JP2007220466A - Lighting system, electro-optical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system which can conduct a luminance adjustment easily and surely. <P>SOLUTION: The lighting apparatus is provided with a light source, a current controlling resistance and a light source driving power source. The light source emits a light when a current is supplied. The current controlling resistance is composed of a plurality of resistances connected in parallel. The light source driving power source supplies a current to the light source via the current controlling resistance. A luminance of a light emitted from the light source is adjusted by adjusting a number of a plurality of resistances. Thus, a resistance value of the current controlling resistance can be decided digitally. By deciding digitally the resistance value of the current controlling resistance, a variation of the resistance value is prevented and a luminance adjustment can be conducted easily and surely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device used for a liquid crystal display device or the like.

  In the liquid crystal display device, an illumination device is provided on the back side of the liquid crystal display panel in order to perform transmissive display. A lighting device having LEDs (Light Emitting Diodes) of red, green, and blue as light sources generates white light by mixing light emitted from each LED, and the generated white light is displayed on a liquid crystal display. Irradiate the back side of the panel. The liquid crystal display device displays color light by transmitting the white light emitted from the illumination device to a color filter that transmits light of each wavelength of red, green, and blue stacked on the substrate of the liquid crystal display panel. Is realized. In the manufacturing process of the liquid crystal display device, in order to adjust the white balance of white light emitted from the lighting device, it is necessary to adjust the luminance of each color LED in the lighting device.

  In the following Patent Document 1, in a lighting device, a variable resistor connected to a light source such as an LED is irradiated with a laser beam, whereby the resistance value of the variable resistor is set to a desired resistance value. A technique for adjusting brightness is described.

JP 2000-310761 A

  However, the technique described in Patent Document 1 may vary in resistance value in the state of laser light or variable resistance, and it is difficult to accurately adjust the luminance of the light source.

  The present invention has been made in view of the above points, and it is an object of the present invention to easily and accurately adjust the luminance in a lighting device.

  In one aspect of the present invention, the lighting device includes a light source that emits light when supplied with a current, a current limiting resistor including a plurality of resistors connected in parallel, and the current limiting resistor with respect to the light source. A light source driving power source for supplying current via the light source, and the brightness of light emitted from the light source is adjusted by adjusting the number of the plurality of resistors.

  The illumination device is used as a backlight of a liquid crystal display device, for example, and includes a light source, a current limiting resistor, and a light source driving power source. The light source is, for example, an LED, and emits light when supplied with current. The current limiting resistor is composed of a plurality of resistors connected in parallel. The plurality of resistors are, for example, a plurality of fuses. The light source driving power source is, for example, an LED driving power source, and supplies a current to the light source via the current limiting resistor. The brightness of the light emitted from the light source is adjusted by adjusting the number of the plurality of resistors. In this way, the resistance value of the current limiting resistor can be determined digitally. By digitally determining the resistance value of the current limiting resistor, variations in the resistance value can be prevented, and the luminance of the lighting device can be adjusted easily and accurately.

  In a preferred embodiment of the lighting device, the plurality of resistors are a plurality of fuses having different resistance values, and one or more fuses among the plurality of fuses are selectively blown by a laser. The brightness of the light emitted from the light source is adjusted.

  In another aspect of the illumination device, the plurality of resistors are configured by connecting a plurality of fuses having the same width to a plurality of wiring resistors having different resistance values, respectively. Among them, the brightness of light emitted from the light source is adjusted by selectively fusing one or more fuses with a laser. Thereby, the cutting efficiency of the laser can be further increased.

  In another aspect of the present invention, an electro-optical device having a display panel and an illumination device used as a backlight of the display panel can be configured. Here, the electro-optical device is, for example, a liquid crystal display device. The lighting device of the present invention can be used as the lighting device.

  In still another aspect of the invention, an electronic apparatus including the electro-optical device described above in a display unit can be configured.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[First Embodiment]
First, the configuration and the like of the liquid crystal display device 100 according to the first embodiment will be described with reference to FIGS.

  FIG. 1 is a plan view schematically showing a schematic configuration of the liquid crystal display device 100 according to the first embodiment. In FIG. 1, a color filter substrate 92 is disposed on the front side (observation side) of the paper, and an element substrate 91 is disposed on the back side of the paper. In FIG. 1, the vertical direction (column direction) on the paper surface is defined as the Y direction, and the horizontal direction (row direction) on the paper surface is defined as the X direction. In FIG. 1, each region corresponding to R (red), G1 (green 1), B (blue), and G2 (green 2) represents one sub-pixel SG, and R, G1, B, A sub-pixel SG of 1 row and 4 columns corresponding to G2 represents one display pixel AG. Here, G1 (green 1) and G2 (green 2) are two kinds of hues selected from hues from blue to yellow. In the first embodiment, as an example, G1 (green 1) generally indicates pure green indicated by G, and G2 (green 2) indicates yellowish green.

  FIG. 2 is an enlarged cross-sectional view of one display pixel AG along the cutting line AA ′ in the liquid crystal display device 100. As shown in FIG. 2, the liquid crystal display device 100 includes an illumination device 10, a liquid crystal display panel 30, a diffusion sheet 14, a prism sheet 15, and a reflection sheet 16. In the liquid crystal display panel 30, an element substrate 91 and a color filter substrate 92 disposed to face the element substrate 91 are bonded together via a frame-shaped sealing material 5, and liquid crystal is enclosed inside the sealing material 5. Thus, the liquid crystal layer 4 is formed. The liquid crystal used for the liquid crystal layer 4 is, for example, a TN (Twisted Nematic) type liquid crystal. The illumination device 10 is provided on the outer surface of the element substrate 91 of the liquid crystal display panel 30.

  The liquid crystal display device 100 according to the first embodiment is a liquid crystal display device for color display configured using four colors of R, G1, B, and G2, and an α-Si TFT (Thin Film) as a switching element. This is an active matrix drive type liquid crystal display device using transistors.

  A planar configuration of the element substrate 91 will be described. On the inner surface of the element substrate 91, a plurality of source lines 32, a plurality of gate lines 33, a plurality of α-Si TFT elements 37, a plurality of pixel electrodes 34, a driver IC 40, an external connection wiring 35, and an FPC ( Flexible Printed Circuit) 41 or the like is formed or mounted.

  As shown in FIG. 1, the element substrate 91 has a protruding region 31 that protrudes outward from one side of the color filter substrate 92, and a driver IC 40 is mounted on the protruding region 31. A terminal (not shown) on the input side of the driver IC 40 is electrically connected to one end side of the plurality of external connection wirings 35, and the other end side of the plurality of external connection wirings 35 is electrically connected to the FPC 41. It is connected. Each source line 32 is formed so as to extend in the Y direction and at an appropriate interval in the X direction, and one end side of each source line 32 is connected to an output side terminal (not shown) of the driver IC 40. Electrically connected.

  Each gate line 33 includes a first wiring 33a formed so as to extend in the Y direction, and a second wiring 33b formed so as to extend in the X direction from the terminal portion of the first wiring 33a. ing. The second wiring 33 b of each gate line 33 is formed to extend in the direction intersecting each source line 32, that is, in the X direction and at an appropriate interval in the Y direction. One end of one wiring 33a is electrically connected to a terminal (not shown) on the output side of the driver IC 40. An α-TFT element 37 is provided at a position corresponding to the intersection of each source line 32 and each gate line 33 with the second wiring 33 b, and each α-TFT element 37 includes each source line 32, each gate line 33, and each gate line 33. It is electrically connected to each pixel electrode 34 and the like. Each α-TFT element 37 and each pixel electrode 34 are provided at positions corresponding to each sub-pixel SG on the substrate 1 such as glass. Each pixel electrode 34 is formed of a transparent conductive material such as ITO (Indium-Tin Oxide).

  A region in which a plurality of display pixels AG are arranged in a matrix in the X and Y directions is an effective display region V (a region surrounded by a two-dot chain line). In the effective display area V, images such as letters, numbers, and figures are displayed. The area outside the effective display area V is a frame area 38 that does not contribute to display. An alignment film (not shown) is formed on the inner surface of each source line 32, each gate line 33, each α-TFT element 37, each pixel electrode 34, and the like.

  Next, the planar configuration of the color filter substrate 92 will be described. As shown in FIG. 2, the color filter substrate 92 is formed on a substrate 2 such as glass on a light shielding layer (generally referred to as “black matrix”, hereinafter simply abbreviated as “BM”), R, G1, B , G2 color layers 6R, 6G1, 6B, 6G2 and the common electrode 8 and the like. The BM is formed at a position that partitions the sub-pixels SG for each color. In the following description or drawings, when a component is shown without specifying the colors of R, G1, B, and G2, it is simply written as “colored layer 6”, and R, G1, B, and G2 In the case of showing the components by distinguishing colors, for example, “colored layer 6R” is used. The sub-pixels SG for each color of R, G1, B, and G2 include R, G1, B, and G2 colored layers 6R, 6G1, 6B, and 6G2, respectively. The colored layers 6R, 6G1, 6B, and 6G2 of R, G1, B, and G2 function as color filters for the respective colors. The common electrode 8 is made of a transparent conductive material such as ITO like the pixel electrode, and is formed over substantially the entire surface of the color filter substrate 92. The common electrode 8 is electrically connected to one end side of the wiring 36 in the corner area E1 of the sealing material 5, and the other end side of the wiring 36 is electrically connected to an output terminal corresponding to the COM of the driver IC 40. It is connected to the.

  Next, the illumination device 10 will be described. The lighting device 10 includes a light guide plate 11 and a light source unit 12. The light source unit 12 emits light L to the end surface 11 c of the light guide plate 11. As will be described in detail later, the light source unit 12 includes a plurality of LEDs (Light Emitting Diodes) 13 as light sources.

  Light L emitted from the light source unit 12 enters the light guide plate 11 through an end surface (hereinafter referred to as “light incident end surface”) 11 c of the light guide plate 11, and is repeatedly reflected on the output surface 11 a and the reflection surface 11 b of the light guide plate 11. Change direction. The light L is emitted from the emission surface 11a of the light guide plate 11 toward the liquid crystal display panel 30 when the angle formed between the emission surface 11a of the light guide plate 11 and the light L exceeds a critical angle. The light L is emitted from the reflective surface 11b of the light guide plate 11 when the angle formed between the reflective surface 11b of the light guide plate 11 and the light L exceeds a critical angle. However, the light emitted from the reflection surface 11 b of the light guide plate 11 is reflected by the reflection sheet 16 that reflects the light and returned to the inside of the light guide plate 11.

  Light L emitted from the emission surface 11 a of the light guide plate 11 toward the liquid crystal display panel 30 passes through the diffusion sheet 14 and the prism sheet 15 and then passes through the liquid crystal display panel 30. The diffusion sheet 14 diffuses and emits the light L. The prism sheet 15 includes prism sheets 15a and 15b. Each of the prism sheets 15 a and 15 b has a prism shape whose cross-sectional shape is substantially triangular, and emits light L toward the liquid crystal display panel 30. The prism sheets 15a and 15b are arranged so that the ridgelines of the prism-shaped prisms are substantially perpendicular to each other. The liquid crystal display device 100 is illuminated by the light L passing through the liquid crystal display panel 30. Thereby, the liquid crystal display device 100 can display images, such as a character, a number, and a figure, and an observer can visually recognize an image.

  In the liquid crystal display device 100, G1, G2,..., Gm−1, Gm (m is a natural number) are generated by the driver IC 40 based on the signal and power from the FPC 41 side connected to the main board or the like of the electronic device. The gate lines 33 are sequentially selected one by one in order, and a gate signal of a selection voltage is supplied to the selected gate lines 33, while the other non-selected gate lines 33 are not selected. A voltage gate signal is provided. Then, the driver IC 40 applies source signals corresponding to display contents to the pixel electrodes 34 located at positions corresponding to the selected gate lines 33, respectively, corresponding S1, S2,..., Sn-1, Sn ( n is a natural number) and is supplied through the α-TFT element 37. As a result, the alignment state of the liquid crystal layer 4 is controlled, and the display state of the liquid crystal display device 100 is switched to the non-display state or the intermediate display state.

  The liquid crystal display device 100 according to the first embodiment is illustrated as a completely transmissive liquid crystal display device, but is not limited thereto, and a transflective liquid crystal display device may be used instead. The liquid crystal display panel 30 uses the α-TFT element 37 as a switching element. However, the liquid crystal display panel 30 is not limited to this, and a polysilicon TFT or a TFD (Thin Film Diode) element may be used instead. Furthermore, the liquid crystal display device 100 according to the first embodiment is configured as four color layers 6R, 6G1, 6B, and 6G2 as a color filter, but is not limited thereto, and instead, a general liquid crystal Similarly to the display device, it may be composed of RGB color filters.

  Further, the liquid crystal display panel 30 is not limited to a liquid crystal display panel having a liquid crystal layer made of TN liquid crystal as described above. Instead, a VA (Vertical Alignment) method, an IPS (In Plane Switching) method, an FFS (Fringe) is used. It is also possible to use a liquid crystal display panel such as a field structure.

  In the first embodiment, the liquid crystal display panel is used as the display panel. However, the present invention is not limited to this, and another display panel such as an electrophoretic display panel may be used instead. it can.

(Configuration of lighting device)
Next, the configuration of the illumination device 10 according to the first embodiment will be specifically described. FIG. 3 is a plan view of the illumination device 10 according to the first embodiment.

  The illumination device 10 includes the light source unit 12 and the light guide plate 11 as described above. The light source unit 12 mainly includes a flexible substrate 72, a plurality of light source packages 71, and LED driving circuits 51 for each color, that is, a plurality of driving circuits 51 for driving the LEDs 13 for each color. The LED drive circuit 51 and the light source package 71 are electrically connected by wiring 61 for each color. The LED driving circuit 51 for each color includes a current limiting resistor 52 and an LED driving power source 54.

  FIG. 4 is a perspective view showing the configuration of the light source unit 12 according to the first embodiment. As shown in FIG. 4, the plurality of light source packages 71 are arranged on a flexible substrate 72. In the light source package 71, a plurality of light sources that respectively emit light of a plurality of colors are packaged together. Such a light source package 71 is also called a so-called 3 in 1 LED package. In the light source unit 12 shown in FIG. 4, LEDs 13R, 13G, and 13B that emit light of each color of RGB are packaged into one light source package 71, respectively. The plurality of light source packages 71 are arranged in parallel so that the light emitted from the LEDs 13R, 13G, and 13B has the same emission direction. As shown in FIG. 3, the light incident end face 11 c of the light guide plate 11 is disposed to face the light emitted from the LEDs 13 R, 13 G, and 13 B, and the light emitted from the LEDs 13 R, 13 G, and 13 B is The light incident on the light incident end face 11 c of the light guide plate 11. As the light emitted from the LEDs 13R, 13G, and 13B diffuses, the light is mixed into the light L that is white light.

  Here, the configuration of the light source package 71 will be described. FIG. 5 is an enlarged cross-sectional view of one light source package 71 taken along the cutting line BB ′ in FIG. The light source package 71 mainly includes a reflection frame 73 and LEDs 13 that emit light of each color of RGB. The reflection frame 73 is formed of a resin or the like and has a mortar-shaped recess, and a reflection film that reflects light by plating or the like is formed on the inner surface of the recess. Since the enlarged sectional view of the light source package 71 shown in FIG. 5 is taken along the cutting line BB ′ in FIG. 4, only the red LED 13R is shown, but actually the light of each color of RGB is shown. Each color LED 13 that emits light is installed on the bottom surface of the concave portion of the reflection frame 73. Electrodes 75 and 76 are provided on the bottom surface of the concave portion of the reflection frame 73. One ends of the electrodes 75 and 76 are connected to the outside of the reflection frame 73, specifically, to the LED drive circuit 51 for driving the LED 13 installed on the flexible substrate 72. On the other hand, the other ends of the electrodes 75 and 76 are connected to the LED 13. For example, as shown in FIG. 5, the anode 77 of the red LED 13 is connected to the electrode 75, and the cathode 78 of the red LED 13 </ b> R is connected to the electrode 76. That is, the red LED 13R is connected to the LED drive circuit 51R via the electrodes 75 and 76. The red LED 13R emits red light when an electric current Ir flows from the outside. If the current amount of the current Ir is increased, the luminance of the red light emitted from the red LED 13R increases, and if the current amount of the current Ir is decreased, the luminance of the red light emitted from the red LED 13R decreases.

  Similarly, for the green LED 13G and the blue LED 13B, the anode and the cathode are respectively connected to electrodes connected to the outside of the reflection frame 73. The green LED 13G and the blue LED 13B are also connected to the LED drive circuits 51G and 51B via the electrodes, respectively. The green LED 13G and the blue LED 13B emit green light and blue light when currents Ig and Ib flow from the outside, respectively. If the current amounts of the currents Ig and Ib are increased, the luminances of the green light and the blue light emitted from the green LED 13G and the blue LED 13B are increased. If the current amounts of the currents Ig and Ib are decreased, the green LED 13G and the blue light are increased. The luminances of green light and blue light emitted from the LED 13B are reduced.

  The reflective frame 73 is provided with LEDs 13 that emit light of each color of RGB on the bottom surface of the concave portion, and then sealed with a transparent resin 74 to complete the light source package 71. Here, a lens may be disposed on the uppermost surface of the resin 74, in other words, on the light emission surface of the light source package 71. For example, if a concave lens is arranged as the lens, the light emitted from each color LED 13 can be diffused more.

  FIG. 6 is a block diagram illustrating a configuration of the illumination device 10. In FIG. 6, two light source packages 71 are shown as an example. As shown in FIG. 4, each light source package 71 includes one LED 13R, 13G, and 13B for each color of RGB. That is, as shown in FIG. 6, one of the two light source packages 71 is provided with a red LED 13R1, a green LED 13G1, and a blue LED 13B1, and the other light source package 71 has a red LED 13R2, a green LED 13G2, and a blue color. Assume that an LED 13B2 is provided.

  The light source unit 12 includes a red LED drive circuit 51R, a green LED drive circuit 51G, and a blue LED drive circuit 51B in addition to the plurality of RGB LEDs 13R, 13G, and 13B packaged in the light source package 71. .

  The red LED drive circuit 51R is connected to the red LEDs 13R1 and 13R2, the green LED drive circuit 51G is connected to the green LEDs 13G1 and 13G2, and the blue LED drive circuit 51B is connected to the blue LEDs 13B1 and 13B2.

  The red LEDs 13R1 and 13R2 are electrically connected in series. The red LEDs 13R1 and 13R2 connected in series are supplied with a current Ir by the red LED driving circuit 51R. In FIG. 6, the flow of current flowing through the red LEDs 13R1 and 13R2 is indicated by solid line arrows. As a result, the current Ir flows through the red LEDs 13R1 and 13R2, and the red LEDs 13R1 and 13R2 can both emit red light having the same luminance.

  In FIG. 6, the flow of current flowing through each of the green LEDs 13G1 and 13G2 and the blue LEDs 13B1 and 13B2 is also indicated by broken-line arrows.

  The green LEDs 13G1 and 13G2 are electrically connected in series. The green LEDs 13G1 and 13G2 connected in series are supplied with a current Ig by the green LED driving circuit 51G. Thereby, the current Ig flows in both the green LEDs 13G1 and 13G2, and the green LEDs 13G1 and 13G2 can both emit green light having the same luminance.

  The blue LEDs 13B1 and 13B2 are also electrically connected in series. The two blue LEDs 13B1 and 13B2 connected in series are supplied with a current Ib by the blue LED driving circuit 51B. Thereby, the current Ib flows through both the blue LEDs 13B1 and 13B2, and both the blue LEDs 13B1 and 13B2 can emit blue light having the same luminance.

  FIG. 7 shows a circuit diagram of the red LED drive circuit 51R according to the first embodiment as an example. The red LED drive circuit 51R includes a current limiting resistor 52R and an LED drive power supply 54R. As will be described in detail later, the current limiting resistor 52R is a variable resistor whose resistance value can be adjusted. The LED drive power supply 54R supplies a pulse current to the red LEDs 13R1 and 13R2. The width and timing of the pulse current supplied to the red LEDs 13R1 and 13R2 can be changed by controlling the LED drive power supply 54R. Each of the green LED drive circuit 51G and the blue LED drive circuit 51B also supplies a pulse current to each of the green LEDs 13G1 and 13G2 and the blue LEDs 13B1 and 13B2 that are electrically connected in the same manner as the red LED drive circuit 51R. LED drive power supplies 54G and 54B and current limiting resistors 52G and 52B are provided.

  As can be seen from the above, in the light source unit 12 according to the first embodiment, the RGB LEDs 13 each have an LED drive circuit 51 for each color. The LED drive circuit 51 connected to each color LED 13 supplies a pulse current to each color LED 13 that is electrically connected. Thus, by providing the LED drive circuit for each LED of each color, it is possible to apply a pulse current separately for each LED of each color.

  FIG. 8 is an example of a timing chart showing a driving sequence of each color LED 13 in the illumination device 10 according to the first embodiment. In FIG. 8, “ON” of each color LED 13 indicates a lighting state, and “OFF” indicates a light-off state. For example, referring to FIG. 6, when the red LED 13R is “ON”, both the red LEDs 13R1 and 13R2 are turned on, and when the red LED 13R is “OFF”, both the red LEDs 13R1 and 13R2 are turned off. In FIG. 8, when the green LED 13G and the blue LED 13B are turned “ON” and “OFF”, both the green LEDs 13G1 and 13G2 and the blue LEDs 13B1 and 13B2 are both turned on and off.

  In the illuminating device 10 which concerns on 1st Embodiment, LED13 of each color becomes a structure which lights in a time division manner. Hereinafter, a period in which the LEDs 13 of each color are “ON” is referred to as a lighting period, and a period in which the LEDs 13 of each color are “OFF” is referred to as a non-lighting period. The chromaticity of the light L emitted from the illuminating device 10 and the chromaticity of the display screen of the liquid crystal display panel 30 are adjusted to a predetermined chromaticity by changing the lighting period of the LEDs 13 of each color of RGB in one frame period. The By doing in this way, the lighting time of LED13 of each color of RGB can be shortened rather than supplying constant current to LED13 of each color of RGB and always lighting, and reduction of power consumption can be aimed at.

  When the LEDs 13 of each color are lit in a time-division manner, the color of the light L looks different to the human eye depending on the period during which the LEDs 13 of each color are lit. Specifically, in the color of the light L, the color component of the light emitted from the LED 13 having a long lighting period is dark in one frame period, and the color component of the light emitted from the LED 13 having a short lighting period is getting thin. Generally, since one frame period is about 1/60 second, even if the LEDs 13 of each color are lit in a time-sharing manner, the color change is not recognized by human eyes due to the afterimage effect. .

(Configuration of current limiting resistor)
Next, the configuration of the current limiting resistor 52 will be described. As an example of the current limiting resistor 52, FIG. 9 shows an enlarged schematic diagram of the current limiting resistor 52R in FIG. The current limiting resistors 52G and 52B have the same structure as the current limiting resistor 52R.

  As shown in FIG. 9, the current limiting resistor 52 has a structure in which fuses 62 a, 62 b, 62 c, and 62 d having different widths are electrically connected in parallel to the wiring 61. In the lighting device 10 according to the first embodiment, the brightness of the light emitted from the LEDs 13 of each color is adjusted by adjusting the number of fuses connected in parallel in the current limiting resistor 52. Specifically, the lighting device 10 according to the first embodiment selectively blows one or more fuses out of the fuses 62a, 62b, 62c, and 62d connected in parallel with a laser, thereby providing a current. The brightness value of the light emitted from each color LED 13 is adjusted by changing the resistance value of the limiting resistor 52R. In FIG. 9, a portion irradiated with a laser for blowing the fuse is shown as a range 63.

  FIG. 10A shows an enlarged cross-sectional view along the cutting line CC ′ of the current limiting resistor 52R, and FIG. 10B shows an enlarged cross section along the cutting line DD ′ of the current limiting resistor 52R. The figure is shown.

  Based on FIGS. 10A and 10B, the configuration of the current limiting resistor 52R will be described. An insulating interlayer film 65 is laminated on the surface of the flexible substrate 72. A polysilicon film is laminated on the surface of the insulating interlayer film 65, and its planar shape is, for example, formed into four rectangular shapes with different widths. The polysilicon films formed in the four rectangular shapes become fuses 62a, 62b, 62c, and 62d. 10A and 10B show enlarged sectional views along the cutting line CC ′ and the cutting line DD ′, only the fuse 62b is shown.

  On the surfaces of the fuses 62a, 62b, 62c, 62d and the insulating interlayer film 65, an insulating interlayer film 66 is formed, and a contact hole 68 is provided. The wiring 61 is connected to the fuses 62a, 62b, 62c, and 62d through the contact holes 68. A protective film 67 is formed on the surface corresponding to the wiring 61 of the insulating interlayer film 66, but the surface corresponding to the range 63 of the insulating interlayer film 66 is a portion that is irradiated with laser, so that protection is provided. The film 67 is not formed.

  Here, the resistance value Rv of each fuse is expressed by the following formula (1), where ρ is the conductivity of the fuse, S is the cross-sectional area of the fuse, and h is the length of the fuse.

Rv = ρh / S (1)
That is, the resistance value Rv of the fuse is inversely proportional to the sectional area S of the fuse and proportional to the length h of the fuse. In the lighting device according to the first embodiment, since the thicknesses and lengths of the fuses 62a, 62b, 62c, and 62d are considered to be the same size, the resistance values of the fuses 62a, 62b, 62c, and 62d are It is thought that each fuse becomes smaller as the width of the fuse increases. This is because the cross-sectional area of the fuse increases as the width of the fuse increases.

  Further, assuming that N fuses are connected in parallel to the current limiting resistor 52, and the resistance value of each fuse is Rvi (i = 1 to N), the resistance value Rv of the current limiting resistor 52 at that time and each fuse The relationship of the resistance value Rvi is expressed by the following equation (2).

1 / Rvs = 1 / Rv1 + 1 / Rv2 + .. + 1 / RvN (2)
FIGS. 11A to 11C are schematic views showing the fuses of the current limiting resistors 52 of the respective colors after adjusting the luminance of the light emitted from the LEDs 13 of the respective colors in the lighting device according to the first embodiment. . 11A to 11C show only a portion related to the range 63 of the current limiting resistor 52 of each color. The fuses 62a, 62b, 62c, and 62d have the widest width of the fuse 62a and the narrowest width of the fuse 62d. The resistance values of the fuses 62a, 62b, 62c, and 62d are 10 [Ω], 20 [Ω], 40 [Ω], and 80 [Ω], respectively.

  FIG. 11A is a schematic diagram showing a fuse of the current limiting resistor 52R. In the current limiting resistor 52R, none of the fuses 62a, 62b, 62c, 62d is blown. Therefore, the resistance value of the current limiting resistor 52R is 5.333 [Ω] using the equation (2).

  FIG. 11B is a schematic diagram showing a fuse of the current limiting resistor 52G. In the current limiting resistor 52G, among the fuses 62a, 62b, 62c, and 62d, the fuses 62a, 62b, and 62c are blown. Therefore, the resistance value of the current limiting resistor 52G is 80 [Ω] because it is the resistance value of the fuse 62d.

  FIG. 11C is a schematic diagram showing a fuse of the current limiting resistor 52B. In the current limiting resistor 52B, only the fuse 62c is blown out of the fuses 62a, 62b, 62c, and 62d. Therefore, the current limiting resistor 52B has the fuses 62a, 62b, and 62d connected in parallel. Therefore, the resistance value of the current limiting resistor 52B is 6.154 [Ω] when Expression (2) is used.

  As described above, in the lighting device 10 according to the first embodiment, the resistance value of the current limiting resistor 52 of each color can be changed by selectively fusing the fuse with the laser. In the illuminating device 10 according to the first embodiment, the amount of current supplied to the LED 13 of each color can be changed by changing the resistance value of the current limiting resistor 52 of each color, and light emitted from the LED 13 of each color. The intensity of the brightness can be changed.

(Brightness adjustment processing)
Next, luminance adjustment processing in the lighting apparatus 10 according to the first embodiment will be described using the flowchart of FIG.

  The brightness adjustment process in the lighting device 10 according to the first embodiment is a process of adjusting the light L to a desired white balance, and is performed using a brightness adjustment device that is an external device of the lighting device 10. The brightness adjusting device is configured to measure the brightness of the light of each color emitted from the LED 13 of each color of the lighting device 10, and laser the fuse of the current limiting resistor 52 of each color based on the measured brightness of the light of each color. Is provided.

  First, the brightness adjusting device measures the brightness of the light of each color emitted from the LED 13 of each color of the lighting device 10 using a measuring means such as a photosensor (Step S1), and measures the brightness of the measured light of each color. It is determined whether or not the ratio is a predetermined ratio, that is, whether the mixed light L is a desired white balance (step S2). If the luminance adjusting device determines that the measured luminance ratio of the light of each color is a predetermined ratio (step S2: Yes), the process ends. On the other hand, when the luminance adjusting device determines that the measured luminance ratio of the light of each color is not a predetermined ratio (step S2: No), the luminance ratio of the light of each color is the predetermined ratio. Thus, the amount of current supplied to each color LED 13 is adjusted. That is, the brightness adjusting device adjusts the resistance value of the current limiting resistor 52 of each color by selectively irradiating the fuse in the current limiting resistor 52 of each color with a laser, and supplies it to the LED 13 of each color. Adjust the amount of current. Thereafter, the brightness adjusting apparatus ends the process (step S3). By doing in this way, the brightness | luminance of the light radiate | emitted from LED13 of each color is adjusted so that the ratio may become a ratio from which the mixed light L becomes a desired white balance.

  As can be seen from the above description, the lighting device 10 according to the first embodiment is connected in parallel in the current limiting resistor by adjusting the number of fuses connected in parallel in the current limiting resistor 52. By selectively fusing one or more fuses of the plurality of fuses with a laser, the brightness of the light emitted from the LEDs 13 of each color is adjusted. As described above, the resistance value of the current limiting resistor can be digitally determined by selectively fusing the fuse and combining a plurality of fuses that have not been blown. Thus, by digitally determining the resistance value of the current limiting resistor, variation in the resistance value can be prevented, and the luminance of the lighting device can be adjusted easily and accurately.

[Second Embodiment]
Next, the illuminating device 10 which concerns on 2nd Embodiment of this invention is demonstrated. The illuminating device 10 according to the second embodiment has substantially the same configuration as the illuminating device 10 according to the first embodiment shown in FIG. 3, but only the structure of the current limiting resistor 52 is different.

  FIG. 13 shows an enlarged schematic diagram of the current limiting resistor 52R according to the second embodiment in FIG. The current limiting resistors 52G and 52B have the same structure as the current limiting resistor 52R.

  As shown in FIG. 13, the structure of the current limiting resistor 52 according to the second embodiment is different from the structure of the current limiting resistor 52 according to the first embodiment, and all of the wiring resistors having different resistance values have the same width. Are connected in parallel to each other. Specifically, fuses 62a, 62b, 62c, 62d all having the same width are connected to the wiring resistors r1, r2, r3, r4, respectively, and these are connected to the wiring 61 in parallel. In other words, the current limiting resistor 52 includes the combined resistor 64a in which the wiring resistor r1 and the fuse 62a are connected in series, the combined resistor 64b in which the wiring resistor r2 and the fuse 62b are connected in series, and the wiring resistor r3 and the fuse 62c in series. It can be said that the combined resistor 64c and the combined resistor 64d in which the wiring resistor r4 and the fuse 62d are connected in series are connected in parallel.

  For example, if the resistance values of the wiring resistors r1, r2, r3, and r4 increase in this order, the resistance values of the combined resistors 64a, 64b, 64c, and 64d are also considered to increase in this order. This is because the fuses 62a, 62b, 62c, and 62d all have the same width, and are therefore considered to have the same resistance value.

  FIGS. 14A to 14C are schematic views showing the fuses of the current limiting resistors 52 of the respective colors after adjusting the luminance of the light emitted from the LEDs 13 of the respective colors in the lighting device according to the second embodiment. . 14A to 14C show only a portion related to the range 63 of the current limiting resistor 52 of each color. FIG. 14A is a schematic diagram showing a fuse of the current limiting resistor 52R. In the current limiting resistor 52R, none of the fuses 62a, 62b, 62c, 62d is blown. FIG. 14B is a schematic diagram showing a fuse of the current limiting resistor 52G. In the current limiting resistor 52G, among the fuses 62a, 62b, 62c, and 62d, the fuses 62a, 62b, and 62c are blown. FIG. 14C is a schematic diagram showing a fuse of the current limiting resistor 52B. In the current limiting resistor 52B, only the fuse 62c is blown out of the fuses 62a, 62b, 62c, and 62d.

  Therefore, when the resistance values of the combined resistors 64a, 64b, 64c, and 64d are, for example, 10 [Ω], 20 [Ω], 40 [Ω], and 80 [Ω], the current limiting resistors 52R, 52G, The resistance values of 52B are the same as those described in FIGS. 11A to 11C of the first embodiment, that is, 5.333 [Ω], 80 [Ω], 6.154 [ Ω].

  From this, also in the illuminating device 10 which concerns on 2nd Embodiment, like the illuminating device 10 which concerns on 1st Embodiment, by adjusting the number of the fuses connected in parallel in the current limiting resistance 52, ie, an electric current. The brightness of the light emitted from the LEDs 13 of each color is adjusted by selectively fusing one or more fuses among the plurality of fuses connected in parallel in the limiting resistor. As described above, the resistance value of the current limiting resistor can be digitally determined by selectively fusing the fuse and combining a plurality of fuses that have not been blown.

  In the illumination device 10 according to the second embodiment, as described above, since the fuses 62a, 62b, 62c, and 62d all have the same width, the laser cutting efficiency at this time has different widths. It becomes higher than the cutting efficiency of the laser in the illuminating device 10 which concerns on 1st Embodiment which equips the current limiting resistance with the several fuse which has.

[Modification]
In the first embodiment, the fuses 62a, 62b, 62c, and 62d in the current limiting resistor 52 are formed separately from the wiring 61, but the present invention is not limited to this. FIG. 15 shows a schematic diagram of a current limiting resistor 52R according to a modification. As shown in FIG. 15, the fuses 62 a, 62 b, 62 c, 62 d may be integrally formed instead of being formed separately from the wiring 61.

  Needless to say, the number of fuses in the current limiting resistor 52 is not limited to the number described in each of the above embodiments. As the number of fuses in the current limiting resistor 52 is increased, the resistance value of the current limiting resistor 52 can be adjusted more finely.

  Instead of arranging a light source package 71 in which LEDs 13 of a plurality of colors are packaged in the light source unit 12 of the lighting device 10, the LEDs 13 of each color of RGB are arranged in parallel as used in a general lighting device. Needless to say, it may be arranged. Moreover, since green light has high visibility for human eyes, when arranging LEDs 13 of RGB colors in parallel, one red LED and one blue LED may be arranged for two green LEDs. . Furthermore, the LED 13 of the light source unit 12 in the illumination device 10 is not limited to the RGB three-color LED, and instead, an LED of four or more colors may be used. For example, in addition to RGB three-color LEDs, a total of four-color LEDs may be used in which LEDs that emit light of a color complementary to any one of RGB are added. Note that the LED of the fourth color is not limited to any one of the complementary colors of the three colors. It is desirable that the four LEDs have colors corresponding to four colored layers of a color filter of the display panel described later.

  Moreover, although the brightness adjusting device is an external device of the lighting device 10, it is not limited thereto, and it goes without saying that the brightness adjusting device may be provided inside the lighting device 10 instead. .

  In each of the embodiments described above, the pulse current is supplied to the LEDs 13 of each color. However, the present invention is not limited to this, and it goes without saying that a constant current may be supplied instead.

[Other embodiments]
In the above description, R, G1, B, and G2 have been described as the colors (colored regions) of the colored layer functioning as a color filter. However, the application of the present invention is not limited to this, and other four colors are used. One display pixel can also be constituted by a colored region.

  Specifically, the four colored areas are blue colored areas (also referred to as “first colored areas”) in a visible light area (380 to 780 nm) in which the hue changes according to the wavelength. A colored region having a red hue (also referred to as a “second colored region”) and two colored regions selected from hues from blue to yellow (“third colored region”, “fourth colored region”). Also called “colored region”. Here, the term “system” is used. For example, if it is a blue system, the color is not limited to a pure blue hue, and includes a blue-violet color, a blue-green color, and the like. If it is a red hue, it is not limited to red but includes orange. These colored regions may be composed of a single colored layer, or may be composed of a plurality of colored layers having different hues. In addition, although these colored regions are described in terms of hue, the hue can be set by changing the saturation and lightness as appropriate.

The specific hue range is
-The colored region of the blue hue is from violet to blue-green, more preferably from indigo to blue.
-The colored region of red hue is from orange to red.
-One coloring area | region selected by the hue from blue to yellow is blue to green, More preferably, it is blue green to green.
-The other coloring area | region selected by the hue from blue to yellow is green to orange, More preferably, it is green to yellow. Or it is green to yellowish green.

  Here, the same hue is not used for each colored region. For example, when a green hue is used in two colored regions selected from hues of blue to yellow, the other uses a blue or yellowish green hue for one green.

  Thereby, a wider range of color reproducibility than the conventional RGB colored region can be realized.

In the above, a wide range of color reproducibility by the colored areas of four colors has been described in terms of hue, but as another specific example, it can be expressed as follows with the wavelength of light transmitted through the colored areas.
The blue colored region is a colored region having a wavelength peak of light transmitted through the colored region at 415 to 500 nm, preferably at 435 to 485 nm.
The red colored region is a colored region having a wavelength peak of light transmitted through the colored region of 600 nm or more, and preferably a colored region of 605 nm or more.
-One colored region selected by hue from blue to yellow is a colored region having a wavelength peak of 485-535 nm of light transmitted through the colored region, preferably a colored region having a wavelength of 495-520 nm. .
The other colored region selected with a hue from blue to yellow is a colored region having a wavelength peak of light transmitted through the colored region of 500-590 nm, preferably 510-585 nm, or 530- This is a colored region at 565 nm.

  In the case of transmissive display, this wavelength is a numerical value obtained by illuminating light from the illumination device through the color filter. In the case of reflective display, the value is obtained by reflecting external light.

As another specific example, when a colored region of four colors is expressed by an x, y chromaticity diagram, it is as follows.
The blue colored region is a colored region where x ≦ 0.151 and y ≦ 0.200, preferably a colored region where 0.134 ≦ x ≦ 0.151 and 0.034 ≦ y ≦ 0.200.
The red colored region is a colored region satisfying 0.520 ≦ x and y ≦ 0.360, and preferably a colored region satisfying 0.550 ≦ x ≦ 0.690 and 0.210 ≦ y ≦ 0.360.
-One of the colored areas selected in hues from blue to yellow is a colored area where x ≦ 0.200 and 0.210 ≦ y, preferably a colored area where 0.080 ≦ x ≦ 0.200 and 0.210 ≦ y ≦ 0.759 is there.
-The other colored region selected with a hue from blue to yellow is a colored region in the range of 0.257 ≦ x, 0.450 ≦ y, preferably a colored region in the range of 0.257 ≦ x ≦ 0.520, 0.450 ≦ y ≦ 0.720 is there.

  In the case of transmissive display, the x, y chromaticity diagram is a numerical value obtained by illuminating light from the illumination device through the color filter. In the case of reflective display, the value is obtained by reflecting external light.

  These four colored areas can be applied within the above-described range when the sub-pixel includes a transmission area and a reflection area.

Moreover, the following are preferable as an RGB light source in the illuminating device 10.
・ B is the wavelength peak of emitted light at 435 nm to 485 nm ・ G is the wavelength peak of emitted light at 520 nm to 545 nm ・ R is the wavelength peak of emitted light at 610 nm to 650 nm And if a color filter is appropriately selected according to the wavelength of the RGB light source, a wider range of color reproducibility can be obtained.

Specific examples of the configuration of the above four colored regions include the following.
・ Colored areas of red, blue, green, and blue-green ・ Colored areas of red, blue, green, and yellow ・ Colored areas of red, blue, dark green, and yellow ・ Hue is red and blue , Emerald green, yellow coloring area / hue is red, blue, emerald green, yellow green coloring area / hue is red, blue, dark green, yellow green coloring area / hue is red, blue green, dark green, Yellow-green colored area
[Electronics]
Next, an embodiment in which the liquid crystal display device according to this embodiment is used as a display device of an electronic apparatus will be described.

  As the image signals input to the liquid crystal display device 100 according to the present embodiment, for example, image signals of each color of R, G1, B, and G2 may be directly input from the outside, or each of RGB colors may be input. An image signal may be input from the outside and converted to an image signal of each color of R, G1, B, and G2.

  Here, in the liquid crystal display device 100, a case where image signals of each color of RGB are converted into image signals of each color of R, G1, B, and G2 will be described.

  FIG. 16 is a circuit block diagram of a schematic configuration showing the overall configuration of the present embodiment. An electronic apparatus shown here includes the liquid crystal display device 100 and a control unit 610. The control unit 610 includes a display information output source 611, a display image conversion circuit 612, and a timing generator 614.

  In the liquid crystal display device 100, when the input RGB image signals are converted into R, G1, B, and G2 image signals, the display image conversion circuit 612 outputs an external display image such as a personal computer. The RGB color image signals output from the source 611 are converted into R, G1, B, and G2 color image signals and output to the liquid crystal display panel 30.

  The display image conversion circuit 612 includes an arithmetic processing unit 612a such as a CPU (Central Processing Unit) and a storage unit 612b such as a RAM (Random Access Memory). The arithmetic processing unit 612a converts the RGB image signals 651R, 651G, 651B of the input image output from the display image output source 611 into the R, G1, B, G2 image signals 652R, 652G1, 652B, 652G2. Convert to The storage unit 612b is provided with an LUT (Look Up Table) in which image signals of RGB colors having a predetermined intensity are associated with image signals of colors R, G1, B, and G2 corresponding thereto. ing. For example, when an RGB image signal for displaying the G2 color is input to the arithmetic processing unit 612a, for example, an RGB color image signal having an intensity of R = 0, G = 100, and B = 100, the calculation is performed. The processing unit 612a has R, G1, B, and G2 color image signals having an intensity corresponding to the RGB image signal intensity (for example, R = 0, G1 = 10, B = 10, G2 = 100). Are obtained from the LUT in the storage unit 612b, and the obtained image signals of the respective colors R, G1, B, and G2 are output to the liquid crystal display panel 30. As a result, not only the RGB colors but also the G2 color can be displayed on the display screen of the liquid crystal display panel 30. Thus, even when an RGB image signal is input as the image signal of the input image, the color reproduction range of the output image can be expanded to the G2 color reproduction range.

  The timing generator 614 has a hard switch or a soft switch for switching the timing mode, and generates the clock signal CLK from the luminance signal of the image signal. The driving sequence of the LED driving circuit 51 for each color of RGB described above is controlled so as to match the clock signal CLK determined by the timing generator 614.

  Next, a specific example of an electronic apparatus to which the liquid crystal display device 100 according to this embodiment can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 17A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal display device 100 according to the present invention is applied.

  Next, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 17B is a perspective view showing the configuration of this mobile phone. As shown in the figure, the cellular phone 720 includes a plurality of operation buttons 721, a reception port 722, a transmission port 723, and a display unit 724 to which the liquid crystal display device 100 according to the present invention is applied.

  Electronic devices to which the liquid crystal display device 100 according to the present invention can be applied include a liquid crystal television and a viewfinder in addition to the personal computer shown in FIG. 17A and the mobile phone shown in FIG. Type / monitor direct-view type video tape recorder, car navigation device, pager, electronic notebook, calculator, word processor, workstation, videophone, POS terminal, digital still camera, etc.

1 is a plan view of a liquid crystal display device according to a first embodiment. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment. It is a perspective view which shows the structure of the light source part which concerns on 1st Embodiment. It is a top view of the illuminating device which concerns on 1st Embodiment. It is an expanded sectional view of a light source package. It is a block diagram which shows the structure of the illuminating device which concerns on 1st Embodiment. It is a circuit diagram of a red LED drive circuit according to the first embodiment. The timing chart which showed the drive sequence of LED of each color in an illuminating device. It is a schematic diagram of the current limiting resistor according to the first embodiment. It is an expanded sectional view of current limiting resistance. It is a schematic diagram which shows the fuse of the current limiting resistance of each color after adjustment of the brightness | luminance of light. It is a flowchart about a brightness adjustment process. It is a schematic diagram of the current limiting resistor according to the second embodiment. It is a schematic diagram which shows the fuse of the current limiting resistance of each color after adjustment of the brightness | luminance of light. It is a schematic diagram of the current limiting resistance which concerns on a modification. 1 is a circuit block diagram of an electronic apparatus to which a liquid crystal display device according to an embodiment is applied. It is a figure which shows the example of the electronic device to which the liquid crystal display device of this embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Light source part, 13 LED, 14 Diffusion sheet, 15 Prism sheet, 10 Illumination device, 30 Liquid crystal display panel, 51 LED drive circuit, 52 Current limiting resistor, 53 LED drive power supply, 71 Light source package, 100 Liquid crystal display device

Claims (5)

A light source that emits light when supplied with current;
A current limiting resistor composed of a plurality of resistors connected in parallel;
A light source driving power source for supplying a current to the light source via the current limiting resistor,
The illumination device, wherein brightness of light emitted from the light source is adjusted by adjusting a number of the plurality of resistors. The plurality of resistors are a plurality of fuses each having a different resistance value,
The illumination device according to claim 1, wherein brightness of light emitted from the light source is adjusted by selectively fusing one or more fuses of the plurality of fuses with a laser. The plurality of resistors are formed by connecting a plurality of fuses each having the same width to a plurality of wiring resistors having different resistance values, respectively.
The illumination device according to claim 1, wherein brightness of light emitted from the light source is adjusted by selectively fusing one or more fuses of the plurality of fuses with a laser. A display panel;
An illuminating device according to claim 1, wherein the electro-optic device is used as a backlight of a display panel.   An electronic apparatus comprising the electro-optical device according to claim 4 in a display unit.

Images