JP7346964B2 - Optical system, image projection device and moving object - Google Patents

Description

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

With the advent of the multimedia era, image projection devices are being used in every scene. In recent years, it has been used not only for front projection type projectors but also for signage and head-up displays (HUDs) mounted on vehicles, and the market field is expanding. Optical systems that incorporate DMD (digital micromirror devices) as light modulation elements have become mainstream in their construction, and are becoming smaller, lighter, brighter, and have a higher dynamic range (higher contrast). There is.

In Patent Document 1, in a projection display device having a reflective light modulator, an illumination optical system for the reflective light modulator includes a light shielding system that blocks unnecessary light by shielding a part of one side cross section of a luminous flux of the illumination optical system. A configuration is disclosed in which a plate is provided in an optical path of an illumination optical system so that it can be inserted into and removed from the optical path.

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

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

The optical system according to claim 1 of the present invention includes a light modulation element that emits incident light in a first direction or a second direction that is different from each other, and a light modulation element that emits incident light in a first direction or a second direction that is different from each other. An optical system comprising: an optical element that emits light toward a modulation element; a first output light that is emitted from the light modulation element in a first direction and is guided to a projection target; It has an interface that transmits one of the second emitted light and the irradiated light emitted in the second direction and reflects the other, and the ray of the second emitted light is sandwiched between the ray of the incident light and the irradiated light. The light modulation element emits the first and second emitted light so as to be located on the opposite side of the beam of the first emitted light, is disposed between the optical element and the light modulation element, and is reflected by the optical element. The interface includes a second optical element that receives the irradiated light, and the interface is such that the first emitted light, the irradiated light, the second emitted light, and the irradiated light are reflected by the second optical element without being transmitted. It is characterized by transmitting one of the reflected light and reflecting the other .

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

1 is a cross-sectional view showing an optical system 100 as an embodiment of the present invention. 2 is a cross-sectional view showing the optical path of the optical element 102 and the light modulation element 103 shown in FIG. 1. FIG. 2 is a diagram showing a detailed configuration of the light modulation element 103 shown in FIG. 1. FIG. 2 is a sectional view showing a partial configuration of a modification of the optical system 100 shown in FIG. 1. FIG. 1. It is a 2nd modification of the optical system 100 shown in FIG. 1, Comprising: It is sectional drawing which shows the optical path of the optical element 102 and the light modulation element 103M. 2 is a sectional view showing a third modification of the optical system 100 shown in FIG. 1. FIG. 7 is a cross-sectional view showing optical paths of optical element 102, optical element 102B, and light modulation element 103 shown in FIG. 6. FIG. 3 is a cross-sectional view showing a fourth modification of the optical system 100 shown in FIG. 1. 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. 3 is a cross-sectional view showing a fifth modification of the optical system 100 shown in FIG. 1. FIG. 11 is a cross-sectional view showing the optical path of the optical element 102R and the light modulation element 103 shown in FIG. 10. FIG. 1 is a cross-sectional view showing an image projection device 300 as an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a sixth modification of the optical system 100 shown in FIG. 1. FIG. 14 is a cross-sectional view showing the optical path of the optical element 102, the light modulation element 103, and the second optical element 105 shown in FIG. 13. FIG. 3 is a cross-sectional view showing a seventh modification of the optical system 100 shown in FIG. 1. FIG. 16 is a cross-sectional view showing optical paths of optical element 102, optical element 102B, second optical element 105, and light modulation element 103 shown in FIG. 15. FIG. FIG. 3 is a cross-sectional view showing an eighth modification of the optical system 100 shown in FIG. 1. FIG. 18 is a cross-sectional view showing 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. 17. FIG. FIG. 3 is a cross-sectional view showing a ninth modification of the optical system 100 shown in FIG. 1. FIG. 20 is a cross-sectional view showing optical paths of the optical element 102R, the second optical element 105, and the light modulation element 103 shown in FIG. 19. FIG. 13 is a sectional view showing a modification of the image projection device 300 shown in FIG. 12. FIG. 1 is a diagram showing a vehicle 400 equipped with an image projection device 300 as an embodiment of the present invention.

FIG. 1 is a sectional view showing an optical system 100 as an 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 the incident light in a first direction or a second direction that is different from each other. , and 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 that correspond one-to-one to the three colors of red (R), blue (B), and green (G), and the wavelength and transmission of the reflected light. The dichroic mirror includes a dichroic mirror that emits light of a predetermined wavelength.

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

The light modulation element 103 is constituted by a DMD (digital micromirror device) having a substantially rectangular mirror surface made up 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 the reflected light 250 enter the light modulation element 103 as incident light 250. A relay optical system may be provided between the light source 101 and the optical element 102 to guide the irradiation light 250 emitted from the light source 101 to the optical element 102.

By time-divisionally driving each micromirror, the light modulation element 103 reflects the incident light 250 in a first direction and outputs the first output light 200, and also reflects the incident light 250 in the second direction. A case where the second emitted light 201 is emitted after reflection is switched. The light modulation element 103 transmits the first and second emitted light 200 such that the second emitted light 201 is located on the opposite side of the first emitted light 200 with the incident light 250 interposed therebetween. , 201 are emitted.

The optical element 102 transmits the first emitted light 200 emitted from the light modulation element 103 in a first direction through the interface C and the interface B, and transmits the first emitted light 200 emitted from the light modulation element 103 in the second direction. The emitted light 201 of No. 2 is reflected by the boundary surface B.

The first output light 200 that has passed through the optical element 102 is guided to the projection unit 104 and is projected onto the projection target, and the second output light 201 that is reflected by the optical element 102 is treated as unnecessary light. For example, re-reflection is prevented by entering mechanical grains or light absorption bands.

With the above configuration, it is possible to move the second emitted light 201 away from the first emitted light 200, so it is possible to suppress the second emitted light 201 from entering the projection unit 104. Thereby, it is possible to increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

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

Furthermore, the same optical element 102 is used on the incident side and the output side of the light modulation element 103, and the irradiated light 250 from the light source 101 and the second emitted light 201 are reflected at the same boundary surface B of the optical element 102. By doing so, the optical system 100 can be made compact.

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiated light 250, the first emitted light 200 is reflected and transmitted through the same boundary surface. On the other hand, it becomes possible to arrange the second emitted light 201 and the irradiated light 250 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 path of the optical element 102 and the light modulation element 103 shown in FIG. 1.

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

A light beam having an angular component of θ2 that is incident on the boundary surface A reaches the boundary surface B of the optical element 102 with an angular component of θ3. At this time, at the boundary surface B, θ3 has the following relationship 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 at 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.

The light then 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 modulation element 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). Minimally divided. The first emitted light 200 is guided to the projection section 104 as necessary light, and the second emitted light 201 is emitted as unnecessary light to a position different from the projection section 104 and processed.

The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward the angle α1 formed with the normal to the surface of the light modulation element 103, and enters the boundary surface C at an incident angle α2, and is refracted at an angle α3. It advances inside the optical element 102.

Thereafter, 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 emitted light 201 (dotted chain line) is reflected by the light modulation element 103 toward the angle β1 formed with the normal to 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 emitted light 201 enters the boundary surface C at an incident angle β2, travels through 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. and heads toward boundary surface A.

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

Assuming that the refractive index of the external environment n1=1.00 and the refractive index of the optical element 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 necessary light and the second emitted light 201 as unnecessary light are clearly separated through the boundary surface B of the optical element 102, and the second emitted light 201 is It can be kept away from the first emitted light 200. Thereby, it is possible to suppress the second emitted light 201 from entering the projection unit 104, and the brightness at the projection target when the first emitted light 200 is emitted and the projection when the second emitted light 201 is emitted. It is possible to increase the difference in brightness from the brightness in the object.

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

Furthermore, the same optical element 102 is used on the incident side and the output side of the light modulation element 103, and the irradiated light 250 from the light source 101 and the second emitted light 201 are reflected at the same boundary surface B of the optical element 102. By doing so, the optical system 100 can be made compact.

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiated light 250, the first emitted light 200 is reflected and transmitted through the same boundary surface. On the other hand, it becomes possible to arrange the second emitted light 201 and the irradiated light 250 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. 1. 3(a) shows a top view of the light modulation element 103, and FIG. 3(b) shows a cross-sectional view of the light modulation element 103.

The light modulation element 103 includes a variable region 103A that modulates incident light 250 in a first or second direction and outputs the modulated light, and is arranged so as to surround the variable region 103A, and modulates the incident light 250 in the second direction without modulating it. It includes a fixed region 103B that emits light while being fixed to.

As explained in FIGS. 1 and 2, the first emitted light 200 emitted from the light modulation element 103 in the first direction is guided to the projection section 104, enters the projection section 104, and is projected onto the projection target. The second emitted light 201 emitted from the modulation element 103 in the second direction is treated as unnecessary light.

In this embodiment, the light emitted from the fixed area 103B is only parallel to the second emitted light 201, and does not include light parallel to the first emitted light 200, so it is guided to the projection unit 104. It will never be illuminated.

As a result, when the second emitted 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 emitted light 200 is It is possible to increase the difference in brightness between the brightness at the projection target when emitting the second emitted light 201 and the brightness at the projection target when the second emitted light 201 is emitted.

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

The 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 an LD (laser diode) shown in FIG.

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

In this modification, 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, but the upper ray 121 and the lower ray 122 also The same content as the irradiation light 250 holds true.

Assuming that the refractive index of the external environment n1=1.00 and the refractive index of the optical element 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 upper ray 121 has the same meaning that the incident angle θ1 with respect to the optical element 102 is inclined by 10 degrees, specific examples of various parameters for 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 light ray 121, the lower light ray 122 has specific examples of various parameters as follows.
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 necessary light and the second emitted light 201 as unnecessary light are clearly separated through the boundary surface B of the optical element 102, and the second emitted light 201 is It can be kept away from the first emitted light 200. Thereby, it is possible to suppress the second emitted light 201 from entering the projection unit 104, and the brightness at the projection target when the first emitted light 200 is emitted and the projection when the second emitted light 201 is emitted. It is possible to increase the difference in brightness from the brightness in the object.

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

Furthermore, the same optical element 102 is used on the incident side and the output side of the light modulation element 103, and the irradiated light 250 from the light source 101 and the second emitted light 201 are reflected at the same boundary surface B of the optical element 102. By doing so, the optical system 100 can be made compact.

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiated light 250, the first emitted light 200 is reflected and transmitted through the same boundary surface. On the other hand, it becomes possible to arrange the second emitted light 201 and the irradiated light 250 on the same side, and the optical element 102 and the optical system 100 can be made compact.

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

The optical system 100 shown in FIG. 5 includes a light modulation element 103M made of MEMS instead of the light modulation element 103 made of a DMD (laser diode) shown in FIG.

The emitted light modulated by the light modulation element 103M is scanned between the α direction (first direction) and the β direction (second direction). That is, as in FIG. 2, the output light modulated by the light modulation element 103M includes a first output light 200 that is output in the α direction (first direction) and a first output light 200 that is output in the β direction (second direction). The third output light 202 is emitted in the γ direction (third direction).

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

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

The third emitted light 202 is reflected by the light modulation element 103M toward the angle γ1 formed with the normal to the surface of the light modulation element 103M, and enters the boundary surface C of the optical element 102 at an incident angle γ2, and the refraction angle It advances inside the optical element 102 at γ3.

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

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

Specific examples of various parameters under the conditions that the scanning range of the light modulation element 103M is 24 degrees (±12 degrees), the refractive index of the external environment n1 = 1.00, and the refractive index of the optical element n2 = 1.59 are as follows. It will be 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
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 necessary light and the second emitted light 201 as unnecessary light are clearly separated through the boundary surface B of the optical element 102, and the second emitted light 201 is It can be kept away from the first emitted light 200. Thereby, it is possible to suppress the second emitted light 201 from entering the projection unit 104, and the brightness at the projection target when the first emitted light 200 is emitted and the projection when the second emitted light 201 is emitted. It is possible to increase the difference in brightness from the brightness in the object.

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

Furthermore, the same optical element 102 is used on the incident side and the output side of the light modulation element 103M, and the irradiated light 250 from the light source 101 and the second emitted light 201 are reflected at the same boundary surface B of the optical element 102. By doing so, the optical system 100 can be made compact.

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiated light 250, the first emitted light 200 is reflected and transmitted through the same boundary surface. On the other hand, it becomes possible to arrange the second emitted light 201 and the irradiated light 250 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.

In addition to the configuration shown in FIG. 1, the optical system 100 includes an optical element 102B configured with a triangular prism. 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, enters it, and is projected onto the projection target. be done. This facilitates correction of aberrations and adjustment of the emission direction.

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. 6. In the figure, the part circled at the bottom left is an enlarged view of the part circled at the top right.

The optical paths of the incident light (irradiation light) 250 and the second emitted light 201 are the same as those in FIG. 2, so their description will be omitted.

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

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 α4', and then reaches the boundary surface (interface) D of the optical element 102B at a refraction angle It is incident at α4'. The optical element 102B has a refractive index n2, and the angle between the boundary surface D and the boundary surface (interface) E is φ.

There is an air layer with a refractive index n1 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 interface B of the optical element 102 and the interface D of the optical element 102B are parallel to each other. Therefore, the angle of incidence α4 on the boundary surface B and the angle of refraction 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 it affects the projected image, so the distance L of the air layer is preferably 10 μm or less.

The first emitted light 200 travels through 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. be done.

Assuming that the refractive index of the external environment n1=1.00 and the refractive index of the optical element 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. 1.

The optical system 100 includes an optical element 102C formed of a triangular prism in place of the optical element 102B shown in FIG. The optical element 102C reflects the first output light 200 that has passed through the optical element 102, and the first output light 200 reflected by the optical element 102B is guided to the projection unit 104 and enters the projection target. projected

With the above configuration, it is possible to move the second emitted light 201 further away from the first emitted light 200, so it is possible to suppress the second emitted light 201 from entering the projection unit 104. Thereby, it is possible to reliably increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

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. In the figure, the part circled at the bottom left is an enlarged view of the part circled at the top right.

The optical paths of the incident light (irradiation light) 250 and the second emitted light 201 are the same as those in FIG. 2, so their description will be omitted.

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

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

There is an air layer with a refractive index n1 between the optical element 102 and the optical element 102C, and the optical element 102 and the optical element 102C are arranged so that the interface B of the optical element 102 and the interface D of the optical element 102C are parallel to each other. Therefore, the angle of incidence α4 on the boundary surface B and the angle of refraction α5 on the surface D are equal. The wider the air layer between the optical element 102 and the optical element 102C, the more it affects the projected image, so the distance L between the air layer is preferably 10 μm or less.

The first emitted light 200 travels through 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. Thereafter, the first emitted light 200 is totally reflected at the boundary surface E, reaches the boundary surface (interface) F at an angle α6', is emitted to the external environment at a refraction angle α', and reaches the projection unit 104. It is incident.

Assuming that the refractive index of the external environment n1=1.00 and the refractive index of the optical element 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 moved further away from the first emitted light 200.

FIG. 10 is a sectional view showing a fifth modification of the optical system 100 shown in FIG. 1. The optical system 100 includes an optical element 102R formed of a triangular prism in place of the optical element 102 shown in FIG.

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

The first output light 200 reflected by the optical element 102R is guided to the projection unit 104 and is projected onto the projection target, and the second output light 201 that has passed through the optical element 102R is treated as unnecessary light. For example, re-reflection may be prevented by entering a mechanical grain or a light absorption band.

Further, the light modulation element 103 is arranged such that the light beam of the second output light 201 is located on the opposite side of the light beam of the first output 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, it is possible to move the second emitted light 201 away from the first emitted light 200, so it is possible to suppress the second emitted light 201 from entering the projection unit 104. Thereby, it is possible to increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

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

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

FIG. 11 is a cross-sectional view showing the optical path of the optical element 102R and the light modulation element 103 shown in FIG. 10.

First, irradiation light 250 (solid line) emitted from a light source is incident on the interface A between the external environment having a refractive index n1 and the optical element 102R having a refractive index n2 at an incident angle θ1, and is refracted at an angle θ2. At the boundary surface A of this entrance surface, Snell's law is followed. Note that the relationship between the refractive indices n1 and n2 is n1<n2.

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

The light beam transmitted through the boundary surface B is emitted to the external environment at a refraction angle θ4. The light then 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 modulation element 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). Minimally divided. The first emitted light 200 is guided to the projection section 104 as necessary light, and the second emitted light 201 is emitted as unnecessary light to a position different from the projection section 104 and processed.

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

Thereafter, the first emitted light 200 reaches the boundary surface A at an angle α4≧θc, is totally reflected, and heads toward the boundary surface C.

Then, the first emitted light 200 is emitted to the external environment at a refraction angle α6 at the boundary surface C, 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 at an angle β1 with the normal to the surface of the light modulation element 103, enters the boundary surface B at an incident angle β2, and is optically reflected at an angle β3 of refraction. Proceed inside the element 102R.

Thereafter, 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 n1=1.00 and the refractive index of the optical element 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 necessary light and the second emitted light 201 as unnecessary light are clearly separated through the interface A of the optical element 102R, and the second emitted light 201 is It can be kept away from the first emitted light 200.

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

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

Furthermore, since the boundary surface A of the optical element 102R reflects the first emitted light 200 and transmits the second emitted light 201 and the irradiated light 250, the first It becomes possible to arrange the second emitted light 201 and the irradiated light 250 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 optical system 100 according to the present embodiment described above, when the boundary surface has no characteristics, 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 the incident light in a first direction or a second direction, which are different directions, and outputs the light. Furthermore, the light source 101 in this embodiment is not limited to LDs and LEDs, but may also use other light emitting elements such as organic EL elements.

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

Image projection device 300 is a front projection type projector and projects an image onto screen 400. Although the image projection device 300 is assumed to be installed in a car, it is not limited to this, and can be used for various purposes, and can also be installed in a motorcycle, an airplane, etc.

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, optical element 102, light modulation element 103, and projection optical system 104 are the same as the light source 101, optical elements 102, 102R, light modulation element 103, and projection optical system 104 in the optical system 100 described with reference to FIGS. It is composed of

The light source 101 includes three color light sources 11R, 11B, and 11G that correspond one-to-one to the three colors of red (R), blue (B), and green (G), and the wavelengths of reflected light and transmitted light. It includes dichroic mirrors 12 and 13 in which 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.

Light modulation element 103 modulates incident light 250 based on image data. The light modulation element 103 is composed of a DMD, and processes and reflects light into an image based on the image data by time-divisionally driving each micromirror based on input 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 enter the light modulation element 103 as incident light 250.

By time-divisionally driving each micromirror, the light modulation element 103 reflects the incident light 250 in a first direction and outputs the first output light 200, and also reflects the incident light 250 in the second direction. A case where the second emitted light 201 is emitted after reflection is switched. The light modulation element 103 transmits the first and second emitted light 200 such that the second emitted light 201 is located on the opposite side of the first emitted light 200 with the incident light 250 interposed therebetween. , 201 are emitted. The optical element 102 transmits the first emitted light 200 emitted from the light modulation element 103 in a first direction, and transmits the second emitted light 201 emitted from the light modulation element 103 in a second direction to a 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 that is emitted in the second direction forms an image. The light may be treated as OFF light that does not form any light, and may prevent re-reflection by, for example, entering a mechanical grain or a light absorption band.

The projection unit 104 projects the first emitted light 200 onto the screen 400 to form an image (an image based on input image data). 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 through the boundary surface B of the optical element 102 and the second emitted light 201 as OFF light that does not form an image can be clearly separated. Thus, the second emitted light 201 can be moved away from the first emitted light 200. Thereby, it is possible to suppress the second emitted light 201 from entering the projection unit 104, and the brightness on 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 onto the screen 400 can be improved.

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

Furthermore, the same optical element 102 is used on the incident side and the output side of the light modulation element 103, and the irradiated light 250 from the light source 101 and the second emitted light 201 are reflected at the same boundary surface B of the optical element 102. By doing so, the optical system 100 can be made compact.

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the second emitted light 201 and the irradiated light 250, the first emitted light 200 is reflected and transmitted through the same boundary surface. On the other hand, it becomes possible to arrange the second emitted light 201 and the irradiated light 250 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. 1.

In addition to the configuration shown in FIG. 1, the optical system 100 includes a second optical element 105 arranged between the optical element 102 and the light modulation element 103. The second optical element 105 is composed of a cover glass arranged parallel to the surface (substrate) of the light modulation element 103, and allows the illumination light 205 reflected by the optical element 102 to enter the light modulation element 103. At the same time, the first outgoing light 200 and the second outgoing light 201 are incident and emitted towards 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 irradiated light 250 reflected at the boundary surface B of the optical element 102 becomes reflected light 251 that is reflected at the surface of the second optical element 105 without being transmitted through the second optical element 105.

The light modulation element 103 is arranged such 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 output lights 200 and 201 are 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 at the interface C and the interface B, and reflects the reflected light 251 and the second output light 201 at the interface B.

The first output light 200 that has passed through the optical element 102 is guided to the projection unit 104 and is projected onto the projection target, and the reflected light 251 and the second output light 201 that are reflected by the optical element 102 are It is treated as unnecessary light, and is prevented from being reflected again by, for example, entering mechanical grains or light absorption bands.

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. Thereby, it is possible to increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

Therefore, even when the projection section 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102 and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the irradiated light 250, the second emitted light 201, and the reflected light 251, the first It becomes possible to arrange the irradiated light 250, the second emitted light 201, and the reflected light 251 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 cross-sectional view showing the optical path of the optical element 102, second optical element 105, and light modulation element 103 shown in FIG. 13.

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

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

The light beam totally reflected by 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, it 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 modulation element 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). Minimally divided.

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

The first emitted light 200 (broken line) is reflected by the light modulation element 103 toward the angle α1 formed with the normal to the surface of the light modulation element 103, and enters the boundary surface C at an incident angle α2, and is refracted at an angle α3. It advances inside the optical element 102.

Thereafter, 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 emitted light 201 (dotted chain line) is reflected by the light modulation element 103 toward the angle β1 formed with the normal to 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 emitted light 201 enters the boundary surface C at an incident angle β2, travels through 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. and heads toward boundary surface A.

Then, the second emitted light 201 is emitted to the external environment at the boundary surface A with a refraction angle β6. The second emitted light 201 is prevented from being reflected again 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. Head towards boundary surface 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, for example, entering a mechanical grain or a light absorption band.

Assuming that the refractive index of the external environment n1 = 1.00, the refractive index of the optical element 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 match and the conditions for transmission and total reflection on the boundary surface B are satisfied, surface reflection/scattered light other than the second optical element 105 Other unnecessary light can also be removed.

With the above configuration, the first emitted light 200 as necessary light, the reflected light 251 as unnecessary light, and the second emitted light 201 are clearly separated through the boundary surface B of the optical element 102, and the reflected light 251 And the second emitted light 201 can be moved away from the first emitted light 200. Thereby, it is possible to suppress the reflected light 251 and the second emitted light 201 from entering the projection unit 104, and the brightness at the projection target when the first emitted light 200 is emitted and the second emitted light 201 is emitted. It is possible to increase the difference in brightness between the brightness of the projection target and the brightness of the projection target.

Therefore, even when the projection section 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102 and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the irradiated light 250, the second emitted light 201, and the reflected light 251, the first It becomes possible to arrange the irradiated light 250, the second emitted light 201, and the reflected light 251 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.

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

Assuming that the refractive index of the external environment n1 = 1.00 and the refractive index of the optical element n2 = 1.641.59, 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 will be as follows.
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 upper ray 121 has the same meaning that the incident angle θ1 with respect to the optical element 102 is inclined by 10 degrees, specific examples of various parameters for 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 light ray 121, the lower light ray 122 has specific examples of various parameters as follows.
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 match and the conditions for transmission and total reflection on the boundary surface B are satisfied, surface reflection/scattered light other than the second optical element 105 Other unnecessary light can also be removed.

In this embodiment, since the modulation angle of the light modulation element 103 is 12 degrees on one side, the angle formed by the extension of the principal ray 120 of the first emitted light 200 and the extension of the principal ray 120 of the reflected light 251 is 24 degrees ( The half 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 between the principal ray 120 and the upper ray 121 or the lower ray 122 of each of the first emitted light 200 and the reflected light 251 is the extension line of the principal ray 120 of the first emitted light 200 and the principal ray of the surface reflected light 251. An angle other than the above may be used as long as it is half or less of the angle formed by the extension of the light ray 120.

As a result, the first emitted light 200, which is necessary light, and the reflected light 251, which is unnecessary light, can be separated without mixing at the boundary surface B of the first optical element 102, and the first emitted light 200 is emitted. It is possible to increase the difference in brightness between the brightness at the projection target when the second emitted light 201 is emitted and the brightness at the projection target when the second emitted light 201 is emitted.

FIG. 15 is a sectional view showing a seventh modification of the optical system 100 shown in FIG. 1.

In addition to the configuration shown in FIG. 13, which is a sixth modification of the optical system 100 shown in FIG. 1, the optical system 100 includes an optical element 102B formed of a triangular prism as in FIG. 6. 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, enters it, and is projected onto the projection target. be done. This facilitates correction of aberrations and adjustment of the emission direction.

FIG. 16 is a cross-sectional view showing optical paths of optical element 102, optical element 102B, second optical element 105, and light modulation element 103 shown in FIG. 15. In the figure, the part circled at the bottom left is an enlarged view of the part circled at the top 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 in FIG. 14, and therefore their description will be omitted.

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

After that, the first output light 200 reaches the interface B with an angle α4<θc, is emitted to the external environment with a refraction angle α4', and then reaches the interface D of the optical element 102B with a refraction angle α4'. It is incident. The optical element 102B has a refractive index n2, and the angle between the boundary surface D and the boundary surface E is φ.

There is an air layer with a refractive index n1 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 interface B of the optical element 102 and the interface D of the optical element 102B are parallel to each other. Therefore, the angle of incidence α4 on the boundary surface B and the angle of refraction 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 it affects the projected image, so the distance L of the air layer is preferably 10 μm or less.

The first emitted light 200 travels through 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. be done.

Assuming that the refractive index of the external environment n1 = 1.00, the refractive index of the optical element 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. 1.

The optical system 100 has the configuration shown in FIG. 15, which is a seventh modification of the optical system 100 shown in FIG. Equipped with The optical element 102C reflects the first output light 200 that has passed through the optical element 102, and the first output light 200 reflected by the optical element 102B is guided to the projection unit 104 and enters the projection target. projected

With the above configuration, the second emitted light 201 and the reflected light 251 can be moved further away from the first emitted light 200, thereby suppressing the second emitted light 201 and the reflected light 251 from entering the projection unit 104. can. Thereby, it is possible to reliably increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

FIG. 18 is a cross-sectional view showing 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. 17. In the figure, the part circled at the bottom left is an enlarged view of the part circled at the top 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 in FIG. 14, and therefore their description will be omitted.

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

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

There is an air layer with a refractive index n1 between the optical element 102 and the optical element 102C, and the optical element 102 and the optical element 102C are arranged so that the interface B of the optical element 102 and the interface D of the optical element 102C are parallel to each other. Therefore, the angle of incidence α4 on the boundary surface B and the angle of refraction 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 it affects the projected image, so the distance L between the air layer is preferably 10 μm or less.

The first emitted light 200 travels through 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. Thereafter, the first emitted light 200 is totally reflected at the boundary surface E, 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 n1 = 1.00, the refractive index of the optical element 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 moved further away from the first emitted light 200.

FIG. 19 is a sectional view showing a ninth modification of the optical system 100 shown in FIG. 1.

The optical system 100 has the configuration shown in FIG. 13, which is a sixth modification of the optical system 100 shown in FIG. Equipped with

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

The first outgoing light 200 reflected by the optical element 102R is guided to the projection unit 104 and is projected onto the projection target, and the reflected light 251 and the second outgoing light 201 that have passed through the optical element 102R are as follows. The light may be treated as unnecessary light, and 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 such that the light beam of the second output light 201 is located on the opposite side of the light beam of the first output 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. Thereby, it is possible to increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

Therefore, even when the projection section 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102 and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

FIG. 20 is a cross-sectional view showing optical paths of the optical element 102R, the second optical element 105, and the light modulation element 103 shown in FIG. 19.

First, irradiation light 250 (solid line) emitted from a light source is incident on the interface A between the external environment having a refractive index n1 and the optical element 102R having a refractive index n2 at an incident angle θ1, and is refracted at an angle θ2. At the boundary surface A of this entrance surface, Snell's law is followed. Note that the relationship between the refractive indices n1 and n2 is n1<n2.

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

The light beam transmitted through the boundary surface B is emitted to the external environment at a refraction angle θ4. The light then 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 modulation element 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). Minimally divided.

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

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

Thereafter, the first emitted light 200 reaches the boundary surface A at an angle α4≧θc, is totally reflected, and heads toward the boundary surface C.

Then, the first emitted light 200 is emitted to the external environment at a refraction angle α6 at the boundary surface C, 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 at an angle β1 with the normal to the surface of the light modulation element 103, enters the boundary surface B at an incident angle β2, and is optically reflected at an angle β3 of refraction. Proceed inside the element 102R.

Thereafter, 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. Thereafter, the reflected light 251 enters the boundary surface B at an incident angle γ2, travels inside 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. Ru.

Assuming that the refractive index of the external environment n1 = 1.00, the refractive index of the optical element 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 to the boundary surface A match and the conditions for transmission and total reflection on the boundary surface A are satisfied, surface reflection/scattered light other than the second optical element 105 Other unnecessary light can also be removed.

With the above configuration, the first emitted light 200 as necessary light and the reflected light 251 and second emitted light 201 as unnecessary light are clearly separated through the interface A of the optical element 102R, and the reflected light 251 And the second emitted light 201 can be moved away from the first emitted light 200.

Therefore, even when the projection section 104 is brought close to the optical element 102R, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102R and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

In addition, the boundary surface A of the optical element 102R reflects the first emitted light 200 and transmits the irradiated light 250, the second emitted light 201, and the reflected light 251, so that the reflection and transmission occur at the same boundary surface. Therefore, it becomes possible to arrange the irradiated light 250, the second emitted light 201, and the reflected light 251 on the same side with respect to the first emitted light 200, and the optical element 102R and the optical system 100 can be made compact. Can be done.

The optical system 100 according to the present embodiment described above may allow 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 the incident light in a first direction or a second direction, which are different directions, and outputs the light.

Furthermore, the light source 101 in this embodiment is not limited to LDs and LEDs, but may also use other light emitting elements such as organic EL elements.

FIG. 21 is a sectional view showing a modification of the image projection device 300 shown in FIG. 12.

Image projection device 300 includes a second optical element 105 in addition to the configuration shown in FIG. The second optical element 105 is configured similarly to the second optical element 105 in the optical system 100 described with reference to FIGS. 13 to 20.

With the above configuration, the first emitted light 200 as ON light that forms an image through the boundary surface B of the optical element 102, and the second emitted light 201 and reflected light 251 as OFF light that does not form an image. It is possible to clearly separate the second emitted light 201 and the reflected light 251 from the first emitted light 200. Thereby, it is possible to suppress the second emitted light 201 and the reflected light 251 from entering the projection unit 104, and the brightness on the screen 400 when the first emitted light 200 is emitted and the second emitted light 201 is emitted. It is possible to increase the difference in brightness from the brightness on the screen 400 when the screen 400 is used. Therefore, the quality of the image projected onto the screen 400 can be improved.

Therefore, even when the projection section 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102 and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

In addition, since the boundary surface B transmits the first emitted light 200 and reflects the irradiated light 250, the second emitted light 201, and the reflected light 251, the first It becomes possible to arrange the irradiated light 250, the second emitted light 201, and the reflected light 251 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 as 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 (windshields) that reflect an image 301 formed by the image projection device 300. The rider 501 can recognize it as a virtual image 600 several meters away. Image projection device 300 is configured similarly to image projection device 300 described with reference to FIGS. 12 and 21.

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

Therefore, even when the projection section 104 is brought close to the optical element 102, it is possible to suppress unnecessary light from entering the projection section 104, so that it is possible to bring the optical element 102 and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

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

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

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 irradiated 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 irradiated light 250.

Thereby, 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. Furthermore, by reflecting and transmitting light at the same boundary surface of the optical elements 102 and 102R, it is possible to arrange the second emitted light 201 and the irradiated light 250 on the same side with respect to the first emitted light 200. Therefore, the optical elements 102, 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 at the projection target when the first output light 200 is emitted and the brightness at the projection target when the second output light 201 is output is increased. be able to.

Therefore, even when the projection target is brought close to the optical elements 102, 102R, it is possible to suppress unnecessary light from entering the projection target, so it is possible to bring the optical elements 102, 102R and the projection target close to each other. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

Further, the optical system 100 according to an embodiment of the present invention includes a light modulation element 103 that emits the incident light 250 in a first direction or a second direction that is different from each other; Optical elements 102 and 102R that transmit one of the first emitted light 200 and the second emitted light 201 emitted in the second direction and reflect the other, the ray of the second emitted light 201 The light modulation element 103 emits the first and second output lights 200 and 201 such that the first output light 200 is positioned on the opposite side of the first output light 200 across the input light 250.

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, the second emitted light 201 can be moved away from the first emitted light 200, so the influence of the second emitted light 201 can be reduced. Therefore, it is possible to increase the difference in brightness between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

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

Further, the optical system 100 according to an embodiment of the present invention includes a light modulation element 103 that emits incident light 250 in a first direction or a second direction that is different from each other, and an irradiation light irradiated from the light source 101. 250 as incident light 250 toward the light modulation element 103; The optical elements 102 and 102R include a second optical element 105 into which light 205 enters, and the optical elements 102 and 102R are equipped with a first output light 200 that is output from the light modulation element 103 in the first direction and guided to the projection target, and a second optical element 105 that receives the light 205. One of the reflected light 251 that was reflected without being transmitted by the second optical element 105 is transmitted, and the other is reflected.

This makes it possible to reliably move the reflected light 251 away from the first emitted light 200, thereby reducing the influence of the reflected light 251 on the projection target.

The optical elements 102 and 102R transmit one of the first emitted light 200 and the second emitted light 201 and reflected light 251 emitted from the light modulation element 103 in the second direction, and reflect the other. do. Thereby, the second emitted light 201 and the reflected light 251 can be reliably kept away 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 emitted light 200 and transmits the second emitted light 201 and the reflected light 251.

In this way, by reflecting and transmitting at the same boundary surface of the optical elements 102 and 102R, the second emitted light 201 and the reflected light 251 can be placed on the same side with respect to the first emitted light 200. This makes it possible to make the optical element 102 and the optical system 100 more compact.

The optical elements 102 and 102R transmit one of the first emitted light 200, the irradiated 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 irradiated 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 irradiated light 250 and the reflected light 251.

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

Then, at 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. The light modulation element 103 emits first and second emitted lights 200 and 201.

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

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

Thereby, even if the optical system 100 includes reflected light 251, which has the most severe conditions, it is possible to extract necessary light and unnecessary light without mixing them.

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

Light modulation element 103 is a digital micromirror device. Thereby, the brightness difference between the brightness at the projection target when the first output light 200 is emitted and the brightness at the projection target when the second output light 201 is output can be easily increased.

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

As a result, the light emitted from the fixed area 103B is only parallel to the second emitted light 201 and does not include light parallel to the first emitted light 200, so that the light is not guided to the projection unit 104. It never happens. Therefore, when the second emitted 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 emitted light 200 is emitted. It is possible to increase the difference in brightness between the brightness at the projection target when the second emitted light 201 is emitted and the brightness at the projection target when the second emitted light 201 is emitted.

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 at the projection target when the first output light 200 is emitted and the brightness at the projection target when the second output light 201 is output. can.

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

With this configuration, the second emitted light 201 can be kept away from the first emitted light 200, and therefore the second emitted light 201 (and the reflected light 251) can be suppressed from entering the projection unit 104. Thereby, it is possible to increase the brightness difference between the brightness at the projection target when the first output light 200 is output and the brightness at the projection target when the second output light 201 is output.

Therefore, even when the projection section 104 is brought close to the optical elements 102, 102R, it is possible to suppress unnecessary light from entering the projection section 104, making it possible to bring the optical elements 102, 102R and the projection section 104 close together. This makes it possible to make the optical system 100 compact and to easily widen the projection target by increasing the magnification.

An image projection device 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 device 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. The emitted light 201 can be moved away from the first emitted light 200. Thereby, the influence of the second emitted light 201 (and reflected light 251) on the projection target can be reduced, and the brightness in the projected image when the first emitted light 200 is emitted and the second emitted light 201 is emitted. The brightness difference between the brightness and the brightness in the projected image can be increased. Therefore, the quality of the projected image can be improved.

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

Further, 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 and the irradiated light 25 and the second emitted light 201 (and reflected light 251). and reflect the other. This allows the irradiated light 250 and the second emitted light 201 (and reflected light 251) to be placed on the same side with respect to the first emitted light 200 by reflecting and transmitting at the same boundary surface. Therefore, the optical elements 102, 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 (irradiated light)
251 Reflected light 300 Image projection device 400 Moving body (vehicle)

Japanese Patent Application Publication No. 2004-258439 Japanese Patent Application Publication No. 2000-258703

Claims (15)

a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
The light modulation element directs the first and second emitted light such that the second emitted light is located on the opposite side of the first emitted light with the incident light ray interposed therebetween. Emits ,
The optical system is characterized in that the interface transmits the first emitted light and reflects the second emitted light and the irradiated light . a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
The light modulation element directs the first and second emitted light such that the second emitted light is located on the opposite side of the first emitted light with the incident light ray interposed therebetween. Emits ,
a second optical element disposed between the optical element and the light modulation element, into which the irradiation light reflected by the optical element is incident;
The interface transmits one of the first emitted light, the irradiated light, the second emitted light, and reflected light that is the irradiated light that is reflected without being transmitted through the second optical element. An optical system characterized by reflecting one object and the other . a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
The interface reflects the first emitted light and transmits the second emitted light and the irradiated light,
a second optical element disposed between the optical element and the light modulation element, into which the irradiation light reflected by the optical element is incident;
The interface transmits one of the first emitted light, the irradiated light, the second emitted light, and reflected light that is the irradiated light that is reflected without being transmitted through the second optical element. An optical system characterized by reflecting one object and the other . 4. 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. 4. The optical system according to claim 2 , wherein the interface transmits the first emitted light and reflects the second emitted light, the irradiated light, and the reflected light. a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
a second optical element disposed between the optical element and the light modulation element, into which the irradiation light reflected by the optical element is incident;
The interface transmits one of the first emitted light, the irradiated light, the second emitted light, and reflected light that is the irradiated light that is reflected without being transmitted through the second optical element. and reflect the other,
The optical system is characterized in that the interface reflects the first emitted light and transmits the second emitted light, the irradiated light, and the reflected light. Any one of claims 2, 3, 5, and 6 , characterized in that, at the interface, the second emitted light is located on the opposite side of the first emitted light with the incident light and the reflected light interposed therebetween. or the optical system described. a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
a second optical element disposed between the optical element and the light modulation element, into which the irradiation light reflected by the optical element is incident;
The interface transmits one of the first emitted light, the irradiated light, the second emitted light, and reflected light that is the irradiated light that is reflected without being transmitted through the second optical element. and reflect the other,
The first emitted light and the reflected light each include a principal ray, and an upper ray and a lower ray each making an angle with the principal ray,
The angle formed by the principal 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 An optical system characterized in that the angle formed by the extension line of the principal ray in the emitted light and the extension line of the principal ray in the reflected light is less than half. 9. The optical system according to claim 1, wherein the light modulation element reflects incident light and emits it in the first or second direction. 10. The optical system according to claim 9 , wherein the light modulation element is a digital micromirror device. a light modulation element that emits incident light in a first direction or a second direction that is different from each other;
An optical system comprising: an optical element that emits illumination light emitted from a light source toward the light modulation element as the incident light,
The optical element emits first light emitted from the light modulation element in the first direction and guided to the projection target, and second light emitted from the light modulation element in the second direction. having an interface that transmits one of the emitted light and the irradiated light and reflects the other;
The optical system is characterized in that the light modulation element includes a variable region that emits incident light in the first or second direction, and a fixed region that emits the incident light while fixing it in the second direction. . The optical system according to claim 1, wherein the optical element is a prism. 13. The optical system according to claim 1, further comprising a projection optical system that receives the first output light that has passed through the optical element and projects it onto a projection target. An image projection device comprising the optical system according to claim 1 and projecting an image. A moving body comprising the image projection device according to claim 14 .

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