JP7054882B2 - Display device - Google Patents

Description

The present invention relates to, for example, a display device that displays information such as characters, figures, and patterns in an electric device or the like.

Conventionally, as a display device of this type, for example, there is one disclosed in Patent Document 1.

The display device shown in FIG. 12A includes a light guide plate 101, light sources 102 and 104 such as LEDs, and lenses 103 and 105. An aggregate of fine reflection prisms 106 and an aggregate of fine reflection prisms 107 are formed on the bottom surface of the light guide plate 101.

The light from the light source 102 enters the light guide plate 101 via the lens 103. The light from the light source 104 enters the light guide plate 101 via the lens 105. The lenses 103 and 105 diffuse the light from the light sources 102 and 104, and serve to inject the light from the side surface of the light guide plate 101 with uniform intensity. Each of the light sources 102 and 104 is composed of a plurality of light sources arranged along the side surface of the light guide plate 101.

As shown in FIGS. 12 (b) and 12 (c), the aggregate of the reflecting prisms 106 is formed in a direction substantially parallel to the side on which the light from the light source 102 of the light guide plate 101 enters, for example, the character “A” as a pattern. It is formed along the shape of. The aggregate of the reflecting prisms 107 is formed in a direction substantially parallel to the side on which the light from the light source 104 of the light guide plate 101 enters, for example, along the shape of the letter "B" as a pattern.

The light 108 emitted from the light source 102 enters light from the side surface of the light guide plate 101 through the lens 103, propagates while being reflected in the light guide plate 101, is reflected by the slope 109 of the reflection prism 106, and is reflected from the front surface of the light guide plate 101. It emits in the direction. As a result, when the light guide plate 101 is viewed from the front, the character "A" is displayed on the main surface as shown in FIG. 12 (b).

The light emitted from the light source 104 passes through the lens 105, enters from the side surface of the light guide plate 101, propagates while being reflected in the light guide plate 101, is reflected on the slope of the reflection prism 107, and is reflected in the front direction from the light guide plate 101. Emit. As a result, when the light guide plate 101 is viewed from the front, the character "B" is displayed on the main surface as shown in FIG. 12 (d).

In this way, the pattern displayed on the light guide plate 101 can be switched depending on whether the light source 102 is turned on or the light source 104 is turned on.

Further, as shown in FIG. 12 (c), when the sheet 111 having a light scattering property is installed on the light emitting side of the light guide plate 101, neither the light sources 102 nor 104 are turned on, and the light guide plate 101 Even if external light is incident on the main surface, the sheet 111 scatters and reflects the external light. This makes it difficult to see the light guide plate 101 through the sheet 111.

Japanese Unexamined Patent Publication No. 2016-180823

The light reflected and emitted from the light source 102 by the reflection prism 106 is not limited to the light directed toward the front of the light guide plate 101. There is also light 110 that is obliquely incident on the reflecting prism 106. This light is reflected by the reflection prism 106 and travels in an oblique direction away from the front. The light deviating from the front direction cannot be seen from the front direction of the light guide plate 101.

Similarly, the light reflected and emitted from the light source 104 by the reflecting prism 107 is not limited to the light directed toward the front surface of the light guide plate 101. There is light obliquely incident on the reflecting prism 107. This light is reflected by the reflection prism 107 and travels in an oblique direction away from the front. The light deviating from the front direction cannot be seen from the front direction of the light guide plate 101.

Here, a case where the light source 104 is turned on to display the character "B" will be described as an example.

In this case, as shown in FIG. 13 (a), since the light incident obliquely from the light source 104 exists in the reflection prism 106 for displaying the letter “A”, as shown in FIG. 13 (b). The light reflected obliquely from the reflecting prism 106 is scattered and reflected by the sheet 111 and can be seen from the front direction of the light guide plate 101. That is, as shown in FIG. 12A, there arises a problem that the character "A" having an unnecessary pattern appears faint while the character "B" is being displayed.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a display device capable of clearly displaying a display pattern even when a sheet for scattering and diffusing light is provided on the front side of a diffuser plate. And.

The display device of the present invention is
It has a main surface, a bottom surface facing the main surface, and first and second side surfaces formed between the main surface and the bottom surface, and light incident on the bottom surface from the first side surface. A first reflecting prism having an inclined surface for reflecting the light toward the main surface side, and a second reflecting surface having an inclined surface for reflecting light incident from the second side surface toward the main surface side. The light guide plate on which the reflection prism is formed,
A first light source that incidents light on the first side surface of the light guide plate,
A second light source that incidents light on the second side surface of the light guide plate, and
A translucent portion arranged on the side of the main surface of the light guide plate to transmit and scatter the light emitted from the main surface.
Is provided,
The width of the second light source is narrower than the width of the region where a plurality of the first reflection prisms are arranged as seen from the second light source side .
In the region where a plurality of the first reflecting prisms are arranged, the longitudinal direction of the inclined surface of the first reflecting prism is parallel to or substantially equal to the line connecting the second light source and the inclined surface of the first reflecting prism. Parallel and
In the region where a plurality of the first reflecting prisms are arranged, the longitudinal direction of the inclined surface of at least a part of the first reflecting prisms is the direction of the light rays incident on the first reflecting prism from the first light source. Inclined from the orthogonal direction,
It is characterized by that.

According to this configuration, by narrowing the width of the light source compared to the width of the light guide plate, the light incident on the prism from the light source on the opposite side can be reduced, and the light is displayed when one of the light sources of the light guide plate is emitted. It is possible to make it difficult for the reflected light from the prism that you do not want to emit from the light guide plate. Therefore, it is possible to obtain a display device in which information that is not desired to be displayed is not displayed in an overlapping manner.

(A) Plan view, (b) Cross-sectional view, and (c) Enlarged perspective view of a prism of the display device according to the first embodiment of the present invention. In the same embodiment, (a) the pattern display state reflected by the first inclined surface 14 of the first reflecting prism 4 and (b) the pattern display state reflected by the first inclined surface 14 of the second reflecting prism 5 will be described. Figure to do An explanatory diagram in the case of (a) a case where the longitudinal direction of the first reflecting prism 4 is parallel to a line connecting the second light source 3 and the center of the first reflecting prism 4 and (b) the second reflecting prism 5 in the same embodiment. Explanatory drawing when it is parallel to the line connecting the longitudinal direction of the first light source 2 and the center of the second reflection prism 5. In the same embodiment, (a) a plan view of the lighting state of the first light source 2, (b) a cross-sectional view, and (c) an explanatory view of light from the first light source 2 and the second light source 3. Explanatory drawing of arrangement place of (a) (b) first and second reflection prisms 4 and 5 in the same embodiment (A) (b) Explanatory drawing of the shape of the first and second reflecting prisms 4 and 5 in the same embodiment. Enlarged perspective view showing another shape of the first and second reflecting prisms 4 and 5 in the same embodiment. Explanatory drawing of arrangement place of (a) (b) first, second reflection prisms 4, 5 of Embodiment 2 of this invention Perspective view of the light guide plate according to the third embodiment of the present invention. Top view of the display device according to the fourth embodiment of the present invention. Explanatory drawing of (a) (b) display state of the same embodiment Explanatory drawing of a conventional display device Explanatory drawing of a conventional display device

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
1 to 7 show Embodiment 1 of the present invention.
FIG. 1A shows a front view of the display device, and FIG. 1B shows a cross-sectional view.

This display device includes a light guide plate 1, first and second light sources 2 and 3 such as LEDs, and a translucent unit 11 that transmits and scatters light.

The light guide plate 1 has a main surface 1a, a bottom surface 1b facing the main surface 1a, and first and second side surfaces 1c and 1d formed between the main surface 1a and the bottom surface 1b. The first and second reflecting prisms 4 and 5 are formed on the bottom surface 1b. As shown in FIG. 1 (b), the first and second reflecting prisms 4 and 5 are all recesses formed in the bottom surface 1b of the light guide plate 1, and the angle with the bottom surface 1b is the first inclination of θa. It has a second inclined surface 15 whose angle between the surface 14 and the bottom surface 1b is θb.

In this embodiment, the first light source 2 having a width W2 narrower than the width W1 of the first side surface 1c of the light guide plate 1 is provided. A second light source 3 having a width W4 narrower than the width W3 of the second side surface 1d of the light guide plate 1 is provided. On the other hand, in FIG. 12, which explains the conventional example, the width W5 of one light source composed of the plurality of light sources 102 and the width W6 of the other light source composed of the plurality of light sources 104 are both light guide plates. It is substantially the same as the width W1 of the side surface of the light guide plate 101, and is configured to illuminate the entire width of the side surface of the light guide plate 101 as uniformly as possible.

As shown in FIG. 2A, the first light source 2 irradiates light toward the first side surface 1c of the light guide plate 1. The light 17 introduced into the light guide plate 1 from the first side surface 1c propagates inside the light guide plate 1.

As shown in FIG. 2B, the second light source 3 irradiates light toward the second side surface 1d of the light guide plate 1. The light 18 introduced into the light guide plate 1 from the second side surface 1d propagates inside the light guide plate 1.

The plurality of first reflecting prisms 4 are arranged so as to receive the light from the first light source 2 on the first inclined surface 14 and reflect it on the side of the main surface 1a of the light guide plate 1. The plurality of second reflecting prisms 5 are arranged so as to receive the light from the second light source 3 on the first inclined surface 14 and reflect it on the side of the main surface 1a of the light guide plate 1.

As shown in FIG. 1A, the width of the region where the second reflection prism 5 is arranged as seen from the first light source 2 side is W2p, and the first reflection prism 4 seen from the second light source 3 side. Let W4p be the width of the area where is arranged. Further, the line along the longitudinal direction of the second reflection prism 5 is L5, the line connecting the end of the light emitting portion of the first light source 2 and the center of the reflection surface of the reflection prism 5 is L2-5, and the line L5 and the line. The angle formed by L2-5 is θ_L2-5. Similarly, the line along the longitudinal direction of the first reflection prism 4 is L4, the line connecting the end of the light emitting portion of the second light source 3 and the center of the reflection surface of the reflection prism 4 is L4-4, and the line L4. Let θ_L4-4 be the angle formed by the line L4-4 and the line L4-4.

Because of this configuration, as shown in FIG. 2A, when the first light source 2 is turned on and the second light source 3 is turned off, the light 17 is emitted on the first inclined surface 14 of each first reflecting prism 4. As shown in FIG. 1B, the light is reflected and emitted from the main surface 1a of the light guide plate 1, and is scattered and displayed by the translucent portion 11.

As shown in FIG. 2B, when the second light source 3 is turned on and the first light source 2 is turned off, the light 18 is reflected by the first inclined surface 14 of each second reflecting prism 5, and the light guide plate is used. It is emitted from the main surface 1a of No. 1 and is scattered and displayed by the translucent portion 11.

Further, in the first reflecting prism 4, the longitudinal direction F4 of the first inclined surface 14 is a prism center of the second light source 3 and the first inclined surface 14 of the first reflecting prism 4, as shown in FIG. 3A. It is arranged parallel to the connecting line 19. In the second reflecting prism 5, the longitudinal direction F5 of the first inclined surface 14 connects the first light source 2 and the prism center of the first inclined surface 14 of the second reflecting prism 5, as shown in FIG. 3 (b). It is arranged parallel to 20.

The behavior of the light on the light guide plate 1 in this case will be described with reference to FIG.
4 (a) and 4 (b) show the state of light propagation when the first light source 2 is turned on and the second light source 3 is turned off.

The light 17 emitted from the first light source 2 having a width W2 narrower than the width W1 of the first side surface 1c of the light guide plate 1 enters from the first side surface 1c of the light guide plate 1 and propagates in the light guide plate 1. The light 17 reflected by the first inclined surface 14 of the first reflecting prism 4 deviates from the front surface of the light guide plate 1 but is emitted to the main surface 1a side of the light guide plate 1. Since the light 17 is scattered and diffused by the light transmitting portion 11 installed on the light guide plate 1, the light 17 can be recognized from the front. Since such a phenomenon occurs in the entire set of the first reflection prisms 4, the pattern as an aggregate can be recognized.

The light 18 when the second light source 3 is turned on and the first light source 2 is turned off enters light from the second side surface 1d of the light guide plate 1 and heads toward the first reflecting prism 4 as shown in FIG. 4 (c). .. As described above, since the longitudinal direction F4 of the first reflection prism 4 is parallel to the line 19 connecting the first reflection prism 4 and the second light source 3, the light 18 from the second light source 3 is the first. Since the light 18 is not reflected by the first inclined surface 14 of the reflecting prism 4, or even if it is reflected, only a slight angle change occurs. Therefore, even after reaching the first reflecting prism 4, the light 18 is emitted from the main surface 1a of the light guide plate 1. Do not pop out.

Similarly, the light 17 when the first light source 2 is turned on and the second light source 3 is turned off enters light from the first side surface 1c of the light guide plate 1 and heads toward the second reflecting prism 5. However, since the longitudinal direction F5 of the second reflection prism 5 is parallel to the line 19 connecting the second reflection prism 5 and the first light source 2, the light 17 from the first light source 2 is the second reflection prism 5. No light 17 is emitted from the main surface 1a of the light guide plate 1 even after reaching the second reflection prism 5, because the light 17 is not reflected by the first inclined surface 14 of the above, or even if it is reflected, only a slight angle change occurs. ..

In this way, the longitudinal directions F4 and F5 of the first and second reflecting prisms 4 and 5 are arranged so as to be parallel to the direction formed by the light source to which the prism does not correspond and the prism, which is unnecessary. It is possible to prevent the pattern from being displayed.

As shown in FIG. 5A, the first and second reflecting prisms 4 and 5 are not arranged on a straight line connecting the centers of the first and second light sources 2 and 3. As shown in FIG. 5B, when the prisms 4 and 5 are installed on a straight line connecting the light sources 2 and 3, the light from any of the light sources 2 and 3 is reflected by the first inclined surface 14. This is because the light source cannot be emitted from the light guide plate 1.

The prism shapes of the first and second reflecting prisms 4 and 5 are preferably as shown in FIGS. 6 (a) and 6 (b). FIG. 6A is a diagram showing the cross-sectional shape of the prism, and FIG. 6B is a view of the prism viewed from the side of the first inclined surface 14, and shows the shape of the prism in the length direction. θc1 and θc2 are the angles of the side surfaces (side walls) 21 and 21 on both sides of the prism.

The following relationship is necessary in order for the light directed to the first inclined surface 14 of the prism to be emitted from the main surface 1a of the light guide plate 1 and the light hitting the side surface 21 of the prism not to be emitted from the light guide plate 1.

θa <θc1
θa <θc2

In addition, the following is desirable.
θc1> 70 °
θc2> 70 °

When the angles θc1 and θc2 of the side surfaces 21 and 21 on both sides of the prism are smaller than 70 °, a component is generated in which the light hitting the side surface (side wall) 21 is emitted to the main surface 1a side of the light guide plate 1.

Further, it is desirable that the angles θc1 and θc2 of the side surfaces 21 and 21 on both sides of the prism are less than 90 °. If the angles θc1 and θc2 are 90 ° or more, there is a problem that the mold does not come off when mass production is attempted by molding, and mass production cannot be performed by molding.

Further, the angle θa is
35 ° <θa <65 °
Is preferable. When the angle θa is outside this range, the action of reflecting the light incident on the light guide plate 1 in the direction of the main surface 1a of the light guide plate 1 becomes extremely small.

The first and second reflecting prisms 4 and 5 may have a reflecting surface even if the cross section is not the triangular prism shown in FIG. 1 (c), and as shown in FIG. 7, a plurality of side surfaces 21 are provided. It may be. The cross section may be trapezoidal. Further, the reflective surface may have a slightly curved surface.

In this way, the longitudinal direction F4 of the first reflection prism 4 and the line 19 connecting the center of the second light source 3 and the center of the first reflection prism 4 are parallel, and the width W4 of the second light source 3 is guided. It is narrower than the width W3 of the second side surface 1d of the light plate 1. As a result, the amount of light obliquely incident on the first reflection prism 4 from the second light source 3 is extremely reduced, and the problem that the unnecessary character "A" appears faint while the character "B" is displayed is avoided. And the letter "B" can be displayed clearly.

Further, the longitudinal direction F5 of the second reflection prism 5 and the line 20 connecting the center of the first light source 2 and the center of the second reflection prism 5 are parallel, and the width W2 of the first light source 2 is the light guide plate. It is narrower than the width W1 of the first side surface 1c of 1. As a result, the amount of light obliquely incident on the second reflection prism 5 from the first light source 2 is extremely reduced, and the problem that the unnecessary character "B" appears faint while the character "A" is displayed is avoided. And the letter "A" can be displayed clearly.

The width W2 of the first light source 2 is narrower than the width W1 of the first side surface 1c of the light guide plate 1, and the width W4 of the second light source 3 is narrower than the width W3 of the first side surface 1d of the light guide plate 1. specifically,
W1 / 2 ≧ W2
W3 / 2 ≧ W4
Is preferable. If the width W2 is larger than W1 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up. If the width W4 is larger than W3 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up.

Further, it is desirable that the size of the light source is limited with respect to the size of the prism display area. Specifically, the width W2 of the first light source 2, the width W2p of the region where the second reflection prism 5 is arranged, the width W4 of the second light source 4, and the first reflection prism 4 are arranged. It is desirable that the following relationship holds with the width W4p of the region.
W2 / W2p ≤ 1/4
W4 / W4p ≤ 1/4

If the width of the light source is large, the light emitted from the end of the light source will be obliquely incident on the reflecting prism of the side that you do not want to display, and this light will be emitted from the light guide plate, resulting in unnecessary patterns. This is because it will be displayed.

Further, it is desirable that the angle between the line segment connecting the end of the light source and the reflecting prism that is not desired to be displayed and the long side of the reflecting prism is limited. Specifically, the line along the longitudinal direction of the second reflection prism 5 is L5, and the line connecting the end of the light emitting portion of the first light source 2 and the center of the reflection surface of the reflection prism 5 is L2-5. Let θ_L2-5 be the angle formed by L5 and the line L2-5. Similarly, the line along the longitudinal direction of the first reflection prism 4 is L4, the line connecting the end of the light emitting portion of the second light source 3 and the center of the reflection surface of the reflection prism 4 is L4-4, and the line L4. When the angle formed by the line L4-4 is θ_L4-4, it is desirable that the following relationship holds.
｜ θ_L2-5 ｜ ≦ 30 °
｜ θ_L4-4 ｜ ≦ 30 °

This is because if these angles are large, the light from the light source that is not desired to be displayed is emitted from the light guide plate, and an unnecessary pattern is displayed.

(Embodiment 2)
FIG. 8 shows a prism arrangement in the display device according to the second embodiment of the present invention when there are a plurality of light sources for displaying each pattern.

The first light source 2 is composed of light sources 2a and 2b arranged close to each other along the first side surface 1c of the light guide plate 1. The width W2 in the direction of the first side surface 1c of the first light source 2 composed of the light sources 2a and 2b is narrower than the width W1 of the first side surface 1c of the light guide plate 1. The second light source 3 is composed of light sources 3a and 3b arranged close to each other along the second side surface 1d of the light guide plate 1. The width W4 of the second light source 3 composed of the light sources 3a and 3b in the second side surface 1d direction is narrower than the width W3 of the second side surface 1d of the light guide plate 1.

As shown in FIG. 8A, the longitudinal direction F4 of the first reflection prism 4 is parallel to the line 19 connecting the center 13 of the second light source 3 between the light sources 3a and 3b and the center of the first reflection prism 4. It is configured in. As shown in FIG. 8B, the longitudinal direction F5 of the second reflecting prism 5 is the center 12 of the first light source 2 between the light sources 2a and 2b and the center of the first inclined surface 14 of the second reflecting prism 5. It is configured in parallel with the line 20 connecting the above. Others are the same as those in the first embodiment.

The width W2 of the light sources 2a and 2b is narrower than the width W1 of the first side surface 1c of the light guide plate 1, and the width W4 of the light sources 3a and 3b is narrower than the width W3 of the first side surface 1d of the light guide plate 1. specifically,
W1 / 2 ≧ W2
W3 / 2 ≧ W4
Is preferable. If the width W2 is larger than W1 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up. If the W width 4 is larger than W3 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up.

Since it is configured in this way, it is possible to realize a display device that does not display an unnecessary pattern as described in the first embodiment.

As described in the first embodiment, it is desirable that the size of the light source is limited with respect to the size of the prism display area. Further, it is desirable that the angle between the line connecting the end of the light source and the reflecting prism that is not to be displayed and the long side (side along the longitudinal direction) of the reflecting prism is limited.

(Embodiment 3)
FIG. 9 shows the third embodiment of the present invention.

The light guide plate 1 of each of the above embodiments has a flat plate shape, and light from the first and second light sources 2 and 3 is directly incident from the first and second side surfaces 1c and 1d. As shown in FIG. 9, the light guide plate 1 is different in that the light from the first and second light sources 2 and 3 is directly incident through the light input portions 22a and 22b.

The light guide plate 1 has three-dimensionally curved light input portions 22a and 22b. Then, the light of the light sources 2 and 3 is configured to enter the main body portion of the light guide plate 1 from the tips (widths W5a and W6a) of the light input portions 22a and 22b.

In this case, it can be considered that the light guide plate 1 has a virtual light source. The width W5b of the base portion of the light entering portion 22a of the light guide plate 1 is narrower than the width W4 of the first side surface 1c of the light guide plate 1. The width W6b of the base portion of the light entering portion 22b of the light guide plate 1 is narrower than the width W3 of the second side surface 1d of the light guide plate 1. Others are the same as those of the first and second embodiments.

Therefore, the longitudinal direction F4 of the first reflection prism 4 is configured to be parallel to the line connecting the center 23 of the base portion of the light input portion 22b of the light guide plate 1 and the center of the first reflection prism 4. The first embodiment is configured such that the longitudinal direction F5 of the reflection prism 5 is parallel to the line connecting the center 24 of the base portion of the light input portion 22a of the light guide plate 1 and the center of the second reflection prism 5. It is possible to realize a display device that does not display unnecessary patterns as described in.

Specifically, the width W5b is narrower than the width W4, and the width W6b is narrower than the width W3.
W4 / 2 ≧ W5b
W3 / 2 ≧ W6b
Is preferable. If the width W5b is larger than W4 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up. If the width W6b is larger than W3 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 to appear as an unnecessary pattern. It ends up.

As described in the first embodiment, it is desirable that the size of the light source is limited with respect to the size of the prism display area. Further, it is desirable that the angle between the line connecting the end of the light source and the reflecting prism that is not to be displayed and the long side (side along the longitudinal direction) of the reflecting prism is limited.

(Embodiment 4)
10 and 11 show Embodiment 4 of the present invention.

In each of the above embodiments, the light from the first light source 2 is incident on the first side surface 1c of the light guide plate 1, and the light from the second light source 3 is directly from the second side surface 1d different from the first side surface 1c. However, in the fourth embodiment, as shown in FIGS. 10 and 11, the light from the first and second light sources 2 and 3 is incident on the first side surface 1c of the light guide plate 1. Only the points are different from the first to third embodiments, and the others are the same.

That is, the first and second light sources 2 and 3 separated from each other are arranged along the first side surface 1c of the light guide plate 1, and the light from the first and second light sources 2 and 3 is directed to the first side surface of the light guide plate 1. It is incident on 1c. The widths W2 and W4 of the first and second light sources 2 and 3 are narrower than the width W1 of the first side surface 1c, respectively.

In the first and second reflecting prisms 4 and 5, the longitudinal directions F4 and F5 of the prisms are parallel to the direction formed by the light source to which the prism does not correspond and the prism, as in each of the above-described embodiments. It is formed like this. FIG. 11A shows a display state in which the light from the first light source 2 is reflected by the first inclined surface 14 of the first reflecting prism 4. FIG. 11B shows a display state in which the light from the second light source 2 is reflected by the first inclined surface 14 of the second reflecting prism 5.

The first reflection prism 4 is formed so that the longitudinal direction F4 of the first reflection prism 4 and the line 19 connecting the center of the second light source 3 and the center of the first reflection prism 4 are parallel to each other. The second reflection prism 5 is formed so that the longitudinal direction F5 of the second reflection prism 5 and the line 20 connecting the center of the first light source 2 and the center of the second reflection prism 5 are parallel to each other.

Moreover, since the width W4 of the second light source 3 is narrower than the width W1 of the first surface 1c of the light guide plate 1, very little light is obliquely incident on the first reflection prism 4 from the second light source 3, and the characters "B". It is possible to avoid the problem that the character "A" of an unnecessary pattern appears faint while displaying "", and the character "B" can be displayed clearly. Similarly, it is possible to avoid the problem that the character "B" having an unnecessary pattern appears faint while displaying the character "A", and the character "A" can be displayed clearly.

Since it is configured in this way, it is possible to realize a display device that does not display an unnecessary pattern as described in the first embodiment.

In the first and second reflecting prisms 4 and 5 of each of the above embodiments, the longitudinal directions F4 and F5 of the prism are formed in parallel with the direction formed by the light source to which the prism does not correspond and the prism. However, the first and second reflecting prisms 4 and 5 may be formed so that the longitudinal directions F4 and F5 of the prisms are substantially parallel to the direction formed by the light source to which the prism does not correspond and the prism. Specifically, in the first and second reflecting prisms 4 and 5, the angle between the longitudinal directions F4 and F5 of the prism and the direction formed by the light source to which the prism does not correspond and the prism is 30 ° or less. Just do it. This is because when the temperature is 30 ° or more, a component is generated in which the light from the uncorresponding light source is reflected from the first inclined surface of the prism and then emitted from the light guide plate.

In both the first and second reflecting prisms 4 and 5 of the above embodiments, the longitudinal directions F4 and F5 of the prism are parallel to or substantially parallel to the direction formed by the light source to which the prism does not correspond and the prism. Since it is formed, the pattern displayed by the second reflecting prism 5 is not displayed faintly in the display state of the pattern displayed by the first reflecting prism 4, and the pattern displayed by the second reflecting prism 5 is not displayed lightly. Even in the display state, the pattern displayed by the first reflecting prism 4 was not displayed faintly, but the longitudinal direction of one of the first, second, and second reflecting prisms 4 and 5 does not correspond to the prism. By forming it parallel to or substantially parallel to the direction formed by one of the light sources and its prism, the unnecessary pattern is thin in the display state of the pattern displayed by the other prisms of the first and second reflecting prisms 4 and 5. Although it is displayed, only in the case of the display state of the pattern displayed by the one prism, it is possible to make a good display state in which the unnecessary pattern is not displayed.

It should be noted that the widths W2 and W4 are narrower than the width W1.
specifically,
W1 / 2 ≧ W2
W1 / 2 ≧ W4
Is preferable. If the widths W2 and W4 are larger than W1 / 2, even if the prism is directed toward the center, the light from the light source located near the end of the light source group is reflected by the prism and emitted from the light guide plate 1 as an unnecessary pattern. I can see it.

As described in the first embodiment, it is desirable that the size of the light source is limited with respect to the size of the prism display area. Further, it is desirable that the angle between the line segment connecting the end of the light source and the reflecting prism that is not desired to be displayed and the long side of the reflecting prism is limited.

The present invention contributes to improving the quality of a display device used for, for example, electric devices and devices for home, industrial, and in-vehicle use, or a display unit of a switch having an input function.

1 Light guide plate 2, 3 First and second light sources 1a Main surface of light guide plate 1 1b Bottom surface of light guide plate 1 1c, 1d First and second side surfaces of light guide plate 1 4 First reflection prism 5 Second reflection prism 11 Transparent Optical unit 14 First inclined surface of the first and second reflecting prisms 4 and 5 15 Second inclined surface of the first and second reflecting prisms 4 and 5 19 Connecting the second light source 3 and the prism center of the first reflecting prism 4. Line 20 Line connecting the center of the prism of the first light source 2 and the second reflecting prism 5 W1 Width of the first side surface 1c of the light guide plate 1 W2 Width of the first light source 2 W3 Width of the second side surface 1d of the light guide plate 1 W4 Second Width of light source 3 F4 Longitudinal direction of first reflecting prism 4 F5 Longitudinal direction of second reflecting prism 5

Claims (13)

It has a main surface, a bottom surface facing the main surface, and first and second side surfaces formed between the main surface and the bottom surface, and light incident on the bottom surface from the first side surface. A first reflecting prism having an inclined surface for reflecting the light toward the main surface side, and a second reflecting surface having an inclined surface for reflecting light incident from the second side surface toward the main surface side. The light guide plate on which the reflection prism is formed,
A first light source that incidents light on the first side surface of the light guide plate,
A second light source that incidents light on the second side surface of the light guide plate, and
A translucent portion arranged on the side of the main surface of the light guide plate to transmit and scatter the light emitted from the main surface.
Is provided,
The width of the second light source is narrower than the width of the region where a plurality of the first reflection prisms are arranged as seen from the second light source side .
In the region where a plurality of the first reflecting prisms are arranged, the longitudinal direction of the inclined surface of the first reflecting prism is parallel to or substantially equal to the line connecting the second light source and the inclined surface of the first reflecting prism. Parallel and
In the region where a plurality of the first reflecting prisms are arranged, the longitudinal direction of the inclined surface of at least a part of the first reflecting prisms is the direction of the light rays incident on the first reflecting prism from the first light source. A display device that is tilted from an orthogonal direction . The width of the first light source is narrower than the width of the region where a plurality of the second reflection prisms are arranged as seen from the first light source side.
In the region where a plurality of the second reflecting prisms are arranged, the longitudinal direction of the inclined surface of the second reflecting prism is parallel to or substantially equal to the line connecting the first light source and the inclined surface of the second reflecting prism. Parallel and
In the region where a plurality of the second reflecting prisms are arranged, the longitudinal direction of the inclined surface of at least a part of the second reflecting prisms is the direction of the light rays incident on the second reflecting prism from the second light source. The display device according to claim 1, which is inclined from an orthogonal direction . The display device according to claim 2, wherein the width of the first light source is narrower than the width of the first side surface of the light guide plate, and the width of the second light source is narrower than the width of the second side surface of the light guide plate. When the width of the first side surface of the light guide plate is W1, the width of the first light source is W2, the width of the second side surface of the light guide plate is W3, and the width of the second light source is W4.
(W1) / 2 ≧ W2
(W3) / 2 ≧ W4
The display device according to claim 3. The width of the region where a plurality of reflecting prisms are arranged is Wp, the width of the light source corresponding to the region where a plurality of reflecting prisms are arranged is Wo, the longitudinal direction of the inclined surface of the reflecting prism, and the reflecting prism. Wo / Wp ≦ 1/4, where θp is the angle formed by the direction of the line segment connecting the center point of the inclined surface and the end point of the light emitting portion of the light source that does not correspond to the reflection prism. The display device according to any one of claims 1 to 4, wherein the display device satisfies | θp | ≦ 30 °. The cross-sectional shape of the first and second reflecting prisms is triangular or trapezoidal, the angle between the surface reflecting light and the bottom surface of the light guide plate is θa, and the side surfaces of the first and second reflecting prisms and the above. The display device according to any one of claims 1 to 5, wherein when the angle with the bottom surface of the light guide plate is θc, θa <θc is satisfied. The display device according to claim 6, wherein the angle θc satisfies θc <90 °. The display device according to claim 6, wherein the angle θa satisfies 35 ° <θa <65 °. The substantially parallel is characterized by being 30 ° or less.
The display device according to any one of claims 1 to 5. The display device according to any one of claims 1 to 5, wherein the first side surface of the light guide plate and the second side surface adjacent thereto are orthogonal to each other. The display device according to any one of claims 1 to 5, wherein the first and second reflecting prisms are not installed on the line connecting the first light source and the second light source in the light guide plate. .. It has a main surface, a bottom surface facing the main surface, and a plurality of side surfaces formed between the main surface and the bottom surface, and light incident on the bottom surface from the side surface is directed to the main surface. A light guide plate with a reflecting prism having an inclined surface that reflects toward the side, and a light guide plate with a reflecting prism.
The first and second light sources that incident light at different angles on one side surface of the light guide plate,
A translucent portion arranged on the side of the main surface of the light guide plate to transmit and scatter the light emitted from the main surface.
Is provided,
The reflection prism of the light guide plate is
A first reflecting prism that reflects light incident from the one light source on the inclined surface toward the main surface of the light guide plate.
A second reflecting prism that reflects the light incident from the two light sources toward the main surface side of the light guide plate on the inclined surface, and
Have,
A display device in which the longitudinal direction of the inclined surface of the first reflecting prism is parallel or substantially parallel to the line connecting the second light source and the inclined surface of the first reflecting prism. 12. The display device according to claim 12, wherein the longitudinal direction of the inclined surface of the second reflecting prism is parallel or substantially parallel to the line connecting the first light source and the inclined surface of the second reflecting prism.

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