JP2008165996A - Surface light source device, liquid crystal display device assembly, light guide member, light detection device, and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide member capable of easily, effectively, and securely measuring light quantity in a place (or a region) where it is necessary to measure the light quantity with a less number of parts. <P>SOLUTION: The light guide member 110 includes a side surface 113, a first end surface 111, and a second end surface 112, and is manufactured of transparent elongated material. A light intake part 120 is provided on the side surface 113. A part of light entering the light intake part 120 intrudes an inside of the light guide member 110 from the light intake part 120, transmits to an inside of the light guide member 110, is emitted from the first end surface 111, and other part of the light entering the light intake part 120 is emitted from the light guide member 110. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light guide member, and a planar light source device, a liquid crystal display device assembly, a light detection device, and an illumination device to which the light guide member is applied.

  In the liquid crystal display device, the liquid crystal material itself does not emit light. Therefore, for example, a direct type planar light source device (backlight) that illuminates the display area of the liquid crystal display device is disposed on the back surface of the display area composed of a plurality of pixels. In the color liquid crystal display device, one pixel is composed of, for example, three types of subpixels: a red light emitting subpixel, a green light emitting subpixel, and a blue light emitting subpixel. Then, by operating the liquid crystal cell constituting each pixel or each sub-pixel as a kind of light shutter (light valve), that is, controlling the light transmittance (aperture ratio) of each pixel or each sub-pixel, An image is displayed by controlling the light transmittance of illumination light (for example, white light) emitted from the planar light source device.

  Conventionally, a planar light source device in a liquid crystal display device assembly illuminates the entire display area with uniform and constant brightness. However, the planar light source device has a configuration different from such a planar light source device, that is, a plurality of planar light source devices. A planar light source device (partial drive type or split drive type planar light source device) having a configuration that changes the distribution of illuminance in a plurality of display area units is disclosed in, for example, 17324. By controlling the planar light source device (also referred to as partial driving or divided driving of the planar light source device), it is possible to increase the white level and increase the contrast ratio due to the black level decrease in the liquid crystal display device. As a result, the quality of image display can be improved and the power consumption of the planar light source device can be reduced. The planar light source unit includes a red light emitting diode, a green light emitting diode, and a blue light emitting diode as light sources.

  By the way, as described above, white light is obtained as illumination light by mixing light of each color emitted from the red light emitting diode, the green light emitting diode, and the blue light emitting diode. When the resulting characteristic change occurs, the chromaticity and white balance (color temperature) of the white light change.

2005-17324

  Therefore, in order to deal with such a change in the characteristics of the light source, an optical sensor for measuring the light emission state (light quantity) of the light source constituting each planar light source unit is arranged. However, disposing one (or one set) photosensor for one planar light source unit not only increases the number of parts and increases the cost of the photodetection circuit, but also increases the planarity. The assembly process of the light source device is complicated, and when the light hits the light sensor, the shadow of the light sensor is generated, and there is a possibility that luminance unevenness occurs in the planar light source unit. On the other hand, disposing one (or one set) of optical sensors for a large number of planar light source units measures the amount of light at a position away from the light source. As a result, the amount of light incident on the optical sensor is reduced. There arises a problem that the required amount of light cannot be obtained.

  Therefore, the first object of the present invention is to easily and effectively perform the light quantity measurement in a place (or region) where the light quantity measurement or the like needs to be performed with a small number of parts. And a planar light source device to which the light guide member is applied, a liquid crystal display device assembly, and a light detection device. The second object of the present invention is to provide a light guide member having substantially the same structure as the light guide member and a lighting device having a simple configuration to which the light guide member is applied.

In order to achieve the above first object, the planar light source device of the present invention is a planar light source for illuminating a transmissive liquid crystal display device having a display area composed of pixels arranged in a two-dimensional matrix from the back. A light source device,
It is assumed that the display area of the liquid crystal display device is divided into P in the first direction and Q in the second direction extending at right angles to the first direction, for a total of P × Q virtual display area units. Corresponding to the P × Q display area units at the time, each consisting of P × Q planar light source units equipped with light sources,
Comprising a photodetection device disposed along the first direction;
The light detection device
(A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
It has
On the side surface of the light guide member, there are provided P light intake portions,
A part of the light incident on each light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end face, and enters the photodetector,
The other part of the light incident on the light intake part is emitted from the light guide member.

In order to achieve the first object, the liquid crystal display device assembly of the present invention comprises:
(A) a transmissive liquid crystal display device having a display region composed of pixels arranged in a two-dimensional matrix, and
(B) The display area of the liquid crystal display device is divided into P in the first direction and Q in the second direction extending perpendicular to the first direction, for a total of P × Q virtual display area units. A planar light source device that corresponds to the P × Q display area units when assumed to have been formed, each of which is composed of P × Q planar light source units each having a light source, and that illuminates the liquid crystal display device from the back side ,
A liquid crystal display device assembly comprising:
Comprising a photodetection device disposed along the first direction;
The light detection device
(A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
It has
On the side surface of the light guide member, there are provided P light intake portions,
A part of the light incident on each light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end face, and enters the photodetector,
The other part of the light incident on the light intake part is emitted from the light guide member.

  In the planar light source device or the liquid crystal display device assembly of the present invention, the light emission state of the light source provided in the planar light source unit can be individually controlled (that is, a partial drive method or a split drive method). .

  In the planar light source device or the liquid crystal display device assembly of the present invention including the preferred embodiments described above, it may be configured to have one photodetecting device, or two or more, at most, Q photodetecting devices. It can also be set as the structure provided with. The light source and the light guide member are disposed on the bottom surface of the casing constituting the planar light source device (specifically, the light source and the light guide member are fixed or movably disposed), and light The detector is preferably arranged outside the side surface of the housing, but is not limited thereto. In particular, the light guide member is mounted at a position where a shadow of the light guide member is caused by the light colliding with the light guide member or a part of the light is refracted and partly brightens. As long as there is no problem of uneven brightness in the light source unit, the light source unit can be set at an arbitrary position.

The light guide member according to the first aspect of the present invention for achieving the first object has a side surface, a first end surface, and a second end surface, and is a light guide made of a transparent elongated material. A member,
A light intake is provided on the side,
A portion of the light incident on the light intake portion enters the light guide member from the light intake portion, travels through the light guide member, and exits from the first end surface.
The other part of the light incident on the light intake part is emitted from the light guide member.

In order to achieve the above first object, the photodetection device of the present invention comprises:
(A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
A photodetecting device comprising:
On the side of the light guide member, a light intake is provided,
A part of the light incident on the light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end surface, and enters the photodetector,
The other part of the light incident on the light intake part is emitted from the light guide member.

  The planar light source device of the present invention including the preferred embodiments and configurations described above, the liquid crystal display device assembly of the present invention, the light guide member according to the first aspect of the present invention, or the light detection device of the present invention (hereinafter referred to as these) In some cases, a part of the light incident on the light intake part enters the inside of the light guide member from the light intake part and totally reflects inside the light guide member. It is desirable that the light transmitted through the first end face is emitted from the first end surface from the viewpoint of preventing attenuation of light transmitted through the light guide member (sometimes referred to as internal transmission light for convenience).

  In the first invention including the preferred form and configuration described above, the light intake portion is at least one kind selected from the group consisting of a concave portion, a convex portion, a concave and convex portion, a groove portion (notch portion), and a bank portion. It is desirable to consist of shapes. One recessed portion may be provided in one light receiving portion, or a plurality of recessed portions may be provided. Examples of the planar shape of the concave portion include a triangle; an arbitrary quadrangle including a square, a rectangle, and a trapezoid; an arbitrary polygon; an arbitrary smooth closed curve including a circle, an oval, an ellipse, and the like. As a cross-sectional shape of the recess when the recess is cut along the depth direction, a triangle; an arbitrary quadrangle including a square, a rectangle, a trapezoid; an arbitrary polygon; an arbitrary smooth including a circle, an oval, an ellipse, etc. A part of the curve can be exemplified. Moreover, one convex part may be provided in the one light intake part, and the several convex part may be provided. Examples of the planar shape of the convex portion include a triangle; an arbitrary quadrangle including a square, a rectangle, and a trapezoid; an arbitrary polygon; an arbitrary smooth closed curve including a circle, an oval, an ellipse, and the like. As a cross-sectional shape of the convex portion when the convex portion is cut along the height direction, a triangle; an arbitrary quadrilateral including a square, a rectangle, a trapezoid; an arbitrary polygon; an arbitrary including a circular, an oval, an ellipse, etc. A part of a smooth curve can be exemplified. The concavo-convex portion may be constituted by a combination of the concave portion and the convex portion described above. The groove portion (notch portion) or bank portion is preferably linear, but is not limited thereto. When the light intake portion is a bank portion, it is desirable that the facing surface (slope) far from the first end surface has an acute inclination angle, and the facing surface close to the first end surface is substantially vertical. However, the present invention is not limited to this.

  Alternatively, the light intake part is a side surface of the light guide member on which light is incident (for example, as described later, when the light guide member is cut along a virtual plane perpendicular to the axis of the light guide member. When the cross-sectional shape is rectangular and the side surface of the light guide member is composed of an upper surface, a lower surface, and two wall surfaces, a planar grating formed on the portion of the light guide member (upper surface of the light guide member) A plurality of parallel grooves are engraved on the surface of the side surface portion, and light incident from the side surface (for example, the upper surface of the light guide member) Can also be composed of a reflective volume hologram diffraction grating provided in a portion that collides with the opposite side surface (for example, the lower surface of the light guide member). The reflective volume hologram diffraction grating means a hologram diffraction grating that diffracts and reflects only + 1st order diffracted light, and interference fringes are formed from the inside to the surface. By appropriately selecting the inclination angle of the interference fringes and the pitch of the interference fringes, a desired diffraction reflection can be generated in light having a desired wavelength. In addition, interference fringes occur that light that is reflected and diffracted in a certain light intake unit and propagates by being totally reflected inside the light guide member collides with another light intake unit existing on the way. By appropriately selecting the inclination angle and the pitch of the interference fringes, it can be eliminated, and the loss of light quantity of the internal transmission light can be further reduced. The reflective volume hologram diffraction grating may be formed with interference fringes corresponding to one type of wavelength band (or wavelength), or a plurality of types of light having different types of wavelength bands (or wavelengths). In order to cope with diffraction reflection, a configuration in which a plurality of types of interference fringes are formed in one layer of a reflection type volume hologram diffraction grating may be adopted. Alternatively, a reflective volume hologram diffraction grating, for example, a reflective volume hologram diffraction grating layer that diffracts red light, a reflective volume hologram diffraction grating layer that diffracts green light, and a reflective volume hologram diffraction grating that diffracts blue light. It can also be composed of a layered structure of layers. Such a reflection type volume hologram diffraction grating layer is laminated by preparing each reflection type volume hologram diffraction grating layer separately and then using each ultraviolet ray curing adhesive, for example, for each reflection type volume hologram diffraction grating layer. Can be laminated (adhered). In addition, after creating a single reflective volume hologram diffraction grating layer using an adhesive photopolymer material, a reflective volume hologram diffraction grating layer is prepared by sequentially sticking an adhesive photopolymer material thereon. By doing so, a laminated structure of a reflective volume hologram diffraction grating layer may be obtained. The interference fringes in the reflection type volume hologram diffraction grating layer are obtained by, for example, transmitting object light from a first predetermined direction on one side with respect to a member (for example, photopolymer material) constituting the reflection type volume hologram diffraction grating layer. Irradiate and simultaneously irradiate the reference light from the second predetermined direction on the other side, and record the interference fringes formed by the object light and the reference light inside the member constituting the reflective volume hologram diffraction grating layer By doing so, it can be formed. By appropriately selecting the first predetermined direction, the second predetermined direction, the wavelength of the object light and the reference light, the desired pitch of the interference fringes and the desired inclination of the interference fringes in the reflective volume hologram diffraction grating layer You can get a corner.

  Alternatively, in the first invention including the preferred embodiment and configuration described above, a plurality of light intake portions (for example, P locations) including groove portions (notches) are provided; the axis of the light guide member and the light It is desirable that the angle formed with the axis of the intake portion is larger as the light intake portion is farther from the first end face; the depth of the light intake portion is preferably shallower as the light intake portion is closer to the first end face. By increasing the angle formed between the axis of the light guide member and the axis of the light intake portion as the light intake portion is farther from the first end surface, the amount of internal transmission light increases as the light intake portion is farther from the first end surface. In addition, if another light intake portion exists in the middle of the internal transmission light, there is a possibility that the internal transmitted light may be emitted to the outside from the other light intake portion. However, by making the depth of the light intake closer to the light intake closer to the first end face, it is possible to reduce the obstruction of the progress of the internal transmission light by other light intakes existing in the middle. Loss of light quantity can be reduced.

  Alternatively, in the first invention including the preferred form and configuration described above, the light intake portion is composed of a groove portion (notch portion) having two opposing surfaces, and the first of the two opposing surfaces of the light intake portion is A facing surface far from one end surface (referred to as a first facing surface for convenience) has an acute inclination angle, and a facing surface close to the first end surface (referred to as a second facing surface for convenience) is substantially vertical. However, the present invention is not limited to this, and both the first facing surface and the second facing surface may be substantially vertical, and the first facing surface is substantially vertical. The two opposed surfaces may have an obtuse inclination angle. By making the light intake portion including the groove portion into such a shape, it is ensured that a part of the light incident on the light intake portion enters the light guide member and is transmitted through the light guide member. be able to.

Alternatively, in the first invention including the preferred form and configuration described above,
The cross-sectional shape of the light guide member when the light guide member is cut in a virtual plane perpendicular to the axis of the light guide member is a rectangle,
The side surface of the light guide member is composed of an upper surface, a lower surface, and two wall surfaces,
A light intake is provided on the top surface,
The end portion of the light guide member constituting the first end surface is guided from the first protrusion extending from the two wall surfaces in a direction perpendicular to the axis of the light guide member, and the leading end of each first protrusion. It can be set as the structure by which the 2nd projection part extended in parallel with the axis line of an optical member and the 1st end surface side is provided. In such a configuration, the shape of the end portion of the light guide member constituting the first end surface viewed from the top surface is generally a “U” shape. In some cases, the second protrusion can be omitted. In this case, the shape of the end portion of the light guide member constituting the first end surface viewed from the top surface is generally “T” -shaped. Further, a cross section of the end portion of the light guide member constituting the first end face (a cross section of the light guide member when the light guide member is cut in a virtual plane perpendicular to the axis of the light guide member) is used as the first end face. In the meantime, it may be a tapered shape (for example, a pyramid shape or a conical shape). By adopting such a shape, the efficiency can be improved by collecting and dispersing light according to the sensitivity of the photodetector. The light can be made to enter the photodetector by being changed.

A light guide member according to a second aspect of the present invention for achieving the above second object has a side surface, a first end surface, and a second end surface, and is made of a transparent elongated material. A member,
A light extraction part is provided on the side,
A part of the light incident from the first end face and transmitted through the inside of the light guide member is emitted from the light extraction part, and the other part of the light is emitted from the second end face.

The lighting device of the present invention for achieving the second object is as follows.
A light guide member having a side surface, a first end surface, and a second end surface and made of a transparent elongated material; and
A light source disposed in the vicinity of the first end face;
A lighting device comprising:
A light extraction part is provided on the side surface of the light guide member,
A part of the light emitted from the light source, incident from the first end face and transmitted through the inside of the light guide member is emitted to the outside from the light extraction part, and the other part of the light is emitted from the second end face. And

  In the light guide member according to the second aspect of the present invention or the lighting device of the present invention (hereinafter, these may be collectively referred to as the second invention), the light incident on the first end face is guided by the light. It is desirable from the viewpoint of preventing the internal transmission light from being attenuated that the inside of the member is transmitted by total reflection and is emitted from the light extraction portion and the second end surface. Moreover, it is desirable that the light extraction part has at least one shape selected from the group consisting of a concave part, a convex part, an uneven part, a groove part (notch part), and a bank part. Here, the configuration of the concave portion, the convex portion, the concave and convex portion, the groove portion (notch portion), or the bank portion can be the same as described in the first invention. In addition, a plurality of light extraction parts each including a groove part are provided; the angle formed by the axis of the light guide member and the axis of the light extraction part is larger as the light extraction part is farther from the first end surface; the depth of the light extraction part is When a constant light amount is to be obtained everywhere, the light extraction part closer to the first end face can be made shallower. Alternatively, the light intake portion is composed of a groove portion having two opposing surfaces, and of the two opposing surfaces of the light extraction portion, the opposing surface (first opposing surface) facing the first end surface has an acute inclination angle. However, the facing surface (second facing surface) close to the first end surface may be substantially vertical, but is not limited thereto. Alternatively, the light extraction portion can be constituted by a diffraction grating such as a planar grating or a reflection volume hologram diffraction grating, as described in the first invention.

  In the first invention or the second invention including the preferred embodiment and configuration described above, the material constituting the light guide member is transparent. Here, “transparent” means that it is incident on the light guide member. Means transparent to light. Examples of light incident on the light guide member include not only visible light such as red light, green light, blue light, and white light, but also ultraviolet rays and infrared rays. Further, as a cross-section of the light guide member when the light guide member is cut in a virtual plane perpendicular to the axis of the light guide member, in addition to the above-described rectangle (square, rectangle), a triangle; any rectangle including a trapezoid Any smooth closed curve can be exemplified, including any polygon; circular, oval, elliptical, etc. That is, the light guide member can be constituted by, for example, a square bar or a round bar. Furthermore, as a material constituting the light guide member, polymethyl methacrylate resin (PMMA), polycarbonate resin (PC), polyarylate resin (PAR), polyethylene terephthalate resin (PET), acrylic resin, polystyrene resin (PS) ) And glass. When the light guide member is made of a polymer material, the light guide member can be manufactured by, for example, an injection molding method. In the case where the light intake portion is constituted by an uneven portion, for example, the uneven portion may be formed based on a sand blast method.

  As the photodetector, a known photodetector suitable for the light to be detected may be selected. For example, a red detection photodiode, a green detection photodiode, a blue detection photodiode, a white detection photodiode, a color Various photodiodes such as a photodiode for use can be exemplified. Alternatively, a well-known CCD device can be used as the photodetector.

  The ratio between the light incident on the light intake portion and emitted from the light guide member (referred to as leakage light from the light intake portion) and the internally transmitted light can be defined by the shape of the light intake portion. For example, it is determined based on the position where the light intake unit is disposed, the positional relationship between the light intake unit and the light source, or the like.

  One end of the light guide member is constituted by a first end face, and the other end is constituted by a second end face. In the first invention, the light reaching the second end face is emitted from the second end face or is reflected by the second end face. In some cases, the second photodetector may be disposed in the vicinity of the second end face.

  Light is randomly incident on the light intake. That is, the incident angle of the light incident on the light intake unit is various angles (for example, 2π radians in solid angle). Accordingly, a part of the light incident on the light intake portion is light that satisfies a specific incident angle condition with respect to the light intake portion, and this light enters the inside of the light guide member from the light intake portion as internal transmission light. Then, the light is transmitted through the light guide member and emitted from the first end face.

  The light source can be composed of, for example, a light emitting diode (LED), but is not limited to this, and is not limited to this. A cold cathode fluorescent lamp, an electroluminescence (EL) device, a cold cathode field emission device (FED) Further, plasma display devices, ordinary lamps, electric lamps, and fluorescent lamps can also be mentioned. When the light source is composed of a light emitting diode, for example, a red light emitting diode that emits red light with a wavelength of 640 nm, for example, a green light emitting diode that emits green light with a wavelength of 530 nm, and a blue light emitting diode that emits blue light with a wavelength of 450 nm, for example. It can be configured to obtain white light, or white light can be obtained by light emission of a white light emitting diode (for example, a light emitting diode that emits white light by combining an ultraviolet or blue light emitting diode and phosphor particles). Depending on the case, a light emitting diode that emits a fourth color other than red, green, blue, fifth color,... May be further provided.

  When the light source is composed of a light emitting diode, for example, as a combination of a red light emitting diode that emits red, a green light emitting diode that emits green, and a blue light emitting diode that emits blue, specifically, (one red light emitting diode) Diode, one green light emitting diode, one blue light emitting diode), (one red light emitting diode, two green light emitting diodes, one blue light emitting diode), (two red light emitting diodes, two green light emitting diodes, one Blue light-emitting diodes) and the like, but are not limited thereto.

  When the light source is formed of a light emitting diode, the light emitting diode may have a so-called face-up structure or a flip chip structure. That is, the light-emitting diode includes a substrate and a light-emitting layer formed on the substrate, and may have a structure in which light is emitted from the light-emitting layer to the outside, or light from the light-emitting layer passes through the substrate. It is good also as a structure radiate | emitted outside. More specifically, the light emitting diode includes, for example, a first compound semiconductor layer having a first conductivity type (eg, n-type) formed on a substrate, an active layer formed on the first compound semiconductor layer, and an active layer. A first electrode having a stacked structure of a second compound semiconductor layer having a second conductivity type (for example, p-type) formed thereon and electrically connected to the first compound semiconductor layer, and a second compound semiconductor A second electrode is electrically connected to the layer. The layer constituting the light emitting diode may be made of a known compound semiconductor material depending on the emission wavelength.

  The planar light source device may include a light diffusing plate, and may further include an optical function sheet group such as a diffusing sheet, a prism sheet, and a polarization conversion sheet, and a reflecting sheet. The optical function sheet group may be configured from various sheets that are spaced apart from each other, or may be stacked and integrated. The light diffusing plate and the optical function sheet group are disposed between the planar light source device and the liquid crystal display device. Examples of the material constituting the light diffusion plate include polycarbonate resin (PC), polystyrene resin (PS), and methacrylic resin.

  A partition may be provided between the planar light source unit and the planar light source unit. Specific examples of the material constituting the partition include polymethyl methacrylate resin (PMMA), polycarbonate resin (PC), polyarylate resin (PAR), polyethylene terephthalate resin (PET), acrylic resin, ABS resin, and glass. It can be mentioned, It can be set as a transparent structure or an opaque structure with respect to the light radiate | emitted from the light source with which the planar light source unit was equipped. A light diffusion reflection function may be imparted to the partition wall surface, or a specular reflection function may be imparted. In order to impart a light diffusing and reflecting function to the partition wall surface, irregularities may be formed on the partition wall surface based on a sandblasting method, or a film (light diffusion film) having irregularities may be attached to the partition wall surface. In addition, in order to impart a specular reflection function to the partition wall surface, a light reflection film may be attached to the partition wall surface, or a light reflection layer may be formed on the partition wall surface by plating, for example.

  The transmissive liquid crystal display device includes, for example, a front panel having a transparent first electrode, a rear panel having a transparent second electrode, and a liquid crystal material disposed between the front panel and the rear panel. Consists of. The liquid crystal display device may be a monochrome liquid crystal display device or a color liquid crystal display device.

  More specifically, the front panel includes, for example, a first substrate made of, for example, a glass substrate or a silicon substrate, and a transparent first electrode (also called a common electrode, for example, ITO provided on the inner surface of the first substrate. And a polarizing film provided on the outer surface of the first substrate. Further, in the transmissive color liquid crystal display device, a color filter covered with an overcoat layer made of acrylic resin or epoxy resin is provided on the inner surface of the first substrate. Examples of the color filter arrangement pattern include a delta arrangement, a stripe arrangement, a diagonal arrangement, and a rectangle arrangement. The front panel further has a configuration in which a transparent first electrode is formed on the overcoat layer. An alignment film is formed on the transparent first electrode. On the other hand, the rear panel more specifically includes, for example, a second substrate made of a glass substrate or a silicon substrate, a switching element formed on the inner surface of the second substrate, and conduction / non-conduction by the switching element. A transparent second electrode to be controlled (also called a pixel electrode, which is made of, for example, ITO) and a polarizing film provided on the outer surface of the second substrate. An alignment film is formed on the entire surface including the transparent second electrode. Various members and liquid crystal materials constituting the liquid crystal display device including these transmissive color liquid crystal display devices can be formed of known members and materials. Examples of the switching element include a three-terminal element such as a MOS type FET and a thin film transistor (TFT) formed on a single crystal silicon semiconductor substrate, and a two-terminal element such as an MIM element, a varistor element, and a diode.

  An area where the transparent first electrode and the transparent second electrode overlap and includes a liquid crystal cell corresponds to one pixel (pixel) or one sub-pixel (sub-pixel). In the transmissive color liquid crystal display device, the red light emitting sub-pixel (which may be referred to as sub-pixel [R]) constituting each pixel (pixel) transmits red light with the liquid crystal cell constituting the region. The green light emitting subpixel (sometimes referred to as subpixel [G]) is composed of a combination of a liquid crystal cell constituting the region and a color filter that transmits green light. The blue light-emitting subpixel (sometimes referred to as subpixel [B]) is composed of a combination of a liquid crystal cell that forms the region and a color filter that transmits blue light. The arrangement pattern of the sub-pixel [R], sub-pixel [G], and sub-pixel [B] matches the arrangement pattern of the color filter described above. The pixel is not limited to a configuration in which three types of sub-pixels [R, G, B], which are a sub-pixel [R], a sub-pixel [G], and a sub-pixel [B], are configured as one set. For example, a set of these three types of sub-pixels [R, G, B] plus one or more types of sub-pixels (for example, one sub-pixel that emits white light to improve brightness) To expand the color reproduction range, one set including sub-pixels that emit complementary colors to expand the color reproduction range, one set including sub-pixels that emit yellow to expand the color reproduction range It can also be composed of a set of subpixels that emit yellow and cyan.

  Here, the light transmittance (also referred to as aperture ratio) Lt of the pixel or sub-pixel, the luminance (display luminance) y of the display area corresponding to the pixel or sub-pixel, and the luminance (light source luminance) of the planar light source unit Y is defined as follows:

Y ₁ ... Is the maximum luminance of the light source luminance, for example, and may be hereinafter referred to as the light source luminance and the first specified value.
Lt ₁ ... Is the maximum value of the light transmittance (aperture ratio) of the pixels or sub-pixels in the display area unit, for example, and may be hereinafter referred to as light transmittance / first specified value.
Lt ₂ ... In the display area unit / input signal maximum value x _U-max that is the maximum value of the values of the input signals input to the drive circuit for driving all the pixels constituting the display area unit. This is the light transmittance (aperture ratio) of the pixel or sub-pixel when it is assumed that a control signal corresponding to an input signal having the same value is supplied to the pixel or sub-pixel. Sometimes called. In addition, 0 ≦ Lt ₂ ≦ Lt ₁
y ₂ ... When the light source luminance is the light source luminance and the first specified value Y ₁ and the light transmittance (aperture ratio) of the pixel or sub-pixel is assumed to be the light transmittance and the second specified value Lt ₂ The display brightness obtained in the following is sometimes referred to as “display brightness / second prescribed value”.
Y ₂ ... ・ In the display area unit ・ Assuming that a control signal corresponding to an input signal having a value equal to the input signal maximum value x _U-max is supplied to the pixel or sub-pixel, Assuming that the light transmittance (aperture ratio) of the sub-pixel is corrected to the light transmittance / first prescribed value Lt ₁ , the luminance of the pixel or the sub-pixel is set to the display luminance / second prescribed value (y ₂ ). The light source brightness of the planar light source unit. However, the light source luminance Y ₂ may be corrected in consideration of the influence of the light source luminance of each planar light source unit on the light source luminance of other planar light source units.

When the planar light source device is partially driven, it is assumed that a control signal corresponding to an input signal having a value equal to the input signal maximum value x _U-max in the display area unit is supplied to the pixel. The luminance of the light source constituting the planar light source unit corresponding to the display area unit is controlled by the drive circuit so that the ratio, the display luminance at the first specified value Lt _1, and the second specified value y ₂ ) are obtained. Specifically, for example, the light source luminance Y ₂ is set so that the display luminance y ₂ can be obtained when the light transmittance (aperture ratio) of the pixel or sub-pixel is, for example, the light transmittance · the first specified value Lt _1. What is necessary is just to control (for example, to reduce). That is, for example, the light source luminance Y ₂ of the planar light source unit may be controlled for each image display frame so as to satisfy the following expression (1). Note that Y ₂ ≦ Y ₁ .

Y ₂ · Lt ₁ = Y ₁ · Lt ₂ (1)

When expressed in pixels arranged in a two-dimensional matrix the number M ₀ × N ₀ of _{(pixels) (M 0, N 0)} , the value of (M _0, N _0), specifically, VGA ( 640,480), S-VGA (800,600), XGA (1024,768), APRC (1152,900), S-XGA (1280,1024), U-XGA (1600,1200), HD-TV ( 1920, 1080), Q-XGA (2048, 1536), (1920, 1035), (720, 480), (1280, 960), etc. It is not limited to these values. Further, the relationship between the value of (M ₀ , N ₀ ) and the value of (P, Q) is not limited, but can be exemplified in Table 1 below. Examples of the number of pixels constituting one display area unit include 20 × 20 to 320 × 240, preferably 50 × 50 to 200 × 200. The number of pixels in the display area unit may be constant or different. The value of P and the value of Q may be exchanged.

  The driving circuit for driving the liquid crystal display device and the planar light source device includes, for example, a planar light source device control circuit and a planar light source configured from a light emitting diode (LED) driving circuit, an arithmetic circuit, a storage device (memory), and the like. A unit drive circuit and a liquid crystal display device drive circuit including a known circuit such as a timing controller are provided. The luminance of the display area (display luminance) and the luminance of the planar light source unit (light source luminance) are controlled for each image display frame. Note that the number of image information (images per second) sent to the drive circuit as electrical signals per second is the frame frequency (frame rate), and the inverse of the frame frequency is the frame time (unit: seconds).

  In the first invention, it is possible to measure the brightness in the space in the vicinity of the light intake portion by providing the light intake portion on the light guide member, so it is necessary to measure the light quantity with a small number of parts. In a certain place (or area), it is possible to measure the light quantity easily, effectively and reliably, and it is only necessary to provide a light intake section, so the degree of freedom of measurement is high and the light quantity is high. Is easy to adjust. In addition, it is possible to easily measure the brightness at a large number of places (or regions) with a single photodetector. In addition, since the other part of the light incident on the light intake part is emitted from the light guide member, it is difficult for the light guide member to be shaded, for example, effectively preventing uneven brightness in the planar light source unit. can do. On the other hand, in the second invention, since the space near the light extraction portion can be illuminated by providing the light extraction portion in the light guide member, the place where the illumination needs to be performed with a small number of parts ( Or, in the area), it is possible to easily, effectively and reliably illuminate, and it is only necessary to provide a light extraction part, so that the degree of freedom of arrangement is high and the adjustment of the light quantity is easy. is there. Moreover, since the first invention or the second invention is only made of a transparent elongated material, it can be manufactured at a low cost, and the cost due to the increase in the number of parts and the complexity of the light detection circuit. And the assembly process of the planar light source device is not complicated as much as the left side.

Furthermore, if a partial drive method (divided drive method) is adopted for the planar light source device, a control signal corresponding to an input signal having a value equal to the input signal maximum value x _U-max in the display area unit is supplied to the pixels. The planar light source unit corresponding to the display area unit is configured so that the pixel brightness (light transmittance, display brightness at the first specified value Lt ₁ , second specified value y ₂ ) when it is assumed Since the brightness of the light source is controlled by the drive circuit, not only can the power consumption of the planar light source device be reduced, but also the white level can be increased or the black level can be decreased, and a high contrast ratio (the screen surface of the liquid crystal display device) The luminance ratio of the all-black display portion and the all-white display portion without external light reflection, etc., and the brightness of the desired display area can be emphasized. To improve Can.

  Hereinafter, the present invention will be described based on examples with reference to the drawings.

  Example 1 relates to a light guide member according to a first aspect of the present invention, a planar light source device to which the light guide member is applied, a liquid crystal display device assembly, and a light detection device.

The liquid crystal display device assembly of Example 1 is
(A) a transmissive color liquid crystal display device 10 having a display area 11 composed of pixels arranged in a two-dimensional matrix, and
(B) The number of display areas 11 of the color liquid crystal display device 10 is P in the first direction and Q in the second direction extending at right angles to the first direction, for a total of P × Q virtual display areas. The color liquid crystal display device 10 corresponds to the P × Q display area units 12 when assumed to be divided into units 12, each of which includes P × Q planar light source units 42 each having a light source 44. A planar light source device 40 for illuminating the light source from the back side,
It has.

  In addition, the planar light source device 40 according to the first embodiment is a planar light source device that illuminates the transmissive color liquid crystal display device 10 having the display region 11 composed of pixels arranged in a two-dimensional matrix from the back. Thus, P display areas 11 of the liquid crystal display device 10 are divided into P in the first direction and Q in the second direction extending perpendicular to the first direction, for a total of P × Q virtual display area units 12. Corresponding to these P × Q display area units 12 when it is assumed that they are divided, each is composed of P × Q planar light source units 42 each having a light source 44.

  In the planar light source device 40 or the liquid crystal display assembly of the first embodiment, the light emission state of the light source provided in the planar light source unit 42 is individually controlled. That is, a partial drive method or a split drive method is adopted.

Specifically, as shown in a conceptual diagram in FIG. 6, the transmissive color liquid crystal display device 10 in the first embodiment has M ₀ pieces along the first direction and N ₀ pieces along the second direction. The display area 11 has a total of M ₀ × N ₀ pixels arranged in a two-dimensional matrix. Here, it is assumed that the display area 11 is divided into P × Q virtual display area units 12. Each display area unit 12 is composed of a plurality of pixels. Specifically, for example, the image display resolution satisfies the HD-TV standard, and the number M ₀ × N ₀ of pixels (pixels) arranged in a two-dimensional matrix is expressed as (M ₀ , N ₀ ). For example, (1920, 1080). In addition, a display area 11 (indicated by a one-dot chain line in FIG. 6) composed of pixels arranged in a two-dimensional matrix is divided into P × Q virtual display area units 12 (the boundary is indicated by a dotted line). ing. The value of (P, Q) is (19, 12), for example. However, in order to simplify the drawing, the number of the display area units 12 (and the planar light source units 42) in FIG. 6 is different from this value. Each display area unit 12 is composed of a plurality of (M × N) pixels, and the number of pixels constituting one display area unit 12 is, for example, about 10,000. Each pixel is configured as a set of a plurality of sub-pixels that emit different colors. More specifically, each pixel has three types of red light emitting subpixel (subpixel [R]), green light emitting subpixel (subpixel [G]), and blue light emitting subpixel (subpixel [B]). Of sub-pixels (sub-pixels). The transmissive color liquid crystal display device 10 is line-sequentially driven. More specifically, the color liquid crystal display device 10 includes scan electrodes (extending along the first direction) and data electrodes (extending along the second direction) that intersect in a matrix. Then, a scanning signal is input to the scanning electrode to select and scan the scanning electrode, and an image is displayed based on the data signal (a signal based on the control signal) input to the data electrode to constitute one screen.

  As shown in the schematic partial cross-sectional view of FIG. 9, the color liquid crystal display device 10 includes a front panel 20 having a transparent first electrode 24, a rear panel 30 having a transparent second electrode 34, and The liquid crystal material 13 is disposed between the front panel 20 and the rear panel 30.

  The front panel 20 includes, for example, a first substrate 21 made of a glass substrate and a polarizing film 26 provided on the outer surface of the first substrate 21. A color filter 22 covered with an overcoat layer 23 made of acrylic resin or epoxy resin is provided on the inner surface of the first substrate 21, and a transparent first electrode (also called a common electrode) is provided on the overcoat layer 23. (For example, made of ITO) 24 is formed, and an alignment film 25 is formed on the transparent first electrode 24. On the other hand, the rear panel 30 more specifically includes, for example, a second substrate 31 made of a glass substrate, and switching elements (specifically, thin film transistors and TFTs) formed on the inner surface of the second substrate 31. 32, a transparent second electrode (also referred to as a pixel electrode, made of, for example, ITO) 34 whose conduction / non-conduction is controlled by the switching element 32, and a polarizing film 36 provided on the outer surface of the second substrate 31, It is composed of An alignment film 35 is formed on the entire surface including the transparent second electrode 34. The front panel 20 and the rear panel 30 are joined via a sealing material (not shown) at their outer peripheral portions. Note that the switching element 32 is not limited to a TFT, and may be composed of, for example, an MIM element. Reference numeral 37 in the drawing is an insulating layer provided between the switching element 32 and the switching element 32.

  Since various members and liquid crystal materials constituting these transmissive color liquid crystal display devices can be composed of well-known members and materials, detailed description thereof is omitted.

  The direct-type planar light source device (backlight) 40 includes P × Q planar light source units 42 corresponding to the P × Q virtual display area units 12. The display area unit 12 corresponding to the light source unit 42 is illuminated with white light from the back. The light sources 44 provided in the planar light source unit 42 are individually controlled. However, the light source luminance of the planar light source unit 42 is not affected by the light emission state of the light sources 44 provided in the other planar light source units 42. In addition, although the planar light source device 40 is located below the color liquid crystal display device 10, the color liquid crystal display device 10 and the planar light source device 40 are separately displayed in FIG. The arrangement and arrangement of light emitting diodes and the like in the planar light source device 40 are schematically shown in FIG. 1A, and a schematic liquid crystal display device assembly including the color liquid crystal display device 10 and the planar light source device 40 is shown. A partial cross-sectional view is shown in FIG. The light source 44 includes a light emitting diode 43 that is driven based on a pulse width modulation (PWM) control method. The luminance of the planar light source unit 42 is increased / decreased by duty ratio increasing / decreasing control in the pulse width modulation control of the light emitting diodes 43 constituting the planar light source unit 42.

  As shown in the schematic partial cross-sectional view of the liquid crystal display device assembly in FIG. 8, the planar light source device 40 includes a casing 51 having an outer frame 53 and an inner frame 54. The end of the transmissive color liquid crystal display device 10 is held by the outer frame 53 and the inner frame 54 so as to be sandwiched between the spacers 55A and 55B. A guide member 56 is disposed between the outer frame 53 and the inner frame 54 so that the color liquid crystal display device 10 sandwiched between the outer frame 53 and the inner frame 54 does not shift. A light diffusion plate 61 is attached to the inner frame 54 via a spacer 55 </ b> C and a bracket member 57 in the upper portion of the housing 51. On the light diffusion plate 61, an optical function sheet group such as a diffusion sheet 62, a prism sheet 63, and a polarization conversion sheet 64 is laminated. A reflection sheet 65 is provided inside and below the housing 51. Here, the reflection sheet 65 is disposed so that the reflection surface thereof faces the light diffusion plate 61, and is attached to the bottom surface 52 </ b> A of the housing 51 via an attachment member (not shown). The reflection sheet 65 can be composed of, for example, a silver-enhanced reflection film having a structure in which a silver reflection film, a low refractive index film, and a high refractive index film are sequentially laminated on a sheet base material. The reflection sheet 65 reflects the light emitted from the plurality of light emitting diodes 43 and the light reflected by the side surface 52B of the housing 51 or the partition wall 41 shown in FIG. Thus, for example, red light emitted from a red light emitting diode 43R that emits red with a wavelength of 640 nm, for example, a green light emitting diode 43G that emits green with a wavelength of 530 nm, and a blue light emitting diode 43B that emits blue with a wavelength of 450 nm, for example. Light and blue light are mixed, and white light with high color purity can be obtained as illumination light. The white illumination light is emitted from the planar light source unit 42 through the light diffusing plate 61, passes through the optical function sheet group such as the diffusing sheet 62, the prism sheet 63, and the polarization conversion sheet 64, and the color liquid crystal display device 10. Illuminate from the back. In FIG. 1A, the light emitting diodes 43R, 43G, and 43B are collectively shown as a light source 44.

  As shown in FIGS. 6 and 7, the driving circuit for driving the planar light source device 40 and the color liquid crystal display device 10 based on the input signal from the outside (display circuit) is based on the pulse width modulation control method. Planar light source device control circuit 70 and planar light source unit driving circuit 80 for performing on / off control of the red light emitting diode 43R, the green light emitting diode 43G, and the blue light emitting diode 43B constituting the planar light source device 40, and a liquid crystal display The apparatus driving circuit 90 is configured.

  The planar light source device control circuit 70 includes an arithmetic circuit 71 and a storage device (memory) 72. On the other hand, the planar light source unit drive circuit 80 includes an arithmetic circuit 81, a storage device (memory) 82, an LED drive circuit 83, a photodetector control circuit 84, switching elements 85R, 85G, 85B composed of FETs, and a light emitting diode drive power source ( Constant current source) 86. These circuits constituting the planar light source device control circuit 70 and the planar light source unit drive circuit 80 can be known circuits. On the other hand, a liquid crystal display device driving circuit 90 for driving the color liquid crystal display device 10 includes a known circuit such as a timing controller 91. The color liquid crystal display device 10 is provided with a gate driver, a source driver, and the like (not shown) for driving the switching element 32 formed of a TFT constituting the liquid crystal cell.

Downstream of the light emitting diodes 43R, 43G, 43B, current detection resistors r _R , r _G , r _B are inserted in series with the light emitting diodes 43R, 43G, 43B, and the resistors r _R , r _G , The operation of the light emitting diode drive power supply 86 is controlled under the control of the LED drive circuit 83 so that the current flowing through r _B is converted into a voltage, and the voltage drop in the resistors r _R , r _G , r _B becomes a predetermined value. Is done. Here, FIG. 7 shows a single light emitting diode driving power source (constant current source) 86, but actually, the light emitting diode driving power source for driving each of the light emitting diodes 43R, 43G, and 43B. 86 is arranged.

  The light emitting states of the light emitting diodes 43R, 43G, and 43B are measured by the photodetector 130, and the output from the photodetector 130 is input to the photodetector control circuit 84. In the photodetector control circuit 84 and the arithmetic circuit 81, The light emitting diodes 43R, 43G, and 43B are, for example, data (signals) as luminance and chromaticity, and the data is sent to the LED driving circuit 83, and the light emitting states of the light emitting diodes 43R, 43G, and 43B thereafter are controlled. The feedback mechanism is formed.

  A display area 11 composed of pixels arranged in a two-dimensional matrix is divided into P × Q display area units. When this state is expressed by “row” and “column”, Q rows × It can be said that the display area unit is divided into P columns. The display area unit 12 is composed of a plurality of (M × N) pixels. When this state is expressed by “row” and “column”, it is composed of pixels of N rows × M columns. I can say. Further, the red light emitting subpixel (subpixel [R]), the green light emitting subpixel (subpixel [G]), and the blue light emitting subpixel (subpixel [B]) are collectively collected as “subpixel [ R, G, B] ”and may be referred to as“ sub-pixel ”for controlling the operation of the sub-pixel [R, G, B] (specifically, for example, controlling the light transmittance (aperture ratio)). The red light emitting subpixel / control signal, the green light emitting subpixel / control signal, and the blue light emitting subpixel / control signal input to [R, G, B] are collectively referred to as “control signal [R, G, B] ”and may be referred to as a red light-emitting subpixel / input signal or a green light-emitting subpixel that is input to the drive circuit from the outside in order to drive the subpixels [R, G, B] constituting the display area unit. The input signal and the blue light emitting subpixel / input signal may be collectively referred to as “input signal [R, G, B]”.

As described above, each pixel includes a red light emitting subpixel (red light emitting subpixel, subpixel [R]), a green light emitting subpixel (green light emitting subpixel, subpixel [G]), and a blue light emitting subpixel ( The blue light emitting subpixel and the subpixel [B]) are configured as a set of three subpixels (subpixels). In the following description of the embodiments, it is assumed that the luminance control (gradation control) of each of the sub-pixels [R, G, B] is 8-bit control and is performed in 2 ⁸ steps from 0 to 255. Therefore, the value of the input signal [R, G, B] input to the liquid crystal display device driving circuit 90 to drive each of the sub-pixels [R, G, B] in each pixel constituting each display area unit 12. x _R, x _G, each x _B, takes a value of 2 ⁸ steps. Further, the pulse width modulation output signal values S _R , S _G , S for controlling the respective light emission times of the red light emitting diode 43R, the green light emitting diode 43G, and the blue light emitting diode 43B constituting each planar light source unit. _B also takes a value of 2 ⁸ steps of 0 to 255. However, the present invention is not limited to this. For example, 10-bit control can be performed in 2 ¹⁰ stages from 0 to 1023. In this case, if an 8-bit numerical expression is multiplied by, for example, 4 times Good.

A control signal for controlling the light transmittance Lt of each sub-pixel is supplied from the drive circuit to each sub-pixel. Specifically, a control signal [R, G, B] for controlling the light transmittance Lt of each of the sub-pixels [R, G, B] is transmitted to each of the sub-pixels [R, G, B]. Supplied from the drive circuit 90. That is, in the liquid crystal display device driving circuit 90, a control signal [R, G, B] is generated from the input signal [R, G, B] that is input, and the control signal [R, G, B] is subpixel. [R, G, B] are supplied (output). Since the light source luminance Y ₂ that is the luminance of the planar light source unit 42 is changed for each image display frame, the control signal [R, G, B] is, for example, the value of the input signal [R, G, B]. Values X _R-corr , X _G-corr , and X _B-corr obtained by performing correction (compensation) based on the change in the light source luminance Y _{2 with} respect to the values obtained by raising x _R , x _G , and x _B to the power of 2.2. Have. Then, the control signal [R, G, B] is sent from the timing controller 91 constituting the liquid crystal display device driving circuit 90 to the gate driver and the source driver of the color liquid crystal display device 10 by a known method. Based on [R, G, B], the switching element 32 constituting each subpixel is driven, and a desired voltage is applied to the transparent first electrode 24 and the transparent second electrode 34 constituting the liquid crystal cell. The light transmittance (aperture ratio) Lt of the sub-pixel is controlled. Here, the larger the values X _R-corr , X _G-corr , and X _B-corr of the control signal [R, G, B], the light transmittance (aperture ratio) Lt of the sub-pixel [R, G, B]. And the value of the luminance (display luminance y) of the display area corresponding to the sub-pixel [R, G, B] increases. That is, an image composed of light passing through the sub-pixels [R, G, B] (usually a kind of dot) is bright.

The display brightness y and the light source brightness Y ₂ are controlled for each image display frame, each display area unit, and each planar light source unit in the image display of the color liquid crystal display device 10. Further, the operation of the color liquid crystal display device 10 and the operation of the planar light source device 40 within one image display frame are synchronized. Note that the number of image information (images per second) sent to the drive circuit as electrical signals per second is the frame frequency (frame rate), and the inverse of the frame frequency is the frame time (unit: seconds).

  As shown in FIG. 1A, the planar light source device 40 or the liquid crystal display device assembly according to the first embodiment includes a light detection device 100 arranged along the first direction. Here, in the first embodiment, Q photodetection devices 100 are provided. The light detection device 100 includes a light guide member 110 and a light detector 130. Note that the number of the planar light source units 42 and the number of the photodetecting devices 100 constituting the planar light source device 40 shown in FIG.

  A schematic view of the light guide member 110 viewed from above is shown in FIG. 1B, and a schematic cross-sectional view of the light guide member 110 viewed from the lateral direction is shown in FIG. FIG. 2A shows a schematic partial end view when the light guide member 110 is cut along a virtual plane that includes the alternate long and short dash line in FIG. In (A) of 2, the oblique lines attached to the cross section are omitted. Furthermore, a schematic partial perspective view of the end portion of the light guide member 110 is shown in FIG.

  Specifically, the light guide member 110 made of a transparent elongate material has a side surface, a first end surface 111, and a second end surface 112. On the other hand, a photodetector 130 made of a color photodiode is disposed in the vicinity of the first end face 111. A plurality of light intake sections 120 (specifically, P locations, five of which are shown in FIG. 1) are provided on the side surface of the light guide member 110. In the first embodiment, specifically, the light guide member 110 is manufactured from a transparent acrylic resin by an injection molding method, and the axis of the light guide member 110 (indicated by an arrow 110A) is used. The cross-sectional shape of the light guide member 110 when the light guide member 110 is cut along a vertical virtual plane is a rectangle (specifically, for example, 5 mm × 5 mm). Specifically, the side surface of the light guide member 110 includes an upper surface 113, a lower surface 114, and two wall surfaces 115A and 115B. The light intake unit 120 is provided on the upper surface 113 of the light guide member 110. The light receiving part 120 formed of a groove part or a notch part has two opposing surfaces 121 and 122. Here, of the two facing surfaces 121 and 122 of the light receiving portion 120, the facing surface (first facing surface 121) far from the first end surface 111 has an acute inclination angle θ (for example, 35 degrees). The opposing surface (second opposing surface 122) close to the first end surface 111 is substantially vertical. By making the light intake part 120 formed of the groove part into such a shape, light from the light source 44 enters the light intake part 120 and enters the light guide member 110 and is transmitted through the light guide member 110. This can be ensured. In the light intake unit 120 having such a structure, the amount of light reaching the light detector 130 is about 1 from the simulation result compared to the structure of the light intake unit 120 shown in FIG. .13 times increase.

  A part of the light incident on the light intake unit 120 enters the light guide member 110 from the light intake unit 120 and is transmitted through the light guide member 110 by total reflection (in FIG. 2A). The light is emitted from the first end face 111 and enters the photodetector 130. As a result, the light transmitted through the light guide member 110 (internal transmission light) is not attenuated. Further, the other part of the light incident on the light intake unit 120 (shown by a solid line in FIG. 2A) does not penetrate deeply into the light guide member 110 from the light intake unit 120, and the light guide member 110 exits. In FIG. 2A, the light that enters the light guide member 110 from the other light receiving portion 120 and propagates through the light guide member 110 by total reflection is indicated by a one-dot chain line. In FIG. 2A, only the behavior of light in a direction parallel to the paper surface of the drawing is illustrated. However, in practice, the direction perpendicular to the paper surface of the drawing or the paper surface of the drawing is arbitrary. Even in the direction of, light that enters the light guide member 110 from the light intake portion 120 and propagates through the light guide member 110 by total reflection, and enters the light guide member 110 deeply from the light intake portion 120. There is no light emitted from the light guide member 110. That is, the light that has entered the light guide member 110 from the light intake 120 is totally reflected on the inner surface of the upper surface 113, the inner surface of the lower surface 114, and the inner surfaces of the two wall surfaces 115A and 115B. It travels through the inside of the optical member 110.

  The light emitted from the plurality of light emitting diodes 43 as the light source is emitted through the light diffusing plate 61, or after being reflected at least once by the reflection sheet 65, the side surface 52B of the casing 51, and the partition wall 41. The light is emitted through the light diffusing plate 61. Accordingly, the light emitted from the plurality of light emitting diodes 43 is incident on the light intake unit 120 at random. That is, the incident angles of light incident on the light intake unit 120 are various angles. Accordingly, a part of the light incident on the light intake unit 120 is light that satisfies a specific incident angle condition with respect to the light intake unit 120, and this light enters the light guide member 110 from the light intake unit 120. The light travels through the light guide member 110 and exits from the first end surface 111. On the other hand, since the other part of the light incident on the light intake unit 120 does not satisfy the specific incident angle condition, the light guide member 110 does not penetrate deeply into the light guide member 110 from the light intake unit 120. Exits from.

  In the first embodiment, the light intake unit 120 includes a linear groove portion or a notch portion. In the plurality of (P places) light intake portions 120, the angle formed between the axis 110 </ b> A of the light guide member 110 and the axis (shown by the arrow 120 </ b> A) of the light intake portion 120 is light far from the first end surface 111. The intake section 120 is as large. For example, the angle formed by the axis 120A of the p-th (p = 1, 2... P) light intake 120 and the axis 110A of the light guide member 110 is about 2.5 × (p−1). ) Degree. The angle is optimized by simulation. Further, the depth of the light intake portion 120 is as shallow as the light intake portion 120 close to the first end surface 111. As described above, by increasing the angle between the axis 110A of the light guide member 110 and the axis 120A of the light receiving portion 120 as the light receiving portion 120 farther from the first end face 111, the amount of the internal transmission light is further increased. be able to. In addition, the internal transmission light may be emitted from the other light intake unit 120 to the outside because the other light intake unit 120 exists in the middle, but the depth of the light intake unit 120 is reduced. By making the light receiving portion 120 closer to the first end surface 111 shallower, it is possible to reduce interference with the progress of the internal transmission light by other light intake portions 120 existing in the middle, and to reduce the amount of light of the internal transmission light. Can be reduced. The light that enters the light intake unit 120 and exits from the light guide member 110 without penetrating deeply into the light guide member 110 from the light intake unit 120 (leakage light from the light intake unit 120), and The ratio to the internally transmitted light can be defined by the shape of the light intake unit 120, and is further determined based on, for example, the position where the light intake unit 120 is disposed.

  The plurality of light emitting diodes 43 and the light guide member 110 that are light sources are disposed (for example, fixed) on the bottom surface 52A of the casing 51 constituting the planar light source device 40 by an appropriate method. Specifically, for example, a boss portion (not shown) is formed in the light guide member 110, and the light guide member 110 is screwed into the boss portion from the bottom surface 52 </ b> A of the housing 51 by screwing the wood screw into the housing 51. Can be disposed on the bottom surface 52A. A through hole (not shown) is provided below the partition wall 41, and the light guide member 110 passes through the through hole. The photodetector 130 is disposed outside the side surface 52 </ b> B of the housing 51.

  As shown in FIGS. 1B and 1C and FIG. 2B, the end of the light guide member 110 constituting the first end surface 111 is guided from two wall surfaces 115A and 115B. A first protrusion 116 extending in a direction perpendicular to the axis 110A of the optical member 110, and a first parallel to the axis 110A of the light guide member 110 from the tip of each first protrusion 116, and the first A second protrusion 117 extending toward the end surface 111 is provided. Note that the shape of the end portion of the light guide member 110 constituting the first end surface 111 as viewed from above is generally a “U” shape. The photodetector 130 is fixed to the first end surface 111 located between the two second protrusions 117 by an appropriate method.

  In the first embodiment, for example, when the operation of the liquid crystal display device assembly starts (when the switch is turned on), each subpixel is configured without displaying an image of the liquid crystal display device, that is, in the liquid crystal display device. By turning on the light sources 44 of the p-th (where p = 1, 2,..., P) planar light source units 42 (total Q pieces) for a predetermined time with the liquid crystal cell closed, Q pieces are turned on. The operation of measuring the light amount of the light source in the Q planar light source units 42 is repeated P times by the light detection device. Then, the measured light quantity value is measured in advance, and the light quantity value or design light quantity value (referred to as a reference value) stored in the liquid crystal display device assembly and the drive circuit (planar light source unit drive circuit 80 described later) Compare. If there is a difference between the light quantity measurement value and the reference value for some reason, the light emission time of the light source 44 in the planar light source unit 42 may be adjusted (corrected). Such a method is referred to as a first adjustment method for convenience.

  Alternatively, during the operation of the liquid crystal display device assembly, for example, in the operation period of the liquid crystal display device corresponding to the vertical blanking period, the light transmittance of all the pixels constituting the display area unit 12 is minimized. The light source 44 constituting the planar light source unit corresponding to the display area unit 12 is set to the light emitting state, the light detecting device 100 measures the light emitting state, and the measurement result is obtained in the driving circuit (planar light source unit driving circuit 80 described later). What is necessary is just to control the light emission state of the light source 44 which comprises the planar light source unit 42 so that it may become equal to a reference value compared with a reference value. Such a method is referred to as a second adjustment method for convenience. During the operation period of the liquid crystal display device corresponding to one vertical blanking period, the light sources 44 constituting all P × Q planar light source units 42 may be in a light emitting state, or one or Q planar light sources. The light source 44 constituting the unit 42 may be in a light emitting state. Further, in the operation period of the liquid crystal display device corresponding to a plurality of vertical blanking periods, the light sources 44 constituting all the P × Q planar light source units 42 may be in a light emitting state once, or one or The light sources 44 constituting the Q planar light source units 42 may be in a light emitting state.

  Hereinafter, a driving method of the liquid crystal display device assembly according to the first embodiment will be described with reference to FIGS. 6, 7, and 10. FIG. 10 is a flowchart for explaining a driving method of the liquid crystal display device assembly according to the first embodiment.

In the first embodiment, a control signal for controlling the light transmittance Lt of each sub-pixel is supplied from the drive circuit to each sub-pixel. More specifically, a control signal [R, G, B] that controls the light transmittance Lt of each of the sub-pixels [R, G, B] is supplied to each of the sub-pixels [R, G, B] constituting each pixel. B] is supplied from the drive circuit 90. Then, in each of the planar light source units 42, inputs input to the drive circuits 70, 80, 90 to drive all the pixels (subpixels [R, G, B]) constituting each display area unit 12. A control signal corresponding to an input signal having a value equal to the maximum value x _U-max in the display area unit that is the maximum value x _R , x _G , x _B of the signals [R, G, B]. Of the pixel (sub-pixel [R, G, B]) (light transmittance, display luminance at the first specified value Lt ₁ , second specified value y ₂ ) is obtained. As described above, the luminance of the light source constituting the planar light source unit 42 corresponding to the display area unit 12 is controlled by the planar light source device control circuit 70 and the planar light source unit drive circuit 80. Specifically, for example, the light source luminance Y ₂ is obtained so that the display luminance y ₂ can be obtained when the light transmittance (aperture ratio) of the pixel or the sub-pixel is, for example, the light transmittance · the first specified value Lt _1. May be controlled (for example, decreased). That is, for example, the light source luminance Y ₂ of the planar light source unit 42 may be controlled for each image display frame so as to satisfy the following expression (1). Note that Y ₂ ≦ Y ₁ .

Y ₂ · Lt ₁ = Y ₁ · Lt ₂ (1)

[Step-100]
An input signal [R, G, B] and a clock signal CLK for one image display frame sent from a known display circuit such as a scan converter are input to the planar light source device control circuit 70 and the liquid crystal display device driving circuit 90. (See FIG. 6). Note that the input signals [R, G, B] are output signals from the image pickup tube, for example, when the input light quantity to the image pickup tube is y ′, and are output from, for example, a broadcasting station and the light transmittance of the sub-pixels. This is an input signal that is also input to the liquid crystal display driving circuit 90 to control Lt, and can be expressed as a function of the input light amount y ′ to the power of 0.45. The values x _R , x _G , x _B of the input signals [R, G, B] for one image display frame input to the planar light source device control circuit 70 constitute the planar light source device control circuit 70. The data is temporarily stored in the storage device (memory) 72. Further, the values x _R , x _G , x _B of the input signals [R, G, B] for one image display frame inputted to the liquid crystal display device driving circuit 90 are also stored in the liquid crystal display device driving circuit 90. (Not shown) once stored.

[Step-110]
Next, in the arithmetic circuit 71 constituting the surface light source device control circuit 70, the value of the input signal [R, G, B] stored in the storage device 72 is read, and the (p, q) th [however, first , P = 1, q = 1] for driving the sub-pixels [R, G, B] in all the pixels constituting the (p, q) -th display region unit 12 The arithmetic circuit 71 obtains the display area unit input signal maximum value x _U-max that is the maximum value of the values x _R , x _G , x _B of the input signals [R, G, B]. Then, the in-display area unit / input signal maximum value x _U-max is stored in the storage device 72. This step is executed for all of m = 1, 2,..., M, n = 1, 2,..., N, that is, for M × N pixels.

For example, when x _R is a value corresponding to “110”, x _G is a value corresponding to “150”, and x _B is a value corresponding to “50”, x _U-max is “150”. Is a value corresponding to.

This operation is repeated from (p, q) = (1, 1) to (P, Q), and the display area unit internal input signal maximum value x _U-max in all the display area units 12 is stored in the storage device 72. Remember.

[Step-120]
Then, the control signal [R, G, B] corresponding to the input signal [R, G, B] having a value equal to the maximum value x _U-max in the display area unit is sub-pixel [R, G, B]. ] Corresponding to the display area unit 12 so that the brightness (light transmittance, display brightness at the first specified value Lt ₁ , second specified value y ₂ ) is obtained by the planar light source unit 42. The luminance (light source luminance Y ₂ ) of the light source 44 constituting the planar light source unit 42 to be controlled is increased or decreased under the control of the planar light source unit drive circuit 80. Specifically, the light source luminance Y ₂ may be controlled for each image display frame and for each planar light source unit so as to satisfy the following expression (1). More specifically, the luminance of the light source 44 (light emitting diode 43) is controlled based on the equation (2) which is the light source luminance control function g (x _nol-max ), and the light source is set so as to satisfy the equation (1). The luminance Y ₂ may be controlled. A conceptual diagram of such control is shown in FIGS. 12 (A) and 12 (B). However, as will be described later, correction based on the influence of the other planar light source unit 42 is performed on the light source luminance Y ₂ as necessary. It should be noted that these relations regarding the control of the light source luminance Y ₂ , that is, the value of the control signal corresponding to the input signal having a value equal to the maximum value x _U-max in the display area unit and the input signal maximum value x _U-max . , The display luminance when assuming that such a control signal is supplied to the pixel (sub-pixel), the second specified value y ₂ , the light transmittance (aperture ratio) of each sub-pixel at this time [light transmittance / first 2 specified value Lt ₂ ], and a planar light source that provides display luminance and second specified value y ₂ when the light transmittance (aperture ratio) of each sub-pixel is set to light transmittance and first specified value Lt _1. The relationship of the brightness control parameters in the unit 42 may be obtained in advance and stored in the storage device 72 or the like.

Y ₂ · Lt ₁ = Y ₁ · Lt ₂ (1)
g (x _nol-max ) = a ₁ · (x _nol-max ) ^2.2 + a ₀ (2)

Here, input signals (input signals [R, G, B]) that are input to the liquid crystal display driving circuit 90 to drive the pixels (or the sub-pixels [R, G, B] constituting the pixels). ) _Is the maximum value x _max
x _nol-max ≡ x _U-max / x _max
And a ₁ and a ₀ are constants,
a ₁ + a ₀ = 1
0 <a ₀ <1, 0 <a ₁ <1
Can be expressed as For example,
a ₁ = 0.99
a ₀ = 0.01
And it is sufficient. The value x _R, x _G of the input signal [R, G, B], each x _B, and takes a value of 2 ⁸ steps, the value of x _max is a value corresponding to "255".

  By the way, in the planar light source device 40, for example, assuming brightness control of the planar light source unit 42 of (p, q) = (1, 1), other P × Q planar light source units. 42 may need to be taken into account. Since the influence of such a planar light source unit 42 from other planar light source units 42 is known in advance by the light emission profile of each planar light source unit 42, the difference can be calculated by back calculation, and as a result, the correction is Is possible. The basic form of calculation will be described below.

The luminance (light source luminance Y ₂ ) required for the P × Q planar light source units 42 based on the requirements of the equations (1) and (2) is represented by a matrix [L _PxQ ]. In addition, the luminance of a certain planar light source unit obtained when only a certain planar light source unit is driven and the other planar light source units are not driven is compared with P × Q planar light source units 42. Obtain in advance. Such luminance is represented by a matrix [L ′ _PxQ ]. Further, the correction coefficient is represented by a matrix [α _PxQ ]. Then, the relationship between these matrices can be expressed by the following equation (3-1). The correction coefficient matrix [α _PxQ ] can be obtained in advance.
[L _PxQ ] = [L ′ _PxQ ] · [α _PxQ ] (3-1)
Therefore, the matrix [L ′ _PxQ ] may be obtained from Expression (3-1). The matrix [L ′ _PxQ ] can be obtained from the inverse matrix operation. That is,
[L ′ _PxQ ] = [L _PxQ ] · [α _PxQ ] ⁻¹ (3-2)
Should be calculated. Then, the light source 44 provided in each planar light source unit 42 may be controlled so that the luminance represented by the matrix [L ′ _PxQ ] is obtained. Specifically, the operation and processing are performed by the storage device. The information (data table) stored in the (memory) 72 may be used. In the control of the light emitting diode 43, the value of the matrix [L ′ _PxQ ] cannot take a negative value, and needless to say, the calculation result needs to be kept in a positive region. Therefore, the solution of equation (3-2) may not be an exact solution but an approximate solution.

As described above, the matrix [L _PxQ ] obtained based on the values of the equations (1) and (2) obtained in the arithmetic circuit 71 constituting the surface light source device control circuit 70, and the correction coefficient matrix [α _PxQ ], As described above, a luminance matrix [L ′ _PxQ ] when it is assumed that the planar light source unit is driven alone is obtained. Further, based on the conversion table stored in the storage device 72, 0 to 0 is obtained. Convert to a corresponding integer (value of the pulse width modulation output signal) in the range of 255. In this way, in the arithmetic circuit 71 constituting the planar light source device control circuit 70, the value S _R of the pulse width modulation output signal for controlling the light emission time of the red light emitting diode 43R in the planar light source unit 42, the green light emitting diode 43G The value S _G of the pulse width modulation output signal for controlling the light emission time and the value S _B of the pulse width modulation output signal for controlling the light emission time of the blue light emitting diode 43B can be obtained.

[Step-130]
Next, the values S _R , S _G , and S _B of the pulse width modulation output signal obtained in the arithmetic circuit 71 constituting the surface light source device control circuit 70 are the surfaces provided corresponding to the surface light source unit 42. Is sent to the storage device 82 of the light source unit driving circuit 80 and stored in the storage device 82. The clock signal CLK is also sent to the planar light source unit drive circuit 80 (see FIG. 7).

[Step-140]
Based on the values S _R , S _G , and S _B of the pulse width modulation output signal, the on time t _R-ON and the off time t _{R-OFF of} the red light emitting diode 43R constituting the planar light source unit 42, the green light emitting diode The arithmetic circuit 81 determines the ON time t _G-ON and OFF time t _{G-OFF of} 43G and the ON time t _B-ON and OFF time t _B-OFF of the blue light emitting diode 43B. still,
t _R-ON + t _R-OFF = t _G-ON + t _G-OFF = t _B-ON + t _B-OFF = constant value t _Const
It is. The duty ratio in driving based on pulse width modulation of the light emitting diode is
t _ON / (t _ON + t _OFF ) = t _ON / t _Const
Can be expressed as

The signals corresponding to the _ON times t _R-ON , t _G-ON , t _B-ON of the red light emitting diode 43R, the green light emitting diode 43G, and the blue light emitting diode 43B constituting the planar light source unit 42 are LED driving circuits. 83, and from the LED drive circuit 83, the switching elements 85R, 85G, 85B turn on the time t _R based on the signal values corresponding to the on times t _R-ON , t _G-ON , t _B-ON. Only _-ON , _{tG -ON} , and _{tB -ON} are turned on, and the LED driving current from the light emitting diode driving power supply 86 is caused to flow to the respective light emitting diodes 43R, 43G, and 43B. As a result, each of the light emitting diodes 43R, 43G, and 43B emits light for the on times t _R-ON , t _G-ON , and t _B-ON in one image display frame. Thus, each display area unit 12 is illuminated at a predetermined illuminance.

The states obtained in this way are indicated by solid lines in FIGS. 11A and 11B. FIG. 11A shows an input signal input to the liquid crystal display device driving circuit 90 to drive the sub-pixels. 12 is a diagram schematically showing a relationship between a value obtained by raising the value of x to the power of 2 (x′≡x ^2.2 ) and a duty ratio (= t _ON / t _Const ). FIG. It is a figure which shows typically the relationship between the value X of the control signal for controlling the light transmittance Lt, and the display brightness | luminance y.

[Step-150]
On the other hand, the values x _R , x _G , x _B of the input signals [R, G, B] input to the liquid crystal display device driving circuit 90 are sent to the timing controller 91, and the timing controller 91 receives the input signals A control signal [R, G, B] corresponding to the input signal [R, G, B] is supplied (output) to the sub-pixel [R, G, B]. The values X _R and X _{G of the} control signal [R, G, B] generated by the timing controller 91 of the liquid crystal display device driving circuit 90 and supplied from the liquid crystal display device driving circuit 90 to the sub-pixels [R, G, B]. , X _B and the values x _R , x _G , x _{B of} the input signals [R, G, B] are expressed by the following equations (4-1), (4-2), and (4-3): There is a relationship. However, _{b1_R} , _{b0_R} , _{b1_G} , _{b0_G} , _{b1_B} , _{b0_B} are constants. Further, since the light source luminance Y ₂ of the planar light source unit 42 is changed for each image display frame, the control signal [R, G, B] basically sets the value of the input signal [R, G, B] to 2. A value obtained by performing correction (compensation) based on a change in the light source luminance Y _{2 with} respect to the squared value. That is, in Example 1, 1 since the light source luminance Y ₂ in each image display frame is changed, the light source luminance Y ₂ (≦ Y ₁₎ Display brightness · second specified value y ₂ is controlled so as to obtain in The values X _R , X _G , and X _B of the signal [R, G, B] are determined, corrected (compensated), and the light transmittance (aperture ratio) Lt of the pixel or sub-pixel is controlled. Here, the functions f _R , f _G , and f _B in the equations (4-1), (4-2), and (4-3) are functions obtained in advance for performing such correction (compensation). is there.

X _R = f _R (b 1 _—R · x _R ^2.2 + b 0 _—R ) (4-1)
X _G = f _G (b 1 _—G · x _G ^2.2 + b 0 _—G ) (4-2)
X _B = f _B (b 1 _—B · x _B ^2.2 + b 0 _—B ) (4-3)

  Thus, the image display operation in one image display frame is completed. Incidentally, as described above, the first adjustment method may be adopted, but the second adjustment method described below may be adopted.

[Step-160]
That is, next, the operation period of the color liquid crystal display device 10 is a vertical blanking operation period. In this vertical blanking operation period, the light transmittance Lt of all the pixels constituting the display area unit 12 is minimized, that is, the color liquid crystal display device 10 is in the “black display” state. The light source 44 constituting the planar light source unit 42 corresponding to the display area unit 12 is set in a light emission state, and these light emission states are measured by the light detection device 100.

The output from the light detector 130 is input to the light detector control circuit 84, and is converted from analog to digital by the light detector control circuit 84 to be converted into luminance data (digital signal) of the light emitting diodes 43R, 43G, and 43B. . Then, the luminance data (digital signal) is sent to the arithmetic circuit 81, and the luminance reference value stored in the storage device 82 is compared with the arithmetic circuit 81. In this way, it is possible to obtain a deviation amount from the luminance reference value of the light emitting diodes 43R, 43G, 43B and a deviation amount from the chromaticity reference value based on the luminance of the light emitting diodes 43R, 43G, 43B. Here, the deviation amount, the correction amount ΔS _R of the value of the pulse width modulation output signal for controlling the light emission time of the red light emitting diode 43R in the planar light source unit 42, and the light emission time of the green light emitting diode 43G are controlled. The correction amount ΔS _G of the value of the pulse width modulation output signal and the correction amount ΔS _B of the value of the pulse width modulation output signal for controlling the light emission time of the blue light emitting diode 43B are determined in advance and stored in the storage device 82. Keep it. Based on these correction amounts ΔS _R , ΔS _G and ΔS _B , the values S _R , S _G and S _B of the pulse width modulation output signal are corrected in [Step-140] in the next image display frame.

  In the first adjustment method, basically, the operation (action) described above is performed.

  In such a driving method of the liquid crystal display device assembly, a partial driving method or a divided driving method is adopted, so that not only can the power consumption of the planar light source device 40 be reduced, but also a high contrast ratio is achieved. Obtainable. In addition, in the vertical blanking operation period, the display region unit 12 is in a state where the light transmittance of all the pixels constituting the display region unit 12 is minimized, that is, in the state where the color liquid crystal display device 10 is in the “black display” state. When the light detection device 100 measures the light emission state by setting the light source 44 constituting the planar light source unit 42 corresponding to the light emission state to the light detection device 100, the light detection device 100 measures the light emission state of the light source 44 under a desired stable condition. can do. Therefore, it is possible to control the luminance and chromaticity of the light source 44 for each image display frame with high accuracy.

  Example 2 relates to a light guide member and a lighting apparatus according to the second aspect of the present invention. A schematic view of the light guide member 140 of Example 2 viewed from above is shown in FIG. 3A, and a schematic cross-sectional view of the light guide member 140 viewed from the lateral direction is shown in FIG. A schematic partial end view when the light guide member 140 is cut along a virtual plane that includes the alternate long and short dash line in FIG. 3A and extends in the direction perpendicular to the paper surface is the same as that shown in FIG. It is.

  The lighting device of Example 2 has a side surface, a first end surface 141, and a second end surface 142, and is disposed in the vicinity of the light guide member 140 made of a transparent elongated material, and the first end surface 141. It is the illuminating device which comprised the light source (not shown). Moreover, the light guide member 140 of Example 2 has a side surface, a first end surface 141, and a second end surface 142, and is made of a transparent elongated material. A light extraction unit 150 is provided on the side surface of the light guide member 140, and a part of the light emitted from the light source, incident from the first end surface 141, and transmitted through the light guide member 140 by total reflection is as follows. The light is extracted from the light extraction unit 150 to the outside, and the other part of the light is emitted from the second end surface 142. The behavior of these lights is the same as that shown in FIG. However, the traveling direction of light is reversed. That is, the light guide member 140 is totally reflected on the inner surface of the upper surface 143, the inner surface of the lower surface 144, and the inner surfaces of the two wall surfaces 145 </ b> A and 145 </ b> B and travels through the light guide member 140.

  Here, the light guide member 140 has substantially the same configuration and structure as the light guide member 110 described in the first embodiment. That is, also in the second embodiment, the light guide member 140 is specifically manufactured from a transparent acrylic resin by an injection molding method, and is hypothetical to the axis 140A of the light guide member 140. The cross-sectional shape of the light guide member 140 when the light guide member 140 is cut in a plane is a rectangle (specifically, for example, 5 mm × 5 mm), and the side surface of the light guide member 140 is specifically the upper surface 143. , A lower surface 144, and two wall surfaces 145A and 145B.

  The light extraction unit 150 is provided on the upper surface 143 of the light guide member 140. The light extraction portion 150 is formed of at least one shape selected from the group consisting of a recess, a concavo-convex portion, and a groove (notch). More specifically, in the second embodiment, a plurality of light extraction portions 150 each including a groove portion are provided; the angle formed by the axis 140A of the light guide member 140 and the axis 150A of the light extraction portion 150 is The light extraction portion 150 that is farther from the first end surface 141 is larger; the depth of the light extraction portion 150 is as shallow as the light extraction portion 150 that is closer to the first end surface 141. In this way, the angle formed between the axis of the light guide member 140 and the axis of the light extraction unit 150 is increased as the light extraction unit 150 farther from the first end surface 141 is incident on the first end surface 141 and the light extraction is performed. The amount of light emitted from the unit 150 can be increased. Further, if the other light extraction unit 150 exists in the middle of the internal transmission light, there is a possibility that a lot of light is emitted from the other light extraction unit 150 to the outside. By making the depth of the light extraction portion 150 close to the first end surface 141 as shallow as possible, it is possible to reduce the interference of the progress of the internal transmission light by the other light extraction portions 150 existing in the middle, and the amount of the internal transmission light Loss can be reduced. In addition, the light intake portion includes a groove portion having two opposing surfaces, and of the two opposing surfaces of the light extraction portion 150, the opposing surface (first opposing surface) 151 facing the first end surface 141 is an acute inclination angle. The opposing surface (second opposing surface) 152 that has θ and is close to the first end surface 141 is substantially vertical.

  At the end of the light guide member 140 constituting the first end surface 141, as in the first embodiment, a first protrusion 146 extending from the two wall surfaces in a direction perpendicular to the axis 140A of the light guide member 140, and A second protrusion 147 extending from the tip of each first protrusion 146 to the first end surface 141 side in parallel to the axis 140A of the light guide member 140 is provided. The shape of the end portion of the light guide member 140 constituting the first end surface 141 when viewed from the upper surface is generally a “U” shape. The light source is fixed to the first end surface 141 located between the two second protrusions 147 by an appropriate method.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The configurations and structures of the transmissive color liquid crystal display device, the planar light source device, the planar light source unit, the liquid crystal display device assembly, and the drive circuit described in the embodiments are examples, and members, materials, and the like constituting these are also examples. This is an example, and can be changed as appropriate. Luminance compensation (correction) and temperature control of the planar light source unit may be performed by monitoring the temperature of the light emitting diode with a temperature sensor and feeding back the result to the planar light source unit drive circuit. In the embodiments, the description has been made on the assumption that the display area of the liquid crystal display device is divided into P × Q virtual display area units. However, in some cases, the transmissive liquid crystal display device has P × Q. You may have the structure divided | segmented into the actual display area unit.

  In some cases, the P × Q planar light source units may include one photodetection device or two or more and less than Q photodetection devices. Further, a second photodetector may be disposed in the vicinity of the second end face 112. In some cases, the second protrusion 117 can be omitted at the end of the light guide member 110 constituting the first end surface 111. In this case, the end of the light guide member 110 constituting the first end surface 111 is omitted. When viewed from above, the shape is generally “T” -shaped.

  Modified examples of the light intake unit 120 in the first embodiment are shown in FIGS. 4A to 4C and FIGS. 5A to 5B. In addition, these figures are typical partial end views when the light guide member 110 is cut along a virtual plane including a one-dot chain line in FIG. 1B and extending in a direction perpendicular to the paper surface. Here, in the example shown in FIG. 4A, both the first facing surface 121 and the second facing surface 122 are substantially vertical. On the other hand, in the example shown in FIG. 4B, the first facing surface 121 is substantially vertical, and the second facing surface 122 has an obtuse angle θ. Further, in the example shown in FIG. 4C, one light receiving portion 120 is provided with one concave portion. Here, the planar shape of the recess is circular, and the cross-sectional shape of the recess when the recess is cut along the depth direction is a part of the circle. That is, the concave portion is composed of a part of a sphere. Furthermore, in the example shown in FIG. 5A, one light receiving portion 120 is provided with one convex portion. Here, the planar shape of the convex portion is a circle, and the cross-sectional shape of the convex portion when the convex portion is cut along the height direction is a part of the circle. That is, the convex part is composed of a part of a sphere. Further, in the example shown in FIG. 5B, the shape of the light intake portion 120 is a straight bank portion, and the opposing surface 121 (slope) far from the first end surface 111 has an acute inclination angle. The opposing surface 122 close to the first end surface 111 is substantially vertical.

1A is a diagram schematically illustrating the arrangement and arrangement of light sources and the like in the planar light source device of Example 1, and FIGS. 1B and 1C are light guide members, respectively. They are the schematic diagram which looked at from the upper part, and the typical sectional view which looked at the light guide member from the horizontal direction. (A) of FIG. 2 is a schematic partial end view of the light guide member when the light guide member is cut along a virtual plane that includes the alternate long and short dash line in FIG. FIG. 2B is a schematic partial perspective view of the end portion of the light guide member. 3B and 3C are a schematic view of the light guide member in Example 2 as viewed from above and a schematic cross-sectional view of the light guide member as viewed from the side. 4A to 4C are schematic diagrams of modified examples of the light guide member similar to the case where the light guide member is cut along a virtual plane that includes the alternate long and short dash line in FIG. It is a typical partial end view. 5A to 5B are schematic diagrams of modified examples of the light guide member similar to those obtained when the light guide member is cut along a virtual plane that includes the alternate long and short dash line in FIG. It is a typical partial end view. FIG. 6 is a conceptual diagram of a liquid crystal display device assembly including a color liquid crystal display device and a planar light source device suitable for use in the embodiment. FIG. 7 is a conceptual diagram of a portion of a drive circuit suitable for use in the embodiment. FIG. 8 is a schematic partial cross-sectional view of a liquid crystal display device assembly including a color liquid crystal display device and a planar light source device according to an embodiment. FIG. 9 is a schematic partial cross-sectional view of a color liquid crystal display device. FIG. 10 is a flowchart for explaining a driving method of the liquid crystal display device assembly in the embodiment. FIG. 11A shows a value (x′≡x ^2.2 ) obtained by multiplying the value of the input signal input to the liquid crystal display device driving circuit to drive the sub-pixel by the power of ^2.2 and the duty ratio (= t _ON / t _Const ) schematically shows the relationship between (T _Const ) and FIG. 11B schematically shows the relationship between the value X of the control signal for controlling the light transmittance of the sub-pixel and the display luminance y. FIG. (A) and (B) in FIG. 12 show the display luminance when assuming that a control signal corresponding to an input signal having a value equal to the input signal maximum value x _U-max is supplied to the pixel. as second predetermined value y ₂ is obtained by the planar light source unit, the light source luminance Y ₂ of the planar light source unit is the conceptual view for describing under the control of the planar light source unit drive circuit, a state of increasing or decreasing .

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Color liquid crystal display device, 11 ... Display area, 12 ... Display area unit, 13 ... Liquid crystal material, 20 ... Front panel, 21 ... 1st board | substrate, 22. ··· Color filter, 23 ... Overcoat layer, 24 ... Transparent first electrode (common electrode), 25 ... Alignment film, 26 ... Polarizing film, 30 ... Rear panel, 31 ..Second substrate 32 ... Switching element 34 ... Transparent second electrode 35 ... Alignment film 36 ... Polarization film 37 ... Insulating layer 40 ... Surface shape Light source device (backlight), 41 ... partition wall, 42 ... planar light source unit, 43, 43R, 43G, 43B ... light emitting diode, 44 ... light source, 51 ... housing, 52A ..Bottom surface of casing, 52B ... side surface of casing, 53 ... outside Frame, 54 ... inner frame, 55A, 55B, 55C ... spacer, 56 ... guide member, 57 ... bracket member, 61 ... light diffusion plate, 62 ... diffusion sheet, 63 ..Prism sheet, 64... Polarization conversion sheet, 65 .. reflection sheet, 70... Planar light source device control circuit, 71... Arithmetic circuit, 72. ..Surface light source unit drive circuit, 81... Arithmetic circuit, 82... Storage device (memory), 83... LED drive circuit, 84 .. photodetector control circuit, 85 R, 85 G, 85 B ..Switching element, 86... Light emitting diode drive power source (constant current source), 90... Liquid crystal display device drive circuit, 91... Timing controller, 100. Light guide 110A, 140A ... axis of the light guide member, 111, 141 ... first end surface, 112, 142 ... second end surface, 113, 143 ... upper surface, 114, 144 ... lower surface, 115A, 115B, 145A, 145B ... wall surface, 116, 146 ... first protrusion, 117, 147 ... second protrusion, 120, 150 ... light intake, 120A, 150A. ..Axis of light intake part, 121, 151 ... first opposing surface, 122, 152 ... first opposing surface, 130 ... photodetector

Claims (20)

A planar light source device for illuminating a transmissive liquid crystal display device having a display area composed of pixels arranged in a two-dimensional matrix from the back,
It is assumed that the display area of the liquid crystal display device is divided into P in the first direction and Q in the second direction extending at right angles to the first direction, for a total of P × Q virtual display area units. Corresponding to the P × Q display area units at the time, each consisting of P × Q planar light source units equipped with light sources,
Comprising a photodetection device disposed along the first direction;
The light detection device
(A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
It has
On the side surface of the light guide member, there are provided P light intake portions,
A part of the light incident on each light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end face, and enters the photodetector,
The planar light source device, wherein the other part of the light incident on the light intake part is emitted from the light guide member.   The planar light source device according to claim 1, wherein the light emission states of the light sources provided in the planar light source unit are individually controlled.   The planar light source device according to claim 1, comprising Q light detection devices. The light source and the light guide member are disposed on the bottom surface of the housing constituting the planar light source device,
The planar light source device according to claim 1, wherein the photodetector is disposed outside a side surface of the housing.   2. A part of the light incident on the light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member by total reflection, and exits from the first end surface. A surface light source device according to claim 1.   2. The planar light source device according to claim 1, wherein the light intake portion has at least one shape selected from the group consisting of a concave portion, a convex portion, a concave and convex portion, a groove portion, and a bank portion. The light intake part consists of a groove part,
The angle formed by the axis of the light guide member and the axis of the light intake portion is larger as the light intake portion is farther from the first end surface,
The planar light source device according to claim 1, wherein the depth of the light intake portion is shallower as the light intake portion is closer to the first end face. The light intake part consists of a groove part with two opposing surfaces,
The opposed surface far from the first end surface of the two opposed surfaces of the light intake portion has an acute inclination angle, and the opposed surface close to the first end surface is substantially vertical. The planar light source device described. The cross-sectional shape of the light guide member when the light guide member is cut in a virtual plane perpendicular to the axis of the light guide member is a rectangle,
The side surface of the light guide member is composed of an upper surface, a lower surface, and two wall surfaces,
A light intake is provided on the top surface,
The end portion of the light guide member constituting the first end surface is guided from the first protrusion extending from the two wall surfaces in a direction perpendicular to the axis of the light guide member, and the leading end of each first protrusion. 2. The planar light source device according to claim 1, wherein a second protrusion extending in parallel to the axis of the optical member and extending toward the first end surface is provided. (A) a transmissive liquid crystal display device having a display region composed of pixels arranged in a two-dimensional matrix, and
(B) The display area of the liquid crystal display device is divided into P in the first direction and Q in the second direction extending perpendicular to the first direction, for a total of P × Q virtual display area units. A planar light source device that corresponds to the P × Q display area units when assumed to have been formed, each of which is composed of P × Q planar light source units each having a light source, and that illuminates the liquid crystal display device from the back side ,
A liquid crystal display device assembly comprising:
Comprising a photodetection device disposed along the first direction;
The light detection device
(A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
It has
On the side surface of the light guide member, there are provided P light intake portions,
A part of the light incident on each light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end face, and enters the photodetector,
The other part of the light incident on the light intake part is emitted from the light guide member.   The liquid crystal display device assembly according to claim 10, wherein the light emission state of the light source provided in the planar light source unit is individually controlled. A light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material,
A light intake is provided on the side,
A portion of the light incident on the light intake portion enters the light guide member from the light intake portion, travels through the light guide member, and exits from the first end surface.
The other part of the light incident on the light intake part is emitted from the light guide member.   The part of the light incident on the light intake part enters the inside of the light guide member from the light intake part, travels through the light guide member by total reflection, and exits from the first end surface. The light guide member described in 1.   The light guide member according to claim 12, wherein the light intake portion has at least one shape selected from the group consisting of a concave portion, a convex portion, a concave and convex portion, a groove portion, and a bank portion. A plurality of light intake parts composed of grooves are provided,
The angle formed by the axis of the light guide member and the axis of the light intake portion is larger as the light intake portion is farther from the first end surface,
The light guide member according to claim 12, wherein the depth of the light intake portion is shallower as the light intake portion is closer to the first end face. The light intake part consists of a groove part with two opposing surfaces,
13. The opposed surface far from the first end surface of the two opposed surfaces of the light intake portion has an acute inclination angle, and the opposed surface close to the first end surface is substantially vertical. The light guide member as described. The cross-sectional shape of the light guide member when the light guide member is cut in a virtual plane perpendicular to the axis of the light guide member is a rectangle,
The side surface of the light guide member is composed of an upper surface, a lower surface, and two wall surfaces,
A light intake is provided on the top surface,
The end portion of the light guide member constituting the first end surface is guided from the first protrusion extending from the two wall surfaces in a direction perpendicular to the axis of the light guide member, and the leading end of each first protrusion. The light guide member according to claim 12, wherein a second protrusion extending in parallel to the axis of the optical member and extending toward the first end face is provided. (A) a light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material; and
(B) a photodetector disposed in the vicinity of the first end face;
A photodetecting device comprising:
On the side of the light guide member, a light intake is provided,
A part of the light incident on the light intake part enters the inside of the light guide member from the light intake part, propagates through the inside of the light guide member, exits from the first end surface, and enters the photodetector,
The other part of the light incident on the light intake part is emitted from the light guide member. A light guide member having a side surface, a first end surface, and a second end surface, and made of a transparent elongated material,
A light extraction part is provided on the side,
A part of the light incident from the first end face and transmitted through the inside of the light guide member is emitted to the outside from the light extraction part, and the other part of the light is emitted from the second end face. . A light guide member having a side surface, a first end surface, and a second end surface and made of a transparent elongated material; and
A light source disposed in the vicinity of the first end face;
A lighting device comprising:
A light extraction part is provided on the side surface of the light guide member,
A part of the light emitted from the light source, incident from the first end face and transmitted through the inside of the light guide member is emitted to the outside from the light extraction part, and the other part of the light is emitted from the second end face. A lighting device.

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