JP2002133927A - Illumination device, liquid crystal display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to display by means of a liquid crystal display device not only on one side thereof but also on the other side thereof. SOLUTION: In a light guide plate that guides light from the light source to both side faces, a primary reflective layer is provided at a region within the surface of the plate of one hand, and a second reflective layer is provided on the surface of the plate of the other hand, at a region different from the one behind the foregoing part. Further, a first liquid crystal display panel is disposed on the other side of the primary reflective layer of the light guide plate as well as a second liquid crystal display panel on the other side of the second reflective layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lighting device, a liquid crystal display device, and an electronic device.

[0002]

2. Description of the Related Art As is well known, liquid crystal display devices are widely used as display devices of various electronic devices such as mobile phones. The liquid crystal display device includes a liquid crystal display panel in which liquid crystal is sealed between a pair of substrates facing each other, and an illumination disposed on one of the substrate surfaces of the liquid crystal display panel to irradiate the liquid crystal display panel with light. It is common to include a device (a so-called backlight unit). In such a configuration, the light emitted from the illumination device is emitted to the observation side after passing through the liquid crystal display panel, thereby realizing a transmission type display. According to such a transmission type liquid crystal display device, even in a dark place where sufficient external light does not exist,
There is an advantage that visibility can be secured.

[0003]

However, when such a liquid crystal display device is used, what can be visually recognized by a user is as follows.
In the liquid crystal display panel, since there is only an image displayed on the observation surface on the side opposite to the illumination device, there has been a problem that the user cannot visually recognize the display on the other side of the liquid crystal display device.

[0004] More specifically, for example, a mobile phone or notebook capable of folding a display-side housing provided with the above-mentioned liquid crystal display device and an operation-side housing provided with operation keys and the like via a hinge. Electronic devices such as portable personal computers are becoming widespread, but in a folded state, the display surface of the liquid crystal display device faces the operation side housing, so that the user cannot view the display. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and has been made in consideration of the above-described circumstances. It is an object of the present invention to provide a lighting device.

[0006]

In order to solve the above-mentioned problems, a lighting device according to the present invention comprises a light source for irradiating light, a light guide plate having a side end face facing the light source, and one of the light guide plates. A first reflection layer provided in a partial area of the substrate surface, and a second reflection layer provided in a different area of the other substrate surface of the light guide plate from the area behind the partial area. And a layer.

According to such an illuminating device, each of the plurality of liquid crystal display panels is placed on the surface of the light guide plate opposite to the first reflection layer and the surface of the light guide plate opposite to the second reflection layer. By arranging them, it is possible to display each liquid crystal display panel on both sides of the lighting device. Further, in spite of employing such a configuration using a plurality of liquid crystal display panels, one light guide plate is sufficient. Therefore, it is not necessary to provide a light source for each liquid crystal display panel, and a sufficiently bright display can be realized with one light source. As a result, the manufacturing cost can be kept low, and the power consumed by the light source can be reduced.

Here, it is preferable that, of the light guide plate in the lighting device, a surface facing the first reflection layer and a surface facing the second reflection layer are roughened.
In this case, by appropriately scattering the light emitted to each liquid crystal display device, a high quality display can be realized. Note that, as a configuration for scattering the emitted light in this way, a first diffusion plate facing the first reflection layer with the light guide plate interposed therebetween, and a second diffusion layer facing the first reflection layer with the light guide plate interposed therebetween. A configuration provided with a second diffusion plate is also desirable.
By doing so, it is not necessary to perform the process of selectively roughening the light guide plate as described above, and it is sufficient to attach the first and second diffusion plates to the light guide plate, thereby simplifying the manufacturing process. There is an advantage that can be.

According to another aspect of the present invention, there is provided a liquid crystal display device including the above-described illumination device and a first liquid crystal display disposed on a side of the light guide plate opposite to the first reflection layer. And a second liquid crystal display panel disposed on a side opposite to the second reflection layer with respect to the light guide plate. According to this liquid crystal display device, the display by the first liquid crystal display panel can be performed on one side, and the display by the second liquid crystal display panel can be performed on the other side.

[0010] The present invention can also be implemented by an electronic apparatus having the above-mentioned liquid crystal display device. For example, such an electronic device includes the liquid crystal display device and a display-side housing that accommodates the liquid crystal display device, and includes a window corresponding to each of the first liquid crystal display panel and the second liquid crystal display panel. A foldable portable type including a display-side housing, an operation-side housing having a plurality of operation keys, and a hinge connecting the display-side housing and the operation-side housing at one end thereof. An information terminal or the like is conceivable. According to such an electronic device, the user can not only visually recognize the display on the first liquid crystal display panel in a normal use state, for example, but also fold the display-side housing toward the operation-side housing, and This is extremely convenient because the display on the second liquid crystal display panel can be visually recognized even in a situation where the display cannot be visually recognized.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Such an embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

<A: Configuration of Embodiment> FIG. 1 is an exploded perspective view schematically illustrating the configuration of a liquid crystal display device according to an embodiment of the present invention, and FIG. FIG. As shown in these drawings, the liquid crystal display device includes a first liquid crystal display panel 11, a second liquid crystal display panel 12, and an illumination device 13 for irradiating light to both of them. Is done.

The first liquid crystal display panel 11 includes a pair of substrates 1.
11 and 112 are bonded together via a sealing material (omitted in FIG. 1) 113, and a liquid crystal 114 is sealed between both substrates. A plurality of strip-shaped segment electrodes are formed on the inner surface of the substrate 111, and a plurality of strip-shaped common electrodes extending in a direction orthogonal to the segment electrodes are formed on the inner surface of the substrate 112. The segment electrode and the common electrode (both not shown) are made of ITO (Indium Tin Oxide).
And the like. Further, both substrates 1
An alignment film (not shown) for defining the alignment direction of the liquid crystal 114 is provided on the opposing surfaces of 11 and 112, respectively.

The second liquid crystal display panel 12 has substantially the same configuration as the first liquid crystal display panel 11. That is, the second liquid crystal display panel 12 includes a substrate 121 on which a segment electrode and an alignment film (both not shown) are formed, and a substrate 122 on which a common electrode and an alignment film are formed, and a sealing material 123.
And a liquid crystal 124 is sealed between the two substrates.

On the other hand, as shown in FIGS. 1 and 2, the lighting device 13 includes a light source 131, a light source-side reflector 132, a light guide plate 133, a first reflector 134a and a second reflector 1a.
34b. The light source 131 is, for example, a cold cathode tube that functions as a line light source. Light source side reflector 13
Numeral 2 is formed of a reflective metal such as aluminum, for example, and reflects light from the light source 131 applied to the opposite side to the light guide plate 133 toward the light guide plate 133. The light guide plate 133 has a side end surface (hereinafter, referred to as a light source 131) facing the light source 131.
It is called "light incident surface". ), And the light from the light source 131 incident on the light incident surface is transmitted to the first liquid crystal display panel 1.
It is a plate-like member for guiding to the first liquid crystal display panel 12 side. The first liquid crystal display panel 11 and the second liquid crystal display panel 12 described above are fixed to the surface of the light guide plate 133 with a double-sided adhesive tape or the like. On the other hand, each of the first reflective layer 134a and the second reflective layer 134b is a thin film formed on the surface of the light guide plate 133 by a reflective metal such as aluminum, and reflects light reaching the surface.

Next, the light guide plate 133 and the first reflection layer 134a
The positional relationship between the first and second reflective layers 134b and the first and second liquid crystal display panels 11 and 12 will be described. In the following, as shown in FIGS. 1 and 2, one surface side (upper side in each drawing) of the light guide plate 133 is referred to as “A side”, and the opposite side (lower side in each drawing) is referred to as “A side”. It is described as "B side".

First, as shown in FIG. 1 and FIG.
The reflection layer 134a is a partial region (hereinafter, referred to as a "first region 133a") of the substrate surface on the B side of the light guide plate 133.
It is arranged to cover. On the other hand, the first liquid crystal display panel 1
1 is disposed on the opposite side of the light guide plate 133 from the first reflection layer 134a (that is, on the A side). That is, the substrate 112 of the first liquid crystal display panel 11 faces the region behind the first region 133a on the substrate surface on the A side of the light guide plate 133.

Further, in the present embodiment, the light guide plate 1
33, the surface of the first region 133a,
The surface covered by the reflective layer 134a is a rough surface on which many fine irregularities are formed. Therefore, the light reflected on the surface of the first reflection layer 134a is appropriately scattered on the rough surface. By doing so, the first reflection layer 13
The light reflected by the surface of 4a is emitted from the light guide plate 133 in a state of being scattered so as to reach the entire surface of the substrate 112 of the first liquid crystal display panel 11. In addition, such a rough surface is
For example, it can be formed by selectively embossing a part of the surface of the light guide plate 133.

On the other hand, the positional relationship between the second reflective layer 134b, the second liquid crystal display panel 12, and the light guide plate 133 is determined by the first reflective layer 134a, the first liquid crystal display panel 11, and the light guide plate 133.
The positional relationship with the position 33 is reversed. That is, in the substrate surface on the A side of the light guide plate 133 (the other substrate surface), a region different from the region behind the first region 133a (in other words, the first surface of the substrate surface on the A side of the light guide plate 133). 1 An area different from the area where the liquid crystal display panel 11 is provided.
This is referred to as a “second region 133b”. ) Is the first area 13
It has a rough surface similar to 3a. Then, the second reflection layer 1
34b is provided so as to cover the second region 133b. On the other hand, the second liquid crystal display panel 12 is disposed on the opposite side (B side) of the light guide plate 133 from the second reflection layer 134b. More specifically, the substrate 1 of the second liquid crystal display panel 12
22 is a region behind the second region 133b (that is, the first region 133a) on the B-side substrate surface of the light guide plate 133.
(The other area).

In such a configuration, a part of the light emitted from the light source 131 passes through the inside of the light guide
After being reflected on the surface of the reflective layer 134a, the light guide plate 133
From the surface on the A side behind the first region 133a in
The light is emitted to the first liquid crystal display panel 11 side. This light is the first
The light enters the substrate 112 of the liquid crystal display panel 11 and
→ the liquid crystal 114 → the substrate 111
Emitted from 1 to the A side. As a result, an image displayed by the first liquid crystal display panel 11 is visually recognized by an observer located on the A side of the liquid crystal display device.

On the other hand, a part of the light emitted from the light source 131 passes through the inside of the light guide plate 133, is reflected on the surface of the second reflection layer 134b, and then is reflected by the second region 133 in the light guide plate.
b, the second liquid crystal display panel 12
Outgoing to the side. This light is incident on the substrate 122 of the second liquid crystal display panel 12, and the substrate 122 → the liquid crystal 124 → the substrate 12
The light is emitted from the substrate 121 to the B side by following the path 1.
As a result, the image displayed by the second liquid crystal display panel 12 is visually recognized by an observer located on the B side of the liquid crystal display device.

As described above, according to the present embodiment, an image can be displayed not only on one side (A side) of the liquid crystal display device but also on the opposite side (B side).

Further, according to the present embodiment, the light source 131
From the first and second liquid crystal display panels 11 and 12
Are realized by one light guide plate 133, and therefore, there is an advantage that manufacturing cost can be reduced and power consumption can be reduced. The details are as follows.

Here, as a configuration for realizing double-sided display, a configuration shown in FIG. 3 is also conceivable. That is,
As shown in FIG. 3, a liquid crystal display device including a lighting device 13 a and a first liquid crystal display panel 11 and a liquid crystal display device including a lighting device 13 b and a second liquid crystal display panel 12 are respectively combined with a lighting device and a liquid crystal display panel. Are arranged so that the positional relationship between them is reversed.

Here, it is assumed that both the first liquid crystal display device 11 and the second liquid crystal display device 12 are irradiated with light using only the light from the light source 131b without providing the light source 131a shown in FIG. Then, the light guide plates 135a and 135a
b, the light from the light source 131b leaks to the outside at the space D between the light guide plate 1b and the light guide plate 1
The amount of light incident on 35a is significantly reduced. As a result, a problem may occur that the first liquid crystal display panel 11 is not irradiated with a sufficient amount of light and the display becomes dark. In order to avoid such inconvenience, as shown in FIG. 3, it is necessary to provide light sources 131a and 131b in both of the illumination devices 13a and 13b, respectively.

On the other hand, in the present embodiment, the first
The light guide plate for guiding light to each of the liquid crystal display panel 11 and the second liquid crystal display panel 12 is one, and does not have a separated portion as in the example of FIG. Therefore,
Even when one light source 131 is used, both liquid crystal display panels 11 and 12 can be irradiated with sufficient light. As a result, according to the present embodiment, as compared with the case where the configuration illustrated in FIG. 3 that requires a plurality of light sources is employed, the manufacturing cost can be reduced, and the power consumed by the light sources can be reduced. There is an advantage that can be. However, also in the present embodiment, a plurality of light sources may be provided so as to face both side end surfaces of the light guide plate 133 in order to further improve the brightness of the display.

<B: Modifications> Although the embodiments of the present invention have been described above, the above embodiments are merely examples, and various modifications may be made to the above embodiments without departing from the spirit of the present invention. Can be added. For example, the following modifications can be considered.

(1) In the above embodiment, the surface of the light guide plate on which the reflection layer is formed is roughened in order to scatter light emitted to the first and second liquid crystal display panels 11 and 12; The configuration for realizing the function is not limited to this, and may be, for example, the configuration shown in FIG. Note that among the elements in FIG. 4, the same elements as those illustrated in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

As illustrated in FIG. 4, in the present modification, the surface of the light guide plate 133 covered by the first reflection layer 134a and the second reflection layer 134b is a flat surface. On the other hand, the surface of the light guide plate 133 opposite to the first reflection layer 134a and the second reflection layer 134b (that is, the first reflection layer 134a and the second reflection layer 134b).
And the first liquid crystal display panel 11 and the second liquid crystal display panel 12).
5b is attached. First diffusion plate 135
a and the second diffusion plate 135b are plate-like members for scattering the light passing therethrough.

In such a configuration, a part of the light emitted from the light source 131 passes through the inside of the light guide plate 133 to be the first light.
After being reflected on the surface of the reflection layer 134a, the first diffusion plate 13
The light is scattered by 5a and emitted to the first liquid crystal display panel 11 side. Similarly, light emitted to the second liquid crystal display panel 12 side is light scattered by the second diffusion plate 135b.

With this configuration, the same effects as in the above embodiment can be obtained. Furthermore, according to this configuration,
There is no need to perform a process of selectively roughening the surface of the light guide plate 133 (e.g., graining), and it is sufficient to attach the diffusion plate 135 to a part of the surface of the light guide plate 133. There is an advantage that can be.

(2) As the liquid crystal display panel of the present invention, a so-called transflective liquid crystal display panel having a structure in which a transflective layer is provided on a substrate facing the light guide plate 133 can be used. The transflective layer has, for example, a plurality of openings for transmitting light from the lighting device 13 and light from the side opposite to the lighting device 13 (for example, indoor lighting light, sunlight, or the like). Is a metal film made of aluminum or the like that can reflect external light. According to such a transflective liquid crystal display device, the power consumption can be reduced by performing the reflective display without using the illumination device 13 in a situation where sufficient external light exists.

(3) In the above-described embodiment and each of the modifications, the case where one liquid crystal display panel is provided on each of the substrate surfaces of the light guide plate 133 is exemplified. However, the liquid crystal display panel provided on each of the substrate surfaces is provided. The number is not limited to this. FIG. 5 is a cross-sectional view illustrating a configuration in which two first liquid crystal display panels 11 are provided on the A side of the light guide plate 133 and one second liquid crystal display panel 12 is provided on the B side. In the present modification, two areas separated from each other on the B-side substrate surface of the light guide plate 133 are the first areas 133a.
It has become. A first reflection layer 133a is provided in each first region 133a, and one first liquid crystal display panel 11 is provided on the opposite side of each light reflection plate 133 with respect to the light guide plate 133. . On the other hand, a second reflection layer 133b is provided in a second region 133b different from a region behind the first region 133a on the substrate surface on the A side of the light guide plate 133, and is opposite to the second reflection layer 133b. The second liquid crystal display panel 12 is disposed on the side substrate surface. The first reflection layer 1 on the substrate surface of the light guide plate 133.
The point that the area covered by the third reflection layer 33a and the second reflection layer 133b is a rough surface is the same as in the above embodiment. Thus, in the present invention, the first reflective layer is provided on the first
Each of the region 133a and the second region 133b provided with the second reflection layer is not limited to only one continuous region, and may be a plurality of regions separated from each other.

(4) In the above embodiment and each of the modifications, the region behind the second region 133b and the first region 1
Although the boundary with 33a (or the boundary between the first region 133a and the second region 133b) is a boundary parallel to the light incident surface of the light guide plate 133, the boundary between these regions is described as an example. The boundary may be perpendicular to the light incident surface. Here, when both regions are partitioned by a boundary parallel to the light incident surface as in the above embodiment (see FIG. 1), the display corresponding to the first region 133a far from the light source 131 is displayed by the light source 131.
May be slightly darker than the display corresponding to the second area 133b close to. On the other hand, if a configuration in which both regions are partitioned by a boundary perpendicular to the light incident surface is adopted, the first region is obtained.
The light amounts from the light source 131 reaching both the region 133a and the second region 133b are equal. As a result, since the amount of light applied to each of the first liquid crystal display panel 11 and the second liquid crystal display panel 12 can be made substantially uniform, there is an advantage that a difference in brightness can be prevented from appearing on the display. There is.

<C: Electronic Apparatus> Next, an electronic apparatus to which the liquid crystal display device according to the above-described embodiment is applied will be described. FIG. 6A is a perspective view illustrating the configuration of a foldable mobile phone as an example of such an electronic device.
FIG. 2B is a perspective view illustrating a state in which the mobile phone is folded. As shown in these figures, this mobile phone has a display-side housing 21 containing a liquid crystal display device according to the present invention, and an operation-side housing including a plurality of operation keys 221 for operating the mobile phone. 22 and a hinge 23 that rotatably connects each housing at an edge. Further, the earpiece 211 and the antenna 212 are provided on the display-side housing 21, while the mouthpiece 222 is provided on the operation-side housing 22. Under such a configuration, the user places the display-side housing 21 on the operation-side housing 22 side (or the operation-side housing 22 on the display-side housing 22) around the hinge 23 as shown in FIG. (To the body 21 side).

Here, the display-side housing 21 is provided with a window 213 corresponding to the first liquid crystal display panel 11 on a surface facing the operation-side housing 22 in a folded state, and on the opposite side. Window 21 corresponding to the second liquid crystal display panel 12
4 is provided. According to such a configuration, the user:
Not only can the display image on the first liquid crystal display panel 11 be visually recognized when the mobile phone is not folded (ie, during a call), but also the display image on the second liquid crystal display panel 12 can be displayed even when the mobile phone is folded. You can see it.

By the way, the lighting device 13 includes the display-side housing 2.
1 is supported by a support mechanism provided in the inside. Here, as shown in FIG. 3, when separate lighting devices 13a and 13b are provided for each liquid crystal display device, it is necessary to provide the support mechanism for each lighting device. In contrast,
According to the liquid crystal display device of the present invention, since there is only one lighting device 13 in spite of having a plurality of display surfaces, the support mechanism of the lighting device 13 has a significantly simpler structure than in the above case. Is obtained.

As described above, the liquid crystal display device according to the present invention has a particularly remarkable effect when applied to a portable electronic device in which one display surface is hidden in a folded state. What you can do is not limited to this. Other electronic devices to which the present invention can be applied include, for example, a liquid crystal television, a notebook personal computer,
Examples include a pager, an electronic organizer, a calculator, a word processor, and a device equipped with a touch panel.

[0039]

As described above, according to the liquid crystal display device of the present invention, display can be performed not only on one side but also on the opposite side.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating the configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line C-C 'in FIG.

FIG. 3 is a cross-sectional view illustrating a comparative configuration for explaining the effect of the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of a liquid crystal display device according to a modified example of the invention.

FIG. 5 is a cross-sectional view illustrating the configuration of a liquid crystal display according to another modification of the present invention.

FIG. 6A is a perspective view illustrating a configuration of a mobile phone as an example of an electronic apparatus to which the liquid crystal display device according to the present invention is applied, and FIG. 6B is a perspective view of the mobile phone in a folded state. It is a perspective view which illustrates a structure.

[Explanation of symbols]

11, 12 ... Liquid crystal display panel, 111, 112, 12
1, 122 ... substrate, 113, 123 ... sealing material, 1
14, 124 liquid crystal, 13 lighting device, 131
Light source 132, light source side reflector 133, light guide plate 1,
33a... First region (partial region), 133b.
Area, 134a First reflective layer, 134b Second reflective layer, 135a First diffuser, 135b Second diffuser, 21 Display casing, 211 Receiver, 212
... antenna, 213, 214 ... window, 22 ... operation side housing, 221 ... operation keys, 222 ... mouthpiece.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 336 H04M 1/02 C H04M 1/02 G02F 1/1335 530 F-term (Reference) 2H038 AA55 BA06 2H089 HA40 QA11 QA16 2H091 FA14Z FA23Z FA31Z FA41Z LA16 5G435 AA00 BB12 BB15 CC13 EE02 EE16 EE27 FF03 FF06 FF08 GG24 GG26 LL07 5K023 AA07 HH05 HH07

Claims (6)

[Claims] A light source for irradiating light; a light guide plate having a side end surface facing the light source; a first reflective layer provided in a partial region of one of the substrate surfaces in the light guide plate; A lighting device, comprising: a second reflection layer provided in a region different from a region behind the partial region on the other substrate surface of the light guide plate. 2. A surface of the light guide plate facing the first reflection layer and a surface facing the second reflection layer,
The lighting device according to claim 1, wherein the lighting device has a rough surface. 3. A light-emitting device comprising: a first diffusion plate sandwiching the light guide plate and facing the first reflection layer; and a second diffusion plate sandwiching the light guide plate and facing the second reflection layer. The lighting device according to claim 1, wherein: 4. The lighting device according to claim 1, wherein: a first liquid crystal display panel disposed on a side opposite to the first reflection layer with respect to the light guide plate; And a second liquid crystal display panel disposed on the opposite side of the second reflective layer. 5. An electronic apparatus comprising the liquid crystal display device according to claim 4. 6. A liquid crystal display device according to claim 4, further comprising a display-side housing for accommodating the liquid crystal display device, wherein windows corresponding to each of the first liquid crystal display panel and the second liquid crystal display panel. , An operation-side housing having a plurality of operation keys, and a hinge connecting the display-side housing and the operation-side housing at one end thereof. And electronic equipment.