JP4947626B2 - Image projection device - Google Patents

Description

  The present invention relates to a portable image projection apparatus, and more particularly to an image projection apparatus that realizes selection of an illumination light amount and low power consumption in accordance with a use situation while realizing a reduction in size and weight.

  Image projection devices range from use in specific places such as conference rooms to portable use and incorporation into smaller devices. Especially in small-sized image projection devices such as portable ones, the amount of projected light and hue may change due to changes in the usage environment (changes in brightness, influence of external light, changes in hue, etc.) and changes in projection images (presentation, video, colorization). Adjustments are required and there are various requirements for the size of the projected image.

  Conventionally, when a desired image is projected by an image projection apparatus using a single light source, it is necessary to adjust the light source. When a light source having a large output is used, the power consumption is large, the size is increased, and the light is too bright. Problems arise. In addition, when a light source with a small output is used, there are problems such as being too dark depending on the situation, and a desired color cannot be achieved.

  Therefore, an auxiliary light source is disposed behind the light source and illumination is performed by the auxiliary light source from the gap between the light sources (see, for example, Patent Document 1), or switching between the projection type and the so-called head mounted type display is performed by the auxiliary light source. An apparatus (for example, see Patent Document 2) that performs the technique has been proposed.

JP 2006-3799 A JP 2002-526791 A

  However, in the configuration of Patent Document 1, it can be used only with the light in the gap, so that the utilization efficiency is poor and the optical system is complicated. Moreover, since the installation location of the light source is limited to one location, the degree of freedom in configuration is small. Patent Document 2 is a projection method switching technique and cannot adjust the light source of a projection image.

The present invention has been made in view of the above problems,
An object of the present invention is to provide an image projection apparatus with low power consumption that achieves both small size and light weight and image projection from a large screen to a small screen.

  In the present invention (Claim 1), the image projection is realized by a plurality of light sources, and a part of the plurality of light source units is detachable. By attaching and detaching the light source, at least one of the functions of light quantity selection, power consumption quantity selection, and reproduction color selection is achieved. It is desirable that the detachable light source is one or plural, and that the apparatus has a minimum volume when the minimum number of light sources is configured.

  In the present invention (Claim 2), the light source unit and a part of the transmission optical system are integrally configured to be detachable. As the transmission optical system, for example, a condensing lens / mirror, a reflection mirror, a color filter, or the like can be selected. In addition, these are aligned in the initial stage, and it is desirable that they can be incorporated into the apparatus without adjustment when mounted.

  According to the present invention (claim 1), it is possible to select a light source having a necessary and sufficient intensity by configuring an image projection apparatus with a plurality of light sources and detaching a part of the light sources. As a result, a decrease in visibility due to a light source having an intensity higher than necessary is suppressed, and miniaturization, weight reduction, and low power consumption can be realized by removing the light source. Further, by attaching and detaching, it is possible to form a larger screen and a bright image without significantly changing the configuration of the main body. Also, in certain situations (for example, when using external presentations), select a usage method such as removing some light sources or turning on light sources with small size and low power consumption, and other situations (for example, meetings with many members in a conference room) Then, it is possible to change the device specifications for each usage situation, such as turning on all light sources or turning on high-power light sources. Thus, by selecting a necessary light source, the device is excellent in portability and inexpensive. Furthermore, it is possible to adjust the uniformity and contrast of the light source by selecting the light source, and it is also possible to select specifications according to the use situation, such as a light source configuration with higher uniformity, a light source configuration with higher contrast, or a lighter light source configuration. Furthermore, since the light source can be attached and detached, it is easy to replace the light source when a malfunction of the light source occurs, and it is possible to cope with a spare light source.

  According to the present invention (Claim 2), since the optical system is configured to be detachable as a unit with the light source, it is possible to correct misalignment when the light source is incorporated, and it is possible to realize the detachment mechanism more easily. By adjusting and arranging the optical system in advance, it can be more easily attached and detached. By attaching and detaching the optical system at the same time, it is possible to reduce the size and weight of the light source in the minimum configuration. Further, by selecting an optical element to be incorporated at the same time, selection of optical characteristics such as a more uniform system and a high contrast system can be realized by a removable element configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1:
FIG. 1 shows an image projection apparatus according to a first embodiment of the present invention. In FIG. 1, 101 is a light source unit, 102 is a plurality of light sources, 103 is an image projector main body, 104 is a white LED (light emitting diode) light source unit, 105 is a reflection mirror, 106 is a condenser lens, 107 is a polarizer, 108 Is a transmissive liquid crystal light valve, 109 is a color filter, 110 is an analyzer, 111 is a projection lens, and 112 is a screen.

  In the first embodiment, the detachable light source unit 101 is connected to the image projection apparatus main body 103 for use. The detachable light source unit 101 is electrically connected to the main body 103 by a connector of the detachable portion, power is supplied to the light source unit 101 from the power source on the main body 103 side, and a control signal line or the like is provided between the main body 103 and the light source unit 101. Is connected.

  The detachable light source unit 101 is provided with a plurality of light sources 102. As the plurality of light sources 102, for example, a white LED light source or the like can be used for miniaturization. A similar white LED light source unit 104 is also provided on the main body 103 side. When the detachable light source unit 101 is not connected, the light source unit 104 is used.

  The light from the light source unit 104 passes through the reflection mirror 105, the condenser lens 106, and the polarizer 107, and only light in one direction enters the transmissive liquid crystal light valve 108. The transmissive liquid crystal light valve 108 alternately arranges color filters 109 for each pixel, controls the liquid crystal by an image signal corresponding to the position of the filter, and performs color reproduction of colors. The analyzer 110 is disposed after the liquid crystal, an image is formed by a change in polarization by the liquid crystal, and an enlarged image is projected on the screen 112 by the projection lens 111.

  In this embodiment, for example, when using a mobile or observing an image of a small number of people, the removable light source unit 101 is removed and used. In addition, the light source unit 101 is connected and used for use in a conference room or for observation with a large number of people. Thus, in this embodiment, the usage method of the light source unit 101 can be appropriately selected. As a result, by removing the light source unit, the size of the light source unit can be reduced and the weight of the light source unit can be reduced, and low power consumption can be realized. In particular, in the case of battery drive, low power consumption enables long-time use. In this embodiment, a single-plate image projection method using transmissive liquid crystal has been described as an example, but the present invention can also be applied to a system using a three-plate method or a reflection method.

Example 2:
FIG. 2 shows an image projection apparatus according to the second embodiment of the present invention. In the second embodiment, the light source units 201a, 201b, and 201c can be attached to and detached from the projection apparatus main body 206, respectively. Each light source unit (201a, 201b, 201c) includes a light source 202, a reflection mirror 203, a field lens 204, and a polarization separation mirror 205, which are integrally attached and detached.

  The projection apparatus main body 206 can select the light quantity by selecting the attachment / detachment of a plurality of light source units (201a, 201b, 201c). The light from these light source units is separated into only one direction of the polarization component by the polarization separation mirror 205 disposed in each unit, and enters the transmission type liquid crystal light valve 207. The color filter 208 arranged for each pixel of the liquid crystal light valve 207 selects the color of the transmitted light, the signal processing of the liquid crystal light valve 207 controls the polarization of the transmitted light for each pixel, and the liquid crystal light valve 207 is detected. A photon 209 forms a color image. By projecting this color image onto the screen 211 by the projection lens 210, an enlarged image is formed.

  In this embodiment, it is possible to reduce the size and weight by removing a part of the detachable light source unit. Each light source unit does not need to be the same, and a plurality of light source units can be added. These detachable light source units are initially adjusted in position, and the light intensity can be easily adjusted without complicated adjustment.

Example 3:
FIG. 3 shows an image projection apparatus according to the third embodiment of the present invention. In the third embodiment, a battery 302 is provided corresponding to each light source 301 in the detachable light source units 301a and 301b. The light source 301 is driven by each battery 302, and the light source is controlled by the control unit 304 of the main body 303. The plurality of light source units 301a and 301b are also controlled by the control unit 304 of the main body 303 at the same time. Normally, in a battery-driven image projection apparatus, the weight of the battery is a major obstacle when carrying it. In the present invention, a battery corresponding to the required light quantity is mounted by attaching and detaching the battery together with the light source. In addition, the user can select the driving time and the amount of light.

Example 4:
FIG. 4 shows an image projection apparatus according to a fourth embodiment of the present invention. In the fourth embodiment, the detachable light source unit 401a is configured by a white LED light source 402a (or a light source in which RGB colors are integrally formed). An enlarged image is projected on the screen 405 by the image projection system 404 (Example 1) of the projector main body 403 using the white LED light source 402a.

  Further, by replacing the detachable light source 402a with an LED unit 401b that is a white LED and has a high illuminance, a projected image with higher brightness can be formed. Further, by using a light source having the same wavelength distribution, the aberration of the optical system due to attachment / detachment can be reduced, and an image with little color change can be selected and used at a desired intensity.

Example 5:
FIG. 5 shows an image projection apparatus according to a fifth embodiment of the present invention. The image projection apparatus of Example 5 is a system using a three-plate transmissive liquid crystal. The detachable light sources 502r1, r2, r3, 502g1, g2, g3, 502b1, b2, and b3 are configured by RGB LEDs or laser diodes, and are disposed at different detachable positions 501r, 501g, and 501b for each color. Light from the light sources of the respective colors is transmitted through the prism 504g, the field lens 505g, and the polarizer 506g to be superimposed, and is incident on the transmissive liquid crystal light valve 507g. The light of each color is further combined by the cross dichroic prism 508, an image is formed by the light that has passed through the analyzer 509, and a projection image is formed on the screen 511 by the projection lens 510.

  Thus, in this embodiment, the degree of freedom of light source arrangement is increased by attaching and detaching the light source for each color, and the uniformity of the projected image is selected by selecting the number of light source units to be connected and the optical characteristics of the light source units. And the contrast can be adjusted.

Example 6:
FIG. 6 shows an image projection apparatus according to Embodiment 6 of the present invention. Example 6 is an example of a system for realizing image formation by a spatial light modulation element using micromachine technology. This method is called the DLP method (DLP: Digital Light Processing, a projection-type image display method developed by Texas Instruments, USA). For example, a small mirror (DMD, digital micromirror device) measuring 13 μm square is used. The directions of the mirrors of each million display elements are controlled based on the video signal, and the light from the light source is reflected to project the video onto the screen.

  As shown in FIG. 6A, this type of video projection apparatus includes a rod integrator 605, a condenser lens 606, an optical path adjustment prism 607, a DMD element 608, and a projection lens 609. As a result, an enlarged projection image is formed on the screen 610.

  The light source includes LED light sources 601r, 602g, and 602b (first to third light sources) corresponding to RGB colors, and these colors are adjusted coaxially by a selective reflection mirror 611 having a specific wavelength. Here, the removable light source unit 602 is an LED light source 601x (fourth light source) having a specific wavelength distribution. For example, a light source having a wavelength region different from RGB as shown in FIG. 6B is used as the LED light source 601x. By using such a light source, the color reproduction range can be expanded.

  With the detachable structure, it is possible to select whether to use the fourth light source according to user needs. When the fourth light source is not used, the size and weight can be reduced, and the power consumption is reduced. The present invention is not limited to an image projection method using DLP, and can be used in various methods by using a light source that lights in time series and a light valve synchronized with the light source. Furthermore, the number of light sources is not limited to four, and five or more light sources having different wavelength distributions can also be used. Further, by replacing one of the RGB light sources with a light source having a different wavelength distribution, it can be used as a projection apparatus capable of reproducing different color ranges. As a result, the user can select the image quality to be projected according to the external environment, for example.

Example 7:
FIG. 7 shows an image projection apparatus according to a seventh embodiment of the present invention. In the seventh embodiment, a fixed light source unit 702 is disposed in the image projection apparatus main body 701, and a polarization separation mirror 704 illuminates a transmissive liquid crystal light valve 706 in which only a polarization component in one direction is disposed for each pixel. In addition, detachable light source units 703a and 703b are provided in the main body 701 as shown in the figure, and a rotationally movable polarization separation mirror 705 is disposed in the optical path of the light source units 703a and 703b.

  The polarization separation mirror 705 is mechanically separated by the projection 708 so that light from the light source unit is guided to the transmissive liquid crystal light valve 706 side only when the detachable light source units 703a and 703b are inserted into the main body 701. The mirror 705 is moved. Accordingly, the polarization separation mirror 705 is inserted only when the light source units 703a and 703b are inserted, and when no light source is inserted, no extra optical system is inserted in the optical path, and energy loss can be suppressed. The movement of the polarization separation mirror 705 is not limited to a rotation mechanism, and can be moved by parallel movement or vertical movement. The movement is not limited to the polarization separation mirror, and various elements such as a prism and a uniform optical system can be used. It is also possible to use.

Example 8:
FIG. 8 shows an image projection apparatus according to an eighth embodiment of the present invention. In the eighth embodiment, the present invention is applied to a DLP projection system using a hollow rod integrator and a field lens as a shared optical system.

  The detachable light source 801 is composed of a plurality of three-color light sources, and all light is collected by a condensing lens 802 onto a common rod integrator 803. In the rod integrator 803, the light is multiple-reflected on the wall surface, and the light from all the light sources is integrated, resulting in a uniform intensity distribution at the emission position. The detachable light source 801 is desirably small and arranged close to each other, and three-color LEDs and LDs can be used as the small light source. The uniformized light is irradiated through the field lens 804 so as to have a uniform intensity distribution on the surface of the DLP 805. Here, the light source is sequentially turned on in time series for each of the three colors, and is formed so as to be synchronized with the image signal for each color formed in the DLP. Thus, the images for each color are enlarged and projected on the screen 806 in time series.

  As described above, by using the same rod integrator, it is possible to form a stable image without adjusting the position of the optical system of the main body regardless of whether or not a detachable light source is inserted. Furthermore, it is possible to reduce the size and weight as compared with the case where a uniform optical system is arranged for each light source. The present invention is not limited to sharing an integrator element, but can also share a mirror, a lens, a polarization separation element, a polarization conversion element, a color filter, and the like.

1 shows an image projection apparatus according to Embodiment 1 of the present invention. 7 shows an image projection apparatus according to a second embodiment of the present invention. 7 shows an image projection apparatus according to Embodiment 3 of the present invention. 6 shows an image projection apparatus according to Embodiment 4 of the present invention. 9 shows an image projection apparatus according to Embodiment 5 of the present invention. 9 shows an image projection apparatus according to Embodiment 6 of the present invention. 9 shows an image projection apparatus according to a seventh embodiment of the present invention. 9 shows an image projection apparatus according to an eighth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Light source unit 102 Multiple light sources 103 Image projector main body 104 White LED light source unit 105 Reflection mirror 106 Condensing lens 107 Polarizer 108 Transmission type liquid crystal light valve 109 Color filter 110 Analyzer 111 Projection lens 112 Screen

Claims (2)

A plurality of light sources, and the light transmission means, a spatial light modulating means for modulating in accordance with an image signal incident light, has a projection means for projecting the light modulated by the spatial light modulating means, said plurality of The light source includes a first LED light source unit on the apparatus body side and a second LED light source unit that can be attached to and detached from the apparatus body. The first LED light source unit, the second LED light source unit, Are arranged in a front-rear relationship on the optical path, and the plurality of LEDs arranged in the second LED light source unit surround the first LED light source unit with the first LED light source unit as the center. An image projection apparatus characterized by the above.   The image projection apparatus according to claim 1, wherein a part of the light source and the transmission optical system are integrally removable.

Images