JP3941487B2 - Display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display device, and more particularly to a display device having a large number of surface-mounted LED chips.
[0002]
[Prior art]
In a display device using LED chips, a plurality of LED chips are arranged in a lattice pattern on a display panel, and a plurality of display panels are combined and arranged to constitute the display device. The display panel is composed of a printed wiring board having opposing main surfaces, and wiring for driving the LED chip is formed on one main surface serving as a display surface, and one or a plurality of one dot constituting one dot is formed. The LED chips are mounted in a 16 × 16 dot array, for example, and mounted on the other main surface serving as a non-display surface, and a driving IC connected to the derived wiring is mounted. The lighting operation of the LED chip group arranged in a lattice shape is controlled by a drive IC or the like, and an image is displayed on the display device based on the input information data. Here, only LED chips emitting monochromatic light are used, and R, G, B LED chips are used for two-color R and G display or full-color display.
[0003]
Further, regarding the display contrast, a black printed wiring board (hereinafter referred to as a black resist wiring board) in which a matte black resist processing layer that has been subjected to insulation treatment is formed on the entire display surface of a normal printed wiring board. ) To improve the contrast due to the lighting of the LED chip and ensure a good display. That is, by providing a black light-shielding layer on the substrate surface and reducing the luminance when the LED chip itself is not lit (hereinafter referred to as dark luminance), the luminance between the lit and dark luminance is reduced. The difference is increased and the contrast is improved.
[0004]
[Problems to be solved by the invention]
However, the black resist wiring board has a problem of high cost while contributing to the improvement of contrast. Further, when the black resist processing layer is made thin, the color gloss tends to be uneven, and there is a problem that the light shielding property of the display surface is remarkably lowered and the contrast is lowered.
[0005]
In view of the above, an object of the present invention is to provide a display device using an LED chip, which can be manufactured at a lower cost without lowering the contrast as compared with the conventional display device.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a display device of the present invention includes a wiring board having surface-mounted LED chips arranged on a display surface, and a plurality of mask members having openings for fitting the surface-mounted LED chips. The plurality of mask members include a black portion between chip rows provided between rows of surface-mounted LED chips arranged on the wiring board, and the mask members include It is characterized by being arranged adjacent to one wiring board by aligning gaps provided adjacent to each other.
[0007]
According to the present invention, since the chip peripheral black portion is formed in the peripheral portion of the mounting position of the LED chip on the wiring board, when the black plate-shaped mask member is attached to the display panel, the wiring board is opened from the opening of the mask member. The surface of is not directly exposed. Therefore, only the light emitting surface of the LED chip is exposed, and the display surface other than the light emitting surface is all black, so that the dark luminance can be reduced. Thereby, the difference between the luminance at the time of lighting and the luminance at the time of non-lighting can be increased, and the contrast can be improved.
Moreover, according to this invention, it can replace with the printed wiring board which has the black resist material layer which carried out the insulation process for the surface panel, and can use the printed wiring board processed with the green resist. Furthermore, since the mask member is separate from the display panel and is detachable from the display panel and can be used repeatedly, the production cost can be reduced.
Each LED chip is arranged in each opening of the mask member so that only the light emitting surface is exposed to the light emission observation surface side, and the periphery is protected by the mask member. As a result, no physical impact is directly applied to the LED chip, and the life of the display device can be improved.
[0008]
In the display device of the present invention, the mask member may be composed of one rectangular mask member, and the one mask member may be disposed on one display panel.
[0010]
Moreover, the display apparatus of this invention can use what used the resin molding for the mask member, and the surface opposite to the main surface which opposes the display surface of a display panel was matted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic exploded perspective view showing a structure of a display unit constituting the display device according to the present embodiment. The display unit 1 includes a display panel 3, a frame 4 that fixes and supports the display panel 3, and one mask member 2 that is detachably held on the display panel 3. On the display surface 3b of the display panel 3, a large number of surface-mounted LED chips 3a are mounted in a grid pattern, and a chip peripheral black portion 3c is formed in the peripheral portion of the mounting position of each LED chip 3a.
[0012]
The display panel 3 is formed of a green printed wiring board having an opposing main surface, and wiring for driving the LED chip 3a is formed on one main surface serving as the display surface 3b. LED chips 3a are mounted in a 16 × 16 dot grid. On the other main surface, a driving IC, an interface unit, and the like (not shown) connected to the derived wiring are mounted.
[0013]
The mask member 2 is made of a black plate-like body, and has 16 × 16 openings 2a arranged in a grid pattern separated by a predetermined pitch by a grid frame 2b. Since the openings 2a are formed so as to have substantially the same pitch as the LED chips 3a, the display surface 3b can be obtained by aligning the LED chips 3a and fitting them into the openings 2a or by locking them with the openings 2a. The mask member 2 can be detachably held. The mask member 2 is locked to the plurality of LED chips 3a, and the positional deviation in the planar direction is prevented. Thereby, the attachment precision of a mask member can be improved. Further, an outer frame 2c composed of a falling portion integrated with the frame is provided at the peripheral edge of the mask member. Since the outer frame 2c prevents displacement of the mask member in the planar direction, the mounting accuracy of the mask member can be further improved. Thereby, when arranging a plurality of display panels side by side, the adjacent display panels can be arranged closer to each other, so that the joint between the adjacent display panels can be reduced.
[0014]
Here, when the mask member 2 is attached to the display panel 3, the light emitting surface on the upper surface of the LED chip 3a is exposed from the opening 2a to the light emission observation surface side. Since the chip peripheral black portion 3c is formed at the peripheral portion at the mounting position of the LED chip 3a, it is possible to prevent the surface of the green printed board from being directly exposed from the gap between the opening 2a and the LED chip 3a. Thereby, only the light emitting surface of the LED chip 3a can be exposed from the opening 2a.
[0015]
The mask member used in the present invention may be a black plate-like body, and a metal thin plate or a resin molded body can be used for the plate-like body, but a resin molded body is preferable. It is lightweight and inexpensive, and also has an effect of preventing electrical conduction between LEDs due to its electrical insulation. As the resin material, a material obtained by coloring a thermoplastic resin such as polycarbonate, polyethylene, or polyethylene terephthalate in black can be used.
[0016]
Further, the thickness of the mask member is preferably at least the thickness of the LED chip in order to protect the LED chip, and the upper limit thereof is preferably a size that does not block the light from the LED chip. .
Further, the size of the opening of the mask member can be appropriately adjusted according to the size of the light emitting surface of the LED chip to be mounted.
Moreover, it is preferable that the shape of the opening of the mask member is a taper shape in which the cross section extends toward the light emission observation surface. As a result, the light from the LED chip can be prevented from being blocked, so that the visibility can be further improved.
[0017]
Moreover, when using a resin molding for a mask member, it is preferable to perform a matte process at least on one side and arrange | position the surface to the display observation surface side. In general, a factor that determines the gloss of a resin molded body is surface reflection due to fine irregularities on the surface of the molded body on the order of μm, and it is known that if the number of fine irregularities increases, the gloss decreases. Therefore, it is possible to suppress reflection on the surface of the mask member by forming fine irregularities on the surface of the molded body on the order of μm. For matting, a conventionally known matting method can be used, for example, a method of roughening the surface of the molded body by transferring irregularities on the surface of the mold to the surface of the molded body at the time of injection molding, or sandblasting The law etc. can be used.
[0018]
Moreover, the black part used for this invention can be formed using the black resist material by which the insulation process was carried out. Here, the black resist material subjected to the insulation treatment includes not only a black resist containing a conductive black pigment covered with an insulating resin but also a black resist containing an insulating black pigment. For example, a black resist containing a black pigment made of carbon black coated with an insulating resin can be used.
The black part uses a silk screen printing method, a black resist material paste is applied to the display surface, heat cured, and black dots are formed on the display surface so that the pitch of the LED chip mounting position is approximately 3 to 20 mm. Can be formed in a grid pattern.
Here, the shape of the black dots is preferably formed in accordance with the shape of the LED chip. For example, a rectangle is preferable if the LED chip is rectangular, and a circle is preferable if the LED chip is circular. The size of the black dots can be adjusted in accordance with the size of the opening of the mask member so that the surface of the wiring board cannot be seen.
[0019]
In addition, as the surface-mount type LED chip used for the display device of the present invention, for example, a light emitting chip is fixed to an insulating resin case having an opening on the surface, and the light emitting chip and the gold are disposed from the inside to the outside of the insulating resin case. It is possible to use an external electrode that is electrically connected by using a wire or the like, and a recess filled with a mold resin that protects the light emitting chip.
To mount the surface mount type LED chip on the front panel, after applying the solder paste to the predetermined part of the wiring on the display surface of the front panel, the LED chip is arranged in a dot lattice shape, and it is bundled using a reflow soldering device etc. And mounting by soldering.
[0020]
One type of light emitting chip can be used, or an LED chip in which a plurality of light emitting chips are arranged close to each other can be used. A display device capable of full color display can be obtained by arranging RGB light emitting chips close to each other. Gallium nitride compound semiconductors are preferably used for green and blue, and gallium, aluminum, arsenic and aluminum / indium / gallium / phosphorus semiconductors are preferably used for red.
Further, by using a light emitting chip that can emit blue light and a fluorescent material that can be excited to emit yellow light, white light can be emitted using one kind of light emitting chip. As the above-mentioned fluorescent material, perylene derivatives and yttrium / aluminum garnet phosphors activated with cerium can be suitably used.
[0021]
Embodiment 2. FIG.
FIG. 2 is a schematic exploded perspective view showing the structure of the display unit 1 ′ constituting the display device according to Embodiment 2 of the present invention. This embodiment mode shows a case where two mask members are used for one display panel.
The display panel 3 ′ is rectangular, LED chips 3 a of 16 × 32 dots are mounted and arranged, and the mask portion is composed of two square mask members 2. Near the center of the display surface 3 b of the display panel 3 ′, a black portion 3 d between the chip rows is formed in a gap between the rows of LED chips 3 a in the short side direction of the display panel 3. The black portions 3d between the chip rows and the gaps between the two adjacent mask members 2 are aligned, and the two mask members 2 are arranged adjacent to each other on the display panel.
[0022]
Similarly to the case of the first embodiment, the inter-chip row black portion 3d can be formed using a silk screen printing method. The width of the black portion 3d between the chip rows can be adjusted within the range of the pitch of the mounting positions of the LED chips 3a, but it is necessary to make it larger than the size of the gap between the adjacent mask members 2 and 2. is there.
[0023]
When a display device is increased in size, a large display panel is often used. In that case, it is necessary to use a large mask member in accordance with the size of the display panel. Furthermore, in a large display panel, the number of dots of LED chips to be mounted also increases, and it is necessary to increase the numerical aperture of the mask member accordingly. However, increasing the numerical aperture requires high dimensional accuracy for the mask member, leading to an increase in the cost of the mask member.
According to the present embodiment, since two mask members are attached to one display panel, a more miniaturized mask member can be used. Thereby, the tolerance with respect to the dimensional accuracy of the mask member can be increased, and the cost of the mask member can be further reduced.
Further, since the black portion between the chip rows can prevent the surface of the wiring board from being exposed from the gap between the two adjacent mask members 2, only the light emitting surface of the LED chip is substantially exposed from the mask body. And the contrast can be improved.
[0024]
In addition, according to this Embodiment, although the example which attached two mask members with respect to one display panel was demonstrated, one display panel is enlarged or one mask member is reduced in size. Thus, the same effect can be obtained when three or more mask members are attached to one display panel.
[0025]
【The invention's effect】
As described above, the display device according to the present invention forms a black portion around the LED chip mounting position on the wiring board, and attaches the black plate-like mask member to the display panel from the opening of the mask member. Since the surface of the wiring board is not directly exposed, the difference between the luminance at the time of lighting and the luminance at the time of non-lighting can be increased to improve the contrast. Further, since it is not necessary to use a high-cost printed wiring board having an insulating black resist material layer for the front panel, the production cost of the display device can be reduced.
[0026]
Further, a plurality of rectangular mask members are formed by aligning a black portion between chip rows formed in a gap between the rows of surface-mounted LED chips on the wiring board and a gap between adjacent mask members. Since the display panels are arranged so as to be adjacent to each other, the contrast can be improved even when a plurality of mask members are used. Moreover, since the mask member reduced in size can be used, the cost of a mask member can be reduced more.
[0027]
In addition, since the main surface of the mask member on the display observation surface side is matted, reflection from the surface of the mask member can be suppressed, and the contrast can be further increased.
[Brief description of the drawings]
FIG. 1 is a schematic exploded perspective view showing a structure of a display unit constituting a display device according to a first embodiment of the present invention.
FIG. 2 is a schematic exploded perspective view showing a structure of a display unit constituting a display device according to a second embodiment of the present invention.
[Explanation of symbols]
1, 1 'display unit, 2 mask member, 2a opening, 2b frame, 2c outer frame, 3, 3' display panel, 3a LED chip, 3b display surface, 3c chip peripheral black part, 3d black part between chip rows, 4 , 4 'frame.

Claims (4)

A display device comprising: a wiring board in which surface-mounted LED chips are arranged on a display surface; and a plurality of mask members having openings into which the surface-mounted LED chips are fitted.
The plurality of mask members include a black portion between chip rows provided between rows of surface-mounted LED chips arranged on the wiring substrate, and a gap provided adjacent to the mask members. A display device, wherein the display device is arranged adjacent to one wiring board by being aligned.   The display device according to claim 1, wherein a width of the black portion between the chip rows is larger than a gap between adjacent mask members.   The display device according to claim 1, wherein a peripheral black portion is provided at a peripheral portion of the surface mount LED chip.   The display device according to claim 1, wherein the mask member is a resin molded body, and a surface of the mask member is matted.

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