JPS636769Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an illumination display device that displays characters, patterns, etc. on automobile instrument panels, etc. Specifically, it guides light from a single light source to clearly illuminate the display board. This invention relates to a light guide plate.

Conventionally, in display devices such as instrument panels, a light guide plate made of a translucent material is interposed between a housing and a display plate, and the light emitted from a light source is directed through the light guide plate. It is known that the display panel is uniformly illuminated by dispersing the light. In order to guide light to parts of the display board that are far from the light source, this light guiding board has a reflective surface on the back side that is sloped so that the thickness of the board gradually decreases as it moves away from the light source. is normal (see Figure 8).

However, with the recent demand for smaller and thinner areas around instrument panels, the above-mentioned type of light guide plate has an inclined surface, which means that the light guide plate itself has become thicker, and the housing that receives it has a deeper depth. This had no choice but to do so, and it did not meet the above requirements.

SUMMARY OF THE INVENTION In order to meet the above-mentioned demands, an object of the present invention is to provide a light guide plate for an illumination display device that can be made as thin as possible and that can effectively irradiate the display plate with light emitted from a light source.

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 1 is the heater control panel 2
A storage groove 1A for storing the light guide plate 4 is formed on the front surface of the housing, and a single small light source 3 is protruded from the center of the housing on the right side in the figure.

Reference numeral 2 denotes a heater control panel (also referred to as a display board) fitted to the front surface of the housing 1, and display sections H to H consisting of letters, patterns, etc. for indicators of heater control are arranged on the surface of the panel. . The display parts H to H are designed to exhibit good translucency, but the other parts are
It is made non-transparent so that it stands out clearly.

The light guide plate 4, which is housed in the storage groove 1A and interposed between the display plate 2 and the display plate 2, is made of a material with good translucency (in this example, made of transparent acrylic resin),
In this example, a pair of long arms 4L, 4L and a pair of short arms 4S, each having a substantially trapezoidal cross section, are used to transmit light through each of the display sections H to H from the back side of the display board 2. 4S and is generally formed into an H-shape. Further, the connecting portion 5 between the long arms 4L, 4L and the short arms 4S, 4S of the light guide plate 4 is formed into a substantially pair of upper and lower wings, and the light source 3 is located in the center of the connecting portion 5.
A storage recess 6 is provided in a penetrating manner. Note that the external shape of the connecting portion 5 is formed in such a shape that the irradiated light from the light source 3 can be well guided to each arm portion 4L, 4S.

Furthermore, three stepped surfaces D1 to D3 shown in the figure are provided on the surface of the connecting portion 5 so as to be concentric with the storage recess 6, and these stepped surfaces D1 to D3 become stepped as they move away from the center. , the irradiated light from the light source 3 can be substantially totally reflected and can be well guided to each arm portion 4L, 4S.

Now, the light guide plate 4 has a predetermined range near the light source 3 (A range AB shown in FIG. 3) with its upper and lower surfaces substantially parallel to each other, and from the parallel portion,
The lower surface side is sloped upward and becomes thinner toward the end.

Furthermore, in each of the arm parts 4L and 4S, an irradiation part is provided in a range corresponding to each display part H to H of the display board 2, and in this example, this irradiation part is provided on the back side in the longitudinal direction. Two types of areas are used: an area with a plurality of V grooves carved along the line (hereinafter referred to as the V groove part 7A) and an area with a satin pattern (hereinafter referred to as the satin area 7B). In order to achieve substantially uniform irradiation by considering the quality of the light transmittance of ~H, for example, they are used selectively as shown in the figure.

Each of the satin-finished portions 7B has a satin-pattern pattern unevenness treatment applied to the front and back surfaces of the light guide plate 4 in substantially equal areas, and the treatment is relatively rough on the front side, and the surface is exposed to light. The reflectance is higher than the transmittance of light to the surface side. On the other hand, since the treatment on the back side has extremely fine irregularities compared to the front side, the irradiated light is scattered over this area, and the light transmittance to the front side can be increased by the scattered light. .

In other words, when the front and back surfaces of the light guide plate 4 are parallel, the irradiated light tends to repeat regular reflection as shown in Figure 5 and become trapped inside, but by applying the satin pattern, the irradiated light can be As shown in FIG. 6, the light is scattered by diffuse reflection on the back side and is transmitted well to the front side, so that the opposing display section H can be clearly illuminated.

Incidentally, the satin pattern is applied as follows, but this processing method is outside the scope of the present invention.

First, the surface of the mold K to be treated is shown in FIG.
As shown in b and c, fine grains T to T of a predetermined density are photoprinted, and then, by chemical treatment, the fine grains T to T are left and other parts are eroded to form the recesses O to O.
(see FIG. 7b), and then further by removing the fine grains T through another chemical treatment, a predetermined satin pattern is applied. A desired molded product can be obtained by pouring resin into the cavity of the mold with the satin pattern by injection molding.

In order to attach the light guide plate 4 to the housing 1, insertion protrusions 8, 8 are integrally formed at the ends of both short arm parts 4S, 4S, respectively, and extend therefrom.
It can be removably inserted into engagement holes 9, 9 provided through the right side surface of the housing 1 in the drawing. Furthermore, abutting pieces 10, 10 are integrally bent toward the front at the tips of the long arms 4L, 4L, and can abut against the inner surface of the housing 1 on the left side in the figure after installation. Further, a connecting piece 11 is horizontally suspended approximately at the center of both long arms 4L, 4L, and is removably engaged with a locking claw piece 12 protruding from the front surface of the housing 1. Lifting is prevented.

Subsequently, the operation and effect of this example configured as described above will be specifically explained.

When light source 3 is turned on by the light switch,
Most of the irradiation light from the light source 3 first enters the storage recess 6.
The light is transmitted through the light guide plate 4 into the interior of the light guiding plate 4, and is totally reflected by each of the step surfaces D1 to D3.
Enters 4S. When traveling through the parallel portion of the light guide plate 4 (range AB in the figure), the irradiated light travels toward the tip side while repeating regular reflections on both the front and back surfaces, but during this time, as described above, Regular reflexes are disturbed.

That is, as mentioned above, the irradiated light is reflected at a high rate by the "coarse" satin pattern on the front side, but is scattered by the "dense" satin pattern on the back side, and part of the scattered light is reflected on the front side. Since light whose incident angle with respect to the outside world is less than the critical angle can be transmitted through the surface, the corresponding display portion H can be irradiated with the required brightness even in this parallel portion without being trapped inside.

Although relatively little light is transmitted to the outside from the satin-finished portion 7B in this parallel portion, it is necessary to adjust the distance from the light source 3 and the display method of the corresponding display portion H (for example, by adjusting the light transmittance). The use of high colors) provides sufficient display illumination. Moreover, if the V-groove portion 7A is provided in this parallel portion, even if the corresponding display portion H has a description with low translucency, it can be irradiated almost uniformly as described above.

The irradiation light passes through the parallel part, and then each arm part 4
When proceeding inside L and 4S toward the distal end, the light guide plate 4
Since the back side of the light source 3 is inclined upward toward the tip, the reflected light and the straight forward light can be focused by the inclined surface, so that the attenuation due to the distance from the light source 3 can be sufficiently compensated for. Further, by providing the V-groove portion 7A and the matte finish portion 7B also in this inclined portion, it is possible to prevent reflected light from being trapped inside the light guide plate 4, and to appropriately arrange both portions 7A and 7B. Therefore, uniform brightness can be obtained on the display section H.

As described above, the light guide plate 4 of this example has a "coarse" satin pattern on the front side and a "dense" satin pattern on the back side in the parallel part near the light source 3, so that the parallel part It is possible to rationally prevent the irradiation light from being concentrated in the area. Therefore, unlike the conventional case, it is not necessary to provide an inclination to the entire back surface, so even when the display section H is present near the light source, the light guide plate 4 can be made as thin as possible, and accordingly, The housing 1 can also be made as thin as possible.

Note that the arrangement of the matte finish portion 7B and the V-groove portion 7A in the light guide plate 4 is determined as appropriate due to differences in the notation methods of the corresponding display portions H (for example, differences in colors such as red and blue), etc. , and the range where it is provided and the display section H corresponding to it.
Of course, the characters, patterns, etc. are not limited to those shown.

As described in detail above, the gist of the present invention is to provide a satin pattern on both the front and back sides of the light guide plate at appropriate locations, and to form the satin pattern more densely on the front side than on the front side. Even if both the front and back surfaces near the light source are formed in parallel, light can be transmitted well to the front side. Therefore, the light guide plate itself can be made as thin as possible, and the housing that houses it can also be made thinner.

[Brief explanation of drawings]

The drawings show one embodiment of the invention,
Figure 1 is an exploded perspective view of the vicinity of the heater control panel, Figure 2 is a front view showing the mounting position of the light guide plate relative to the heater control panel, Figure 3 is a front cross-sectional view of the light guide plate, and Figures 4 to 6. The figure is an explanatory diagram explaining the optical path of the irradiated light from the light source, Figure 7a, b,
FIG. 8c is an explanatory view showing a satin pattern processing method, and FIG. 8 is a front sectional view showing a conventional light guide plate. 1...Housing, 2...Display board, 3...Light source, 4...
Light guide plate, 7B...Nashiji part.

Claims (1)

[Scope of utility model registration request] Interposed between a display board having a translucent display portion and a housing that holds the display board on the front thereof, the display board is provided with a light source for substantially uniformly irradiating the display board with light from a single light source. An illumination display characterized in that a light guide plate made of a translucent material is provided with a fine satin pattern on both the front and back surfaces at appropriate locations, and the satin pattern on the back side is formed in a finer shape than on the front side. Light guiding plate in the device.