JP4656444B2 - projector - Google Patents

Description

  The present invention relates to a projector.

  Conventionally, as a projector that displays images by enlarging and projecting an image of a liquid crystal display element, a single liquid crystal display element is illuminated from behind with a metal halide lamp, and an image displayed on the liquid crystal display element is enlarged and projected by a projection lens. There was something configured.

For example, in Japanese Patent Laid-Open Nos. 62-237485, 3-75737, and 8-111107, a metal halide lamp or a halogen lamp is used as a light source, and light emitted from these light sources is hollow. The structure of the invention is described in which the light is guided by the light guide structure and guided to the liquid crystal display element.
JP-A-62-237485 JP-A-3-75737 JP-A-8-111107

  However, since the conventional technology uses a lamp as a light source, there is a limit to reducing the size of the light source itself. Therefore, it has been difficult to downsize the entire projector. In recent years, there are many portable information terminal devices, and it is not always necessary to project an image with a large size exceeding 60 inches as a projector. For example, there may be a case where the size of the projected image may be as small as about 10 inches or 20 inches. In such a projected image size, a light emitting element (such as a light emitting diode or a semiconductor laser) can be used as a light source, so that it is expected that the size of the projector can be extremely reduced.

  However, since a small light emitting device such as a light emitting element is generally a point light source, it is difficult to uniformly illuminate a liquid crystal display element having a certain area. Even if a plurality of light emitting diodes are arranged to illuminate a wide area, the light intensity is uneven in a two-dimensional plane because it is merely a collection of point light sources.

  Japanese Patent Laid-Open No. 10-123512 discloses a projector technology using a two-dimensional array of light emitting diodes as a light source. In order to effectively guide the radiated light from the light emitting diode, which is a point light source, to the liquid crystal display element, the light from the light emitting diode is converted into planar light by a microlens array that is an array of lens elements formed corresponding to each light emitting diode. It has been converted.

  However, the microlens array has a problem in that it is difficult to make illumination light uniform because the lens action at the boundary between adjacent lens elements becomes weak due to manufacturing errors and the like.

  In addition, there is a configuration that guides light by bending the optical axis by 90 ° as in JP-A-9-73807, but a technique for obtaining planar light by linearly moving the optical axis of a point light source has not been established.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a projection type liquid crystal display device (projector) having a light source structure suitable for miniaturization in which a plurality of light sources are arranged in a planar shape. . Another object of the present invention is to provide a structure capable of emitting uniform light using a plurality of point light sources such as light emitting diodes, thereby displaying a projection image that is compact and has no unevenness in light intensity. It is an object of the present invention to provide a projection type liquid crystal display device that can be used.

  In order to achieve this object, the present invention provides light guide means having end faces facing each other, guiding light emitted from one end face to the other end face, and the side of the one end face in the light guide means. A light source unit configured by a plurality of light sources, a light modulation element that is disposed on the other end face side of the light guide unit and modulates light emitted from the light source, and the light modulation element And a lens that projects the modulated light.

  The present invention is further characterized by further comprising a screen on which light from the lens is projected. Still further, the invention is characterized in that the plurality of light sources are a plurality of light emitting diodes, and the projector according to claim 1. Furthermore, the invention is characterized in that the light modulation element is a liquid crystal display element.

  In the form of the present invention described below, the plurality of light sources is, for example, a point light source array in which a plurality of point light sources are arranged in a planar shape. The light guide means causes light from the light source to enter at least from one end side, mix uniformly, and guide and emit the light to the other end face side. The light source and the light guiding means are provided separately.

  In order to reduce the size of the light source, the present inventors diligently studied the relationship between the point light source array arranged in a planar shape and the light guide means. As a result, the light incident on the light guide means for the point light source and incident on the light guide means. It has been found that the object can be achieved by linearly or in series with the light exit surface, and by uniformly diffusing incident light from a point light source in the light guide. The present invention has been made based on such knowledge.

  In the present invention, the point light source is a monochromatic light emitting element. As the light emitting element, a point light source such as a light emitting diode (hereinafter referred to as LED) or a semiconductor laser (LD) can be applied, and the light emitting element is not limited to the light emission color. That is, a single color (for example, a light emitting diode that emits white LED or B (blue)) may be used.

  When a single color such as B (blue) is used, it is preferable to arrange a wavelength conversion element that converts white light on the optical path. In the present invention, the point light sources are light emitting elements of different colors, and the light sources are a combination of the light emitting elements.

  As a combination of light emitting elements, not only the three primary colors of RGB but also colors other than the three primary colors (for example, orange, yellow-green, etc.) may be used, or a combination of two colors or four or more colors may be used.

The light guide means is a hollow or solid light guide made of a transparent material. As a 1st aspect of a light guide, it is a hollow light guide path block, and may be a polygonal shape or a cylindrical shape. Moreover, the thing provided with the metal reflective surface in the hollow light-guide path block side surface (inner wall surface and inner peripheral surface) is also included. Further, as a second aspect of the light guide, there is a solid light guide block instead of the hollow body. The solid light guide block side surface includes a total reflection surface or a metal reflection surface. Alternatively, the light guide may be configured as a so-called Selfoc lens (registered trademark of Nippon Sheet Glass Co., Ltd.) in which a plurality of optical fibers each composed of a clad and a core are bundled.

  The projector according to the present invention includes the light source device, a liquid crystal display element that is disposed to face an end face from which the light from the light guide unit emits, and that modulates the light from the light guide unit, and light is emitted from the liquid crystal display element. A magnifying lens disposed on the optical path of the modulated outgoing light; Furthermore, it may have a screen configured to project an image of the liquid crystal display element by the magnifying lens. By irradiating the liquid crystal display element with light emitted from the end face of the light source device having the above-described configuration, the image displayed on the liquid crystal display element can be directly viewed, enlarged, or projected.

  In the present invention, it is preferable that light emitted from the light source device is moved straight without bending its optical axis, and light guide means for uniformly irradiating the area (region) necessary for image display is arranged therebetween. In this case, the irradiated light was effectively irradiated to the irradiated region while preventing leakage of the irradiated light outside the irradiated region (image display region in the case of a liquid crystal display device).

  An example of the light guide means in the present invention includes a light guide path block having an inner wall having light reflectivity and formed in a hollow shape so as to constitute a light guide path. Light can be emitted from a plurality of light sources opposed to one end face of the light guide block to the light guide. According to this configuration, the light emitted from the point light source located near the center of the point light source array is emitted from the other end face of the light guide without being reflected by the inner wall of the light guide block. On the other hand, the light emitted from the point light source near the periphery of the point light source array is reflected by the inner wall of the light guide block and emitted from the other end face. Light emitted from each point light source through different paths is uniformly mixed in the light guide. When the length of the light guide path in the optical axis direction is adjusted, the light intensity is made uniform on the light exit surface of the light guide path.

  Here, for example, the point light source is a light emitting diode. Further, for example, the light guide block has a polygonal column shape (such as a quadrangular column) whose inner wall is configured by a plurality of flat reflecting surfaces. For example, the light guide block has a cylindrical shape or an elliptical cylindrical shape whose inner wall is configured by a curved surface.

  The end face of the hollow light guide block is a face corresponding to the end face of the solid block when the block is assumed to be solid.

  The present invention relates to a liquid crystal display element that is arranged opposite to the other end face of the light guide block and is configured to be able to modulate light emitted from the light guide path, and an optical path of the emitted light that is light-modulated by the liquid crystal display element. For example, it is used for a head mounted display or the like that can confirm an image of a liquid crystal display element by directly looking into the lens. The present invention may further include a screen configured to project an image of the liquid crystal display element with a magnifying lens. This configuration can be applied to a projector or the like.

  Further, the present invention is arranged so as to be opposed to the other end face of the light guide means and configured to be able to modulate the light emitted from the light guide path and configured to emit light in the wavelength region of each primary color. A color synthesizing unit such as a dichroic prism configured to synthesize light emitted from each specific color modulation unit, and a synthesizing unit. And a projection lens disposed on the optical path of the synthesized emitted light.

  The present invention also provides a light source device configured to emit white light, a liquid crystal display element arranged to face the other end surface of the light guide means, and configured to modulate light emitted from the light guide path, A dichroic comprising a filter configured to transmit light in the wavelength region of each primary color and a specific color modulation unit corresponding to the primary color, and configured to be able to synthesize light emitted from each specific color modulation unit It may be provided with a prism and a projection lens arranged on the optical path of the emitted light synthesized by the dichroic prism. The light source device includes a surface light source array in which a plurality of light emitting elements that emit light of three primary colors are arranged in a planar shape, a light guide made of a transparent material that guides incident light from the surface light source array to the outgoing light side, May be provided. The light source device includes a surface light source array in which a plurality of light emitting elements that emit monochromatic light are arranged in a planar shape, and a light guide body made of a transparent material that guides incident light from the surface light source array to the outgoing light side. And a fluorescent film that changes the monochromatic light to white light may be disposed opposite the incident surface or the light exit surface of the light guide. The light source device is provided with a circuit for simultaneously or sequentially lighting the light emitting elements that emit the respective colors. The light emitting element may be a light emitting diode.

  In another embodiment of the present invention, images are sequentially formed on the liquid crystal display elements based on image signals separated for each color in synchronization with the light emitting diodes being sequentially turned on. Here, white light is preferable as the light emitting diode. As an embodiment for generating white light, it is conceivable to mix white LEDs or LEDs that develop colors of RGB. When a light emitting diode of a single color (for example, blue) is applied, a fluorescent film that converts light emitted in a single color by the light emitting diode into white light is disposed opposite to the incident surface or the light emitting surface of the light guide. That's fine. The light emitting diodes are composed of a plurality of colors based on the three primary colors, and are turned on simultaneously or sequentially to obtain white light respectively. In the case of sequential lighting, an afterimage of human eyes is used.

  Further, according to another aspect of the present invention, the light emitting diodes are composed of a plurality of colors based on the three primary colors and are sequentially turned on, and the liquid crystal display elements are separated for each color in synchronization with the sequential lighting of the light emitting diodes. In this case, images are sequentially formed based on the image signals, and an image for each color can be displayed, so that a high resolution can be achieved. Also in this case, a color image can be obtained by an afterimage. In the present invention, the light guide means is a function realizing means for realizing a function of guiding light from a light source. One aspect of the light guide means is a light guide as a member that realizes a light guide function, and one aspect of the light guide is a light guide block. The light guide includes a hollow or solid member. As described above, preferably, when the light guide is hollow, a metal reflection film, which is a means having a characteristic of totally reflecting light, is formed on the inner surface of the light guide.

  The light guide has a shape and dimensions that allow light to be mixed uniformly. Further, the configuration of the point light source array is also adjusted so that the characteristics of the point light source array such as the arrangement pitch of the point light sources can be uniformly mixed in the light guide.

  According to the present invention, since a light guide path structure capable of guiding light to an irradiated region, for example, a display area of a liquid crystal display element, using a plurality of point light source illuminations such as light emitting diodes without loss of light, it is small and lightweight. It is possible to provide a light source and a projection type liquid crystal display device which are inexpensive and can display a projected image with uniform light intensity.

  In addition to the above effects, the light emitted from a plurality of light-emitting elements arranged two-dimensionally is propagated through the light guide means to make the intensity distribution uniform, for example, uniformly illuminate the liquid crystal display device. It has the effect that a small light source device can be configured.

  Furthermore, in addition to the above effects, when an LED is used as a light emitting element, light emission by a battery is possible, and further miniaturization is possible.

  The preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The light source device of the present invention will be described. FIG. 1 is a perspective view of a light source device 100 according to this embodiment. FIG. 2 shows a cross-sectional view when the light source device 100 is cut along the optical axis. The light source device 100 includes a light guide block 10 and an LED (light emitting diode) array 20.

  The light guide block 10 has a prismatic shape having a hollow structure constituted by a plurality of (four surfaces) wall surfaces. The inner wall is composed of a reflective surface 11 having light reflectivity. The light guide block 10 is configured, for example, by bonding four mirrors each having the size of one wall so that the mirror surfaces face each other. However, it may be configured by attaching four sheets of metal plates such as Al deposited on a resin plate or the like, or a reflective film attached with an adhesive. Whatever configuration is adopted, in order to suppress the loss of light, the inner wall of the light guide block 10 is finished with a smooth mirror surface so that light can be totally reflected.

  The LED array 20 is configured by integrating light emitting diodes (LEDs) 21 that are point light sources in a plurality of planes, for example, two-dimensionally. Are arranged. Each LED 21 is patterned so that the positive and negative lead wires of each LED are connected in parallel, and is soldered and fixed to a substrate on which insert holes are formed corresponding to the arrangement of the LEDs. The LED array 20 includes a light emitting surface having an area substantially equal to the cross-sectional area of the light guide block 10, which is aligned so that the light emission directions of the LEDs 21 are directed in substantially the same direction. The light emitting surface of the LED array 20 is disposed at a position facing one end surface of the light guide block 10. Desirably, it is preferable to arrange the light emitting portion of the LED inside the light guide block 10 so as to be accommodated in order to eliminate light leakage. Each LED 20 is current-controlled so that, for example, an optimum forward current, for example, about 20 mA, is configured to be able to emit light simultaneously by an external power source (not shown). The emission color of the LED is preferably white, particularly when performing color display.

  Alternatively, single-color light of the three primary colors of red, green, and blue can be turned into white planar light by arranging light emitting LEDs in a predetermined pattern and lighting them all. This is advantageous in the following points. That is, when a white LED is used, the structure thereof is, for example, a structure in which light from a blue LED is color-converted by a phosphor. In this case, the outer dimension of one white LED includes a phosphor portion. So get bigger.

  On the other hand, since the LEDs that emit red, blue, or green primaries need only have the outer dimensions of the light emitting chip, the number of white LEDs that can be arranged per unit area is arranged. Can be more than Therefore, when white LEDs are obtained by arranging LEDs that emit primary colors of red, blue, or green to be fully lit, white plane light with greater intensity can be obtained. However, a single color light source device can be constructed by using an LED that emits light of a single color of red, green or blue instead of white. This monochromatic light source device can be used for primary color light emission of a color display device.

  In the above configuration, a resin mold type LED having a convex lens structure at the tip is used as a point light source. However, an LED having a planar resin package or an LED chip not covered with a resin mold may be used. Further, as long as it is a point light source that emits light with low power, another light emission principle such as a semiconductor laser element may be used.

  In the light source device having the structure shown in FIG. 1 described above, the light from the LED array 20 is uniformly mixed while being reflected by the inner wall surface (reflecting surface 11) in the light guide block 10 as shown in FIGS. Then, the light is emitted from the end surface facing the surface on which the LED array 20 is provided.

Here, in the light source device, in order for light from the LED array 20 to be uniformly mixed in the light guide block 10 and to emit plane light with uniform intensity, the light guide path of the light guide block 10 shown in FIG. From the optical axis where the length L (= L ₁ ) and the spacing P between adjacent LEDs in the LED array are such that the intensity of light emitted from each LED is half the intensity on the optical axis of the light from the LED Is set so as to satisfy the relationship of L ≧ P / (tan θ). By setting in this way, the radiated light from the adjacent LEDs is added to make the intensity distribution uniform. When the length L of the light guide path is less than P / (tan θ), there is a possibility that a place with low intensity is generated between adjacent LEDs, and the intensity distribution may not be uniform.

  In FIG. 2, the inner diameter D1 (cross-sectional area) and the total length L1 of the light guide path block 10 can be appropriately changed. The inner diameter D1, that is, the vertical width and the horizontal width of the inner wall are set corresponding to the outer shape of the liquid crystal display element used in combination with the light source device. The liquid crystal display element is configured to have an inner diameter capable of irradiating light to all pixels. The number and arrangement of the LEDs 21 are determined so that the LED array 20 can also enter light with no gap in the inner diameter set in the light guide block 10. The total length L1 of the light guide block 10 is set to such a length that the light from the point light source is dispersed by the reflection by the reflection surface 11 so that the light is emitted with sufficiently uniform intensity at the output end surface. For example, if the size of the inner diameter D1 of the light guide block 10 is 24 mm in width and 18 mm in length, the LED array 20 is arranged with a total of 48 LEDs 21 (diameter 3 mm) arranged in 8 rows and 6 columns. The total length L1 of the light guide block 10 is about 30 mm. If the size of the inner diameter D1 is smaller and a long light guide path length is required to obtain light of uniform intensity, a smaller inner diameter D2 and a longer total length L2 may be used as shown in FIG.

  In the above configuration, as shown in FIG. 2, the light emitted from the LED 21 located near the center of the LED array 20 is emitted from the other end face of the light guide without being reflected by the reflecting surface 11. On the other hand, the light emitted from the LEDs 21 located near the periphery of the LED array 20 is reflected by the reflecting surface 11 and emitted from the other end surface. Thus, the light emitted from each LED 21 is mixed in the light guide block 10. If the length L1 of the light guide block 10 in the optical axis direction is appropriately adjusted, light having a uniform intensity is emitted from the light exit surface of the light guide block 10. This uniform intensity light is suitable for light incident on a liquid crystal display element used in a projector or a head mounted display.

  As described above, according to the light source device of the first embodiment, the light from the LED, which is a point light source, is properly mixed while propagating through the light guide block, the intensity is uniformed, and uniform planar light is emitted. Therefore, it is suitable as a light source for various liquid crystal display devices such as projectors and head mounted displays.

  A point light source such as an LED is small and light and has low power consumption, and can be driven by a portable power source such as a battery. Therefore, the point light source is suitable as illumination for a portable display device.

  Furthermore, since the light guide block has a simple structure in which mirror surfaces are bonded together, it can be manufactured easily and inexpensively.

(Embodiment 2)
The second embodiment of the present invention is a small projection type liquid crystal display device suitable for using the light source device described in the first embodiment. FIG. 4 shows an optical system configuration diagram of the projection type liquid crystal display device 300 of the present embodiment.

  As shown in FIG. 4, the projection liquid crystal display device 300 includes a light source device 100, a liquid crystal display element 30, a projection lens 31, and a screen 32 housed in a housing 33. The light source device 100 is the same as that in the first embodiment. The light emission color of the light source device 100 is white. The liquid crystal display element 30 is configured to be able to control light transmission and non-transmission in units of pixels in accordance with a drive signal (not shown). That is, the liquid crystal display element 30 can receive the light emitted from the light source device 100, modulate the light in accordance with the logical state of the drive signal, and output it as an image. Specifically, the liquid crystal display element controls the transmission / non-transmission of light by changing the optical characteristics of the liquid crystal layer by changing the arrangement and orientation of regularly arranged liquid crystal molecules by an electric field or heat. It is possible to apply various known structures. In addition, the liquid crystal display element 30 includes a color filter, and a color pixel is configured by a plurality of pixels corresponding to primary colors. Color display is possible by controlling the transmission of primary color light.

  The projection lens 31 is designed so that an image light-modulated by the liquid crystal display element 30 can be formed on the screen 32. The screen 32 is translucent and is configured to be able to diffusely reflect light, so that a display image can be observed from the opposite side of the projection lens 31.

  When the present invention is applied to a liquid crystal display device such as a head-mounted display or a viewfinder, an enlarged liquid crystal is displayed when the liquid crystal display element is disposed at a position closer to the front focal length of the projection lens and the projection lens is viewed. The display element is configured so that an image can be observed.

  In addition, when the present invention is applied to a direct-view liquid crystal display device used for a personal computer or a portable electronic terminal, the liquid crystal display element can be directly observed by omitting a projection lens and a screen.

  According to the above configuration, white light with uniform intensity is emitted from the light source device 100 and is subjected to light modulation including color by the liquid crystal display element 30. The light-modulated image can be directly viewed, but is refracted by the projection lens 31 for further enlarged display. On the screen 32, an image light-modulated at an enlargement ratio determined by the distance between the projection lens 31 and the screen 32 is enlarged and displayed.

  If a stronger light quantity is required to increase the magnification of the projected image, a projection type liquid crystal display device having a liquid crystal display element for each primary color as shown in FIG. 5 may be used. The projection liquid crystal display device 400 of FIG. 5 includes a light source device 100 and a filter 40 for each primary color, and further includes a dichroic prism 41, a projection lens 42, a screen 43, and a housing 44. The filter 40 (R, G, B) converts white light from the light source device 100 into light of each primary color. The filters 40 (R, G, B) may be arranged between the light source device 100 and the liquid crystal display element 30. Note that if the LED 21 that defines the emission color of the light source device 100 is composed of elements that emit light of each primary color, the filter 40 is unnecessary. Higher light emission can be expected than when a white light emitting LED and a filter are combined. The dichroic prism 41 includes a multilayer film 41R capable of reflecting only red and a multilayer film 41B capable of reflecting only blue. The dichroic prism 41 is configured to synthesize a light-modulated image for each primary color and emit the image toward the projection lens 42. ing. The projection lens and the screen are the same as in the first embodiment. In this projection type liquid crystal display device, it can be expected that a bright image is obtained.

(Modification)
The present invention can be applied with various modifications without being restricted by the above embodiment. For example, in the light source device, the light guide block is not limited to the quadrangular prism shape as described above, but is configured to have other shapes matching the outer shape of the display area of the liquid crystal display element, a triangular prism, a pentagonal prism, or other polygonal shapes. Also good. Furthermore, the inner wall may be configured with a curved surface, and the cross section may be configured with a circular column or elliptical shape. In addition to making the hollow structure constituting the light guide hollow, a transparent material may be filled.

  As the point light source array, point light sources other than LEDs can be used as described above. The array shape is not limited to the one-dimensional two-dimensional arrangement described above, but may have a two-stage structure so that light emitted from the lower layer is not easily blocked by the upper LED. That is, the shape of the point light source array may be any shape as long as the projected shape of the point light source array is substantially equal to the end face of the light guide block facing it.

(Embodiment 3)
A third embodiment according to the present invention will be described with reference to FIGS. A light emitting diode (LED) 103 which is opposed to one end face (incident end face) of the light guide body 102 which is an acrylic resin square bar and separate from the light guide body 102 and serves as a point light source is planar, specifically 2 It is arranged on the dimension. A liquid crystal display element 101 is disposed so as to face the other end face (outgoing end face) of the light guide 102. The liquid crystal display element 101 is irradiated with light emitted from the emission end face of the light guide 102. An image displayed on the liquid crystal display element 101 is enlarged by the projection lens 104 and projected onto the screen 105.

  The size of the display area of the liquid crystal display element 101 is, for example, 10.2 mm × 7.6 mm (diagonal 0.5 inch), and an element capable of color display provided with a color filter for each pixel.

  The light guide 102 has a size of 12 mm × 8 mm and a length of 50 mm at an end face facing the liquid crystal display element 101 and the LED 103 which are moved up and down. The outer dimension of the end face of the light guide may be 10.2 mm × 7.6 mm of the display area of the liquid crystal display element 101, but is slightly larger than the display area in this embodiment. The light propagating in the light guide repeats total reflection on the side surface of the light guide 102, but this side surface is a mirror surface or a total reflection surface in order to suppress light loss due to scattering.

  As the material of the light guide 102, a transparent resin other than acrylic, glass, or the like can also be used.

  The color of the emitted light from the LED 103 is white. The LED 103 has a structure in which a light emitting element is covered with, for example, a resin, and a lens shape is formed at the tip thereof. The LED 103 has a diameter of 3 mm, and six LEDs are arranged in a 3 × 2 two-dimensional array so as to face the incident end face of the light guide 102.

  The light emitted from each LED is mixed while propagating through the light guide 102 and the intensity distribution is made uniform, and the display area of the liquid crystal display element 101 is illuminated uniformly. The length of the light guide 102 needs to be optimized depending on the size of the display area, the number and arrangement interval of the LEDs 103, or the directivity of the emitted light depending on the lens shape at the tip.

  Preferably, in order to mix light uniformly in the light guide 102 and emit plane light with a uniform intensity distribution, the length L of the light guide path in the light guide 102 and the interval P between adjacent LEDs 103 are: The angle θ from the optical axis at a position where the intensity of light emitted from each LED is half the intensity distribution on the optical axis of the light from the LED is set so as to satisfy the relationship L ≧ P / (tan θ). The By setting in this way, the radiated light from the adjacent LEDs is added to make the intensity distribution uniform. If the length L of the light guide path is less than P / (tan θ), a weak place may occur between adjacent LEDs, and the intensity distribution may be uneven.

  The array of LEDs 103 is separate from the light guide 102 and is preferably provided with the light guide 102 via an air layer. In such a structure, the inner wall of the side part other than the light exit surface of the light guide is subjected to processing such as polishing, so that the light is totally reflected by the side inner wall in the light guide and the light is mixed and the intensity distribution is uniform. Turn into. Moreover, even if it is the solid light guide 102, you may provide reflective films, such as a metal thin film, in a side part end surface.

  The projection lens 104 is composed of a plurality of lenses, and has a diameter of 30 mm, for example. An image of the liquid crystal display element 101 having a display area of 0.5 inch diagonal is enlarged to 7 inches diagonal and projected onto the screen 105.

  When a video image or a television image is displayed on the liquid crystal display element 101, a known circuit is used for a display circuit (not shown) connected to the liquid crystal display element, and the display can be performed with a DC voltage of about 5V. . Further, since the LED 103 emits light with a DC voltage of about 3 V, a battery can be used as a power source for the liquid crystal display element of the present embodiment (Embodiment 3). Therefore, the entire apparatus can be remarkably reduced in size as compared with a conventional projection type liquid crystal display apparatus using a metal halide lamp or the like as a light source.

  In the present embodiment (Embodiment 3), the configuration of a display device that illuminates a liquid crystal display device using a color filter with a white LED has been described. However, a liquid crystal display element that omits the color filter emits light in a single color, for example, green. It is also possible to configure an apparatus that obtains a color image by mixing monochromatic images illuminated by LEDs or projecting them on one screen in a time-sharing manner.

  Further, as the LED 103, an LED having a lens shape at a portion where light is emitted is used, but an LED having a flat end surface at a portion where light is emitted can also be used. In this case, it is necessary to optimize the length of the light guide 102 in order to make the distribution of the front light in the liquid crystal display element uniform.

  In the light source device according to the present embodiment (Embodiment 3), the light source in which a plurality of LEDs are arranged has been described. However, even when one LED is used as the light source, the intensity distribution of the radiated light is generated by the light guide. A configuration in which the emitted light of the LED is guided to the liquid crystal display element while approaching uniformly can be considered.

  Further, when a support member for supporting and fixing the light guide 102 to the liquid crystal display device comes into contact with the side surface of the light guide 102, light is scattered or absorbed at that portion, and the amount of light reaching the liquid crystal display element is reduced. Therefore, it is possible to return the light into the light guide by depositing a metal thin film on the surface of the light guide at the portion where the support member contacts or by attaching a mirror-like reflective member, so that the light use efficiency is not lowered. It is effective for.

(Embodiment 4)
Embodiment 4 according to the present invention will be described below. In the fourth embodiment, the same parts as those in the third embodiment are denoted by the same component numbers, and the description of the configuration is omitted.

  As shown in FIGS. 8 and 9, the feature of the fourth embodiment is that, for example, an LED 103 </ b> B that emits blue light is applied as the light emitting diode (LED) 103.

  As shown in FIG. 10, the LEDs 103B are two-dimensionally arranged in three rows and six columns on the substrate 109. For example, the spacing between the rows is 2.5 mm and the spacing is 2 mm. This arrangement is not limited.

A fluorescent film 107 is disposed on the light exit surface side of the light guide 102. The fluorescent film 107 is excited by blue light and undergoes color conversion. In the present embodiment (Embodiment 4), a red phosphor and a green phosphor are used as the phosphors. White light is generated including blue light passing therethrough.
With respect to such a light source device, the liquid crystal display element 101, the projection lens 104, and the screen 105 can be arranged on the downstream side of the fluorescent film 107 to constitute a liquid crystal display device.

  This is advantageous in the following points. That is, when a white LED is used, the structure thereof is, for example, a structure in which light from a blue LED is color-converted by a light guide. In this case, the outer dimension of one white LED also includes the light guide part. It becomes so big. On the other hand, since the LED that emits blue light only needs the size of the light-emitting chip, the number of LEDs that can be arranged is larger than the number of white LEDs that can be arranged per unit area. it can. Therefore, stronger white light can be obtained by arranging and using only the blue LED array and performing color conversion while increasing the energy of the emitted light.

(Embodiment 5)
Embodiment 5 according to the present invention will be described below. In the fifth embodiment, the same parts as those in the third embodiment are denoted by the same component numbers, and the description of the configuration is omitted.

  As shown in FIGS. 11 and 12, the feature of the fifth embodiment is that LEDs 103 </ b> R, 103 </ b> G, and 103 </ b> B that emit colors of RGB are applied as the light emitting diode (LED) 103.

  As shown in FIG. 13, the LEDs 103R, 103G, and 103B are two-dimensionally arranged on the substrate 109 in three rows and six columns, with a row spacing of 2.5 mm and a column spacing of 2 mm. Each color is arranged in a staggered manner. This arrangement is not limited.

  In the present embodiment (Embodiment 5), LEDs corresponding to the three primary colors are used. However, if there is no problem in generating a color image, light is emitted in a color such as orange instead of red and yellow green instead of green. You may use LED to do.

  In the fifth embodiment, since a color filter is attached to each pixel of the liquid crystal display element, white light is preferable as the light source color. Therefore, it is general that all the LEDs 103 on the substrate 109 are turned on at the same time. Thus, by passing through the light guide 102, each color is mixed and white light can be obtained.

  In the present embodiment, as described above, since the LEDs emitting light of the primary colors of red, blue, or green whose outer dimensions are smaller than those of the white LEDs are planarly arranged, specifically two-dimensionally arranged to emit light, the density of the light source Becomes larger and plane light with higher intensity can be obtained.

  Note that the LEDs 103R, 103G, and 103B may be separated and lighted sequentially for each color in a very short time. This uses an afterimage of the human eye, and is a method that applies an interlace method for television images. By sequentially lighting, the unit power consumption can be reduced, and the battery and the like can be prolonged for that amount.

(Modification)
FIG. 14 shows a modification of the color image display device using sequential lighting.
Each pixel of the liquid crystal display element 101 applied to this modification has no color filter, and forms an image for each color in synchronization with the sequential lighting of the LEDs 103R, 103G, and 103B, and displays a color image. It is like that.

  That is, the image signal is input to the color separation circuit 210 and separated for each color signal. Each color signal color-separated by this color separation signal is supplied to the synchronization circuit 212 and the LCD driver 214. The LCD dry 214 controls the liquid crystal display element 101 based on the input color signal to form an image.

  On the other hand, the synchronization circuit 212 synchronizes with the color signal corresponding to the image displayed by the LCD driver 214 and supplies it to the multiplexer 216. The multiplexer 216 sequentially selects the R driver 218, the G driver 220, and the B driver 222, and supplies a lighting signal. As a result, the LEDs 103R, 103G, and 103B are turned on with colors that match the liquid crystal display element 101. As described above, the image displayed on the screen 105 is an image in which three colors are mixed due to the afterimage effect.

  According to the above configuration, since each color image can be expressed using all the pixels of the liquid crystal display element 101, the resolution of the image can be tripled compared to the color filter type liquid crystal display element.

It is a perspective view of the light source device of the first embodiment. It is optical axis direction sectional drawing of the light source device in Embodiment 1 of this invention. It is optical axis direction sectional drawing of the modification of the light source device in Embodiment 1 of this invention. 1 is a configuration diagram of an optical system of a projection type liquid crystal display device in Embodiment 1. FIG. FIG. 5 is a configuration diagram of an optical system of a projection type liquid crystal display device in Embodiment 2. It is a top view of the main optical systems of the light source device and the projection type liquid crystal display device in the third embodiment. It is a perspective view of the main optical systems of the light source device and projection type liquid crystal display device in Embodiment 3. FIG. 6 is a top view of main optical systems of a light source device and a projection type liquid crystal display device in Embodiment 4. It is a perspective view of the main optical systems of the light source device and projection type liquid crystal display device in Embodiment 4. It is a top view of the light source part in Embodiment 4. FIG. 10 is a top view of main optical systems of a light source device and a projection type liquid crystal display device in Embodiment 5. FIG. 10 is a perspective view of main optical systems of a light source device and a projection type liquid crystal display device in Embodiment 5. 10 is a plan view of a light source unit in Embodiment 5. FIG. FIG. 10 is a top view and a drive circuit diagram of main optical systems of a light source device and a projection type liquid crystal display device in a modification of Embodiment 5.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Light guide block, 11 Reflecting surface, 20 LED array, 21 LED, 100 Light source device, 300,400 Projection type liquid crystal display device, 101 Liquid crystal display element, 102 Light guide, 103 LED, 104 Projection lens, 105 Screen, 107 Fluorescent film, 210 color separation circuit, 212 synchronization circuit, 214 LCD driver, 216 multiplexer, 218 R driver, 220 G driver, 222 B driver

Claims (5)

Light guide means comprising end faces facing each other, for guiding and emitting light incident from one end face to the other end face;
A light source unit disposed on the side of the one end face of the light guide means and configured by a plurality of light emitting units;
A light modulation element that is disposed on the other end face side of the light guiding means and modulates light emitted from the light source unit;
A lens for projecting light modulated by the light modulation element;
A projector comprising:
The light guide means includes a hollow light guide portion having an inner wall having light reflectivity, and the light from the light source portion is mixed by being incident from at least one end face, and faces the surface on which the light source is provided. Led to the other end face side to emit,
The one end face in the hollow light guide portion is configured to house a plurality of light emitting portions on the inside of the hollow light guide section, and a substantially equal cross-sectional area to the area of the plurality of light emitting portions Have
A projector characterized by that.   The projector according to claim 1, wherein the one end surface and the other end surface are arranged in parallel.   The projector according to claim 1, wherein the light guide unit has a polygonal column shape in which the inner wall includes a plurality of reflection surfaces.   The said light guide part has a quadrangular prism shape comprised from four side surfaces corresponding to the said one end surface, said other end surface, and the inner wall provided with light reflectivity. Projector.   The projector according to claim 1, wherein the light guide portion has a cylindrical shape in which the inner wall is configured by a curved surface.

Images