmission wavelength band of the second optical filter includes at least a portion of the transmission wavelength band of the third optical filter and at least a portion of the transmission wavelength band of the fourth optical filter. The first to fourth optical filters are arranged in a two-dimensional manner. An image display device, A third optical element separates the second light into a third light corresponding to the green wavelength band and a fourth light corresponding to the blue wavelength band, A first optical modulation element that modulates the first light, The third optical modulation element modulates the light, The fourth optical modulation element and A color synthesis unit that synthesizes the first light modulated by the first optical modulation element, the third light modulated by the second optical modulation element, and the fourth light modulated by the third optical modulation element. Furthermore, it is equipped with, The first optical modulation element is arranged on the optical path of the first light, along the first surface of the color synthesis unit, The second optical modulation element is arranged on the optical path of the third light, along the second surface of the color synthesis unit. The third optical modulation element is arranged on the optical path of the fourth light, along the third surface of the color synthesis unit. Image display device.

5. An image display device according to any one of claims 2 to 4, The light source, the first optical element, and the third optical element are arranged in this order in a straight line along the optical path of the light emitted from the light source. Image display device.

6. An image display device according to any one of claims 2 to 5, The first and third optical elements are dichroic mirrors. Image display device.

7. An image display device according to any one of claims 1 to 6, The second optical element and the color synthesis unit are arranged in a straight line on the optical path of the first light. Image display device.

8. An image display device according to any one of claims 1 to 7, The second optical element has a light-separating surface that is positioned obliquely to the incident direction of the first light incident on the second optical element. Image display device.

9. An image display device according to any one of claims 1 to 8, The second optical element is positioned on the main optical path of the first light modulated by the first optical modulation element, and emits the first separated light along the main optical path and the second separated light along the other optical path. The sensor unit is arranged on the other optical path. Image display device.

10. An image display device according to any one of claims 1 to 9, The second optical element has a first emission surface that emits the first separation light and a second emission surface that emits the second separation light which is different from the first emission surface. The sensor unit is positioned on the second emission surface side. Image display device.

11. An image display device according to any one of claims 1 to 10, The second optical element separates the first separated light such that the amount of light from the first separated light is greater than the amount of light from the second separated light. Image display device.

12. An image display device according to any one of claims 1 to 11, The wavelength range of light transmitted by the second optical filter is wider than the predetermined wavelength range. Image display device.

13. An image display device according to any one of claims 1 to 12, The first optical modulation element is a transmissive optical modulation element. Image display device.

14. An image display device according to any one of claims 1 to 13, The second optical element is a half-mirror. Image display device.

15. An image display device according to any one of claims 1 to 14, The sensor unit detects the intensity of the second separated light. Image display device.

16. An image display device according to any one of claims 1 to 15, further, The device comprises a polarizing plate positioned adjacent to the first optical modulation element. Image display device.

17. An image display device according to any one of claims 1 to 16, The second optical element separates the first light into a first separated light which is reflected light and a second separated light which is transmitted light. The sensor unit is positioned on the optical path of the second separated light, which is transmitted light. Image display device.

18. An image display device according to any one of claims 1 to 17, The sensor unit detects the state of separated light corresponding to the first image light that constitutes the right-eye image of the stereoscopic image and the second image light that constitutes the left-eye image of the stereoscopic image. Image display device.

19. An image display device according to any one of claims 1 to 18, Projecting the first and second image beams, which are identical image beams generated based on the same image signal. Image display device.

20. An image display device according to any one of claims 1 to 19, further, The system includes a control unit that automatically rotates the axis of the waveplate based on the detection results from the aforementioned sensor unit. Image display device.

21. An image display device according to claim 20, The control unit rotates the axis of the waveplate based on user operation. Image display device.

22. An image display device according to any one of claims 1 to 21, further, The device comprises a first fly-eye lens positioned between the light source and the first optical element, having a lens array convex in the direction of the light source, and a second fly-eye lens having a lens array convex in the direction of the first optical element. Image display device.

23. A light source unit comprising a solid-state light source that emits light in the blue wavelength band, and a phosphor that is excited by the blue wavelength band light emitted from the solid-state light source and emits fluorescence in the yellow wavelength band, wherein white light is generated by combining the blue wavelength band light emitted from the solid-state light source and the yellow wavelength band fluorescence emitted from the phosphor, A first optical element separates the white light emitted from the light source into a first light corresponding to the red wavelength band and a second light including light corresponding to the green and blue wavelength bands. A second optical element that separates the first light into a first separated light and a second separated light that travel in different directions from each other, A sensor unit is positioned on the optical path of the second separated light and detects the state of the second separated light, It is equipped with, The sensor unit includes a first optical filter that transmits light in a predetermined wavelength band corresponding to the red color, a second optical filter that has a wavelength band that includes at least a part of the predetermined wavelength band and has a transmission wavelength band different from the predetermined wavelength band, a third optical filter that transmits light in a predetermined wavelength band corresponding to the green color, and a fourth optical filter that transmits light in a predetermined wavelength band corresponding to the blue color. The transmission wavelength band of the second optical filter includes at least a portion of the transmission wavelength band of the third optical filter and at least a portion of the transmission wavelength band of the fourth optical filter. The first to fourth optical filters are arranged in a two-dimensional manner. An image display device, A third optical element separates the second light into a third light corresponding to the green wavelength band and a fourth light corresponding to the blue wavelength band, A first optical modulation element that modulates the first light, The third optical modulation element modulates the light, The fourth optical modulation element and A color synthesis unit that synthesizes the first light modulated by the first optical modulation element, the third light modulated by the second optical modulation element, and the fourth light modulated by the third optical modulation element. Furthermore, it is equipped with, The first optical modulation element is arranged on the optical path of the first light, along the first surface of the color synthesis unit, The second optical modulation element is arranged on the optical path of the third light, along the second surface of the color synthesis unit. The third optical modulation element is arranged on the optical path of the fourth light, along the third surface of the color synthesis unit. In an image display device, The brightness of the output image is adjusted based on the detection results of the aforementioned sensor. Control method.

Images