JP2011175077A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector in which light can be utilized effectively by preventing blue light from a blue illuminant from being reflected from a color wheel. <P>SOLUTION: The blue light from the blue illuminant 21 is made incident on the color wheel 25 through a lens 23 and an integrator rod 24. The color wheel 25 is composed of a portion of a green phosphor layer and a transparent portion. When the blue light enters the green phosphor layer, green light is generated. The blue light and the green light transmit through the color wheel 25 and a dichroic mirror 26 and are processed time-sequentially in a digital micromirror device 29 together with the red light from a red illuminant 22. An image is projected on a screen 31 through a projection optical system 30. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projector for enlarging and projecting a display image by a projection optical system to obtain a display image on a large screen, and more particularly to a projector using a color wheel as a filter element of a time division type spectroscopic device. .

  Projectors (projection-type image display devices) that are used in home theaters, presentations, and the like to enlarge and project a display image using a projection optical system and obtain a large-screen display image have been commercialized. Some projectors display an image on a screen via an electro-optical device using a spatial light modulator such as a digital micromirror device or a liquid crystal display element using light emitted from a light source as illumination light. . Some projectors use a high-pressure mercury lamp or a xenon lamp as a light source, but they are not preferable because of mercury content and heat generation. Therefore, in recent years, projectors using light emitting diodes (LEDs) and lasers have been devised.

For example, there is a projector of Casio Computer Co., Ltd. exhibited at the International CES (Consumer Electronics Show) (2010), which is a consumer electronics trade show held in the United States, using LEDs and lasers. Here, an LED is used as a red light source, a blue laser is used as a blue light source, and a phase and wavelength of a blue laser are converted as a green light source (hereinafter, this type of projector is referred to as a “hybrid type”).
In such a projector, a color wheel that rotates at high speed is generally used as a time-division filter element (see, for example, Patent Document 1).
Further, in such a projector, there is a projector that uses an integrator rod in order to effectively use light from a light source (for example, Patent Document 2).

JP 2004-341105 A Japanese Patent No. 3589225 (paragraph 0020, FIG. 8)

  FIG. 8 shows a schematic diagram of the color composition method of the hybrid projector. In FIG. 8, a projector 100 includes a blue light source 1, a red light source 2, a color wheel 5, dichroic mirrors 3, 8, lenses 4, 9, mirrors 6, 7, a digital micromirror device 10 as a spatial light modulator, projection optics. A system 11 and a screen 12 are provided. The blue light (B) emitted from the blue light source 1 passes through the dichroic mirror 3 and the lens 4 that transmit the blue light, and is applied to the color wheel 5. The main body of the color wheel 5 is a metal disk, and a phosphor that emits green light (G) (hereinafter referred to as “green phosphor”) is formed in a part of the circumferential direction of the color wheel 5. The blue light passes through a portion where the green phosphor is not provided (circumferential cutout portion of the color wheel main body), passes through the dichroic mirror 8, is collected by the lens 9, and is collected on the digital micromirror device 10. Reach.

  Part of the blue light reflected from the color wheel 5 returns to the blue light source 1 side. When blue light is irradiated onto the green phosphor, green light is emitted. This green light is reflected by the dichroic mirror 3 that reflects the green light through the lens 4, and is further reflected by the mirrors 6 and 7 and the dichroic. The light is reflected by the mirror 8, collected by the lens 9, and reaches the digital micromirror device 10.

The red light (R) from the red light source 2 passes through the dichroic mirror 3, is reflected by the mirrors 6 and 7, is reflected by the dichroic mirror 8, is collected by the lens 9, and reaches the digital micromirror device 10. .
The three primary colors of blue light (B), green light (G), and red light (R) incident on the digital micromirror device 10 are processed in time series as images of the respective colors by synchronizing the switching of the incident light. Then, an image is projected onto the screen 12 via the projection optical system 11.

  By the way, in a projector such as the hybrid type, blue light passes through a notch portion of a metal color wheel, and the blue light is incident on a green phosphor formed on the color wheel and emits green light. However, there is also reflection of blue light from the color wheel body toward the blue light source, and blue light is not effectively used.

  The present invention has been made in view of the above problems, and provides a projector that effectively uses blue light in a conventional projector.

  In order to achieve the above object, a projector according to claim 1 is a projector including at least a light source, a color wheel, a condenser lens, a spatial light modulator, and a projection optical system. The light source that emits blue light, the light-transmitting material disk formed of a phosphor layer that emits green light, a portion that includes a filter and an antireflection layer, and a portion that includes an antireflection layer. A color wheel, wherein the blue light is incident on a phosphor layer of the color wheel to emit green light, and the blue light and the green light are transmitted through the color wheel, and the spatial light modulator together with the red light. It is set as the structure which injects into this.

  The projector according to claim 2 is a projector including at least a light source, a color wheel, a condenser lens, a spatial light modulator, and a projection optical system, and the light source that emits blue light; The color wheel comprising a disk made of a light-transmitting material formed of a phosphor layer that emits red light and green light, a portion made of a filter and an antireflection layer, and a portion made of an antireflection layer, and The blue light enters the phosphor layer of the color wheel and emits green light and red light, and the blue light, green light, and red light pass through the color wheel and enter the spatial light modulator. It is characterized by being configured.

According to a third aspect of the present invention, in the projector according to the first or second aspect, an integrator rod is provided between the condenser lens and the color wheel.
According to a fourth aspect of the present invention, in the projector according to the first or second aspect, an antireflection layer is further formed on the phosphor layer.
According to a fifth aspect of the present invention, in the projector according to any one of the first to third aspects, the surface of the phosphor layer has a rough structure.

The invention according to claim 1 of the present application is a type in which blue light and green light pass through a color wheel. In the conventional hybrid projector, the blue light irradiated to the green phosphor increases in reflected light due to reflection from the green phosphor interface and reflection from the underlying color wheel body. Since light and green light pass through the color wheel without being reflected, blue light can be used effectively.
In the invention according to claim 2 of the present application, blue light, green light from the green phosphor, and red light from the red phosphor pass through the color wheel, and thus any of the above-described lights can be used effectively. Since the light source is only a blue light source, the power source can be reduced.
According to the third aspect of the present invention, the light beam reflected from the color wheel to the light source side using the integrator rod is incident on the integrator rod, reflected inside, and further toward the color wheel side. The reflected light can be reused. Light from the green phosphor can also be reused.
According to the invention of claim 4 of the present application, since the antireflection layer is formed on the phosphor, reflection of blue light from the phosphor can be reduced, and blue light can be effectively used.
According to the invention of claim 5 of the present application, since the phosphor is roughened, the reflection of blue light is reduced and the blue light can be effectively used.

1 is a schematic diagram showing a projector as a two-light source projection image display apparatus according to an embodiment of the present invention. It is a figure which shows arrangement | positioning of the fluorescent substance in the color wheel used in FIG. It is a figure which shows typically the cross-section of the color wheel in embodiment of FIG. 1, (a) is the cross-section part in which the green fluorescent substance was formed in the color wheel main body, and the green light G emitted by the green fluorescent substance, It is a figure which shows notionally the relationship with the blue light B and the red light R, (b) is a cross-sectional part through which only the blue light passes without forming a fluorescent substance in the color wheel main body, and the blue light B and green It is a figure which shows notionally the relationship with the light G and the red light R. 1 is a schematic diagram showing a projector as a single light source type projection image display apparatus according to an embodiment of the present invention. It is a figure which shows arrangement | positioning of the fluorescent substance in the color wheel used in FIG. It is a figure which shows typically the cross-section of the color wheel in embodiment of FIG. 4, (a) is the cross-section part in which the green fluorescent substance was formed in the color wheel main body, and the green light G light-emitted by a green fluorescent substance, It is a figure which shows notionally the relationship with the blue light B and the red light R, (b) is the cross-sectional part in which the red fluorescent substance was formed, the red light R emitted by the red fluorescent substance, and the blue light B, It is a figure which shows notionally the relationship with the green light G, (c) is a cross-sectional part through which only the blue light passes, and the blue light B, the green light G, and red, in which a fluorescent substance is not formed in a color wheel main body. It is a figure which shows notionally the relationship with the light R. It is a figure which shows the roughening process of the fluorescent substance surface formed in the color wheel which can be utilized by this invention. It is a schematic diagram of a conventional hybrid projector.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A projector according to a first embodiment of the present invention will be described with reference to FIGS.
The rotation control of the color wheel and the control of the light after passing through the color wheel are well-known techniques and will not be described here.
In FIG. 1, the blue light source 21 includes a laser light source, a light emitting diode, and the like. The blue light emitted from the blue light source 21 passes through the condenser lens 23 and then enters the integrator rod 24. The integrator rod 24 may be a known one that repeatedly reflects light inside. The light that has passed through the integrator rod 24 enters the color wheel. The color wheel is a disk whose main body is made of a light-transmitting substance (optical glass, synthetic resin, etc.), and is rotated at a high speed by a motor (not shown).
For example, as shown in FIG. 2, a green phosphor layer 252 that emits green light is formed on the color wheel 25 over a portion of 240 degrees in the circumferential direction of the disk, and a remaining portion 251 is formed. It is made transparent. The range in which the phosphor layer is formed can be changed according to the ratio of transmitted light. A green light is transmitted between the green phosphor layer 252 and the color wheel main body 250, but an antireflection layer 250R that cuts blue light is provided, and a filter having a function of cutting blue light is provided on the emission side. 250F is provided (FIG. 3).
Further, if necessary, a diffusing plate that diffuses light on the emission side or a fluorescent material that broadens the blue band on the incident side transparent portion of the color wheel may be formed.

As the color wheel 25 rotates, when the green phosphor 252 (FIG. 3) is irradiated with blue light, green light is emitted. The green light passes through the color wheel 25 and passes through the dichroic mirror 26. To do. The blue light applied to the transparent portion 251 of the color wheel 25 passes through the dichroic mirror 26. The dichroic mirror 26 is manufactured so as to transmit blue light and green light but reflect red light.
Of the blue light, the blue light BR reflected from the color wheel 25 is retroreflected in the rod integrator 24 and travels toward the color wheel 25 again. The same applies to the green light GR reflected by the color wheel 25.

  The red light from the red light source 22 is reflected by the mirror 27 and the dichroic mirror 26. The blue light and green light transmitted through the dichroic mirror 26 and the reflected red light are incident on the digital micromirror device 29 through the lens 28, processed in time series, and passed through the projection optical system 30. An image is projected on the screen 31.

  According to the first embodiment, the green light emitted by irradiating the green phosphor with the blue light is transmitted through the color wheel, and the reflection of the blue light is reduced, and the blue light is more effective than the conventional device. Can be used.

Next, a second embodiment of the single light source type will be described. In FIG. 4, the blue light from the blue light source 31 passes through the lens 32 and enters the color wheel 34 via the integrator rod 33. As shown in FIG. 5, the color wheel 34 is divided into three parts by 120 degrees in the circumferential direction on a disk of the color wheel main body 340 made of a light-transmitting substance, and the green wheel 342 and the red phosphor 343 are respectively divided. It is composed of a formed portion and a transparent portion 341 that transmits blue light.
As shown in FIGS. 6A to 6C, an antireflection layer (AR coating) is formed between the green phosphor layer 342 and the red phosphor layer 343 and the glass 340 of the color wheel main body, and is emitted. A filter is formed on the side. In addition, antireflection layers are formed on both sides of the glass 340 of the transparent portion 341.
When blue light is incident on the color wheel 34, green light is emitted from the portion incident on the green phosphor 342, red light is emitted from the portion incident on the red phosphor 343, and blue light is emitted from the transparent portion 341. Is done.
The blue light, green light, and red light from the color wheel 34 pass through the lens 35, enter the digital micromirror device 29, are processed in time series, and are imaged on the screen 38 via the projection optical system 37. Is projected.

According to the second embodiment, as compared with the conventional device, the light source is only a blue light source, not only can the light be used effectively, but also optical elements such as a condensing lens, a mirror, and a dichroic mirror can be omitted. The device configuration is simplified.

  The basic configuration of the color wheel is as described above. As shown in FIG. 7 in the first or second embodiment, in the color wheel, the glass 350 is interposed with the antireflection layer 350R. The surface of the phosphor on the blue light incident side may be roughened. In addition, 350F is a filter layer. Even if it does so, reflection of light can be prevented and reflection in the interface of a fluorescent substance layer and an air layer is further suppressed. Such a roughening treatment of the phosphor surface can be formed by a known mold, nanoimprint or the like.

Examples of the phosphor material include the following.
For example, as a phosphor for red light emission, Y ₂ O ₃ : Eu, Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O ₁₂ : Eu, Zn ₃ (PO ₄ ) ₂ : Mn, YBO ₃ : Eu, (Y, Gd) BO ₃ 3: Eu, GdBO ₃ : Eu, ScBO ₃ : Eu, LuBO ₃ : Eu, and the like.
As the phosphor for green light emission, Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, SrAl ₁₂ O ₁₉ : Mn, ZnAl ₁₂ O ₁₉ : Mn, CaAl ₁₂ O ₁₉ : Mn, YBO ₃ : Tb, LuBO ₃ : Tb, GdBO ₃ : Tb, ScBO ₃ : Tb, Sr ₄ Si ₃ O ₈ Cl ₄ : Eu, and the like.
Examples of blue phosphors include CaWO ₄ : Pb, Y ₂ SiO ₅ : Ce, BaMgAl ₁₄ O ₂₃ : Eu, and the like.

In the material of the filter and the antireflection layer, TiO ₂ , HfO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , ZrO ₂ , and the like can be cited as high refractive materials, and SiO ₂ , MgF _{2, and the} like can be cited as low refractive materials. .

  21, 31: Blue light source, 22: Red light source, 24, 33: Integrator rod, 25, 34: Color wheel, 29, 36: Digital micromirror device, 30, 37: Projection optical system, 31, 38: Screen, 252 342: Green phosphor, 251, 341: Transparent portion, 343: Red phosphor, 250, 340: Glass, 250R, 340R: Antireflection layer (AR coating), 250F, 340F: Filter

Claims (5)

A projector comprising at least a light source, a color wheel, a condenser lens, a spatial light modulator, and a projection optical system,
The light source emitting red light and blue light respectively;
A portion comprising a phosphor layer that emits green light, a filter and an antireflection layer, and the color wheel comprising a disk of a light transmissive material formed from a portion comprising an antireflection layer, and
The blue light enters the phosphor layer of the color wheel and emits green light, and the blue light and green light pass through the color wheel and enter the spatial light modulator together with the red light. A projector characterized by that. A projector comprising at least a light source, a color wheel, a condenser lens, a spatial light modulator, and a projection optical system,
The light source emitting blue light;
The color wheel comprising a disk made of a light-transmitting material formed of a phosphor layer that emits red light and green light, a portion made of a filter and an antireflection layer, and a portion made of an antireflection layer, and
The blue light enters the phosphor layer of the color wheel and emits green light and red light, and the blue light, green light, and red light pass through the color wheel and enter the spatial light modulator. A projector characterized by being configured.   The projector according to claim 1, wherein an integrator rod is provided between the condenser lens and the color wheel.   The projector according to claim 1, wherein an antireflection layer is further formed on the phosphor layer.   The projector according to claim 1, wherein a surface of the phosphor layer has a rough surface structure.

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