JP4176225B2 - Liquid crystal display element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmissive / semi-transmissive liquid crystal display element used in combination with an analog indicator, and more particularly, to a liquid crystal display element that uses backlight light as illumination light for a pointer of an analog indicator. Is.
[0002]
[Prior art]
For example, some models of automobile analog speedometers and analog timepieces are provided with an illuminating device so that a pointer can be displayed even in dark conditions such as at night.
[0003]
In many cases, the lighting device is arranged on the back side of the panel (dial), and the light is guided to the front side of the panel through a light guide such as acrylic resin to illuminate the entire surface of the panel or as a pointer. It is made to irradiate and shine.
[0004]
In particular, in an automobile speedometer, the entire meter panel (background) is dim, and the pointer is illuminated by a dedicated light guide to make it light-emitting. I try to put it out.
[0005]
In contrast to the analog indicator, the liquid crystal display panel is a so-called digital display because the position of each pixel is fixed and information is displayed by lighting or non-lighting. It is increasingly used in combination.
[0006]
As an example, a case where it is used as a meter panel of an automobile speedometer will be described. In the manufacturing process of a liquid crystal display panel, a hole sealing material is provided in advance in the cell gap. Then, a through hole is formed so as to pass through the hole sealing material after the panel is manufactured, and the pointer rotation shaft of the speedometer is inserted into the through hole.
[0007]
[Problems to be solved by the invention]
In this way, the liquid crystal display panel is used as a meter panel of an automobile speedometer, but this has the following problems in terms of illumination.
[0008]
By using a transmissive or transflective liquid crystal display element, it is possible to brighten the entire meter panel (background) with the light of the backlight, but in the prior art, the pointer is brighter than the background. It was difficult to make it look good at night.
[0009]
In other words, in order to bring out the pointer and bring out a high-class feeling, light is guided from the light source on the back side of the meter panel to the pointer by a light guide dedicated to the pointer, but the liquid crystal display panel as a meter panel has an analog instrument. The light guide hole cannot be opened unnecessarily like the panel (clockface).
[0010]
Most likely, the light guide can be led out from the back side of the liquid crystal display panel to the front side of the panel through the side, but this leads to sacrifice of the display area of the liquid crystal display panel. Therefore, it is not a realistic solution.
[0011]
In addition, it is conceivable to insert the light guide into the through hole of the liquid crystal display panel together with the pointer rotation shaft. However, as a result, the diameter of the through hole is inevitably increased, and the liquid crystal display range is narrowed accordingly. Therefore, this is also not a preferable method.
[0012]
[Means for Solving the Problems]
The present invention has been made to solve such a problem, and its object is to sacrifice the display area of the liquid crystal display panel when the liquid crystal display panel is used in combination with the pointer of the analog indicator. It is another object of the present invention to provide a liquid crystal display element capable of effectively guiding light from a backlight for a liquid crystal display element to a pointer so that the pointer display at night can have a high-class feeling.
[0013]
According to the present invention, this object is achieved by bonding a pair of transparent electrode substrates through a peripheral sealing material and a hole sealing material, and coaxially perforating each transparent electrode substrate through the hole sealing material. A liquid crystal display panel having a through-hole, a polarizing plate pasted on both front and back surfaces of the liquid crystal display panel excluding the portion of the through-hole, and a backlight disposed on the back side of the liquid crystal display panel; In the liquid crystal display element in which the pointer rotation shaft of the analog indicating instrument is inserted into the through hole, a light diffusing member is included in the hole seal material, and a reflection light guide plate is provided at the shaft end of the pointer rotation shaft. A pointer is attached via the light guide, and the light emitted from the backlight is diffused by the light diffusing member in the hole seal material and is incident on the reflective light guide plate, and is applied to the pointer as illumination light from the reflective light guide plate. It is achieved by Rukoto.
[0014]
In the present invention, the light diffusing member is preferably a fine bead having a refractive index different from the refractive index of the hole sealing material. According to this, only by dispersing the beads in the hole sealing material, Good light diffusibility can be obtained.
[0015]
In addition, it is preferable that the polarizing plate has a hole having a diameter substantially equal to the diameter of the hole sealing material coaxially with respect to the through hole. According to this, the loss of light reaching the pointer Can be reduced as much as possible.
[0016]
By forming a light shielding film disposed in a donut shape along the periphery of the hole sealing material on the inner surface of at least one transparent electrode substrate, the leakage of diffuse stray light in the liquid crystal inside the hole sealing material is reduced. Thus, a decrease in contrast of the liquid crystal display around the through hole can be prevented, and this is also one of the features of the present invention.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described in more detail on the basis of the embodiment shown in FIG.
[0018]
The liquid crystal display element 1 is a transmissive or transflective type including a liquid crystal display panel 2 and a backlight 3 disposed on the back side of the liquid crystal display panel 2. The liquid crystal display panel 2 includes, for example, The pointer rotating shaft 4 of the analog speedometer of the automobile is inserted.
[0019]
The liquid crystal display panel 2 is composed of a substrate laminate in which a first transparent electrode substrate 21 and a second transparent electrode substrate 22 are bonded together via a peripheral sealing material 23 so that a predetermined cell gap G is generated therebetween. In this case, a hole sealing material 24 is provided at a predetermined position between the first and second transparent electrode substrates 21 and 22 (where the pointer rotating shaft 4 is inserted).
[0020]
The hole sealing material 24 is made of, for example, an epoxy resin, like the peripheral sealing material 23, and before the first and second transparent electrode substrates 21 and 22 are bonded together, either one of the transparent electrode substrates, which in this embodiment is anti-reverse. On the backlight 3 side, it is applied to the first transparent electrode substrate 21 on the display surface side with a thickness thicker than the cell gap G, and is crushed into a disk shape by the pressure applied when the transparent electrode substrates 21 and 22 are bonded together. It is.
[0021]
After filling the liquid crystal display panel 2 and filling a predetermined liquid crystal substance into the cell gap G, the transparent electrode substrates 21 and 22 are coaxially connected to each transparent electrode substrate 21 and 22 through the hole seal material 24. Two through holes 25 are formed.
[0022]
The polarizing plates 26 and 27 are attached to both the front and back surfaces of the liquid crystal display panel 2 obtained in this way, and each polarizing plate 26 and 27 has a hole coaxially aligned with the through hole 25. 261 and 271 are provided, respectively.
[0023]
In this embodiment, the backlight 3 is a side light type, and includes a light guide plate 31 made of acrylic resin or the like, and light sources 32 and 32 arranged on both sides thereof. The light guide plate 31 is also provided with a shaft insertion hole 311 for inserting the pointer rotation shaft 4.
[0024]
In order to efficiently guide the light from the light source 32 to the liquid crystal display panel 2 side, a light reflecting sheet is preferably provided on the bottom surface of the light guide plate 31. Although there is no restriction | limiting in particular in the kind of light source 32, CFL (cold-cathode tube), a bean ball, etc. are illustrated. In some cases, the backlight 3 may be an EL panel.
[0025]
A pointer 42 is attached to the shaft end of the pointer rotation shaft 4 via a reflective light guide plate 41. In this embodiment, the reflection light guide plate 41 is fixed in a disc shape so as to be orthogonal to the pointer rotation shaft 4 and has a light reflection effect of directing light from the backlight 3 in the radial direction.
[0026]
The pointer 42 is connected to the outer peripheral end surface of the reflective light guide plate 41 via, for example, an adhesive. The pointer 42 is preferably made of a transparent synthetic resin needle such as an acrylic resin, and may be appropriately colored or may be coated with a fluorescent paint. In this embodiment, a transparent fluorescent paint is applied.
[0027]
In order to diffuse and guide the light from the backlight 3 along the pointer rotation axis 4 to the pointer 42 side, the hole sealing material 24 includes a light diffusion member (not shown). In this embodiment, minute beads having a refractive index different from the refractive index of the hole sealing material 24 are mixed and dispersed in the hole sealing material 24 as a light diffusion member.
[0028]
Further, according to this embodiment, in order to reduce the loss of light reaching the pointer 42 as much as possible, the holes 261 and 271 of the polarizing plates 26 and 27 are set to have a size substantially equal to the diameter of the hole sealing material 24. .
[0029]
A light shielding film 28 is arranged in a donut shape along the periphery of the hole sealing material 24. The light shielding film 28 is for preventing the diffusion stray light generated in the hole sealing material 24 from leaking into the liquid crystal, thereby reducing the contrast of the liquid crystal display around the through hole 25. In this embodiment, It is formed on the inner surface of the second transparent electrode substrate 22 on the side close to the backlight 3. The inner and outer diameters of the light shielding film 28 are appropriately determined in relation to the size of the hole sealing material 24.
[0030]
According to this configuration, the light of the backlight 3 is diffused (lightened) by the hole sealing material 24, and the diffused light is guided to the pointer 42 via the reflective light guide plate 41. Therefore, the pointer 42 is displayed so as to be lightly raised with the liquid crystal display panel 2 as a background, and a high-class feeling can be created.
[0031]
【Example】
Example 1
A hole in which 5% by weight of 0.5 μm glass beads (refractive index 1.50) is dispersed in an epoxy-based sealing material (refractive index 1.65) at a predetermined through-hole position on one transparent electrode substrate side on the surface side The sealing material was applied so that the diameter after press bonding the substrate was 5 mm.
A light-shielding film was formed in a donut shape having an inner diameter of 4.5 mm and an outer diameter of 8 mm at a position corresponding to the hole sealing material on the other transparent electrode substrate side on the back surface side.
Each of these transparent electrode substrates was pressure-bonded through a peripheral sealing material to produce a negative transmission type STN liquid crystal display panel having a cell gap of 6 μm.
A through hole having a diameter of 2.5 mm was drilled in the liquid crystal display panel so as to pass through the center of the hole sealant.
Then, a retardation plate and a polarizing plate each having a 5 mm diameter hole at the position of the through hole were attached to the liquid crystal display panel. Further, on the back side of the liquid crystal display panel, a sidelight type backlight using CFL as a light source and having a shaft insertion hole in the light guide plate is arranged.
Next, as an analog instrument, a pointer coated with transparent fluorescent paint is attached to the shaft end of the pointer rotation shaft through the reflective light guide plate, and this pointer rotation shaft is inserted into the through hole of the liquid crystal display panel and the shaft insertion hole of the backlight. And fixed via a bearing member.
When the backlight was turned on, the pointer was illuminated by the faint light diffused by the glass beads in the hole sealing material, and the surface appeared neatly on the liquid crystal panel. In addition, no contrast reduction was observed around the through-hole.
[0032]
【The invention's effect】
As described above, according to the present invention, it is possible to guide the light of the backlight of the liquid crystal display panel to the pointer of the analog instrument without causing the light guide to be routed, and to display the pointer so as to be raised. . Therefore, an analog / digital display liquid crystal display element that is extremely inexpensive and full of luxury can be obtained.
[0033]
In addition, since it is not necessary to pass the light guide dedicated to the pointer illumination through the through hole (shaft insertion hole) of the liquid crystal display panel, the diameter of the through hole may be small, and the liquid crystal display range can be reduced by opening the through hole. Can be minimized.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an embodiment of a liquid crystal display element according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Liquid crystal display panel 21 and 22 Transparent electrode board | substrate 23 Peripheral sealing material 24 Hole part sealing material 25 Through-hole 26, 27 Polarizing plate 261,271 Hole 28 Light-shielding film 3 Backlight 31 Light guide plate 32 Light source 4 Pointer rotating shaft 41 reflective light guide plate 42 pointer

Claims (4)

A liquid crystal display panel in which a pair of transparent electrode substrates are bonded together via a peripheral sealing material and a hole sealing material, and each transparent electrode substrate has a through-hole formed coaxially through the hole sealing material. A polarizing plate attached to both front and back surfaces of the liquid crystal display panel except for the through-hole portion, and a backlight disposed on the back side of the liquid crystal display panel, and an analog instruction in the through-hole In the liquid crystal display element through which the indicator rotation shaft of the instrument is inserted,
A light diffusing member is included in the hole sealing material, and a pointer is attached to a shaft end of the pointer rotation shaft via a reflective light guide plate, and light emitted from the backlight is transmitted to the hole sealing material. A liquid crystal display element characterized by being diffused by the light diffusing member and entering the reflective light guide plate and being provided as illumination light from the reflective light guide plate to the pointer. The liquid crystal display element according to claim 1, wherein the light diffusing member is made of a fine bead having a refractive index different from that of the hole sealing material. 3. The liquid crystal display element according to claim 1, wherein a hole having a hole diameter substantially equal to a diameter of the hole sealing material is coaxially formed in the polarizing plate with respect to the through hole. 4. The liquid crystal display element according to claim 1, wherein a light shielding film disposed in a donut shape is formed on the inner surface of at least one transparent electrode substrate along the periphery of the hole sealing material.

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