JP6928781B2 - Projection type image display device - Google Patents

Description

The present disclosure relates to a projection type image display device using a light source device including a light source that emits blue excitation light and a light emitting body that emits light in response to the excitation light.

Patent Document 1 provides a blue laser light emitter as an excitation light source, diffuses the emitted light from the excitation light source by a diffuser plate, and uses the diffused light as a light source light in the blue wavelength band. A projector capable of projecting a high-quality color image by providing a light source device having a wide wavelength distribution in the light source light is disclosed.

Japanese Unexamined Patent Publication No. 2011-128521

The present disclosure provides a projection type image display device capable of optimizing the chromaticity of blue light.

The projection type image display device of the present disclosure has a solid-state light source that emits blue light having a first wavelength band, and is located on a longer wavelength side than the first wavelength band by irradiation with blue light, and is in the first wavelength band. A wheel having a light emitter that emits light emitted in an adjacent second wavelength band, blue light, a light homogenizing element that homogenizes the emitted light, and light that modulates the light homogenized by the light homogenizing element. A dichroic film that includes a modulation element and a projection unit that projects light modulated by an optical modulation element, partially reflects blue light on the incident side of the blue light of the illuminant, and transmits the emitted light. Is formed.

According to the present disclosure, the chromaticity of blue light displayed on a projection type image display device can be improved.

The figure which shows the projection type image display device in Embodiment 1. The figure which shows the phosphor wheel in Embodiment 1. The figure which shows the principle of color generation (yellow and green) in Embodiment 1. The figure which shows the principle of color generation (blue) in Embodiment 1. The figure which shows the color wheel in Embodiment 1. Spectral diagram of yellow component light in the projection type image display device of the first embodiment Spectral diagram of green component light in the projection type image display device of the first embodiment Spectral diagram of blue component light in the projection type image display device of the first embodiment The figure which shows the chromaticity diagram for demonstrating the effect of Embodiment 1. The figure which shows the phosphor wheel in Embodiment 2. The figure which shows the principle of color generation (blue) in Embodiment 2. The figure which shows the color wheel in Embodiment 2.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[Embodiment 1]
(Projection type video display device)
Hereinafter, the configuration of the projection type image display device according to the first embodiment will be described with reference to FIGS. 1 to 6. FIG. 1 is a diagram showing an optical configuration of the projection type image display device 100 according to the first embodiment. In the first embodiment, when red component light R, green component light G, blue component light B (first blue component light B ₁ + second blue component light B ₂ ), and yellow component light Y are used as the image light. Illustrate.

As shown in FIG. 1, first, the projection type image display device 100 includes a light source unit 10, a dichroic mirror 20, a phosphor wheel 30, a λ / 4 plate 40, a color wheel 50, and a rod integrator 60. A DMD (Digital Mirror Device) 70, and a projection unit 80.

The light source unit 10 is composed of, for example, a plurality of solid-state light sources such as a laser diode (LD: Laser Diode) and a light emitting diode (LED: Light Emitting Diode). In this embodiment, a laser diode, particularly a laser diode 11 that emits blue light, is used as a solid-state light source.

The light emitted from the light source unit 10 is blue light having a wavelength of 455 nm, and is used as image light (first blue component light B ₁ ) and also as excitation light for exciting a phosphor. However, the wavelength of the light emitted from the light source unit 10 is not limited to 455 nm, and may be, for example, a wavelength of 440 to 460 nm. The wavelength of this blue light is an example of the first wavelength band.

The blue light emitted from the light source unit 10 passes through the lens 111, the lens 112, and the diffuser plate 141 and is incident on the dichroic mirror 20. The dichroic mirror 20 reflects the first blue component light B ₁ (excitation light). The first blue component light B ₁ reflected by the dichroic mirror 20 is focused by the lenses 113 and 114 to excite the phosphor of the phosphor wheel 30 to emit light.

Further, the light emitted from the light source unit 10 is S-polarized light, and the dichroic mirror 20 reflects the first blue component light B ₁ (S-polarized light) and emits yellow light Y Y emitted by the phosphor wheel 30. , Green emitted light G ₁ and the first blue component light B ₁ (P-polarized light) reflected by the phosphor wheel are transmitted. That is, the dichroic mirror 20 reflects the first blue component light B ₁ of the S polarized light and transmits emitted light Y and green emission light G ₁ Yellow first blue component light B ₁ and unpolarized light of P-polarized light ..

As shown in FIG. 2, the phosphor wheel 30 comprises a substrate 31, a reflective film 32 formed on the substrate 31, a phosphor film 33 formed by coating on the reflective film 32 in an annular shape, and the substrate 31. It is composed of a motor 35 for rotating. FIG. 2A is a view of the phosphor wheel viewed in the −x direction of FIG. 1, and FIG. 2B is a view of the phosphor wheel viewed in the z direction of FIG.

Further, as shown in FIG. 2, a dielectric multilayer film 34 is formed on the phosphor film 33. As shown in FIG. 2A, the phosphor film 33 is composed of a yellow fluorescent film 33Y, a first green fluorescent film 33G _1, and a second green fluorescent film 33G ₂ . .. As shown in FIG. 2A, the dielectric multilayer film 34 is composed of an antireflection film 34C and a blue partial reflection film 34B. In FIG. 2A, the parenthesized code means that the component of the code without parentheses is located on the upper layer side thereof. That is, the reflective film 32 is arranged on the substrate 31, the _{antireflection film 34C is arranged on each of the yellow fluorescent film 33Y and the first green fluorescent film 33G 1} , and the second green fluorescent film 33G is arranged. It shows that the blue partial reflection film 34B is arranged on the _2. The phosphor film 33 is an example of a light emitter, and the phosphor wheel 30 is an example of a wheel.

The phosphor film 33 can be produced, for example, by mixing ceramic phosphor powder with an adhesive (silicone resin), applying it to a substrate, and curing it at a high temperature. Examples of the ceramic phosphor used for the phosphor film 33 include a YAG phosphor and a LAG phosphor, which are active garnet-structured phosphors with cerium.

As shown in FIG. 2A, the phosphor wheel 30 is composed of four segments in the circumferential direction. The first segment (angle region θ _R ) is a region for generating the red component light R. The second segment (angle region θ _G ) is a region for generating the green component light G. The third segment (angle region θ _B ) is a region for generating the blue component light B. The fourth segment (angle region θ _Y ) is a region for generating the yellow component light Y.

The yellow phosphor film 33Y has a phosphor Y that emits yellow emission light Y in response to _{the first blue component light B 1} (excitation light) emitted from the light source unit 10. The yellow phosphor film 33Y is formed in a fourth segment and a first segment (predetermined angle region θ _Y + θ _R ) in the annular region in which the phosphor film 33 is formed. _{The yellow phosphor film 33Y is a region to which the first blue component light B 1} (excitation light) is irradiated while the phosphor wheel 30 is rotating. In other words, on the yellow phosphor film 33Y, first blue component light _{B 1} by the lens 114 is focused.

The first green phosphor layer 33G ₁ has a phosphor G ₁ for emitting green light beam G ₁ according to the first blue component light B _{1 (excitation} light) emitted from the light source unit 10. The first green phosphor film 33G ₁ is formed in the second segment (predetermined angle region θ _G ) of the annular region in which the phosphor film 33 is formed. The first green phosphor film 33G _{1 is a region to which the first blue component light B 1} (excitation light) is irradiated while the phosphor wheel 30 is rotating. In other words, the first _{blue component light B 1} is focused by the lens 114 on _{the first green phosphor film 33G 1.}

Second green phosphor layer 33G ₂ has a phosphor G ₂ for emitting green light beam G ₂ according to the first blue component light B _{1 (excitation} light) emitted from the light source unit 10. At this time, the green emitted light G _{2 includes the second blue component light B 2} for adjusting the chromaticity of the blue component light B which is the image light. The second green phosphor film 33G ₂ is formed in a third segment (predetermined angle region θ _B ) of the annular region in which the phosphor film 33 is formed. The blue partial reflection film 34B reflects a part of the incident first blue component light B ₁ (excitation light), transmits the rest, and transmits the green emission light G ₂ . The blue partial reflection film 34B is an example of a dichroic film. The second green phosphor film 33G _{2 is a region to which the first blue component light B 1} (excitation light) is irradiated while the phosphor wheel 30 is rotating. In other words, the first blue component light B ₁ is focused by the lens 114 on the second green phosphor film 33G _2.

Next, the principle of color generation in the peripheral portion of the phosphor wheel 30 will be described with reference to FIGS. 3A and 3B.

FIG. 3A shows a case where the first blue component light B ₁ (excitation light) is irradiated to any _{of the angular regions θ Y} , θ _R , and θ _{G of the phosphor wheel 30.} In the present embodiment, the S-polarized first blue component light B ₁ (excitation light L1) is emitted from the light source unit 10. Excitation light L1 by passing through the lambda / 4 plate 40, a first blue component light _{B 1} of the circularly polarized light (excitation light L2). The excitation light L2 passes through the antireflection film 34C (excitation light L3a), and due to the effect of the antireflection film 34C, the excitation light L3a maintains a light intensity of 95% or more of the excitation light L2, and the yellow phosphor film 33Y. Alternatively, the first green phosphor film 33G ₁ is irradiated.

The yellow phosphor film 33Y or the first green phosphor film 33G ₁ emits yellow emission light Y or green emission light G ₁ when irradiated with excitation light L3a. Emitting light Y and green emission light G ₁ of yellow, but is emitted in full 360 ° -direction, the light emitted toward the substrate 31 is reflected by the reflection film 32. Therefore, it emitted light Y and green emission light G ₁ yellow is emitted to the traveling direction of the excitation beam L3a toward the lambda / 4 plate 40 in the opposite direction. The yellow emitted light Y and the green emitted light G ₁ are unpolarized because they are fluorescent light, and are unpolarized even if they pass through the λ / 4 plate 40.

FIG. 3B shows a case where the first blue component light B ₁ (excitation light) is applied to _{the angle region θ B of the phosphor wheel 30.} In the present embodiment, the S-polarized first blue component light B ₁ (excitation light L1) is emitted from the light source unit 10. Excitation light L1 by passing through the lambda / 4 plate 40, a first blue component light _{B 1} of the circularly polarized light (excitation light L2). 35% of the excitation light L2 passes through the blue partial reflection film 34B to become the excitation light L3b and irradiates the _{second green phosphor film 33G 2.} The remaining 65% of the excitation light L2 is reflected by the blue partial reflection film 34B to become the image light L4.

The second green phosphor film 33G ₂ emits green emission light G ₂ when irradiated with the first blue component light B ₁ (L3b). The green emitted light G ₂ is emitted in all directions of 360 °, and the light emitted in the direction toward the substrate 31 is reflected by the reflective film 32. Therefore, the green light emitting light G ₂ is emitted toward the λ / 4 plate 40 in the direction opposite to the traveling direction of the excitation light L3b. Blue partial reflection film 34B is transmitted through the green light beam _{G 2.} That is, the blue partial reflection film 34B, the first blue wavelength band of the light component _{B 1} to 35% transmittance (65% reflection) of light (455 nm), green wavelength band of the emission light _{G 2} of (460～750Nm) It is a dichroic film that transmits light. Further, the image light L4 reflected by the blue partial reflection film 34B is a first blue component light B ₁ similarly circularly polarized light and the pumping light L2, by passing through the lambda / 4 plate 40 again, the P-polarized light It becomes the first blue component light B ₁ (image light L5). The transmittance of the blue partial reflective film 34B should be adjusted as necessary, and may be in the range of 10 to 60%.

As described above, the light emitted through the dichroic mirror 20 emits yellow light Y in the angle region θ _Y + θ _{R and} green light in _{the angle region θ G as the phosphor wheel 30 rotates.} In the light G ₁ and the angle region θ _B , the first blue component light B ₁ (image light L5) and the green emission light G ₂ are combined light.

Returning to FIG. 1, the light emitted from the dichroic mirror 20 passes through the lens 131, is reflected by the mirror 124, the optical path is bent in the perpendicular direction, passes through the lens 132, and is incident on the color wheel 50.

As shown in FIG. 4, the color wheel 50 includes a transparent substrate 51, a dielectric multilayer film 52 formed on the substrate 51, and a motor 53 for rotating the substrate 51. FIG. 4A is a view of the color wheel viewed in the z direction of FIG. 1, and FIG. 4B is a view of the color wheel viewed in the −y direction of FIG.

As shown in FIG. 4, the dielectric multilayer film 52 has _{a red transmissive dichroic film 52R formed in a predetermined angle region θ R} (first segment) and a predetermined angle region θ _G (second segment). Antireflection formed in the formed green transmissive dichroic film 52G, _{the blue transmissive dichroic film 52B formed in the predetermined angle region θ B} (third segment), and the predetermined angle region θ _Y (fourth segment). It is composed of a film 52C.

The color wheel 50 is controlled so that its rotation is synchronized with the phosphor wheel 30. That is, at the timing when the light is incident on the angle region θ _R of the phosphor wheel 30, the light is incident on the angle region θ _R of the color wheel 50. At the timing when the light is incident on the angle region θ _G of the phosphor wheel 30, the light is incident on the angle region θ _G of the color wheel 50. At the timing when the light is incident on the angle region θ _B of the phosphor wheel 30, the light is incident on the angle region θ _B of the color wheel 50. At the timing when the light is incident on the angle region θ _Y of the phosphor wheel 30, the light is incident on the angle region θ _Y of the color wheel 50.

In this way, the light generated by the phosphor wheel 30 and the color wheel 50 in the angle regions θ _R , θ _G , θ _B , and θ _Y is emitted in a time-division manner. That is, each color component light including the red component light R, the green component light G, the blue component light B, and the yellow component light Y is generated by the phosphor wheel 30 and the color wheel 50 and emitted in a time-divided manner.

The color generation in each angle region (segment) will be described below with reference to the spectra shown in FIGS. 5A to 5C.

In the angle region θ _R , yellow emission light Y (solid line in FIG. 5A) is emitted from the yellow phosphor film 33Y of the phosphor wheel 30, and is transmitted through the red transmissive dichroic film 52R of the color wheel 50 to form a red component. Light R (broken line in FIG. 5A). By adjusting the spectral characteristics of the red transmission dichroic film 52R of the color wheel 50, the color purity of the red component light R can be adjusted.

In the angular region θ _G , the green emission light G _{1 (solid line in FIG. 5B) is emitted from the first green phosphor film 33G 1} of the phosphor wheel 30, and is transmitted through the green transmissive dichroic film 52G of the color wheel 50. As a result, the green component light G (broken line in FIG. 5B) is obtained. By adjusting the spectral characteristics of the green transmissive dichroic film 52G of the color wheel 50, the color purity of the green component light G can be adjusted.

In the angular region θ _B , the green emission light G ₂ (the green emission light G ₂ includes the second blue component light B _{2 ) from the second} green phosphor film 33 G 2 of the phosphor wheel 30 and blue. _{The first blue component light B 1} reflected by the partial reflection film 34B is synthesized and transmitted through the blue transmissive dichroic film 52B of the color wheel 50 to become the blue component light B. The blue transmissive dichroic film 52B extracts the second blue component light B _{2 by transmitting the first blue component light B 1} and transmitting the short wavelength side of the green light emitting light G _2. The second blue component light B ₂ is adjusted to the optimum blue chromaticity by mixing with the first blue component light B _{1 having a wavelength of 455 nm.} Here, the wavelength band of 460 nm to 750 nm, which is the wavelength band of the green emitted light G _{2, is an example of the second wavelength band.}

In the present embodiment, the main wavelength of the second blue component light B ₂ is 515 nm, but the present invention is not limited to this. _{It is desirable to select the second green phosphor film 33G 2} and design the spectral characteristics of the blue transmissive dichroic film 52B so that the main wavelength of the second blue component light B ₂ is within the range of 470 to 530 nm. _{The wavelength band of the second blue component light B 2 having} a main wavelength of 515 nm in the present embodiment, 460 to 560 nm, is an example of the third wavelength band. In FIG. 5C, the _{scale of the first blue component light B 1} is 1/100. The second green phosphor film 33G ₂ of the phosphor wheel 30 may be the same as or different from the first green phosphor film 33G _1.

In the angular region θ _Y , yellow emission light Y is emitted from the yellow phosphor film 33Y of the phosphor wheel 30, and passes through the antireflection film 52C of the color wheel 50 to become yellow component light Y. The change in color due to the yellow emitted light Y passing through the antireflection film 52C of the color wheel 50 is at a negligible level.

Returning to FIG. 1, the light emitted from the color wheel 50 is incident on the rod integrator 60. The rod integrator 60 is a solid rod made of a transparent member such as glass. The rod integrator 60 equalizes the light emitted from the light source unit 10 and the light emitted from the phosphor wheel 30. The rod integrator 60 may be a hollow rod whose inner wall is formed of a mirror surface. The rod integrator 60 is an example of a light homogenizing element.

The light emitted from the rod integrator 60 passes through the lens 151, the lens 152, and the lens 153, is incident on the total reflection prism composed of the triangular prism 161 and the triangular prism 162, and then is incident on the DMD 70.

The DMD 70 modulates each color component light generated by the light source unit 10, the phosphor wheel 30, and the color wheel 50 in a time division manner. Specifically, the DMD 70 is composed of a plurality of micromirrors, and the plurality of micromirrors are movable. Each micromirror basically corresponds to one pixel. The DMD 70 switches whether or not to reflect light to the projection unit 80 side by a modulation operation that changes the angle of each minute mirror according to the video signal.

The DMD 70 expresses the gradation of each color corresponding to _{the angle regions θ R} , θ _G , θ _B , and θ _Y described with reference to FIGS. 2 and 4. That is, the red component light R (image light) is modulated during the time when the angle region θ _{R is irradiated with light.} During the time when the angle region θ _G is irradiated with light, the green component light G (image light) is modulated. During the time when the angle region θ _B is irradiated with light, the blue component light B (image light) is modulated. During the time when the angle region θ _Y is irradiated with light, the yellow component light Y (image light) is modulated. The DMD 70 is an example of a light modulation element.

The video light modulated by the DMD 70 passes through the triangular prisms 161 and 162 and is incident on the projection unit 80. The image light incident on the projection unit 80 is magnified and projected on a screen (not shown).

FIG. 6 shows a chromaticity diagram, and as shown in this chromaticity diagram, the color gamut A of the projection type image display device 100 of the present embodiment includes sRGB (only each color point is shown in FIG. 6). You can see that it is doing. The chromaticity of the second blue component light B ₂ is a point indicated by a triangle in FIG. 6, and the blue chromaticity is optimized by mixing the color with _{the first blue component light B 1.}

On the other hand, it can be seen that the color gamut B in the case where only the first blue component light B ₁ is used as the image light without using the second blue component light B _{2 has a region that does not include sRGB.}

(Action and effect)
In the first embodiment, by forming the blue partial reflection film 34B on the second green phosphor film 33G ₂ , the second blue component light B ₂ can be mixed with _{the first blue component light B 1, and the second blue component light B 2 can be mixed.} gamut including sRGB that could not be included in 1 blue component light B ₁ is be realized.

[Embodiment 2]
In the second embodiment, the fluorescent wheel 37 and the color wheel 57 are used instead of the fluorescent wheel 30 and the color wheel 50 described in the first embodiment, and the other configurations are the same as those in the first embodiment. The description will be omitted.

FIG. 7 is a diagram showing a phosphor wheel 37 used in the second embodiment. In the first embodiment, as shown in FIG. 2, a part of the first blue component light B _{1 is formed on the surface of the second} green phosphor film 33G _{2 formed in the angular region θ B of the phosphor wheel 30.} the transmitted and reflected residual, the green light beam G ₂ to form a blue partial reflection film 34B of property of transmitting, extracted by the color wheel 50, green from emitting light G ₂ second blue component light B ₂ structure Was supposed to be. In the second embodiment, as shown in FIG. 7, a part of the first blue component light B _{1 is formed on the surface of the second} green phosphor film 33G _{2 formed in the angular region θ B of the phosphor wheel 37.} A dichroic film 38B having a characteristic of transmitting and reflecting the residue and transmitting the short wavelength side (second blue component light B _{2 ) of the green emission light G 2 is formed.} In the angular region θ _B , as shown in FIG. 8, the dichroic film 38B extracts the second blue component light B _{2 from the green luminescent light G 2.}

FIG. 9 shows a color wheel 57 used in the second embodiment, in which the color wheel 57 rotates a transparent substrate 51, a dielectric multilayer film 52 formed on the substrate 51, and the substrate 51. It is composed of a motor 53 for the purpose. FIG. 9A is a view of the color wheel 57 viewed in the z direction of FIG. 1, and FIG. 9B is a view of the color wheel 57 viewed in the −y direction of FIG.

In the first embodiment, as shown in FIG. 4, in the angular region theta _B of the color wheel 50, blue light transmission dichroic film 52B was formed. In the second embodiment, as shown in FIG. 9, an antireflection film 52C is formed in _{the angle region θ B} of the color wheel 57 as in the angle region θ _Y. That is, the color change due to the first blue component light B ₁ and the second blue component light B ₂ emitted from the phosphor wheel 37 passing through the antireflection film 52C in the angle region θ _{B of the color wheel 57 is negligible.} Is.

[Other embodiments]
As described above, Embodiments 1 and 2 have been described as examples of the techniques disclosed in the present application. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. have been made. It is also possible to combine the components described in the first and second embodiments to form a new embodiment. Therefore, other embodiments will be illustrated below.

In the first and second embodiments, the DMD 70 is exemplified as the light modulation element, but the embodiment is not limited to this. The light modulation element may be one liquid crystal panel or three liquid crystal panels (red liquid crystal panel, green liquid crystal panel and blue liquid crystal panel). The liquid crystal panel may be a transmissive type or a reflective type.

In the first and second embodiments, the phosphor wheel is exemplified as the phosphor that generates the emitted light, but the embodiment is not limited to this. The phosphor may be a static inorganic phosphor ceramic.

Since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent scope thereof.

The present disclosure can be applied to a projection type image display device such as a projector.

10 Light source unit 20 Dichroic mirror 30, 37 Fluorescent wheel 31 Substrate 32 Reflective film 33 Fluorescent film 33Y Yellow phosphor film 33G ₁ First green phosphor film 33G ₂ Second green phosphor film 34 Dielectric multilayer film 34C Anti-reflective coating 34B Blue partial anti-reflective coating 35,53 Motor 38B Dichroic coating 40 λ / 4 plate 50,57 Color wheel 52 Dielectric multilayer film 52C Anti-reflective coating 51 Substrate 60 Rod integrator 70 DMD
80 Projection unit 100 Projection type image display device 111, 112, 113, 114 Lens 124 Mirror 131, 132 Lens 141 Diffusing plate 151, 152, 153 Lens 161, 162 Triangular prism

Claims (1)

A solid-state light source that emits blue light having a first wavelength band,
By irradiation of the blue light, is in the first long wavelength side than the wavelength band of, have a light emitter for emitting luminescent light of the second wavelength band adjacent to the first wavelength band, the light emitter A wheel having a dichroic film formed on the incident side of the blue light
The blue light, a light homogenizing element that homogenizes the emitted light, and the like.
An optical modulation element that modulates the light homogenized by the optical homogenization element, and
A projection unit that projects light modulated by the light modulation element is provided.
The emitted light in the second wavelength band includes light in a third wavelength band adjacent to the first wavelength band.
The light in the third wavelength band is blue component light having a main wavelength in the range of 470 to 530 nm.
The dichroic film partially reflects the blue light and transmits the emitted light including the blue component light, and generates blue light in which the blue light and the blue component light are mixed. , Projection type image display device.

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