JP4638815B2 - Light guide plate having light lens array, light irradiation device, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate capable of diffusing optical source light for emitting uniform surface light in a liquid crystal display device, increasing luminance, and properly setting light collecting power in the height direction and width direction and a view angle in the non-light collecting direction. <P>SOLUTION: In this light guide plate 4, in which light from a light source 9 is directly incident on an incoming face 4a to be guided in the direction parallel to an outgoing face 4b and surface light is emitted from the outgoing face 4b, the microlens array 2, in which a plurality of micro anamorphic lenses 2a having light gathering function in the predetermined direction are arranged at random, is integrally formed on the incoming face 4a and/or the outgoing face 4b. The respective light gathering cross sectional faces (main meridional planes) of a plurality of micro anamorphic lens 2a arranged on the incoming face 4a or the outgoing face 4b are arranged in the same direction. Light is irregularly reflected by an irregular pattern of the microlens array 2 arranged in the light guide plate 4. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a light guide plate that converts light from a light source into a planar shape. More specifically, the light from a light source is directly incident on an incident surface to be guided in a direction parallel to the exit surface, and the surface from the exit surface. The present invention relates to a light guide plate that emits light in a shape, and a light irradiation device and a liquid crystal display device including the light guide plate.

The light guide plate is used in various illuminating devices used for backlights of liquid crystal display devices, light emitting display plates, and the like, and the conventional technology in which the conventional light guide plates are used for backlights of liquid crystal display devices is described in detail below. To do.
FIG. 14 shows a conventional liquid crystal display device 101 described in Japanese Patent Laid-Open No. 5-173133 (Patent Document 1). The liquid crystal display device 101 includes a light source 106 that illuminates the liquid crystal panel 108 from behind, and the light source 106 includes a hot cathode U-tube 106a and a reflector 106b. Light irradiated backward from the hot cathode U-shaped tube 106a is reflected to the liquid crystal panel 108 by the reflecting plate 106b. The liquid crystal display device 101 further includes a diffusion plate 107 that diffuses light from the light source 106 to the liquid crystal panel. Further, a translucent light guide plate 104 that guides light from the light source 106 in a direction parallel to the liquid crystal panel 108 is provided behind the diffuser plate 107, and light from the light source 106 is provided on the rear surface of the light guide plate 104. A light-transmitting scattering film 111 that scatters while transmitting is formed.

  A light diffusing sheet 110 is provided in front of the diffusing plate 107 to collect the light from the diffusing plate 104 forward and prevent the interference. Light from the light source 106 enters the light guide plate 104, is scattered by the light transmissive scattering film 22, and enters the light guide plate 21 in an oblique direction. The light in the light guide plate 104 is guided over a wide range in the direction parallel to the liquid crystal panel 108, and the uneven brightness is reduced. Thereafter, the light is emitted forward from the light guide plate 108, passes through the diffusion plate 107 and the light diffusion sheet 110, and then illuminates the liquid crystal panel 108 from the rear.

  FIG. 15 is an exploded perspective view of the liquid crystal display device 101 on which a conventional light guide plate is disposed. A reflector 106b on the back side of the light source 106 made of a fluorescent lamp is arranged, and a diffuser plate 107 for uniformly diffusing the light source light in all directions is arranged on the front surface of the light source 106. A liquid crystal panel 108 is disposed opposite to the front surface of the diffusion plate 107, an incident polarizing plate 108a is disposed on the rear surface of the liquid crystal panel 108, and an output polarizing plate 108b is disposed on the front surface. The prism sheet 109 for efficiently condensing the diffused light from the diffuser plate 107 within the viewing angle between the diffuser plate 107 and the liquid crystal panel 108 to increase the front luminance is the left-right direction (horizontal direction). It is arranged in the state.

The transmission axis direction (arrow direction) of the incident polarizing plate 108a is the vertical direction, that is, the direction perpendicular to the ridge line direction (vertical direction), and the transmission axis direction (arrow direction) of the output polarizing plate 108b is the horizontal direction (horizontal direction). Has been. Therefore, it is possible to use the P wave having a higher transmittance than the S wave, and the transmission axis direction (arrow) of the incident polarizing plate 108a is set to be perpendicular to the ridge line direction of the prism sheet 109. As a result, the prism sheet 109 is limited to one to ensure a relatively large luminance viewing angle.
JP-A-5-173133 JP 2003-295186 A

  In the liquid crystal display device 101 shown in FIG. 14, a light diffusing plate 107 that diffuses light from the light source 106 to the liquid crystal panel and a light transmissive scattering film 111 that scatters while transmitting light from the light source 106 are provided. Also. In the liquid crystal display device 101 of FIG. 15, a diffusion plate 107 that uniformly diffuses light source light in all directions, and a prism sheet for concentrating the diffused light from the diffusion plate 107 within the viewing angle efficiently to increase the front luminance. 109 is provided. A loss of light amount of about 8% or more (Fresnel loss) occurred for one of these optical members, and this loss was accumulated in a multiplicative manner. Accordingly, there has been a demand for reducing the loss of light quantity by reducing the number of optical members as described above.

  Further, the liquid crystal display device has a lower luminance than a cathode ray tube (CRT) display, and in principle can further save energy. However, a liquid crystal display device used for a television (TV) or the like is a screen. In the case of 60 inches or more, power consumption exceeds 600 W, and more efficient use of energy (light) has been demanded.

  The present invention has been made in view of the above problems, and provides a uniform surface light source of a liquid crystal display panel such as a TV by uniformly diffusing a cold-cathode tube or a light-emitting diode (LED) light source to white. By condensing the light from the light source, the light transmittance of the liquid crystal panel can be increased, the brightness of the liquid crystal display panel can be increased, and the light intensity in the height and width directions can be set appropriately. An object of the present invention is to provide a light guide plate capable of improving the viewing angle in the light collecting direction.

  The present invention has been proposed in order to solve the above-described problem. In the first embodiment of the present invention, the light from the light source is directly incident on the incident surface and guided in the parallel direction of the output surface, In a light guide plate that emits light in a planar shape from an exit surface, a microlens array in which a plurality of microanamorphic lenses having a condensing function in a predetermined direction are irregularly arranged is on the entrance surface and / or the exit surface And a plurality of minute anamorphic lenses provided on the entrance surface or the exit surface are arranged in the same direction, and the microscopic lens array irregularly reflects light. A light guide plate having a lens array.

  According to a second aspect of the present invention, in the first aspect, each condensing axis of a plurality of micro anamorphic lenses provided on the incident surface or the exit surface is in the height direction or the width direction of the exit surface. A light guide plate having a microlens array in which the microlens arrays are arranged so as to coincide with each other.

  According to a third aspect of the present invention, in the first or second aspect, the condensing cross-sectional directions of the microlens arrays provided on the entrance surface and the exit surface are arranged so as to be substantially orthogonal or substantially coincide with each other. A light guide plate having a microlens array.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the microlens array includes two or more types of microanamorphic lenses having different sizes and / or shapes. A light guide plate having an array.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the curvature radius of the microscopic anamorphic lens in the condensing cross-sectional direction is 0.01 mm to 1 mm, and is orthogonal to the condensing surface. It is a light-guide plate which comprises the micro lens array whose curvature radius of a non-light-condensing cross-sectional direction is 10 mm-100 mm.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the length of the microscopic anamorphic lens in the condensing cross-sectional direction is 0.1 to 1 mm, and the non-condensing cross-sectional direction is It is a light-guide plate which comprises the micro lens array whose length is 1-10 mm.

  According to a seventh aspect of the present invention, in any one of the first to fifth aspects, the micro anamorphic lens is a circular lens having different curvatures in the condensing cross-sectional direction and the non-condensing cross-sectional direction. A light guide plate having a microlens array.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the micro lens array is an irregular array in which the micro lens intervals in a predetermined direction are irregularly shifted from an equal interval position. It is a light guide plate comprising a microlens array that is a pattern and has a deviation width from the equally spaced position of 1/1000 to 1/10 of the average distance.

  According to a ninth aspect of the present invention, there is provided a light guide plate including the microlens array according to any one of the first to eighth aspects, and at least one light source disposed on the incident surface side of the light guide plate. The light irradiation device is configured to irradiate light from the light source by converting the light into a planar shape by the light guide plate.

  A tenth aspect of the present invention is the light irradiating device according to the ninth aspect, wherein the light source includes a cold cathode tube and a reflector that reflects light from the cold cathode tube toward the incident surface. .

  An eleventh aspect of the present invention is the light irradiation apparatus according to the ninth aspect, wherein the light source is formed of a white light emitting diode.

  According to a twelfth aspect of the present invention, in the ninth aspect, the light source is composed of light emitting diodes of RGB (red, green, blue) three colors, and light irradiation for whitening the RGB light by the micro lens array Device.

  A thirteenth aspect of the present invention includes a backlight composed of the light irradiation device according to the tenth or eleventh aspect, and a liquid crystal panel that displays an image by transmitting planar light emitted from the backlight. This is a liquid crystal display device.

According to the first aspect of the present invention, the micro lens array in which a plurality of micro anamorphic lenses are irregularly arranged on the incident surface and / or the output surface of the light guide plate is integrally formed. The light from the point light source and / or the line light source can be converted into uniform planar light by the light guide plate according to the invention and emitted from the emission surface. As described above, in order to convert the light from a point light source or a line light source into planar light using a conventional light guide plate, a light diffusion sheet or the like is provided between the light guide plate and the light source to equalize the amount of light. In addition, it is necessary to dispose an optical member such as a lens sheet that collects light on the exit surface side. However, since the microlens array having an irregular pattern is integrally formed in the light guide plate according to the present invention, it is not necessary to dispose a light diffusion sheet and a condensing lens sheet, and the loss of light amount in these optical members ( Since there is no Fresnel loss, light from the light source can be converted into planar light with high efficiency. The light guide plate according to the present invention can be manufactured from acrylic resin (PMMA), polycarbonate (PC), cyclic polyolefin (COP), and polystyrene (PS) by injection molding using a mold, and is also a thermosetting resin or ultraviolet ray. It can be formed from various light transmissive resins such as a curable resin.
In addition, since the boundary between the minute anamorphic lens and the light guide plate is irregularly formed, light is irregularly reflected by the irregular pattern, and the formation of an interference pattern can be prevented. Can be injected. Further, since the plurality of micro anamorphic lenses provided on the entrance surface or the exit surface are arranged in the same direction in each condensing section, the condensing section direction is appropriately set and light is emitted in a desired direction. Can be condensed. Here, the light collection cross section is a plane parallel to the lens cross section in which the curvature of the convex surface or the concave surface is maximum in the micro anamorphic lens, and is also called a main meridional plane (Warren J. Smith, “ Modern Optical Engineering (second edition) McGraw-Hill, Inc. 1990 (Non-Patent Document 1)) In this specification, as will be described later (see, for example, FIG. 9), the light concentration of the micro anamorphic lens is the largest. The cross-sectional direction and the plane direction parallel to the cross-sectional direction are referred to as the condensing cross-sectional direction, and the surface direction perpendicular to the condensing cross-sectional direction with respect to the optical axis is the non-condensing cross-sectional direction. The micro anamorphic lens according to the present invention only needs to have a large curvature in the condensing cross-sectional direction and a small curvature in the non-condensing cross-sectional direction. Micro anamorph In a cross lens, the cross section in the short direction corresponds to the condensing cross section direction, the cross section in the longitudinal direction corresponds to the non-condensing cross section direction, and the cross section is against rotation about the optical axis (or central axis). The degree of condensing may be designed to decrease from the condensing cross-section direction to the non-condensing cross-section direction, and all surfaces parallel to the condensing cross-section direction or non-condensing cross-section direction are designed to have substantially the same curvature. You can also
The light guide plate according to the present invention can convert light from one or a plurality of point light sources or line light sources into planar light, and can be used for various light irradiation devices. For example, uniform planar light can be applied to a headlight of an automobile, a room light, a spotlight, a backlight for liquid crystal display, a light emitting display board, and the like.
Warren J. Smith, “Modern Optical Engineering (second Edition) McGraw-Hill, Inc. 1990

According to the second aspect of the present invention, the respective light collecting cross sections of the plurality of minute anamorphic lenses provided on the incident surface or the exit surface are aligned with the height direction or the width direction of the exit surface. Since the microlens array is disposed, the light transmitted through the light guide plate according to the present invention can be focused in the condensing section direction. In liquid crystal display devices used for personal computer displays and televisions, it is necessary to secure a viewing angle in the width direction, but since the user views at almost the same height, the viewing angle in the height direction is In many cases, there is no problem even if it is relatively narrow. Therefore, high luminance can be ensured by making the light collection cross section coincide with the height direction to suppress diffusion from the display screen and collect light.
Moreover, even when the light guide plate of the second form is used for a light emitting display device such as a signboard or an emergency light, or a lighting fixture, by setting the light collecting cross section direction in a predetermined direction, Light from the light source can be irradiated with high efficiency. For example, when the area irradiated by the lighting fixture extends only in a specific direction, the diffusion cross section direction is set to suppress the diffusion of light in a predetermined axial direction and irradiate only the irradiation area with high efficiency. be able to. In addition, when the light guide plate according to the present invention is used in a light emitting display device, it is possible to enhance luminance in a desired direction and display various information with high efficiency.

According to the third aspect of the present invention, when the condensing cross-sectional directions of the microlens arrays provided on the entrance surface and the exit surface are arranged so as to be substantially orthogonal to each other, planar transmitted light is transmitted as a single piece. It is possible to collect light in the emission direction and to emit high-luminance transmitted light with high efficiency. For example, a display device used for a mobile phone, an automatic teller machine (ATM), etc. displays important personal information in a public place, and provides information to only one user with a narrow viewing angle. It is required to do. Accordingly, when displaying information only to a specific user, by providing the light guide plate according to the present invention, planar light is focused only in a specific direction, and information visible only to the user is output. A display device can be provided. In addition, for example, in a lighting device installed in an airplane or an automobile, it is required to irradiate only a specific target with light. By using the light guide plate according to the present invention, uniform planar light can be converged and irradiated onto a predetermined region.
Further, according to the third aspect, when the micro lens arrays are arranged so that the light collecting cross-sectional directions thereof are substantially coincident with each other, the light condensed and scattered (homogenized) on the incident surface is collected again on the output surface. Since it emits light, the degree of concentration of transmitted light can be significantly improved. Therefore, diffusion of light in a predetermined direction can be suppressed and focused.

  According to the fourth aspect of the present invention, since the microlens array is composed of two or more types of microanamorphic lenses having different sizes and / or shapes, the irregularity of the microlens array is enhanced, Light from the light source can be uniformly scattered on the entrance surface and / or the exit surface, and converted into planar light having no intensity unevenness. In addition, the generation of interference fringes by the lens array can be reliably prevented.

  According to the fifth aspect of the present invention, the curvature radius of the micro anamorphic lens in the condensing cross-sectional direction is 0.01 mm to 1 mm, and the radius of curvature in the non-condensing cross-sectional direction orthogonal to the condensing cross-section is 10 mm. Since it is ˜100 mm, as will be described in detail later, the light collection degree in the height direction and the width direction can be set to a suitable ratio. That is, it is possible to emit transmitted light having a suitable luminance and spreading in a predetermined direction. For example, if the light guide plate of the fifth embodiment is used in a liquid crystal display device, the viewing angle in the width direction can be suitably maintained, and an image having a preferable luminance can be displayed by focusing in the height direction. In addition, when used in a lighting device or the like, light can be irradiated with high brightness only in a desired direction, and light can be irradiated with high efficiency without diffusing light in unnecessary directions. For example, in an elongated space such as a passage, light can be diffused and irradiated only in the direction of traffic.

  According to the sixth aspect of the present invention, the length of the microscopic anamorphic lens in the condensing cross-sectional direction is 0.1 to 1 mm, and the length of the non-condensing cross-sectional direction is 1 to 10 mm. A light guide plate having a micro lens array having a suitable lens area and radius of curvature can be provided. Therefore, the light transmitted through the micro lens array can be condensed and diffused with high efficiency.

  According to the seventh aspect of the present invention, since the micro anamorphic lens is a circular lens having different curvatures in the condensing cross-sectional direction and the non-condensing cross-sectional direction, the micro anamorphic lens can be freely used. Can be irregularly arranged. As described above, in the present specification, lenses having different curvatures in at least the orthogonal condensing / non-condensing cross-section (main meridional plane) directions are called anamorphic lenses. Compared to a semi-cylindrical anamorphic lens, a circular anamorphic lens has a high degree of freedom in arrangement and can be arranged in an irregular and dense state. Therefore, the light can be efficiently focused and the uniformity of the intensity of the emitted planar light can be remarkably improved.

  According to the eighth aspect of the present invention, the lens interval in the predetermined direction of the micro lens array is an irregular pattern arranged irregularly from an equidistant position, and a deviation width from the equidistant position is set. Since the average interval is set to 1/1000 to 1/10, a suitable irregular pattern can be designed easily. For example, when the average interval of the minute anamorphic lens is set to 10 mm, the irregular pattern can be easily formed by arranging the minute anamorphic lens by shifting from the equal interval position vertically or horizontally about 0.01 mm to 1 mm. Can be designed.

  According to the ninth aspect of the present invention, the light irradiation device includes a light guide plate including the microlens array of any one of the first to eighth aspects, and at least one disposed on the incident surface side of the light guide plate. Since it is comprised from two or more light sources, the light irradiation apparatus which irradiates planar light with high uniformity can be provided. If the light guide plate according to the present invention is used, the light condensing cross-sectional direction can be set to a predetermined direction. Therefore, a light irradiation device that emits uniform planar light according to an object to be irradiated with light or a space is provided. It can be designed easily, and various light irradiation devices can be provided.

  According to a tenth aspect of the present invention, the light source is composed of a cold cathode tube and a reflector that reflects light from the cold cathode tube in the direction of the incident surface, and direct light and reflection from the cold cathode tube. The light irradiation apparatus which irradiates the reflected light reflected by the board as uniform planar light can be provided. Since the light is irregularly reflected by the irregular pattern of the minute anamorphic lens provided on the light guide plate according to the present invention, it is possible to provide a light irradiation device with a small loss of light amount and high energy efficiency.

  According to the eleventh aspect of the present invention, since the light source is composed of a white light emitting diode with low power consumption and high energy efficiency, further energy saving can be achieved. Further, the light source is provided with a reflection plate that reflects the light of the white light emitting diode in the direction of the incident surface, and the direct light from the white light emitting diode and the reflected light reflected by the reflection plate are made into uniform planar light. A light irradiation device for irradiation can be provided. Since the light is irregularly reflected by the irregular pattern of the minute anamorphic lens provided on the light guide plate according to the present invention, it is possible to provide a light irradiating apparatus with extremely low energy loss and extremely high energy efficiency.

  According to the twelfth aspect of the present invention, the light source is composed of RGB (red, green, blue) light emitting diodes, and the RGB light from the light emitting diodes is diffusely reflected by the micro lens array. Can be converted to uniform white light to provide a white light source. Since the light source is composed of a light emitting diode, it is possible to provide a white light irradiation apparatus with low power consumption and extremely high energy efficiency.

  According to the thirteenth aspect of the present invention, from the backlight comprising the light irradiating device of the tenth or eleventh aspect, and the liquid crystal panel that transmits the planar light emitted from the backlight and displays an image. As a result, a high-brightness liquid crystal display device can be provided. The light guide plate according to the present invention has a microlens array having an irregular pattern and does not require a light diffusing plate or the like, so that loss of light quantity can be reduced and high brightness image display can be realized. it can. Furthermore, since the light guide plate according to the present invention can set the light collecting axis direction to a predetermined direction, the viewing angle can be freely set according to the method of using the liquid crystal display device.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an apparatus according to the present invention will be described in detail with reference to FIGS.
FIG. 1 is a schematic configuration diagram of a liquid crystal display device 1 according to the present invention. The liquid crystal display device 1 includes a light guide plate 4 having a micro lens array 2, a light source 6, a liquid crystal panel 8, and a diffuser plate 10. A micro anamorphic lens 2 a is provided on an incident surface 4 a of the light guide plate 4. The irregularly arranged microlens array 2 is integrally formed. In FIG. 1, only a part of the microlens array 2 is illustrated, but the microlens array 2 is formed on substantially the entire incident surface 4a (not shown). As will be described later, the anamorphic lens has different curvatures in the height direction and the width direction, and has a condensing cross-sectional direction in which the curvature radius of the lens is set small and a non-condensing cross-sectional direction in which the curvature is set large. Different light collecting functions are given in predetermined directions. The light source 6 is composed of a cold cathode tube 6a and a reflector 6b, and the reflected light from the reflector 6b is irradiated in the direction of the light guide plate together with the direct light from the cold cathode tube 6a.

  In this embodiment, the minute anamorphic lenses are arranged so that the longitudinal direction thereof coincides with the X-axis direction, and the Y-axis direction is set as the condensing cross-sectional direction. Accordingly, the light incident from the light source 6 is irregularly reflected by the boundary 2b between the microlens array 2 and the light guide plate body 4c, and the incident light is converged in the condensing cross-section direction by the microanamorphic lens, and the exit surface The brightness of the planar light emitted from 4b is made uniform and the brightness is increased. In other words, since the light from the light source 6 is converted into planar light that has been made uniform and brightened by the light guide plate 4 without passing through a light diffusing plate or the like, it is possible to suppress loss of light amount. it can. The planar light is guided to a liquid crystal panel including a pair of polarizing plates 8a and 8b. Further, when a large viewing angle is required, as shown in FIG. 1, by arranging a diffusion plate 10, planar light that has been imaged through the liquid crystal panel 8 is incident on the light diffusion plate 10. Thus, it is possible to enlarge the viewing angle in the left and right and up and down directions, and the viewing angle can be increased to 170 ° or more.

  FIG. 2 is a schematic configuration diagram of the liquid crystal display device 1 in which the light guide plate 4 in which the microlens array 3 according to the present invention is integrally formed on the emission surface 4b is provided. Hereinafter, about the same member shown by FIG. 1, a code | symbol and description are partially abbreviate | omitted, when there is no additional description. In this embodiment, the minute lens arrays 2 and 3 composed of the minute anamorphic lenses 2a and 3a are integrally formed on the exit surface 4b side as well as the incident surface 4a side. These microlens arrays 2 and 3 are both arranged in the Y-axis direction so as to be in the condensing section direction. Therefore, the light from the light source 6 is condensed in the Y-axis direction by the minute lens arrays 2 and 3 on the incident surface 4a and the exit surface 4b, and the boundary 2c between the minute lens arrays 2 and 3 and the light guide plate body 4c. The light is irregularly reflected by 3c, and the amount of light is made more uniform.

  FIG. 3 is a schematic configuration diagram of the liquid crystal display device 1 in which the light guide plates 2 in which the light collection cross-sectional directions of the microlens arrays 2 and 3 according to the present invention are orthogonal to each other are arranged. In this embodiment, the microlens arrays 2 and 3 integrally formed on the incident surface 4a and the exit surface 4b of the light guide plate 4 are configured so that the light collection cross-sectional directions are orthogonal to each other. Therefore, the light passing through the light guide plate 4 is condensed in the Y-axis direction by the microlens array 2 on the incident surface 4a, and further condensed in the X-axis direction by the microlens array 3 on the exit surface 4b. Therefore, an extremely high-brightness liquid crystal image without unevenness is provided. Further, by appropriately designing the condensing degree of the micro lens array 2 on the incident surface side and the micro lens array 3 on the output surface side, desired viewing angles in the height direction and the width direction can be realized.

  FIG. 4 is a schematic configuration diagram of the liquid crystal display device 1 in which a light source is disposed on the end face of the light guide plate 4 according to the present invention. The backlight unit is composed of a light guide plate 4 and light sources 6 and 6 disposed on the end face of the light guide plate. The light source light enters the light guide plate 4 from the incident surface 4a, and repeats total reflection to be inside the light guide plate 4. Is guided. Furthermore, the back surface 4d of the light guide plate 4 is provided with a diffraction grating, a dot pattern, or the like (not shown) by printing or processing, and a part of the light scattered by these members is emitted from the emission surface 4b. In FIG. 4, a micro lens array composed of micro anamorphic lenses 2a is integrally formed on the exit surface 4b, and the light emitted from the exit surface 4b after being guided through the light guide plate 4 is emitted from the micro lens array. As a result, the light is focused in the direction of the light condensing section and is diffusely reflected by the boundary portion 2c to make the light quantity of the planar light uniform. Although not shown, a reflector can be provided on the back of each of the light sources 6 and 6.

  FIG. 5 is an array diagram of the micro anamorphic lens 2a according to the present invention. The microlens array 2 shown in (5A) is a microlens array in which microanamorphic lenses 2a are irregularly arranged so that the Y-axis direction is the focusing direction, and is integrally formed on the incident surface 4a of FIG. A part of 2 is shown. The minute anamorphic lens 2a has an elliptical shape, is designed so that the curvature in the short direction is large and the curvature in the long direction is small, and the short direction is the condensing cross-sectional direction. . In (5B), the minute anamorphic lenses 2a are irregularly arranged so that the light collecting cross-sectional direction 2c is oriented in the X-axis direction. Similarly to (5A), the micro anamorphic lens 2a of (5B) has a large curvature in the short direction and is set in the condensing section direction 2c. Further, as described above, the light source light is irregularly reflected by the light guide plate 4 and the boundary portions 2b and 2b of the minute anamorphic lens 2a formed integrally with the light guide plate 4.

  FIG. 6 is a schematic cross-sectional view of the light guide plate 4 according to the present invention. (6A) is an X-axis cross section of FIG. 5 (5A), and as shown in the figure, the minute anamorphic lens 2a is integrally formed with the light guide plate body 4c. The light guide plate provided with the microlens array 2 is preferably integrally formed by injection molding of resin or glass material. (6B) corresponds to a cross-sectional view in the Y-axis direction in FIG. 5 (5A). As is clear from the figure, the short direction of the minute anamorphic lens 2a has a much larger curvature than the long direction.

FIG. 7 is an explanatory diagram showing a method for designing an irregular pattern of the minute anamorphic lens 2a according to the present invention. In FIG. 5, the minute anamorphic lenses 2a are arranged irregularly densely, but as a simple design method of the irregular pattern, as shown in FIG. 7 (7A), each minute anamorphic lens 2a is arranged. Can be designed by irregularly shifting from each equally spaced position P. As shown in (7B), the k-th micro anamorphic lens in the X-axis direction and the n-th micro anamorphic lens in the Y-axis direction are shifted from the equally spaced position P by ΔX _{kn in} the X-axis direction and ΔY _{kn in the} Y-axis direction, An irregular pattern is designed by setting ΔX _kn and ΔY _kn at random within the range. Alternatively, an irregular pattern may be designed by setting one of ΔX _kn and ΔY _kn and irregularly shifting the arrangement in either the X-axis direction or the Y-axis direction. When only ΔX _kn is set, the value of | ΔX _kn | can be set randomly in the range of d / 10 to d / 1000 with respect to the average interval d shown in (7A). For example, when the average distance d is about 10 mm, the value of | ΔX _kn | may be set in the range of 0.01 mm to 1 mm. Further, the irregular pattern may be designed by fixing the value of ΔX _kn and irregularly determining the shifting direction and order. According to this method, an irregular pattern can be designed easily. The irregular pattern of the micro lens array is designed based on the design method as described above, an injection mold for the light guide plate provided with the micro lens array is manufactured, and the light guide plate according to the present invention is formed by injection molding. It can be produced with high efficiency.

  FIG. 8 is a schematic configuration diagram of the microlens array 5 in which two types of microanamorphic lenses 5a and 5b having different sizes are arranged. By arranging the two kinds of minute anamorphic lenses 5a and 5b, an extremely complicated irregular pattern of the minute lens array 3 can be designed. Although not shown, a microlens array may be configured using a plurality of types of microanamorphic lenses having different sizes, and the curvatures of the microanamorphic lenses 5a and 5b having different sizes are condensed. As long as they are arranged so that the cross-sectional directions coincide with each other, they may be the same or different.

  FIG. 9 is an explanatory diagram relating to the focal length f in the condensing section direction and the non-condensing section direction of the micro anamorphic lens according to the present invention. (9A) is a perspective view of the minute anamorphic lens 2a. In the micro anamorphic lens 2a, the curvature of the convex surface is maximum at the lens cross section 2d, and as described above, this is also called the main meridional plane. The condensing cross-sectional direction 2g indicates the cross-sectional direction in which the fine anamorphic lens 2a has the highest condensing degree. Further, the light collecting cross-sectional direction 2g and the plane direction parallel to the light collecting cross-sectional direction 2g may be referred to as a light collecting cross-sectional direction 2g. A surface direction perpendicular to the light collection cross-sectional direction 2a and including the lens cross-section 2e is referred to as a non-light-collecting cross-sectional direction 2g. In the small anamorphic lens 2a of (9A), the cross section in the short direction corresponds to the condensing cross section direction 2f, the cross section in the longitudinal direction corresponds to the non-condensing cross section direction 2g, and the cross section is the optical axis (or the central axis). ) Is designed so that the degree of condensing decreases from the condensing cross-sectional direction 2f to the non-condensing cross-sectional direction 2g with respect to rotation about the axis.

The lens formula is expressed as the following equation (1).
1 / f = (n−1) [(1 / R ₁ ) − (1 / R ₂ )
+ T (n-1) / (R ₁ · R ₂ · n)] (1)
Here, f is the focal length, n is the refractive index, R ₁ is the radius of curvature on the exit side (convex surface side in the figure), R ₂ is the radius of curvature on the incident side (plane side in the figure), and t is the thickness of the lens. Show. In the present invention, the light guide plate and the minute anamorphic lens are integrally formed, but it is assumed that there is a boundary on the incident side. (9B) shows a cross section in the non-condensing cross section direction 2g, that is, the XX cross section (lens cross section 2d) of the microanamorphic lens shown in (9A). In (9B), since R _{2 to} ∞ on the incident side, Equation (1) indicates that 1 / f _X = (1.5-1) (1 / R when the refractive index n is set to n = 1.5. ₁ ) (2)
It becomes. Therefore, when the range of the radius of curvature R ₁ is set to ₁ mm ≦ R ₁ ≦ 10 mm, the focal length f _{X in the} non-condensing cross-sectional direction 2 g is expressed as f _X = R ₁ /0.5=1 to 10 from the equation (2). /0.5=2 to 20 mm. Similarly, set in the Y-Y cross section of the micro anamorphic lens shown in shown in (9C) (9A) (lens sectional 2e), the range of the radius of curvature _{R 1} to 0.04 mm ≦ _{R 1} ≦ 0.4 mm If you, the focal length _{f Y} of the condensing section direction 2f becomes _f Y ₌ R 1 _{/0.5=0.04~0.4/0.5=0.08~0.8mm.} That is, in this embodiment, compared with the non-light-collecting section direction 2g, the focal length f _Y of the condensing section direction 2f is set to 1/25, has a high current intensity. Further, here, the diameter Dx in the longitudinal direction is preferably set to 1 to 10 mm and the diameter Dy in the short direction is set to 0.1 to 1 mm, and the diameter Dx is preferably set to 1 to 5 mm and the diameter in the short direction. More preferably, Dy is set to 0.1 to 0.5 mm.

  FIG. 10 is a schematic configuration diagram showing another embodiment of a micro anamorphic lens according to the present invention. The micro anamorphic lens 2a is designed so that the curvature of the lens cross section 2d in the short direction is substantially the same, and is formed so that the light collection degree in the light collection cross section direction 2f is the same in each cross section. Yes. Similarly, the curvature of the lens section 2e in the longitudinal direction is designed to be substantially the same, and the degree of condensing in the non-condensing section direction 2g is designed to be the same in each section. By arranging such minute anamorphic lenses 2a, it is possible to relatively easily set the degree of light collection by the minute lens array.

FIG. 11 is a schematic configuration diagram illustrating another embodiment of the micro anamorphic lens according to the present invention. The micro anamorphic lens according to the present invention can be set in a condensing cross-sectional direction and has a condensing function in a predetermined direction, and has a circular shape as shown in (11A) to (11B). A minute anamorphic lens 5 may be used. That is, in the present specification, a micro anamorphic lens is defined as having a different curvature in a plane perpendicular to the optical axis, and one of these two cross sections has a high light collecting function. This circular microanamorphic lens 5 has a substantially circular shape with a diameter D from the top surface as shown in (11A), and has a focal length f as shown in side views (11B) and (11C). compared to the long non-condensing cross-sectional direction of _X, the short condenser sectional direction focal length f _Y, are designed to the curvature increases.

  FIG. 12 is a schematic configuration diagram when the light source 12 of the liquid crystal display device 1 according to the present invention is an RGB (red, green, blue) light emitting diode. In the liquid crystal display device 1, the light source 12 is composed of RGB light emitting diodes, and a red (R) light emitting diode 12a, a green (G) light emitting diode 12b, and a blue (B) light emitting diode 12c are arranged. By arranging the light guide plate 4 according to the present invention, the light from the RGB light emitting diodes 12a, 12b, 12c is diffusely reflected by the micro lens arrays 2, 2 having an irregular pattern integrally formed with the light guide plate 4. , RGB light emitting diode light is mixed and whitened, and the amount of emitted surface light is made uniform. Furthermore, in this embodiment, the microlens array is integrally formed on the incident surface 4a and the exit surface 4b so that the condensing cross-sectional directions are orthogonal to each other, so that the brightness can be remarkably increased.

  FIG. 13 is a schematic configuration diagram when the white light source 14 of the liquid crystal display device 1 according to the present invention includes white light emitting diodes 14a and 14b. All of the RGB light emitting diodes 12a, 12b, and 12c constituting the light source 12 of FIG. 12 can be replaced with white (W) light emitting diodes 14a, 14b,... A white light source 14 is configured. The light from the white light source 14 is converted into uniform planar light by the light guide plate 4 according to the present invention. Since the microlens arrays 2 and 3 having an irregular pattern are integrally formed on the light guide plate 4, the number of additional optical elements can be reduced, the loss of light amount can be reduced, the power consumption is low, and the energy is reduced. Since the highly efficient white light-emitting diode 14a is used as the white light source 14, further energy saving is realized.

  The present invention is not limited to the above-described embodiments and modifications, and includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.

  In the light guide plate according to the present invention, a micro lens array in which a plurality of micro anamorphic lenses are irregularly arranged on an incident surface and / or an output surface is integrally formed, and a light diffusion sheet and a condensing lens sheet are provided. Since there is no need to dispose and there is no loss of light quantity in these optical members, light from the light source can be converted into planar light with high efficiency. The light guide plate according to the present invention can convert light from one or a plurality of point light sources or line light sources into gold planar light, and can be used for various light irradiation devices. For example, uniform planar light can be applied to automobile headlights, room lights, spotlights, liquid crystal display backlights, light-emitting display boards, and the like. Furthermore, in a liquid crystal display device used for a display for personal computers (PCs), a television, or the like, it is necessary to secure a viewing angle in the width direction. High luminance can be ensured by matching the light in the height direction to suppress diffusion from the display screen and collecting light.

  In addition, even when the light guide plate according to the present invention is used in a light emitting display device such as a signboard or an emergency light, or a lighting fixture, the light source via the light guide plate is set by setting the light collecting cross-sectional direction in a predetermined direction. Can be irradiated with high efficiency. Furthermore, in a display device used for a mobile phone, an automatic teller machine (ATM), etc., it is possible to condense flat transmitted light in one emission direction and to emit high-luminance transmitted light with high efficiency. It is possible to provide a display device that outputs information that is visible only to the user. In addition, in a lighting fixture installed in an airplane or an automobile, uniform planar light can be focused and irradiated onto a predetermined area.

1 is a schematic configuration diagram of a liquid crystal display device according to the present invention. 1 is a schematic configuration diagram of a liquid crystal display device provided with a light guide plate 4 in which a microlens array according to the present invention is integrally formed on an emission surface. FIG. 3 is a schematic configuration diagram of a liquid crystal display device in which light guide plates 2 in which light collection cross-sectional directions of a microlens array according to the present invention are orthogonal to each other are arranged. 1 is a schematic configuration diagram of a liquid crystal display device 1 in which a light source is disposed on an end face of a light guide plate according to the present invention. It is an arrangement | sequence figure of the micro anamorphic lens which concerns on this invention. It is a section schematic diagram of a light guide plate concerning the present invention. It is explanatory drawing which shows the design method of the irregular pattern of the micro anamorphic lens which concerns on this invention. 1 is a schematic configuration diagram of a microlens array in which two types of microanamorphic lenses a and 3b having different sizes according to the present invention are arranged. It is explanatory drawing regarding the focal distance f of the condensing cross-section direction of the micro anamorphic lens which concerns on this invention, and a non-condensing cross-section direction. It is the structure schematic which shows the other form of the microanamorphic lens which concerns on this invention. It is the structure schematic which shows the other form of the microanamorphic lens which concerns on this invention. It is a structure schematic diagram in case the light source of the liquid crystal display device which concerns on this invention is a RGB (red, green, blue) light emitting diode. It is the structure schematic when the light source of the liquid crystal display device which concerns on this invention is comprised from a white light emitting diode. It is the conventional illuminating device for liquid crystals. It is a perspective view of the decomposition | disassembly state of the liquid crystal display device by which the conventional light-guide plate was arrange | positioned.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Micro lens array 2a Micro anamorphic lens 2b Boundary part 2c Condensing cross section direction 2e Lens cross section 2d Lens cross section 2f Condensing cross section direction 2g Non-condensing cross section direction 3 Micro lens array 3a Micro anamorphic lens 3b Boundary 4 Light guide plate 4a Incident surface 4b Output surface 4c Light guide plate body 4d Back surface 6 Light source 6 Reflector plate 8 Liquid crystal panel 8a Polarizing plate 8b Polarizing plate 10 Light diffusing plate 12 Light source 12a Red (R) light emitting diode 12b Green (G) light emission Diode 12c Blue (B) light emitting diode 14 White light source 14a White light emitting diode 101 Liquid crystal display device 104 Light guide plate 106 Light source 106a Hot cathode U-tube 106b Reflector plate 107 Diffuser plate 108 Liquid crystal panel 108a Incident polarizing plate 108b Outgoing polarizing plate 109 Prism sheet 111 Light-scattering scattering film 110 Light diffusion film Preparative d average distance D diameter _{f X} focal length _{f Y} focal length P equidistant position t thickness

Claims (12)

In a light guide plate that makes light from a light source directly incident on an incident surface, guides the light in a direction parallel to the exit surface, and emits light in a planar shape from the exit surface, a plurality of minute anamorphs having a condensing function in a predetermined direction A microlens array having irregularly arranged Fick lenses is integrally formed on the entrance surface and / or the exit surface, and each of the light condensings of a plurality of minute anamorphic lenses provided on the entrance surface or the exit surface. The cross-sections (main meridional planes) are arranged in the same direction, and the condensing sections (main meridional planes) of the microlens arrays provided on the entrance surface and the exit surface are arranged so as to be substantially orthogonal or substantially coincide with each other. A light guide plate comprising a microlens array , wherein the light is irregularly reflected by an irregular pattern of the microlens array. In a light guide plate that makes light from a light source directly incident on an incident surface, guides the light in a direction parallel to the exit surface, and emits light in a planar shape from the exit surface, a plurality of minute anamorphs having a condensing function in a predetermined direction A microlens array having irregularly arranged Fick lenses is integrally formed on the entrance surface and / or the exit surface, and each of the light condensings of a plurality of minute anamorphic lenses provided on the entrance surface or the exit surface. Cross-sections (main meridional planes) are arranged in the same direction, and the microlens array is an irregular pattern in which microlens intervals in a predetermined direction are irregularly shifted from equidistant positions. deviation of the position is 1 / 1,000 to 1/10 of the average interval, the light guide plate having a micro-lens array to the irregular pattern of the micro lens array, characterized in that diffusely reflect light The microlens array is disposed so that the respective condensing axes of a plurality of microanamorphic lenses provided on the entrance surface or the exit surface coincide with the height direction or the width direction of the exit surface. A light guide plate comprising the microlens array according to 1 or 2 .   The light guide plate including the microlens array according to any one of claims 1 to 3, wherein the microlens array includes two or more types of microanamorphic lenses having different sizes and / or shapes. The micro anamorphic lens has a radius of curvature of 0.01 mm to 1 mm in the condensing cross-sectional direction and a radius of curvature of 10 mm to 100 mm in a non-condensing cross-sectional direction orthogonal to the condensing cross-section. A light guide plate comprising the microlens array according to any one of the above. 6. The microscopic anamorphic lens according to claim 1, wherein a length in the condensing cross-sectional direction is 0.1 to 1 mm, and a length in the non-condensing cross-sectional direction is 1 to 10 mm. A light guide plate comprising a lens array.   The light guide plate having a microlens array according to any one of claims 1 to 5, wherein the microanamorphic lens is a circular lens having different curvatures in the condensing cross-sectional direction and the non-condensing cross-sectional direction. A light guide plate comprising the microlens array according to any one of claims 1 to 7 and at least one light source disposed on an incident surface side of the light guide plate, wherein light from the light source is A light irradiating apparatus, wherein the light irradiating device converts the surface into a planar shape and irradiates the light. The light source according to claim 8 , wherein the light source includes a cold cathode tube and a reflecting plate that reflects light from the cold cathode tube toward the incident surface. The light illumination device according to claim 8 , wherein the light source includes a white light emitting diode. The light irradiation apparatus according to claim 8 , wherein the light source is composed of light emitting diodes of three colors of RGB (red, green, and blue), and whitens the RGB light by the micro lens array. A backlight formed of a light irradiation device according to claim 9 or 10, the liquid crystal display device, characterized in that it is a liquid crystal panel for displaying an image transmitted through the to the planar light emitted from the backlight .

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