JP3901707B2 - projector - Google Patents

Description

  The present invention relates to a projector, and more particularly, to a projector including an integrator that converts light from a light source into rectangular planar light.

2. Description of the Related Art Conventionally, a projector including an integrator for converting light from a light source into planar uniform light is known (for example, see Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 7-120753 JP 2002-62585 A

  By the way, a general projector is often configured to project image light from above or below the screen, rather than projecting image light from the front to the screen. . At this time, the optical axis of the image light projected from the projector deviates from the center of the screen projection surface. For example, when the projector is positioned on the lower side with respect to the screen and the image light from the projector is inclined upward and projected onto the screen, the image light This optical axis is shifted downward from the center of the screen projection surface. Further, when projecting image light onto a screen, the amount of light decreases from the center of the optical axis toward the periphery. Due to these reasons, in the screen on which the image from the projector arranged on the lower side is projected, the lower side is brightest than the center, while the left and right ends of the upper end are darkest. End up.

  In view of such circumstances, the present invention is intended to provide a projector capable of making the light quantity distribution of image light projected on a screen uniform.

In order to achieve the above-mentioned object, the invention according to claim 2 is a schematic diagram of a light source for generating light, a light separating unit for separating light from the light source into RGB light, and collecting output light from the light separating unit. A rod integrator that converts light into a rectangular surface and an image generation element that modulates the light from the rod integrator into image light. The image light from the image generation element is tilted upward and projected onto a screen. In the projector configured as described above, the rod integrator includes a first transparent member and a second transparent member disposed below the first transparent member and having a refractive index of light smaller than that of the first transparent member. And a transparent member .

  The light source for generating light, the light separating means for separating the light from the light source into RGB light, and the output light from the light separating means in a substantially rectangular planar shape according to claim 2 configured as described above. A light integrator, and an image generation element that modulates the light from the integrator into image light, so that the image light from the image generation element is projected upward or downward on the screen. A projector is configured.

  The rod integrator is configured to increase the amount of light emitted from the side opposite to the direction of deviation of the optical axis of the image light with respect to the center of the projection surface of the screen image. For example, when the optical axis of the image light is shifted downward with respect to the center of the projection surface of the screen image, as described above, the lower side is brightest than the center of the projection surface, The left and right sides of the upper end of the projection surface are darkest. However, in the present invention, since the integrator is configured so that the amount of light emitted from the upper part of the integrator is increased, the right and left sides of the upper end portion of the projection surface are corrected to be bright, and as a result, It is possible to make the light quantity distribution of the image light projected on the screen uniform.

  Correction is made so that both the left and right sides of the upper end portion of the projection surface of the screen image are brightened. As a result, the light quantity distribution of the image light projected on the screen can be made uniform.

  When light enters a transparent member having a high refractive index from a transparent member having a low refractive index, total reflection occurs when the light is incident at an incident angle greater than the critical angle, and the incident light is reflected. As a result, it is possible to increase the amount of light at the top of the integrator where the transparent member having a large refractive index is arranged.

According to a third aspect of the present invention, the first transparent member is constituted by two columnar rod integrators having a substantially right triangle shape in cross section, and the second transparent member is a column shape having a substantially home base shape in cross section. The two rod integrators constituting the first transparent member are respectively arranged on the upper left and right sides of the second transparent member, and form a columnar body having a substantially rectangular shape in cross section as a whole. It is as a configuration.
In the third aspect configured as described above, it is possible to increase the amount of light on the upper left side and the upper right side of the projection surface that becomes the darkest when image light is projected from below the screen. It is possible to make the light amount distribution of the projected image light uniform.

According to a fourth aspect of the present invention, the refractive index (N1) of the first transparent member and the refractive index (N2) of the second transparent member satisfy the following relationship.
N1-N2 <0.003 ... Formula (1)
When the refractive index (N1) of the said 1st transparent member and the refractive index (N2) of the said 2nd transparent member satisfy | fill the said (1) Formula in Claim 4 comprised as mentioned above, it is on a screen. The light quantity distribution of the projected image light is made more uniform.

According to the first and second aspects of the present invention, the light quantity distribution of the image light projected on the screen can be made uniform.
In the invention according to claim 3, it is possible to equalize the amount of image light projected onto the screen.
In the invention according to claim 4, the light quantity distribution of the image light projected on the screen is made more uniform.

  FIG. 1 is an external view schematically showing a projector according to the present invention, and FIG. 2 is a layout diagram of components in the optical system of the projector shown in FIG. In the following embodiments, a case where the projector of the present invention is a DLP (Digital Light Processing) type projector using a DMD (Digital Mirror Device) as an image generation element will be described. For example, a liquid crystal projector using a liquid crystal panel as an image generating element may be used.

  In FIG. 1, the projector 10 is provided with a projection lens 26. Image light from the projection lens 26 is projected onto a screen or the like (not shown), so that an image is displayed on the screen.

  2, the optical system of the projector 10 includes a light source device 20 capable of generating white light, a disk-shaped color wheel 21 having RGB color filters (not shown), and a color wheel. A rod integrator 22 that collects R, G, or B light separated by the light 21 and guides the light to a mirror 23 to be described later; and a mirror 23 that reflects light from the rod integrator 22; A DMD 25 having a plurality of micromirrors, and a projection lens 26 for projecting light from the DMD 25 onto the screen. Illumination lenses 27 and 28 are provided between the rod integrator 22 and the mirror 23 and between the mirror 23 and the DMD 25, respectively.

  The light source device 20 includes a lamp 20a that generates white light and a parabolic reflector 20b that reflects light emitted backward from the lamp 20a. The light generated by the lamp 20a -It emits toward the lens 21. As the lamp 20a, for example, a halogen lamp, a metal halide lamp, a high-pressure mercury lamp, or the like can be used. Moreover, as the reflector 20, a parabolic mirror, an ellipsoidal mirror, or the like can be used.

  The color wheel 21 has a substantially disk shape, and RGB color filters (not shown) are arranged at equal intervals. As the color wheel 21 rotates, the white light emitted from the light source device 20 is sequentially separated into R, G, and B light. The rod integrator 22 will be described in detail later with reference to the drawings. The rod integrator 22 is a columnar body having a substantially rectangular shape in cross-section, and the incident light from the color wheel 21 is converted into a substantially rectangular uniform planar light. And converted to Mira-23. The illuminating lens 27 is for condensing the light from the rod integrator 22 on the mirror 23, and the illuminating lens 28 is for condensing the light reflected by the mirror 23 on the DMD 25. belongs to.

  As shown in FIG. 3, the DMD 25 includes a plurality of micromirrors 25a as modulation elements that modulate each RGB light for each pixel in accordance with image data. Each micromirror 25a is individually provided. Drive-controlled, the angle of the reflecting surface can be inclined by a predetermined angle (for example, 12 degrees).

  The projection lens 26 is for enlarging and projecting the image light modulated by the DMD 25 onto the screen, and for the purpose of preventing blurring of the projected image due to chromatic aberration of each color light of RGB and the like. It is configured as a combined lens in which elements are arranged along the optical axis direction.

  In the figure, an arrow of a two-dot chain line indicates a traveling direction of light. White light emitted from the light source device 20 is separated into RGB color lights by a color wheel 21, and the separated light is collected by a rod integrator 22 and guided to a mirror 23. The light emitted from the rod integrator 22 is collected by the illuminating lens 27 interposed between the rod integrator 22 and the mirror 23, is incident on the mirror 23, and is reflected by the mirror 23. . The light reflected by the mirror 23 is collected by the illuminating lens 28 and enters the DMD 25. The image light modulated by the DMD 25 is enlarged and projected onto the screen by the projection lens 26.

  FIG. 4 is a cross-sectional view schematically showing a state in which image light is projected onto the screen from the projection lens of the projector according to the embodiment. In the figure, the image light from the projection lens 26 is projected upward on the screen 100 while being inclined upward. At this time, the intersection B between the optical axis X of the image light from the projection lens 26 and the screen 100 is shifted downward with respect to the center A of the projection surface in the screen 100. Therefore, in the image projected on the screen 100, the portion of the intersection B below the center A of the projection plane is brightest, while the portion farthest from the intersection B, that is, the left and right sides of the upper end of the projection plane. Becomes the darkest.

Next, a rod integrator provided in the projector according to the embodiment will be described.
FIG. 5 is a cross-sectional view of the rod integrator according to the embodiment. In the same figure, a mirror part 22a for reflecting light passing through the inside is provided at the peripheral part of the rod integrator 22 having a substantially rectangular shape as a whole. Further, a transparent portion 22b through which light passes is disposed inside the mirror portion 22a. The transparent portion 22b is composed of two first transparent members 22b1 having a substantially right triangle shape in cross section and one second transparent member 22b2 having a substantially home base shape in cross section, and the second transparent member 22b2. Two first transparent members 22b1 are respectively arranged on the upper left and right sides of the first and second members.

The refractive index (N1) of the first transparent member 22b1 is larger than the refractive index (N2) of the second transparent member, and N1 and N2 satisfy the following expression (1).
N1-N2 <0.003 ... Formula (1)
Thereby, among the light incident on the second transparent member 22b2 from the first transparent member 22b1, the light incident on the second transparent member 22b at an incident angle larger than the critical angle (θ) is reflected. The critical angle (θ) can be calculated by the following equation (2).
θ = arcsin (N1 / N2) (2)

  As described above, a part of the light traveling from the first transparent member 22b1 to the second transparent member 22b2 is reflected, so that two of the first transparent members 22b1 out of the light emitted from the rod integrator 22 are arranged. The amount of light in the portion that has been increased will increase. As a result, the light quantity at the darkest part of the projected image, that is, the left and right light amounts at the upper end of the projection surface is increased, and the light quantity distribution on the projection surface is corrected to be uniform.

  FIG. 6 is a view showing a light amount distribution of the light emitting portion of the rod integrator 22 shown in FIG. 5, and FIG. 7 has the same shape as that of the rod integrator shown in FIG. These are figures which show the light quantity distribution of the light emission part of the rod integrator which a transparent part consists of the same transparent member. 6 and 7, the direction indicated by the arrow A is the upward direction of the rod integrator. FIG. 7 shows the light emitting part of the rod integrator whose transparent part is made of the same transparent member, that is, the whole transparent part has the same refractive index. The light intensity distribution is almost uniform.

  On the other hand, FIG. 6 shows the light emitting part of the rod integrator 22 shown in FIG. 5, but the light emitting part is caused by the reflection of light by the second transparent member 22b2 as described above. The amount of light in the upper portion of the first, particularly the portion where the first transparent member 22b1 is located is large. When light having a light amount distribution as shown in FIG. 6 is emitted from the rod integrator 22, converted into image light by the DMD 25, and projected onto the screen from the projection lens 26, left and right of the upper end of the projection surface The light quantity on both sides is increased, and the light quantity distribution on the projection surface is corrected to be uniform.

  In the above-described embodiment, the case where the projector 10 is configured such that the light emitted from the light pipe 22 is reflected by the mirror 23 and enters the DMD 25 has been described. Need not be provided with a mirror, and may be configured such that light from the light pipe is directly incident on the DMD.

  In the above-described embodiment, the case where the projector 10 is a one-chip type projector including only one DMD 25 has been described. However, the present invention includes three DMDs corresponding to the three colors of RGB light. The present invention can also be applied to a three-chip projector or a two-chip projector including two DMDs.

  As described above, in the projector 10 according to the embodiment, the rod integrator 22 has a refractive index smaller than that of the two first transparent members 22b1 and the first transparent member 22b1 having a right triangle shape in cross section, and has a cross section. Since one second transparent member having a visual home base shape is disposed so as to be substantially rectangular as a whole, the light traveling from the first transparent member 22b1 to the second transparent member 22b2 When a part of the light is reflected, the amount of light emitted from the rod integrator 22 is increased at the portion where the two first transparent members 22b1 are disposed. As a result, the light amounts on both the left and right sides of the upper end of the projection surface are increased, and the light amount distribution on the projection surface is corrected to be uniform.

It is an external view which shows a projector typically. FIG. 3 is a layout diagram of components in an optical system of a projector. It is a figure which shows the structure of DMD. It is sectional drawing which shows typically a mode that image light is projected on a screen from the projection lens of a projector. It is sectional drawing of the rod integrator concerning embodiment. FIG. 6 is a diagram showing a light amount distribution of a light emitting portion of the rod integrator shown in FIG. 5. It is a figure which shows the light quantity distribution of the light emission part of the rod integrator which a transparent part consists of the same transparent member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Projector 20 ... Light source device 20a ... Lamp 20b ... Reflector 21 ... Color wheel 22 ... Rod integrator 22a ... Mirror part 22b ... Transparent part 22b1 ... 1st transparent member 22b2 ... 2nd transparent member 23 ... Mirror −
25 ... DMD
26 ... Projection lenses 27, 28 ... Illumination lens 100 ... Screen

Claims (4)

A light source that generates light, a light separation unit that separates light from the light source into RGB light, an integrator that collects output light from the light separation unit to form a substantially rectangular planar light, and And an image generating element that modulates the light into image light,
In the projector configured so that the image light from the image generation element is projected upward on the screen,
The integrator includes two columnar first transparent members having a substantially right-angled triangular shape in cross section, and one columnar first transparent member having a refractive index of light smaller than that of the first transparent member and having a home base shape in cross section. A rod integrator comprising two transparent members;
The two first transparent members are arranged on the upper left and right sides of the second transparent member, respectively, and form a columnar body having a substantially rectangular shape in cross section as a whole,
The refractive index (N1) of the first transparent member and the refractive index (N2) of the second transparent member satisfy the following relationship, and the light of the image light with respect to the center of the projection surface of the screen image: A projector characterized in that the projector is arranged so that the amount of light emitted from the side opposite to the direction of axis deviation increases.
N1-N2 <0.003 ... Formula (1) A light source that generates light, a light separating unit that separates light from the light source into RGB light, a rod integrator that collects output light from the light separating unit to form a substantially rectangular planar light, and the rod An image generating element that modulates light from the integrator into image light,
In the projector configured so that the image light from the image generation element is projected upward on the screen,
The above rod integrator
A first transparent member;
A projector comprising: a second transparent member disposed below the first transparent member and having a light refractive index smaller than that of the first transparent member . The first transparent member is composed of two columnar rod integrators having a substantially right triangle shape in cross-section,
The second transparent member is a columnar rod integrator having a substantially home base shape in cross section,
The two rod integrators constituting the first transparent member are respectively disposed on the upper left and right sides of the second transparent member, and form a columnar body having a substantially rectangular shape in cross section as a whole. Project described in. 4. The refractive index (N1) of the first transparent member and the refractive index (N2) of the second transparent member satisfy the following relationship. The projector described.
N1-N2 <0.003 ... Formula (1)

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