JP2020071474A - Optical system, image projection device, and movable body - Google Patents

Abstract

To provide an optical system that reduces the influence of unnecessary light with a compact light path configuration, an image projection device, and a movable body.SOLUTION: An optical system 100 comprises: a light modulation element 103 that emits incident light 250 in a first direction or a second direction that are different from each other; and an optical element 102 that emits radiation light 250 radiated from a light source 101 toward the light modulation element 103 as the incident light 250. The optical element 102 has a boundary surface B that transmits first emission light 200 emitted in a first direction from the light modulation element 103 and guided to a projection object, and one of second emission light 201 emitted in a second direction from the light modulation element 103 and the radiation light 250, and reflects the other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical system, an image projection device and a moving body.

  With the advent of the multimedia age, image projection devices have been used in all situations. In recent years, not only front projection type projectors have been developed, but they have been applied to signage and head-up displays (HUD) mounted on vehicles, and the market field is expanding. Optical systems that incorporate DMD (Digital Micromirror Device) as a light modulator are becoming mainstream to construct them, and they are becoming smaller, lighter, higher in brightness, and higher in dynamic range (higher contrast). There is.

  In Patent Document 1, in a projection display device having a reflection-type light modulator, an illumination optical system for the reflection-type light modulator shields a part of one side cross section of a light flux of the illumination optical system to shield unnecessary light. It discloses a configuration in which the plate is provided so as to be insertable into and removable from the optical path of the illumination optical system.

  In Patent Document 2, in an optical system including a prism having a first surface that transmits the light reflected by the DMD, the prism reflects the light transmitted through the first surface by a mirror element in an ON state. Disclosed is a configuration having a second surface that transmits the reflected light and reflects the light reflected by the mirror element in the off state.

  An object of the present invention is to provide an optical system, an image projection device, and a moving body that have a compact optical path structure and reduce the influence of unnecessary light.

  The optical system according to the present invention is directed to a light modulation element that emits incident light in a first direction or a second direction that is different from each other, and an irradiation light emitted from a light source that is directed to the light modulation element as incident light. An optical system that emits light in a first direction from the light modulation element in a first direction and is guided to a projection target; and a second direction from the light modulation element. It is characterized in that it has an interface that transmits one of the second emitted light and the emitted light emitted to and reflects the other.

  According to the present invention, it is possible to provide an optical system, an image projection apparatus, and a moving body that have a compact optical path configuration and reduce the influence of unnecessary light.

It is a sectional view showing optical system 100 as one embodiment of the present invention. FIG. 3 is a cross-sectional view showing optical paths of an optical element 102 and a light modulation element 103 shown in FIG. 1. FIG. 3 is a diagram showing a detailed configuration of a light modulation element 103 shown in FIG. 1. It is sectional drawing which shows the partial structure of the modification of the optical system 100 shown in FIG. FIG. 14 is a cross-sectional view showing a second modified example of the optical system 100 shown in FIG. 1 and showing optical paths of an optical element 102 and a light modulation element 103M. It is sectional drawing which shows the 3rd modification of the optical system 100 shown in FIG. 7 is a cross-sectional view showing optical paths of the optical element 102, the optical element 102B, and the light modulation element 103 shown in FIG. It is sectional drawing which shows the 4th modification of the optical system 100 shown in FIG. 9 is a cross-sectional view showing optical paths of the optical element 102, the optical element 102C, and the light modulation element 103 shown in FIG. 8. FIG. It is sectional drawing which shows the 5th modification of the optical system 100 shown in FIG. FIG. 11 is a cross-sectional view showing optical paths of the optical element 102R and the light modulation element 103 shown in FIG. 10. It is a sectional view showing image projection device 300 as one embodiment of the present invention. It is sectional drawing which shows the 6th modification of the optical system 100 shown in FIG. FIG. 14 is a cross-sectional view showing the optical paths of the optical element 102, the light modulation element 103, and the second optical element 105 shown in FIG. 13. It is sectional drawing which shows the 7th modification of the optical system 100 shown in FIG. 16 is a cross-sectional view showing the optical paths of the optical element 102, the optical element 102B, the second optical element 105, and the light modulation element 103 shown in FIG. It is sectional drawing which shows the 8th modification of the optical system 100 shown in FIG. FIG. 18 is a cross-sectional view showing the optical paths of the optical element 102, the optical element 102C, the second optical element 105, and the light modulation element 103 shown in FIG. It is sectional drawing which shows the 9th modification of the optical system 100 shown in FIG. It is sectional drawing which shows the optical path of the optical element 102R, the 2nd optical element 105, and the light modulation element 103 which were shown in FIG. FIG. 13 is a cross-sectional view showing a modified example of the image projection device 300 shown in FIG. 12. It is a figure which shows the vehicle 400 carrying the image projection apparatus 300 as one Embodiment of this invention.

  FIG. 1 is a sectional view showing an optical system 100 as one embodiment of the present invention.

  The optical system 100 includes a light source 101 that emits light, an optical element 102 that transmits or reflects incident light, and a light modulation element 103 that emits incident light in a first direction or a second direction which are different directions. , A projection unit 104 as an example of a projection optical system that projects incident light onto a projection target.

  The light source 101 includes an LD (laser diode), and has three color light sources corresponding to three colors of red (R), blue (B), and green (G) in a one-to-one relationship, and the wavelength and transmission of reflected light. It includes a dichroic mirror in which light of a predetermined wavelength is predetermined.

  The optical element 102 is preferably composed of a prism having two or more surfaces, and in the present embodiment, is composed of a total reflection triangular prism unit (so-called TIR prism unit).

  The light modulation element 103 is composed of a DMD (digital micromirror device) having a substantially rectangular mirror surface composed of a plurality of micromirrors.

  In the above configuration, the optical element 102 reflects the irradiation light 250 emitted from the light source 101 at the boundary surface (interface) B, and makes it incident as the incident light 250 toward the light modulation element 103. A relay optical system that guides the irradiation light 250 emitted from the light source 101 to the optical element 102 may be provided between the light source 101 and the optical element 102.

  The light modulation element 103 drives the respective micromirrors in a time-division manner to reflect the incident light 250 in the first direction and emit the first outgoing light 200, and when the incident light 250 is directed in the second direction. The case of reflecting and emitting the second outgoing light 201 is switched. The light modulation element 103 is arranged so that the light beam of the second emitted light 201 is located on the opposite side of the light beam of the first emitted light 200 with the light beam of the incident light 250 interposed therebetween. , 201 is emitted.

  The optical element 102 transmits the first emitted light 200 emitted from the light modulation element 103 in the first direction at the boundary surface C and the boundary surface B, and emits the first emitted light 200 from the light modulation element 103 in the second direction. The second outgoing light 201 is reflected by the boundary surface B.

  The first emitted light 200 that has passed through the optical element 102 is guided to the projection unit 104, enters the projection unit 104, is projected on the projection target, and the second emitted light 201 reflected by the optical element 102 is processed as unnecessary light. Re-reflection is prevented by, for example, entering a mechanical grain or a light absorption band.

  With the above configuration, the second emitted light 201 can be kept away from the first emitted light 200, so that the second emitted light 201 can be suppressed from entering the projection unit 104. This makes it possible to increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration and The optical element 102 can be made compact.

  Further, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 are reflected by the same boundary surface B of the optical element 102. As a result, the optical system 100 can be made compact.

  Further, since the boundary surface B transmits the first outgoing light 200 and reflects the second outgoing light 201 and the irradiation light 250, the first outgoing light 200 is reflected and transmitted at the same boundary surface. On the other hand, the second emitted light 201 and the irradiation light 250 can be arranged on the same side, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 2 is a cross-sectional view showing the optical paths of the optical element 102 and the light modulation element 103 shown in FIG.

  First, the irradiation light 250 (solid line) emitted from the light source 101 enters the boundary surface (interface) A between the external environment having the refractive index n1 and the optical element 102 having the refractive index n2 at the incident angle θ1 and is refracted at θ2. .. The relationship between θ1 and θ2 follows Snell's law (n2 / n1 = sin θ1 / sin θ2). The relationship between the refractive indices n1 and n2 is n1 <n2.

  A ray having an angle component of θ2 incident on the boundary surface A reaches the boundary surface B of the optical element 102 with an angle component of θ3. At this time, at the boundary surface B, θ3 has the following relation with respect to the critical angle θc of the total reflection condition, and the light is totally reflected (θ3 ≧ θc: θc [= arcsin (n1 / n2) {n1 <n2 }]).

  The light beam totally reflected on the boundary surface B reaches the boundary surface (interface) C of the optical element 102 at an angle θ4 and is emitted to the external environment at a refraction angle θ5.

  Then, the light reaches the surface of the light modulation element 103 at an angle θ6, enters the light modulation element 103 as incident light 250, and is reflected and modulated by the light modulation element 103.

  The emitted light modulated by the light modulator 103 is divided into a first emitted light 200 emitted in the α direction (first direction) and a second emitted light 201 emitted in the β direction (second direction). At least divided. The first outgoing light 200 is guided as necessary light to the projection unit 104, and the second outgoing light 201 is escaped to a position different from that of the projection unit 104 as unnecessary light and processed.

  The first outgoing light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface C at an incidence angle α2, and has a refraction angle α3. To proceed inside the optical element 102.

  After that, the first emitted light 200 reaches the boundary surface B at an angle α4 <θc, is emitted to the external environment at a refraction angle α5, and is incident on the projection unit 104.

  On the other hand, the second outgoing light 201 (dashed-dotted line) is reflected by the light modulation element 103 toward the angle β1 formed with the normal line of the surface of the light modulation element 103. Here, the ray of the second emitted light 201 is located on the opposite side of the ray of the first emitted light 200 with the ray of the incident light 250 interposed therebetween.

  The second outgoing light 201 enters the boundary surface C at an incident angle β2, travels inside the optical element 102 at a refraction angle β3, reaches the boundary surface B at an angle β4 ≧ θc, and is totally reflected at the boundary surface B. Then, it goes to the boundary surface A.

  Then, the second emitted light 201 is emitted to the external environment at the interface A with a refraction angle β6. The second emitted light 201 is prevented from being re-reflected by, for example, entering a mechanical grain or a light absorption band.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.59, specific examples of various parameters are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
θ1 = 0
θ2 = 0
θ3 = 46.2 {≧ θc}
θ4 = 2.4
θ5 = 3.8
θ6 = 3.8
α1 = 27.8
α2 = 27.8
α3 = 17.0
α4 = 26.8 {<< θc}
α5 = 45.8
β1 = 20.2
β2 = 20.2
β3 = 12.5
β4 = 56.4 {≧ θc}
β5 = 10.2
β6 = 16.3

  With the above configuration, the first emitted light 200 as the necessary light and the second emitted light 201 as the unnecessary light are clearly separated via the boundary surface B of the optical element 102 to form the second emitted light 201. It can be kept away from the first emitted light 200. As a result, it is possible to suppress the second emitted light 201 from entering the projection unit 104, the brightness of the projection target when the first emitted light 200 is emitted, and the projection when the second emitted light 201 is emitted. The difference in brightness from the brightness of the target can be increased.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration and The optical element 102 can be made compact.

  Further, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 are reflected by the same boundary surface B of the optical element 102. As a result, the optical system 100 can be made compact.

  Further, since the boundary surface B transmits the first outgoing light 200 and reflects the second outgoing light 201 and the irradiation light 250, the first outgoing light 200 is reflected and transmitted at the same boundary surface. On the other hand, the second emitted light 201 and the irradiation light 250 can be arranged on the same side, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 3 is a diagram showing a detailed configuration of the light modulation element 103 shown in FIG. 3A shows a top view of the light modulation element 103, and FIG. 3B shows a cross-sectional view of the light modulation element 103.

  The light modulation element 103 is arranged so as to surround the variable region 103A that modulates the incident light 250 in the first or second direction and emits the light and the variable region 103A, and does not modulate the incident light 250 in the second direction. A fixed region 103B that is fixed and emitted.

  As described with reference to FIGS. 1 and 2, the first emission light 200 emitted from the light modulation element 103 in the first direction is guided to the projection unit 104 and is incident on the projection target to be projected onto the projection target. The second emitted light 201 emitted from the modulation element 103 in the second direction is processed as unnecessary light.

  In the present embodiment, the light emitted from the fixed region 103B is only the light parallel to the second emitted light 201 and does not include the light parallel to the first emitted light 200, and thus is guided to the projection unit 104. There is no light.

  Accordingly, when the second emission light 201 is emitted as unnecessary light from the variable region 103A, the light emitted from the fixed region 103B is not projected onto the projection target, and the first emission light 200 is emitted. The brightness difference between the brightness of the projection target when the light is emitted and the brightness of the projection target when the second outgoing light 201 is emitted can be increased.

  FIG. 4 is a sectional view showing a partial configuration of a modified example of the optical system 100 shown in FIG.

  An optical system 100 shown in FIG. 4 includes a light source 101E including an LED light source optical system, instead of the light source 101 including the LD (laser diode) shown in FIG.

  The light source 101E includes an LED 110 that divergently emits light, and a coupling lens 111 that gently collects the emitted light emitted from the LED 110. At this time, the upper light ray 121 and the lower light ray 122 emitted from the coupling lens 111 are at an angle of 10 degrees with respect to the principal ray 120 emitted from the coupling lens 111.

  In this modified example, the upper ray 121 and the lower ray 122 are incident on the optical element 102 with an inclination of 10 degrees with respect to the principal ray 120. However, the upper ray 121 and the lower ray 122 in FIG. 1 and FIG. The same contents as the irradiation light 250 are established.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.59, specific examples of various parameters in the chief ray 120 are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
θ1 = 0
θ2 = 0
θ3 = 46.2 {≧ θc}
θ4 = 2.4
θ5 = 3.8
θ6 = 3.8
α1 = 27.8
α2 = 27.8
α3 = 17.0
α4 = 26.8 {<< θc}
α5 = 45.8
β1 = 20.2
β2 = 20.2
β3 = 12.5
β4 = 56.4 {≧ θc}
β5 = 10.2
β6 = 16.3

Since the incident angle θ1 of the upper ray 121 with respect to the optical element 102 is inclined by 10 degrees, specific examples of various parameters of the upper ray 121 are as follows.
θ1 = 10.0
θ2 = 6.3
θ3 = 39.9 {≧ θc}
θ4 = 6.3
θ5 = 10.0
θ6 = 10.0
α1 = 17.8
α2 = 17.8
α3 = 11.1
α4 = 32.7 {<< θc}
α5 = 59.4
β1 = 30.2
β2 = 30.2
β3 = 18.4
β4 = 62.2 {≧ θc}
β5 = 16.0
β6 = 26.1

Similar to the upper ray 121, the lower ray 122 has the following specific examples of various parameters.
θ1 = 10.0
θ2 = 6.3
θ3 = 52.5 {≧ θc}
θ4 = 8.6
θ5 = 13.8
θ6 = 13.8
α1 = 37.8
α2 = 37.8
α3 = 22.7
α4 = 21.1 {<< θc}
α5 = 35.0
β1 = 10.2
β2 = 10.2
β3 = 6.4
β4 = 50.2 {≧ θc}
β5 = 4.0
β6 = 6.4

  With the above configuration, the first emitted light 200 as the necessary light and the second emitted light 201 as the unnecessary light are clearly separated via the boundary surface B of the optical element 102 to form the second emitted light 201. It can be kept away from the first emitted light 200. As a result, it is possible to suppress the second emitted light 201 from entering the projection unit 104, the brightness of the projection target when the first emitted light 200 is emitted, and the projection when the second emitted light 201 is emitted. The difference in brightness from the brightness of the target can be increased.

  Then, the light ray of the incident light 250 (main ray 120) to the light modulation element 103 is arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path configuration and the optical element 102 can be made compact.

  Further, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 are reflected by the same boundary surface B of the optical element 102. As a result, the optical system 100 can be made compact.

  Further, since the boundary surface B transmits the first outgoing light 200 and reflects the second outgoing light 201 and the irradiation light 250, the first outgoing light 200 is reflected and transmitted at the same boundary surface. On the other hand, the second emitted light 201 and the irradiation light 250 can be arranged on the same side, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 5 is a cross-sectional view showing a second modification of the optical system 100 shown in FIG. 1 and showing the optical paths of the optical element 102 and the light modulation element 103M.

  The optical system 100 shown in FIG. 5 includes an optical modulation element 103M configured by MEMS, instead of the optical modulation element 103 configured by DMD (laser diode) shown in FIG.

  The outgoing light modulated by the light modulation element 103M is scanned between the α direction (first direction) and the β direction (second direction). That is, the emitted light modulated by the light modulation element 103M is, similarly to FIG. 2, the first emitted light 200 emitted in the α direction (first direction) and the emitted light in the β direction (second direction). The second emitted light 201 is emitted, and the third emitted light 202 emitted in the γ direction (third direction) is included.

  The optical paths of the first emitted light 200 and the second emitted light 201 are the same as those in FIG. 2, and the description thereof will be omitted.

  The third emitted light 202 is a light ray within the scanning range of the light modulation element 103M, that is, between the light ray of the first emitted light 200 and the light ray of the second emitted light 201, and is incident on the boundary surface B of the optical element 102. An optical path whose angle is equal to the critical angle.

  The third outgoing light 202 is reflected by the light modulation element 103M toward an angle γ1 formed with the normal line of the surface of the light modulation element 103M, enters the boundary surface C of the optical element 102 at the incidence angle γ2, and has a refraction angle of γ2. At γ3, the optical element 102 advances.

  After that, the third emitted light 202 reaches the boundary surface B at the angle γ4 = θc and is totally reflected by the boundary surface B, so that it is not emitted to the external environment and goes to the boundary surface A of the optical element 102.

  The third emission light 202 reaches the boundary surface A at an angle γ5 and is emitted to the external environment at a refraction angle γ6. With the incident angle γ4 of the third outgoing light 202 on the boundary surface B as a boundary, the necessary light that passes through the boundary surface B similarly to the first outgoing light 200 and the boundary surface similar to the second outgoing light 201. The unnecessary light reflected by B is switched.

Specific examples of various parameters are as follows under the condition that the scanning range of the light modulation element 103M is 24 degrees (± 12 degrees), the refractive index of the external environment is n1 = 1.00, and the refractive index of the optical element is n2 = 1.59. It becomes the street.
θc = 38.9 {= arcsin (1.00 / 1.59)}
θ1 = 0
θ2 = 0
θ3 = 46.2 {≧ θc}
θ4 = 2.4
θ5 = 3.8
θ6 = 3.8
α1 = 27.8
α2 = 27.8
α3 = 17.0
α4 = 26.8 {<< θc}
α5 = 45.8
β1 = 20.2
β2 = 20.2
β3 = 12.5
β4 = 56.4 {> θc}
β5 = 10.2
β6 = 16.3
γ1 = 7.8
γ2 = 7.8
γ3 = 4.9
γ4 = 38.9 {= θc}
γ5 = 7.3
γ6 = 11.6

  With the above configuration, the first emitted light 200 as the necessary light and the second emitted light 201 as the unnecessary light are clearly separated via the boundary surface B of the optical element 102 to form the second emitted light 201. It can be kept away from the first emitted light 200. As a result, it is possible to suppress the second emitted light 201 from entering the projection unit 104, the brightness of the projection target when the first emitted light 200 is emitted, and the projection when the second emitted light 201 is emitted. The difference in brightness from the brightness of the target can be increased.

  Since the light ray of the incident light 250 on the light modulation element 103M is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103M, the optical path configuration and The optical element 102 can be made compact.

  Further, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103M, and the irradiation light 250 from the light source 101 and the second emission light 201 are reflected on the same boundary surface B of the optical element 102. As a result, the optical system 100 can be made compact.

  Further, since the boundary surface B transmits the first outgoing light 200 and reflects the second outgoing light 201 and the irradiation light 250, the first outgoing light 200 is reflected and transmitted at the same boundary surface. On the other hand, the second emitted light 201 and the irradiation light 250 can be arranged on the same side, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 6 is a sectional view showing a third modification of the optical system 100 shown in FIG.

  The optical system 100 includes an optical element 102B configured by a triangular prism in addition to the configuration shown in FIG. The optical element 102B transmits the first outgoing light 200 that has passed through the optical element 102, and the first outgoing light 200 that has passed through the optical element 102B is guided to the projection unit 104 and enters to be projected onto a projection target. To be done. This facilitates correction of aberrations and adjustment of the emission direction.

  FIG. 7 is a sectional view showing the optical paths of the optical element 102, the optical element 102B, and the light modulation element 103 shown in FIG. In the figure, the circled portion at the lower left is an enlarged view of the circled portion at the upper right.

  The optical paths of the incident light (irradiation light) 250 and the second outgoing light 201 are the same as those in FIG.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, and is incident on the boundary surface C of the optical element 102 at an incidence angle α2. , Proceeds through the optical element 102 at a refraction angle α3.

  After that, the first outgoing light 200 reaches the boundary surface B at an angle α4 <θc, is emitted to the external environment at a refraction angle α4 ′, and then is refracted at the boundary surface (interface) D of the optical element 102B. It is incident at α4 '. The optical element 102B has a refractive index n2, and the angle formed by the boundary surface D and the boundary surface (interface) E is φ.

  An air layer having a refractive index n1 is provided between the optical element 102 and the optical element 102B, and the optical element 102 and the optical element 102B are arranged so that the boundary surface B of the optical element 102 and the boundary surface D of the optical element 102B are parallel to each other. Since they are arranged, the incident angle α4 on the boundary surface B and the refraction angle α5 on the boundary surface D are equal. The wider the air layer between the optical element 102 and the optical element 102B, the more the projected image is affected. Therefore, the distance L of the air layer is preferably 10 μm or less.

  The first emitted light 200 travels inside the optical element 102B at a refraction angle α5, reaches the boundary surface E of the optical element 102B at an angle α6 <θc, is emitted to the external environment at a refraction angle α7, and enters the projection unit 104. To be done.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.59, specific examples of various parameters are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
φ = 40.0
θ1 = 0
θ2 = 0
θ3 = 46.2 {≧ θc}
θ4 = 2.4
θ5 = 3.8
θ6 = 3.8
α1 = 27.8
α2 = 27.8
α3 = 17.0
α4 = 26.8 {<< θc}
α4 ′ = 45.8
α5 = 26.8
α6 = 13.2 {<< θc}
α7 = 21.3
β1 = 20.2
β2 = 20.2
β3 = 12.5
β4 = 56.4 {≧ θc}
β5 = 10.2
β6 = 16.3

  FIG. 8 is a sectional view showing a fourth modification of the optical system 100 shown in FIG.

  The optical system 100 includes an optical element 102C configured by a triangular prism, instead of the optical element 102B shown in FIG. The optical element 102C reflects the first outgoing light 200 that has passed through the optical element 102, and the first outgoing light 200 that is reflected by the optical element 102B is guided to the projection unit 104 and is incident on the projection target. Projected

  With the above configuration, the second emitted light 201 can be further distanced from the first emitted light 200, so that the second emitted light 201 can be suppressed from entering the projection unit 104. As a result, it is possible to surely increase the brightness difference between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted.

  FIG. 9 is a sectional view showing the optical paths of the optical element 102, the optical element 102C, and the light modulation element 103 shown in FIG. In the figure, the circled portion at the lower left is an enlarged view of the circled portion at the upper right.

  The optical paths of the incident light (irradiation light) 250 and the second outgoing light 201 are the same as those in FIG.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, and is incident on the boundary surface C of the optical element 102 at an incidence angle α2. , Proceeds through the optical element 102 at a refraction angle α3.

  Then, the first outgoing light 200 reaches the boundary surface B at an angle α4 <θc and is emitted to the external environment at a refraction angle α4 ′, and then at the boundary surface D of the optical element 102C at a refraction angle α4 ′. It is incident. The optical element 102C has a refractive index n2, and the angle between the boundary surface D and the boundary surface E is φ.

  An air layer having a refractive index n1 is formed between the optical element 102 and the optical element 102C, and the optical element 102 and the optical element 102C are arranged such that the boundary surface B of the optical element 102 and the boundary surface D of the optical element 102C are parallel to each other. Since they are arranged, the incident angle α4 on the boundary surface B and the refraction angle α5 on the surface D are equal. The wider the air layer between the optical element 102 and the optical element 102C, the more the projected image is affected. Therefore, the distance L of the air layer is preferably 10 μm or less.

  The first outgoing light 200 travels inside the optical element 102C at a refraction angle α5 and reaches the boundary surface E of the optical element 102C at an angle α6 ≧ θc. After that, the first emitted light 200 is totally reflected on the boundary surface E, then reaches the boundary surface (interface) F at an angle α6 ′, and is emitted to the external environment at a refraction angle α ′ ′ to the projection unit 104. It is incident.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.59, specific examples of various parameters are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
φ = 100.0
θ1 = 0
θ2 = 0
θ3 = 46.2 {≧ θc}
θ4 = 2.4
θ5 = 3.8
θ6 = 3.8
α1 = 27.8
α2 = 27.8
α3 = 17.0
α4 = 26.8 {<< θc}
α4 ′ = 45.8
α5 = 26.8
α6 = 73.2 {≧ θc}
α6 ′ = 23.2
α7 = 38.9
β1 = 20.2
β2 = 20.2
β3 = 12.5
β4 = 56.4 {≧ θc}
β5 = 10.2
β6 = 16.3

  With the above configuration, the second emitted light 201 can be further separated from the first emitted light 200.

  FIG. 10 is a sectional view showing a fifth modification of the optical system 100 shown in FIG. The optical system 100 includes an optical element 102R configured by a triangular prism, instead of the optical element 102 shown in FIG.

  The optical element 102R reflects the first emission light 200 emitted from the light modulation element 103 in the first direction at the boundary surface A, and irradiates the irradiation light 250 emitted from the light source 101 and the second light from the light modulation element 103. The second emission light 201 emitted in the direction is transmitted through the boundary surface A and the boundary surface B.

  The first outgoing light 200 reflected by the optical element 102R is guided to the projection unit 104, is incident on the projection target, and is projected on the projection target. The second outgoing light 201 transmitted through the optical element 102R is processed as unnecessary light. The re-reflection may be prevented by, for example, entering a mechanical grain or a light absorption band.

  Further, the light modulation element 103 is arranged so that the light beam of the second emitted light 201 is located on the opposite side of the light beam of the first emitted light 200 with the light beam of the incident light 250 interposed therebetween. Emit light 200 and 201.

  Further, the optical element 102R transmits the irradiation light 250 emitted from the light source 101 toward the light modulation element 103 as incident light 250.

  With the above configuration, the second emitted light 201 can be kept away from the first emitted light 200, so that the second emitted light 201 can be suppressed from entering the projection unit 104. This makes it possible to increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration and The optical element 102R can be made compact.

  Further, the optical system 100 can be made compact by using the same optical element 102R on the incident side and the emitting side of the light modulation element 103.

  FIG. 11 is a sectional view showing the optical paths of the optical element 102R and the light modulation element 103 shown in FIG.

  First, the irradiation light 250 (solid line) emitted from the light source enters the boundary surface A between the external environment having the refractive index n1 and the optical element 102R having the refractive index n2 at the incident angle θ1 and is refracted at θ2. The boundary surface A of the incident surface conforms to Snell's law. The relationship between the refractive indices n1 and n2 is n1 <n2.

  A ray having an angle component of θ2 incident on the boundary surface A reaches the boundary surface B of the optical element 102R with an angle component of θ3. At this time, on the boundary surface B, with respect to the critical angle θc of the total reflection condition, θ3 has the following relationship, and light is transmitted (θ3 <θc: θc [= arcsin (n1 / n2) {n1 <n2}). ).

  The light ray transmitted at the boundary surface B is emitted to the external environment at a refraction angle θ4. Then, it reaches the surface of the light modulation element 103 at an angle θ5, enters the light modulation element 103 as incident light 250, and is reflected and modulated by the light modulation element 103.

  The emitted light modulated by the light modulator 103 is divided into a first emitted light 201 emitted in the α direction (first direction) and a second emitted light 201 emitted in the β direction (second direction). At least divided. The first outgoing light 200 is guided as necessary light to the projection unit 104, and the second outgoing light 201 is escaped to a position different from that of the projection unit 104 as unnecessary light and processed.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 as an angle α1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface B at an incidence angle α2, and is optically reflected at a refraction angle α3. Proceed through the element 102R.

  After that, the first outgoing light 200 reaches the boundary surface A at an angle α4 ≧ θc, is totally reflected, and goes to the boundary surface C.

  Then, the first emitted light 200 is emitted to the external environment at the boundary surface C at a refraction angle α6 and is incident on the projection unit 104.

  On the other hand, the second emitted light 201 is reflected by the light modulation element 103 as an angle β1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface B at an incident angle β2, and is optically reflected at a refraction angle β3. Proceed through the element 102R.

  After that, the second emitted light 201 reaches the boundary surface A at an angle β4 <θc and is emitted to the external environment at a refraction angle β5.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.59, specific examples of various parameters are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
θ1 = 46.0
θ2 = 26.9
θ3 = 3.1 {<θc}
θ4 = 5.0
θ5 = 5.0
α1 = 29.0
α2 = 29.0
α3 = 17.7
α4 = 47.7 {≧ θc}
α5 = 12.3
α6 = 19.8
β1 = 19.0
β2 = 19.0
β3 = 11.8
β4 = 18.2 {<< θc}
β5 = 29.8

  With the above configuration, the first emitted light 200 as the necessary light and the second emitted light 201 as the unnecessary light are clearly separated through the boundary surface A of the optical element 102R to form the second emitted light 201. It can be kept away from the first emitted light 200.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration and The optical element 102R can be made compact.

  Further, the optical system 100 can be made compact by using the same optical element 102R on the incident side and the emitting side of the light modulation element 103.

  Further, the boundary surface A of the optical element 102R reflects the first outgoing light 200 and transmits the second outgoing light 201 and the irradiation light 250. Therefore, by reflecting and transmitting at the same boundary surface, The second emitted light 201 and the irradiation light 250 can be arranged on the same side with respect to the emitted light 200, and the optical element 102R and the optical system 100 can be made compact.

  In the case where the optical system 100 according to the present embodiment described above does not have a feature in the boundary surface, the irradiation light emitted from the light source 101 is incident on the light modulation element 103 without passing through the optical elements 102 and 102R. You may. In that case, the light modulation element 103 may be configured as a transmissive type that transmits incident light in a first direction or a second direction which are different from each other and emits the light. Further, the light source 101 in the present embodiment is not limited to the LD and the LED, and other light emitting elements such as an organic EL element may be used.

  FIG. 12 is a sectional view showing an image projection device 300 as an embodiment of the present invention.

  The image projection device 300 is a front projection type projector and projects an image on the screen 400. The image projection device 300 is supposed to be mounted on an automobile, but the present invention is not limited to this, and can be used for various purposes, and can be mounted on a motorcycle, an aircraft, or the like.

  The image projection apparatus 300 shown in FIG. 12 includes a light source 101, a relay optical system 301, an optical element 102, a light modulation element 103, and a projection optical system 104.

  The light source 101, the optical element 102, the light modulation element 103, and the projection optical system 104 are the same as the light source 101, the optical elements 102 and 102R, the light modulation element 103, and the projection optical system 104 in the optical system 100 described in FIGS. Is composed of.

  The light source 101 includes three color light sources 11R, 11B, and 11G corresponding to three colors of red (R), blue (B), and green (G) in a one-to-one correspondence with the wavelength of reflected light and the wavelength of transmitted light. Dichroic mirrors 12, 13 whose light is predetermined.

  The relay optical system 301 includes a fly-eye lens 14, a condenser lens 15, and a folding mirror 16, and guides irradiation light 250 emitted from the light source 101 to the optical element 102.

  The light modulation element 103 modulates the incident light 250 based on the image data. The light modulation element 103 is composed of a DMD, and drives each micromirror on a time-division basis based on input image data to process and reflect light into an image based on the image data.

  In the above configuration, the optical element 102 reflects the irradiation light 250 guided from the relay optical system 301 at the boundary surface B and makes it incident as the incident light 250 toward the light modulation element 103.

  The light modulation element 103 drives the respective micromirrors in a time-division manner to reflect the incident light 250 in the first direction and emit the first outgoing light 200, and when the incident light 250 is directed in the second direction. The case of reflecting and emitting the second outgoing light 201 is switched. The light modulation element 103 is arranged so that the light beam of the second emitted light 201 is located on the opposite side of the light beam of the first emitted light 200 with the light beam of the incident light 250 interposed therebetween. , 201 is emitted. The optical element 102 transmits the first emission light 200 emitted from the light modulation element 103 in the first direction and transmits the second emission light 201 emitted from the light modulation element 103 in the second direction on the boundary surface. Reflect at B.

  The first emitted light 200 that has passed through the optical element 102 is guided to the projection unit 104 as ON light that forms an image based on image data, and the second emitted light 201 emitted in the second direction is an image. Re-reflection may be prevented by being treated as OFF light that does not form light, and may enter a mechanical grain or a light absorption band, for example.

  The projection unit 104 projects the first emitted light 200 onto the screen 400 to form an image (an image based on the input image data). The screen 400 may be a multi-layer array (MLA).

  With the above configuration, the first emitted light 200 as ON light that forms an image and the second emitted light 201 as OFF light that does not form an image are clearly separated via the boundary surface B of the optical element 102. As a result, the second emitted light 201 can be kept away from the first emitted light 200. Accordingly, it is possible to suppress the second emitted light 201 from entering the projection unit 104, the brightness of the screen 400 when the first emitted light 200 is emitted, and the screen when the second emitted light 201 is emitted. The difference in brightness from the brightness at 400 can be increased. Therefore, the quality of the image projected on the screen 400 can be improved.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration and The optical element 102 can be made compact.

  Further, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 are reflected by the same boundary surface B of the optical element 102. As a result, the optical system 100 can be made compact.

  Further, since the boundary surface B transmits the first outgoing light 200 and reflects the second outgoing light 201 and the irradiation light 250, the first outgoing light 200 is reflected and transmitted at the same boundary surface. On the other hand, the second emitted light 201 and the irradiation light 250 can be arranged on the same side, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 13 is a sectional view showing a sixth modification of the optical system 100 shown in FIG.

  The optical system 100 includes a second optical element 105 arranged between the optical element 102 and the light modulation element 103, in addition to the configuration shown in FIG. The second optical element 105 is composed of a cover glass arranged in parallel with the surface (substrate) of the light modulation element 103, and makes the irradiation light 205 reflected by the optical element 102 enter the light modulation element 103. The first emitted light 200 and the second emitted light 201 are made incident, and emitted toward the optical element 102.

  In the above configuration, the optical element 102 reflects the irradiation light 250 emitted from the light source 101 at the boundary surface B and makes it enter the second optical element 105. The second optical element 102 transmits the irradiation light 250 reflected by the boundary surface B of the optical element 102 and makes it enter the light modulation element 103 as incident light 250. A part of the irradiation light 250 reflected by the boundary surface B of the optical element 102 becomes the reflected light 251 reflected by the surface of the second optical element 105 without being transmitted by the second optical element 105.

  The light modulation element 103 is arranged so that the light beam of the second emitted light 201 is located on the opposite side of the light beam of the first emitted light 200 with the light beam of the incident light 250 and the reflected light 251 interposed therebetween. The emitted light 200, 201 is emitted. The second optical element 105 transmits the first emitted light 200 and the second emitted light 201 emitted from the light modulation element 103 and emits them toward the optical element 102.

  The optical element 102 transmits the first emitted light 200 on the boundary surface C and the boundary surface B, and reflects the reflected light 251 and the second emitted light 201 on the boundary surface B.

  The first outgoing light 200 that has passed through the optical element 102 is guided to the projection unit 104, enters, is projected onto the projection target, and the reflected light 251 and the second outgoing light 201 reflected by the optical element 102 are: It is treated as unnecessary light, and re-reflection is prevented by, for example, entering a mechanical grain or a light absorption band.

  With the above configuration, the reflected light 251 and the second emitted light 201 as unnecessary light can be kept away from the first emitted light 200, so that the reflected light 251 and the second emitted light 201 enter the projection unit 104. Can be suppressed. This makes it possible to increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  Therefore, even when the projection unit 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102 and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path structure and the optical element 102 can be made compact.

  Furthermore, the same optical element 102 is used on the incident side and the emitting side of the light modulation element 103, and the irradiation light 250, the second emission light 201, and the reflected light 251 from the light source 101 are formed on the same boundary surface of the optical element 102. By reflecting at B, the optical system 100 can be made compact.

  Further, the boundary surface B transmits the first outgoing light 200 and reflects the irradiation light 250, the second outgoing light 201, and the reflected light 251, so that the boundary surface B is reflected / transmitted at the same boundary surface. The emitted light 250, the second emitted light 201, and the reflected light 251 can be arranged on the same side with respect to the emitted light 200, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 14 is a sectional view showing the optical paths of the optical element 102, the second optical element 105, and the light modulation element 103 shown in FIG.

  First, the irradiation light 250 (solid line) emitted from the light source 101 is incident on the boundary surface A between the external environment having the refractive index n1 and the optical element 102 having the refractive index n2 at the incident angle θ1 and is refracted at θ2. The relationship between θ1 and θ2 follows Snell's law (n2 / n1 = sin θ1 / sin θ2). The relationship between the refractive indices n1 and n2 is n1 <n2.

  A ray having an angle component of θ2 incident on the boundary surface A reaches the boundary surface B of the optical element 102 with an angle component of θ3. At this time, since the critical angle θc of the total reflection condition is set on the boundary surface B, the light ray is totally reflected (θ3 ≧ θc: θc [= arcsin (n1 / n2) {n1 <n2}]).

  The light ray totally reflected at the boundary surface B reaches the boundary surface C of the optical element 102 at an angle θ4 and is emitted to the external environment at a refraction angle θ5.

  Then, the light passes through the second optical element 105, reaches the surface of the light modulation element 103 at an angle θ6, enters the light modulation element 103 as incident light 250, and is reflected and modulated by the light modulation element 103. ..

  The emitted light modulated by the light modulator 103 is divided into a first emitted light 200 emitted in the α direction (first direction) and a second emitted light 201 emitted in the β direction (second direction). At least divided.

  Further, at this time, the reflected light 251 reflected by the surface of the second optical element 105 without being transmitted by the second optical element 105 in the γ direction (third direction) is emitted. The first emitted light 200 is guided to the projection unit 104 as necessary light, and the second emitted light 201 and the reflected light 251 are emitted as unnecessary light to a position different from the projection unit 104 and processed.

  The first outgoing light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface C at an incidence angle α2, and has a refraction angle α3. To proceed inside the optical element 102.

  After that, the first emitted light 200 reaches the boundary surface B at an angle α4 <θc, is emitted to the external environment at a refraction angle α5, and is incident on the projection unit 104.

  On the other hand, the second outgoing light 201 (dashed-dotted line) is reflected by the light modulation element 103 toward the angle β1 formed with the normal line of the surface of the light modulation element 103. Here, the ray of the second emitted light 201 is located on the opposite side of the ray of the first emitted light 200 with the ray of the incident light 250 interposed therebetween.

  The second outgoing light 201 enters the boundary surface C at an incident angle β2, travels inside the optical element 102 at a refraction angle β3, reaches the boundary surface B at an angle β4 ≧ θc, and is totally reflected at the boundary surface B. Then, it goes to the boundary surface A.

  Then, the second emitted light 201 is emitted to the external environment at the interface A with a refraction angle β6. The second emitted light 201 is prevented from being re-reflected by, for example, entering a mechanical grain or a light absorption band.

  The reflected light 251 is reflected on the surface of the second optical element 105 at a reflection angle γ1. After that, the reflected light 251 enters the boundary surface C at an incident angle γ2, travels inside the optical element 102 at a refraction angle γ3, reaches the boundary surface B at an angle γ4 ≧ θc, and is totally reflected at the boundary surface B, Go to boundary A.

  The reflected light 251 reaches the boundary surface A at an angle γ5 and is emitted to the external environment at a refraction angle γ6. Similar to the second emitted light 201, the reflected light 251 is prevented from being re-reflected by being incident on, for example, a mechanical grain or a light absorption band.

Assuming that the refractive index of the external environment is n1 = 1.00, the refractive index of the optical element is n2 = 1.64, and the modulation angle of the light modulation element 103 is 12 degrees on one side, specific examples of various parameters are as follows.
θc = 37.6 {= arcsin (1.00 / 1.6)}
θ1 = 0
θ2 = 0
θ3 = 45.0 {≧ θc}
θ4 = 0
θ5 = 0
θ6 = 0
α1 = 24.0
α2 = 24.0
α3 = 14.3
α4 = 30.7 {<< θc}
α5 = 56.9
β1 = 24.0
β2 = 24.0
β3 = 14.3
β4 = 59.3 {≧ θc}
β5 = 14.3
β6 = 24.0
γ1 = 0
γ2 = 0
γ3 = 0
γ4 = 45.0 {≧ θc}
γ5 = 0
γ6 = 0

  Regarding the above, if the incident angles to the boundary surface B are the same or if the conditions of transmission and total reflection on the boundary surface B are satisfied, the surface reflected / scattered light other than the second optical element 105 Other unnecessary light such as can be removed.

  With the above configuration, the first emitted light 200 as the necessary light and the reflected light 251 and the second emitted light 201 as the unnecessary light are clearly separated through the boundary surface B of the optical element 102 and the reflected light 251 is obtained. Further, the second emitted light 201 can be separated from the first emitted light 200. As a result, the reflected light 251 and the second emitted light 201 can be suppressed from entering the projection unit 104, and the brightness of the projection target when the first emitted light 200 is emitted and the second emitted light 201 are emitted. It is possible to increase the brightness difference from the brightness of the projection target in the case of.

  Therefore, even when the projection unit 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102 and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path structure and the optical element 102 can be made compact.

  Further, the same optical element 102 is used on the input side and the output side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 and the reflected light 251 are on the same boundary surface of the optical element 102. By reflecting at B, the optical system 100 can be made compact.

  Further, the boundary surface B transmits the first outgoing light 200 and reflects the irradiation light 250, the second outgoing light 201, and the reflected light 251, so that the boundary surface B is reflected / transmitted at the same boundary surface. The emitted light 250, the second emitted light 201, and the reflected light 251 can be arranged on the same side with respect to the emitted light 200, and the optical element 102 and the optical system 100 can be made compact.

  Subsequently, in the case where the optical system 100 shown in FIGS. 13 and 14 is provided with the light source 101E including the LED light source optical system as shown in FIG. 4, in place of the light source 101 including the LD (laser diode), This will be described below.

Assuming that the refractive index of the external environment is n1 = 1.00 and the refractive index of the optical element is n2 = 1.641.59 and the modulation angle of the light modulation element 103 is 12 degrees on one side, specific examples of various parameters in the chief ray 120 are as follows. It becomes the street.
θc = 37.6 {= arcsin (1.00 / 1.64)}
θ1 = 0
θ2 = 0
θ3 = 45.0 {≧ θc}
θ4 = 0
θ5 = 0
θ6 = 0
α1 = 24.0
α2 = 24.0
α3 = 14.3
α4 = 30.7 {<< θc}
α5 = 56.9
β1 = 24.0
β2 = 24.0
β3 = 14.3
β4 = 59.3 {≧ θc}
β5 = 14.3
β6 = 24.0
γ1 = 0
γ2 = 0
γ3 = 0
γ4 = 45.0 {≧ θc}
γ5 = 0
γ6 = 0

Since the incident angle θ1 of the upper ray 121 with respect to the optical element 102 is inclined by 10 degrees, specific examples of various parameters of the upper ray 121 are as follows.
θ1 = 10.0
θ2 = 6.1
θ3 = 38.9 {≧ θc}
θ4 = 6.1
θ5 = 10.0
θ6 = 10.0
α1 = 14.0
α2 = 14.0
α3 = 8.5
α4 = 36.5 {<< θc}
α5 = 80.0
β1 = 34.0
β2 = 34.0
β3 = 19.9
β4 = 64.9 {≧ θc}
β5 = 19.9
β6 = 34.0
γ1 = 10.0
γ2 = 10.0
γ3 = 6.1
γ4 = 51.1 {≧ θc}
γ5 = 6.1
γ6 = 10.0

Similar to the upper ray 121, the lower ray 122 has the following specific examples of various parameters.
θ1 = 10.0
θ2 = 6.1
θ3 = 51.1 {≧ θc}
θ4 = 6.1
θ5 = 10.0
θ6 = 10.0
α1 = 34.0
α2 = 34.0
α3 = 19.9
α4 = 25.1 {<< θc}
α5 = 44.2
β1 = 14.0
β2 = 14.0
β3 = 8.5
β4 = 53.5 {≧ θc}
β5 = 8.5
β6 = 14.0
γ1 = 10.0
γ2 = 10.0
γ3 = 6.1
γ4 = 38.9 {≧ θc}
γ5 = 6.1
γ6 = 10.0

  Regarding the above, if the incident angles to the boundary surface B are the same or if the conditions of transmission and total reflection on the boundary surface B are satisfied, the surface reflected / scattered light other than the second optical element 105 Other unnecessary light such as can be removed.

  In the present embodiment, since the modulation angle of the light modulation element 103 is 12 degrees on one side, the angle formed by the extension line of the principal ray 120 of the first outgoing light 200 and the extension line of the principal ray 120 of the reflected light 251 is 24 degrees ( Half the angle is 12 degrees). On the other hand, the angle formed by the principal ray 120 of each light and the upper ray 121 or the lower ray 122 is 10 degrees.

  The angle formed by the chief ray 120 and the upper ray 121 or the lower ray 122 in each of the first outgoing light 200 and the reflected light 251 is the extension of the principal ray 120 of the first outgoing light 200 and the principal ray of the surface reflected light 251. Angles other than the above may be used as long as they are half or less of the angle formed by the extension line of the light ray 120.

  As a result, the first emitted light 200 that is the necessary light and the reflected light 251 that is the unnecessary light can be separated without being mixed at the boundary surface B of the first optical element 102, and the first emitted light 200 is emitted. In this case, the difference in brightness between the brightness of the projection target in this case and the brightness of the projection target when the second outgoing light 201 is emitted can be increased.

  FIG. 15 is a sectional view showing a seventh modification of the optical system 100 shown in FIG.

  The optical system 100 includes an optical element 102B configured by a triangular prism as in FIG. 6, in addition to the configuration shown in FIG. 13 which is the sixth modification of the optical system 100 shown in FIG. The optical element 102B transmits the first outgoing light 200 that has passed through the optical element 102, and the first outgoing light 200 that has passed through the optical element 102B is guided to the projection unit 104 and enters to be projected onto a projection target. To be done. This facilitates correction of aberrations and adjustment of the emission direction.

  16 is a cross-sectional view showing the optical paths of the optical element 102, the optical element 102B, the second optical element 105, and the light modulation element 103 shown in FIG. In the figure, the circled portion at the lower left is an enlarged view of the circled portion at the upper right.

  The optical paths of the incident light (irradiation light) 250, the second emitted light 201, and the reflected light 251 are the same as those in FIG.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, and is incident on the boundary surface C of the optical element 102 at an incidence angle α2. , Proceeds through the optical element 102 at a refraction angle α3.

Then, the first outgoing light 200 reaches the boundary surface B at an angle α4 <θc and is emitted to the external environment at a refraction angle α4 ′, and then at the boundary surface D of the optical element 102B at a refraction angle α4 ′. It is incident. The optical element 102B has a refractive index n2, and the angle formed by the boundary surface D and the boundary surface E is φ.

  An air layer having a refractive index n1 is provided between the optical element 102 and the optical element 102B, and the optical element 102 and the optical element 102B are arranged so that the boundary surface B of the optical element 102 and the boundary surface D of the optical element 102B are parallel to each other. Since they are arranged, the incident angle α4 on the boundary surface B and the refraction angle α5 on the boundary surface D are equal. The wider the air layer between the optical element 102 and the optical element 102B, the more the projected image is affected. Therefore, the distance L of the air layer is preferably 10 μm or less.

  The first emitted light 200 travels inside the optical element 102B at a refraction angle α5, reaches the boundary surface E of the optical element 102B at an angle α6 <θc, is emitted to the external environment at a refraction angle α7, and enters the projection unit 104. To be done.

Assuming that the refractive index of the external environment is n1 = 1.00, the refractive index of the optical element is n2 = 1.64, and the modulation angle of the light modulation element 103 is 12 degrees on one side, specific examples of various parameters are as follows.
θc = 37.6 {= arcsin (1.00 / 1.64)}
φ = 30.7
θ1 = 0
θ2 = 0
θ3 = 45.0 {≧ θc}
θ4 = 0
θ5 = 0
θ6 = 0
α1 = 24.0
α2 = 24.0
α3 = 14.3
α4 = 30.7 {<< θc}
α4 ′ = 56.9
α5 = 30.7
α6 = 0 {<< θc}
α7 = 0
β1 = 24.0
β2 = 24.0
β3 = 14.3
β4 = 59.3 {≧ θc}
β5 = 14.3
β6 = 24.0
γ1 = 0
γ2 = 0
γ3 = 0
γ4 = 45.0 {≧ θc}
γ5 = 0
γ6 = 0

  FIG. 17 is a sectional view showing an eighth modification of the optical system 100 shown in FIG.

  The optical system 100 is the seventh modification of the optical system 100 shown in FIG. 1 and has the structure shown in FIG. Equipped with. The optical element 102C reflects the first outgoing light 200 that has passed through the optical element 102, and the first outgoing light 200 that is reflected by the optical element 102B is guided to the projection unit 104 and is incident on the projection target. Projected

  With the above configuration, the second emitted light 201 and the reflected light 251 can be further separated from the first emitted light 200, so that the second emitted light 201 and the reflected light 251 are prevented from entering the projection unit 104. it can. As a result, it is possible to surely increase the brightness difference between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted.

  18 is a cross-sectional view showing the optical paths of the optical element 102, the optical element 102C, the second optical element 105, and the light modulation element 103 shown in FIG. In the figure, the circled portion at the lower left is an enlarged view of the circled portion at the upper right.

  The optical paths of the incident light (irradiation light) 250, the second emitted light 201, and the reflected light 251 are the same as those in FIG.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward an angle α1 formed with the normal line of the surface of the light modulation element 103, and is incident on the boundary surface C of the optical element 102 at an incidence angle α2. , Proceeds through the optical element 102 at a refraction angle α3.

Then, the first outgoing light 200 reaches the boundary surface B at an angle α4 <θc and is emitted to the external environment at a refraction angle α4 ′, and then at the boundary surface D of the optical element 102C at a refraction angle α4 ′. It is incident. The optical element 102C has a refractive index n2, and the angle between the boundary surface D and the boundary surface E is φ.

  An air layer having a refractive index n1 is formed between the optical element 102 and the optical element 102C, and the optical element 102 and the optical element 102C are arranged such that the boundary surface B of the optical element 102 and the boundary surface D of the optical element 102C are parallel to each other. Since they are arranged, the incident angle α4 on the boundary surface B and the refraction angle α5 on the boundary surface D are equal. The wider the air layer between the optical element 102 and the optical element 102C, the more the projected image is affected. Therefore, the distance L of the air layer is preferably 10 μm or less.

  The first outgoing light 200 travels inside the optical element 102C at a refraction angle α5 and reaches the boundary surface E of the optical element 102C at an angle α6 ≧ θc. After that, the first emitted light 200 is totally reflected by the boundary surface E, then reaches the boundary surface F at an angle α6 ′, is emitted to the external environment at a refraction angle α ′, and is incident on the projection unit 104. ..

Assuming that the refractive index of the external environment is n1 = 1.00, the refractive index of the optical element is n2 = 1.64, and the modulation angle of the light modulation element 103 is 12 degrees on one side, specific examples of various parameters are as follows.
θc = 37.6 {= arcsin (1.00 / 1.64)}
φ = 90.0
θ1 = 0
θ2 = 0
θ3 = 45.0 {≧ θc}
θ4 = 0
θ5 = 0
θ6 = 0
α1 = 24.0
α2 = 24.0
α3 = 14.3
α4 = 30.7 {<< θc}
α4 ′ = 56.9
α5 = 30.7
α6 = 59.3 {≧ θc}
α6 ′ = 9.3
α7 = 15.5
β1 = 24.0
β2 = 24.0
β3 = 14.3
β4 = 59.3 {≧ θc}
β5 = 14.3
β6 = 24.0
γ1 = 0
γ2 = 0
γ3 = 0
γ4 = 45.0 {≧ θc}
γ5 = 0
γ6 = 0

  With the above configuration, the second emitted light 201 and the reflected light 251 can be further separated from the first emitted light 200.

  FIG. 19 is a sectional view showing a ninth modification of the optical system 100 shown in FIG.

  The optical system 100 is the sixth modification of the optical system 100 shown in FIG. 1 and has the configuration shown in FIG. Equipped with.

  The optical element 102R reflects the first outgoing light 200 on the boundary surface A, and transmits the irradiation light 250, the reflected light 251 and the second outgoing light 201 emitted from the light source 101 on the boundary surface A and the boundary surface B. ..

  The first emitted light 200 reflected by the optical element 102R is guided to the projection unit 104, enters the projection unit 104, is projected on the projection target, and the reflected light 251 and the second emitted light 201 transmitted through the optical element 102R are: Re-reflection may be prevented by being treated as unwanted light and entering, for example, mechanical wrinkles or light absorption bands.

  Further, the light modulation element 103 is arranged so that the light beam of the second emitted light 201 is located on the opposite side of the light beam of the first emitted light 200 with the light beam of the incident light 250 interposed therebetween. Emit light 200 and 201.

  Further, the optical element 102R transmits the irradiation light 250 emitted from the light source 101 toward the light modulation element 103 as incident light 250.

  With the above configuration, the reflected light 251 and the second emitted light 201 as unnecessary light can be kept away from the first emitted light 200, so that the reflected light 251 and the second emitted light 201 enter the projection unit 104. Can be suppressed. This makes it possible to increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  Therefore, even when the projection unit 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102 and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path configuration and the optical element 102R can be made compact.

  Further, the optical system 100 can be made compact by using the same optical element 102R on the incident side and the emitting side of the light modulation element 103.

  20 is a sectional view showing the optical paths of the optical element 102R, the second optical element 105, and the light modulation element 103 shown in FIG.

  First, the irradiation light 250 (solid line) emitted from the light source enters the boundary surface A between the external environment having the refractive index n1 and the optical element 102R having the refractive index n2 at the incident angle θ1 and is refracted at θ2. The boundary surface A of the incident surface conforms to Snell's law. The relationship between the refractive indices n1 and n2 is n1 <n2.

  A ray having an angle component of θ2 incident on the boundary surface A reaches the boundary surface B of the optical element 102R with an angle component of θ3. At this time, on the boundary surface B, with respect to the critical angle θc of the total reflection condition, θ3 has the following relationship, and light is transmitted (θ3 <θc: θc [= arcsin (n1 / n2) {n1 <n2}). ).

  The light ray transmitted at the boundary surface B is emitted to the external environment at a refraction angle θ4. Then, the light passes through the second optical element 105, reaches the surface of the light modulation element 103 at an angle θ5, enters the light modulation element 103 as incident light 250, and is reflected and modulated by the light modulation element 103. ..

  The emitted light modulated by the light modulator 103 is divided into a first emitted light 200 emitted in the α direction (first direction) and a second emitted light 201 emitted in the β direction (second direction). At least divided.

  Further, at this time, the reflected light 251 reflected by the surface of the second optical element 105 without being transmitted by the second optical element 105 in the γ direction (third direction) is emitted. The first emitted light 200 is guided to the projection unit 104 as necessary light, and the second emitted light 201 and the reflected light 251 are emitted as unnecessary light to a position different from the projection unit 104 and processed.

  The first emitted light 200 (broken line) is reflected by the light modulation element 103 as an angle α1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface B at an incidence angle α2, and is optically reflected at a refraction angle α3. Proceed through the element 102R.

  After that, the first outgoing light 200 reaches the boundary surface A at an angle α4 ≧ θc, is totally reflected, and goes to the boundary surface C.

  Then, the first emitted light 200 is emitted to the external environment at the boundary surface C at a refraction angle α6 and is incident on the projection unit 104.

  On the other hand, the second emitted light 201 is reflected by the light modulation element 103 as an angle β1 formed with the normal line of the surface of the light modulation element 103, enters the boundary surface B at an incident angle β2, and is optically reflected at a refraction angle β3. Proceed through the element 102R.

  After that, the second emitted light 201 reaches the boundary surface A at an angle β4 <θc and is emitted to the external environment at a refraction angle β5.

  The reflected light 251 is reflected on the surface of the second optical element 105 at a reflection angle γ1. After that, the reflected light 251 enters the boundary surface B at an incident angle γ2, travels in the optical element 102R at a refraction angle γ3, reaches the boundary surface A at an angle γ4 <θc, and is emitted to the external environment at a refraction angle γ5. It

Assuming that the refractive index of the external environment is n1 = 1.00, the refractive index of the optical element is n2 = 1.59, and the modulation angle of the light modulation element 103 is 12 degrees on one side, specific examples of various parameters are as follows.
θc = 38.9 {= arcsin (1.00 / 1.59)}
θ1 = 46.0
θ2 = 26.9
θ3 = 3.1 {<θc}
θ4 = 5.0
θ5 = 5.0
α1 = 29.0
α2 = 29.0
α3 = 17.7
α4 = 47.7 {≧ θc}
α5 = 12.3
α6 = 19.8
β1 = 19.0
β2 = 19.0
β3 = 11.8
β4 = 18.2 {<< θc}
β5 = 29.8
γ1 = 5.0
γ2 = 5.0
γ3 = 3.1
γ4 = 33.1 {<< θc}
γ5 = 60.4

  Regarding the above, if the incident angles on the boundary surface A are the same or if the conditions of transmission and total reflection on the boundary surface A are satisfied, the surface reflection / scattered light other than the second optical element 105 Other unnecessary light such as can be removed.

  With the above configuration, the first emitted light 200 as the necessary light and the reflected light 251 and the second emitted light 201 as the unnecessary light are clearly separated through the boundary surface A of the optical element 102R to separate the reflected light 251. Further, the second emitted light 201 can be separated from the first emitted light 200.

  Therefore, even when the projection unit 104 is brought close to the optical element 102R, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102R and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path configuration and the optical element 102R can be made compact.

  Further, the optical system 100 can be made compact by using the same optical element 102R on the incident side and the emitting side of the light modulation element 103.

  The boundary surface A of the optical element 102R reflects the first emitted light 200 and transmits the irradiation light 250, the second emitted light 201, and the reflected light 251. Therefore, the boundary surface A should be reflected and transmitted at the same boundary surface. Thus, the irradiation light 250, the second emission light 201, and the reflected light 251 can be arranged on the same side with respect to the first emission light 200, and the optical element 102R and the optical system 100 can be made compact. You can

  The optical system 100 according to the present embodiment described above may cause the irradiation light emitted from the light source 101 to enter the light modulation element 103 without passing through the optical elements 102 and 102R. In that case, the light modulation element 103 may be configured as a transmissive type that transmits incident light in a first direction or a second direction which are different from each other and emits the light.

  Further, the light source 101 in the present embodiment is not limited to the LD and the LED, and other light emitting elements such as an organic EL element may be used.

  21 is a cross-sectional view showing a modified example of the image projection apparatus 300 shown in FIG.

  The image projection device 300 includes a second optical element 105 in addition to the configuration shown in FIG. The second optical element 105 has the same configuration as the second optical element 105 in the optical system 100 described with reference to FIGS.

  With the above configuration, the first emitted light 200 as ON light that forms an image and the second emitted light 201 and reflected light 251 as OFF light that does not form an image are formed via the boundary surface B of the optical element 102. The second emitted light 201 and the reflected light 251 can be clearly separated and separated from the first emitted light 200. Accordingly, the second emitted light 201 and the reflected light 251 can be suppressed from entering the projection unit 104, and the brightness in the screen 400 when the first emitted light 200 is emitted and the second emitted light 201 are emitted. The brightness difference from the brightness on the screen 400 in the case of performing can be increased. Therefore, the quality of the image projected on the screen 400 can be improved.

  Therefore, even when the projection unit 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102 and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path structure and the optical element 102 can be made compact.

  Further, the same optical element 102 is used on the input side and the output side of the light modulation element 103, and the irradiation light 250 from the light source 101 and the second emission light 201 and the reflected light 251 are the same boundary surface of the optical element 102. By reflecting at B, the optical system 100 can be made compact.

  Further, the boundary surface B transmits the first outgoing light 200 and reflects the irradiation light 250, the second outgoing light 201, and the reflected light 251, so that the boundary surface B is reflected / transmitted at the same boundary surface. The emitted light 250, the second emitted light 201, and the reflected light 251 can be arranged on the same side with respect to the emitted light 200, and the optical element 102 and the optical system 100 can be made compact.

  FIG. 22 is a diagram showing a moving body 400 equipped with an image projection device 300 according to an embodiment of the present invention.

  A vehicle (moving body) 400 includes an image projection device 300 that projects an image, and optical components 401A, 401B, and 401C (windshield) that reflect the image 301 formed by the image projection device 300, and boarded the vehicle 400. The occupant 501 can recognize it as a virtual image 600 several meters ahead. The image projection device 300 has the same configuration as the image projection device 300 described with reference to FIGS. 12 and 21.

  With the above configuration, the first emitted light 200 as ON light that forms an image and the second emitted light 201 and reflected light 251 as OFF light that does not form an image are clearly separated, and the second emitted light is separated. The emitted light 201 and the reflected light 251 can be kept away from the first emitted light 200. As a result, the second emitted light 201 and the reflected light 251 can be suppressed from entering the projection unit 104, and the brightness in the virtual image 600 when the first emitted light 200 is emitted and the second emitted light 201 are emitted. It is possible to increase the difference in brightness from the brightness in the virtual image 600 in the case of performing. Therefore, the image quality of the virtual image 600 can be improved.

  Therefore, even when the projection unit 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical element 102 and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  The light ray of the incident light 250 and the light ray of the reflected light 251 to the light modulation element 103 are arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path structure and the optical element 102 can be made compact.

  As described above, the optical system 100 according to the embodiment of the present invention irradiates the incident light 250 from the light modulation element 103 that emits the incident light 250 in the first direction or the second direction which are different from each other and the light source 101. The optical elements 102 and 102R that emit the emitted light 250 toward the light modulation element 103 as incident light 250 are emitted from the light modulation element 103 in the first direction. One of the first emitted light 200 guided to the projection target, the second emitted light 201 and the irradiation light 250 emitted in the second direction from the light modulation element 103 is transmitted, and the other is reflected. Has a boundary surface (interface).

  That is, the optical element 102 has a boundary surface (interface) B that transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiation light 250. Alternatively, the optical element 102R has a boundary surface (interface) A that reflects the first emitted light 200 and transmits the second emitted light 201 and the irradiation light 250.

  As a result, the second emitted light 201 can be moved away from the first emitted light 200, so that the influence of the second emitted light 201 on the projection target can be reduced. Further, by reflecting / transmitting at the same boundary surface between the optical elements 102 and 102R, the second outgoing light 201 and the irradiation light 250 can be arranged on the same side with respect to the first outgoing light 200. Therefore, the optical elements 102 and 102R and the optical system 100 can be made compact.

  Therefore, while making the optical system 100 compact, the difference in brightness between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted is increased. be able to.

  Therefore, even when the projection target is brought close to the optical elements 102, 102R, it is possible to prevent unnecessary light from entering the projection target, and thus it is possible to bring the optical elements 102, 102R close to the projection target. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  In addition, the optical system 100 according to the embodiment of the present invention emits the incident light 250 in the first direction and the light modulation element 103 that emits the incident light 250 in the first direction or the second direction which are different from each other. The first emitted light 200 and the optical elements 102 and 102R that transmit one of the second emitted light 201 emitted in the second direction and reflect the other, and the light beam of the second emitted light 201. However, the light modulation element 103 emits the first and second outgoing lights 200 and 201 so as to be located on the opposite side of the light beam of the first outgoing light 200 with the ray of the incident light 250 interposed therebetween.

  Specifically, on the boundary surface B of the optical element 102 or the boundary surface A of the optical element 102R, the second emitted light 201 is located on the opposite side of the first emitted light 200 with the incident light 250 interposed therebetween.

  With this configuration, since the second emitted light 201 can be kept away from the first emitted light 200, the influence of the second emitted light 201 can be reduced. Therefore, it is possible to increase the brightness difference between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted.

  Since the light ray of the incident light 250 on the light modulation element 103 is arranged between the light ray of the first emitted light 200 and the light ray of the second emitted light 201 from the light modulation element 103, the optical path configuration is changed. Can be made compact.

  In addition, the optical system 100 according to the embodiment of the present invention includes the light modulation element 103 that emits the incident light 250 in the first direction or the second direction that is different from each other, and the irradiation light emitted from the light source 101. Irradiation emitted from the optical elements 102 and 102R, which is disposed between the optical elements 102 and 102R and the optical modulation element 103, and the optical elements 102 and 102R that emit 250 as incident light 250 toward the optical modulation element 103. The optical element 102, 102R is provided with the second optical element 105 that makes the light 205 incident, and the optical elements 102 and 102R are the first emitted light 200 that is emitted from the light modulation element 103 in the first direction and is guided to the projection target. One of the reflected light 251 reflected without being transmitted by the second optical element 105 is transmitted and the other is reflected.

  As a result, the reflected light 251 can be reliably kept away from the first outgoing light 200, so that the influence of the reflected light 251 on the projection target can be reduced.

  The optical elements 102 and 102R transmit one of the first emitted light 200, the second emitted light 201 and the reflected light 251 emitted from the light modulation element 103 in the second direction, and reflect the other. To do. As a result, the second emitted light 201 and the reflected light 251 can be reliably separated from the first emitted light 200, and the influence of the second emitted light 201 and the reflected light 251 on the projection target can be reduced. ..

  The optical element 102 has a boundary surface B that transmits the first emitted light 200 and reflects the second emitted light 201 and the reflected light 251. Alternatively, the optical element 102R has a boundary surface A that reflects the first outgoing light 200 and transmits the second outgoing light 201 and the reflected light 251.

  In this way, the second outgoing light 201 and the reflected light 251 can be arranged on the same side with respect to the first outgoing light 200 by reflecting and transmitting at the same boundary surface between the optical elements 102 and 102R. It becomes possible, and the optical element 102 and the optical system 100 can be made compact.

  The optical elements 102 and 102R transmit one of the first emitted light 200, the irradiation light 25, and the reflected light 251, and reflect the other.

  The optical element 102 has a boundary surface B that transmits the first emitted light 200 and reflects the irradiation light 250 and the reflected light 251. Alternatively, the optical element 102R has a boundary surface A that reflects the first emitted light 200 and transmits the irradiation light 250 and the reflected light 251.

  In this way, by reflecting / transmitting at the same boundary surface of the optical elements 102 and 102R, it becomes possible to arrange the irradiation light 250 and the reflected light 251 on the same side with respect to the first outgoing light 200. , The optical elements 102 and 102R and the optical system 100 can be made compact.

  Then, on the boundary surface B of the optical element 102 or the boundary surface A of the optical element 102R, the second emitted light 201 is positioned on the opposite side of the first emitted light 200 with the incident light 250 and the reflected light 251 interposed therebetween. In addition, the light modulation element 103 emits the first and second emitted lights 200 and 201.

  With this configuration, since the second emitted light 201 can be kept away from the first emitted light 200, the influence of the second emitted light 201 can be reduced. Therefore, it is possible to increase the brightness difference between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted.

  The first emitted light 200 and the reflected light 251 respectively include a chief ray and an upper ray and a lower ray that form an angle with the principal ray, respectively. The angle formed by the lower ray and the angle formed by the principal ray in the reflected light 251 and the upper ray or the lower ray are formed by the extension line of the principal ray in the first outgoing light 200 and the extension line of the principal ray in the reflected light 251. Is less than half of.

  As a result, even when the optical system 100 includes the reflected light 251 having the most severe conditions, it is possible to extract the necessary light and the unnecessary light without mixing them.

  The light modulation element 103 reflects the incident light 250 and emits it in the first or second direction. As a result, the incident light 250, the first emitted light 200, and the second emitted light 201 are arranged on the front surface side of the light modulation element 103, so that the optical system 100 can be made compact.

  The light modulation element 103 is a digital micromirror device. This makes it possible to easily increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  The light modulation element 103 includes a variable region 103A that emits the incident light 250 in the first or second direction, and a fixed region 103B that fixes the incident light 250 in the second direction and emits it.

  As a result, the light emitted from the fixed region 103B is only the light parallel to the second emitted light 201 and does not include the light parallel to the first emitted light 200, and thus is guided to the projection unit 104. There is no such thing. Therefore, when the second emission light 201 is emitted from the variable region 103A as unnecessary light, the light emitted from the fixed region 103B is not projected onto the projection target and the first emission light 200 is emitted. It is possible to increase the brightness difference between the brightness of the projection target in the case of performing and the brightness of the projection target in the case of emitting the second emission light 201.

  The optical elements 102 and 102R are prisms. With this, with a simple configuration, it is possible to increase the brightness difference between the brightness of the projection target when the first outgoing light 200 is emitted and the brightness of the projection target when the second outgoing light 201 is emitted. it can.

  The optical system 100 includes a projection optical system 104 that receives the first outgoing light 200 that has passed through the optical elements 102 and 102R and projects the first outgoing light 200 onto a projection target.

  With this configuration, the second outgoing light 201 can be kept away from the first outgoing light 200, so that the second outgoing light 201 (and the reflected light 251) can be suppressed from entering the projection unit 104. This makes it possible to increase the luminance difference between the luminance of the projection target when the first emitted light 200 is emitted and the luminance of the projection target when the second emitted light 201 is emitted.

  Therefore, even when the projection unit 104 is brought close to the optical elements 102 and 102R, it is possible to prevent unnecessary light from entering the projection unit 104, and thus it is possible to bring the optical elements 102 and 102R and the projection unit 104 close to each other. This makes it possible to make the optical system 100 compact and increase the magnification to easily widen the angle of projection.

  An image projection apparatus 300 according to an embodiment of the present invention includes the optical system 100 having the above configuration, and a moving body according to an embodiment of the present invention includes the image projection apparatus 300 having the above configuration.

  With this configuration, the first emitted light 200 as ON light that forms an image and the second emitted light 201 (and reflected light 251) as OFF light that does not form an image are clearly separated, and the second emitted light 201 (and reflected light 251) is separated. The emitted light 201 can be kept away from the first emitted light 200. Thereby, the influence of the second emitted light 201 (and the reflected light 251) on the projection target can be reduced, and the brightness in the projection image when the first emitted light 200 is emitted and the second emitted light 201 are emitted. In this case, the difference in brightness from the brightness in the projected image can be increased. Therefore, the quality of the projected image can be improved.

  The light ray of the incident light 250 (and the light ray of the reflected light 251) to the light modulation element 103 is arranged between the light ray of the first emission light 200 and the light ray of the second emission light 201 from the light modulation element 103. Therefore, the optical path structure can be made compact.

  The boundary surface B of the optical element 102 or the boundary surface A of the optical element 102R transmits one of the first emitted light 200, the irradiation light 25, and the second emitted light 201 (and the reflected light 251). And reflect the other. This allows the irradiation light 250 and the second emission light 201 (and the reflection light 251) to be arranged on the same side with respect to the first emission light 200 by reflecting and transmitting at the same boundary surface. Therefore, the optical elements 102 and 102R and the optical system 100 can be made compact.

100 optical system 101 light source 102 optical element A boundary surface (interface)
B Boundary surface (interface)
103 Light Modulation Element 104 Projection Unit 105 Second Optical Element 200 First Emitted Light 201 Second Emitted Light 250 Incident Light (Irradiation Light)
251 Reflected light 300 Image projection device 400 Moving body (vehicle)

JP, 2004-258439, A JP-A-2000-258703

Claims (17)

A light modulation element for emitting incident light in a first direction or a second direction which are different from each other,
An irradiation light emitted from a light source, an optical element that emits toward the light modulation element as the incident light, an optical system comprising:
The optical element includes a first emission light emitted from the light modulation element in the first direction and guided to a projection target, and a second emission light emitted from the light modulation element in the second direction. An optical system having an interface that transmits one of the emitted light and the irradiation light and reflects the other.   The optical system according to claim 1, wherein the interface transmits the first emitted light and reflects the second emitted light and the irradiation light.   The optical system according to claim 1, wherein the interface reflects the first emitted light and transmits the second emitted light and the irradiation light.   The light modulator modulates the first and second emitted light so that the light beam of the second emitted light is located on the opposite side of the light beam of the first emitted light with the light beam of the incident light interposed therebetween. The optical system according to claim 1, wherein the optical system emits light.   The optical system according to claim 1, wherein, at the interface, the second emitted light is located on the opposite side of the first emitted light with the incident light interposed therebetween. A second optical element that is disposed between the optical element and the light modulation element and that enters the irradiation light reflected by the optical element,
The interface transmits one of the first outgoing light, the irradiation light, the second outgoing light, and reflected light obtained by reflecting the irradiation light without passing through the second optical element. The optical system according to claim 1, wherein the optical system reflects the other.   The optical system according to claim 6, wherein the interface transmits the first emitted light and reflects the second emitted light, the irradiation light, and the reflected light.   7. The optical system according to claim 6, wherein the interface reflects the first emitted light and transmits the second emitted light, the irradiation light and the reflected light.   9. The optical device according to claim 6, wherein the second outgoing light is located on the opposite side of the first outgoing light with the incident light and the reflected light interposed therebetween at the interface. system. The first emitted light and the reflected light each include a chief ray, and an upper ray and a lower ray that make an angle with the principal ray, respectively.
The angle formed by the chief ray in the first emitted light and the upper ray or the lower ray, and the angle formed by the principal ray in the reflected light and the upper ray or the lower ray are The optical system according to any one of claims 6 to 9, wherein an angle between an extension line of the principal ray in the emitted light and an extension line of the principal ray in the reflected light is equal to or less than half.   The optical system according to claim 1, wherein the light modulation element reflects incident light and emits the light in the first direction or the second direction.   The optical system according to claim 11, wherein the light modulation element is a digital micromirror device.   The light modulation element includes a variable region for emitting incident light in the first or second direction and a fixed region for fixing incident light in the second direction and emitting the fixed light. The optical system according to any one of 1 to 12.   The optical system according to claim 1, wherein the optical element is a prism.   The optical system according to any one of claims 1 to 14, further comprising a projection optical system that receives the first emitted light that has passed through the optical element and projects the first emitted light onto a projection target.   An image projection apparatus, comprising the optical system according to claim 1, and projecting an image.   A moving body comprising the image projection device according to claim 16.