JP6118171B2 - Light guide plate for instrument - Google Patents

Description

  The present invention relates to an instrument light guide plate.

In-vehicle meters (water temperature meters, fuel meters) and the like are generally provided in automobile combination meters. For example, a water temperature meter indicates the cooling water temperature in the engine of the automobile by rotating a pointer along the surface of the dial. And these vehicle-mounted instruments are illuminated by a design portion such as a scale formed on the dial plate by an illumination structure using an instrument light guide plate, thereby improving visibility.
For example, a light guide plate (light guide plate) in an automobile combination meter disclosed in Patent Document 1 guides incident light from a plurality of light sources toward a through hole portion, and emits a light emission indicator by the introduced light.
Moreover, the light guide plate in the vehicle-mounted instrument of patent document 2 is provided in the plane each part of the shape corresponding only to the range in which the shift stage design (design part) was formed, and the character other than the shift stage design. And a daylighting unit for daylighting direct light from a dial design light source for illuminating the board design (design part).

  By the way, in a water thermometer including a pointer shaft that rotates the pointer, the light guide plate may be formed in a shape that avoids the position of the pointer shaft. As shown in FIG. 5, in such a thermometer, a prism 503 (light guide plate) is arranged under a dial plate (not shown) having a through hole for a pointer shaft. In the prism 503, the flat surface portion 505 is formed in a shape that avoids the through-hole 501 of the main body case 507 through which the pointer shaft passes. The prism 503 is provided with a plurality of positioning portions 509 for the dial and a plurality of locking portions 511 for fixing to the main body case 507. A plurality of daylighting units (first daylighting unit 513 and second daylighting unit 515) are formed in the prism 503, and the first daylighting unit 513 and the second daylighting unit 515 are arranged in a lower main body case 507. The first light source 517 and the second light source 519 are opposed to each other.

  When the first light source 517 and the second light source 519 are driven, the light from the first light source 517 and the second light source 519 is correspondingly provided in the prism 503 with the first and second light collecting units 513 and 515. More incident on the plane portion 505. The light introduced from the first daylighting unit 513 and the second daylighting unit 515 is emitted from the plane portion 505 while propagating through the plane portion 505, and illuminates the upper dial.

JP 2003-97980 A JP 2005-331456 A

  However, depending on the illumination structure such as an in-vehicle instrument (water temperature gauge, fuel gauge), the position of the light source and the shape of the light guide plate cannot always be ideally arranged and shaped due to restrictions such as the design of the dial. Therefore, in the prism 503 as described above, a light concentration portion 521 that is a portion where the light from the first light source 517 and the second light source 519 intersect and concentrate is generated, and such light concentration portion 521 has uneven luminance. There was a problem of causing.

  This invention is made | formed in view of the said condition, The objective is to provide the light guide plate for instruments which reduces a brightness nonuniformity and provides favorable illumination.

The above object of the present invention is achieved by the following configuration.
(1) An instrumental light guide plate disposed under a design portion formed on a dial plate, a plane portion having a shape corresponding to a range in which the design portion is formed, and an optical axis of light from a light source Are provided at a light concentration portion of the plane portion where the incident light from the plurality of daylighting portions and the plurality of daylighting portions intersect and gather, and diffusely reflect the incident light. An instrument light guide plate comprising: a brightness adjusting hole having a reflective surface.

  According to the instrument light guide plate having the configuration (1), when a plurality of light sources are driven, light from each light source is incident on the plane portion from a plurality of corresponding daylighting units. The light introduced from each daylighting unit propagates through the plane part. Here, when a light beam propagating in parallel with the plane part is considered, the optical axes of the light beams from the respective daylighting units intersect in the plane part. A brightness adjusting hole is formed in the light concentration portion of the flat surface where incident light from each daylighting portion gathers. The brightness adjusting hole is formed in the thickness direction of the flat portion, thereby forming a boundary surface with the outside (air) in the flat portion. The light propagating in the plane part is a reflecting surface at this boundary surface, and part of the light having a small incident angle is refracted and transmitted, and part of the light having an incident angle larger than the total reflection angle is again into the plane part. Reflected back. That is, since the incident light from the plurality of daylighting portions is diffusely reflected by the luminance adjusting hole, the luminance unevenness can be reduced by reducing the amount of light at the light concentrating portion in the plane portion where the incident light intersects and gathers. . In addition, by changing the size, shape, and number of the brightness adjusting holes, the size, angle, position, and number of the reflecting surfaces can be set as appropriate. As a result, it is easy to reduce luminance unevenness even for a light source with particularly strong directivity.

(2) The instrument light guide plate having the configuration of (1), wherein the flat portion is formed in a shape that bypasses a pointer shaft that rotates the pointer.

  According to the instrument light guide plate having the configuration (2), there is no need to provide a through hole for inserting the pointer shaft in the flat portion, and injection molding with a synthetic resin material becomes easy (weld line during injection molding). Is less likely to occur).

(3) An in-vehicle instrument characterized in that the instrument light guide plate having the configuration (1) or (2) is used.

  According to the in-vehicle instrument having the configuration of (3) above, even in an in-vehicle instrument having an instrument light guide plate having a complicated shape in order to avoid the pointer shaft, uneven brightness is reduced and good visibility is achieved. can get.

  According to the instrument light guide plate of the present invention, it is possible to reduce luminance unevenness and obtain good illumination.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

It is a front view of the meter for vehicles in which the thermometer provided with the light guide plate for instruments concerning one embodiment of the present invention was attached. It is a perspective view of the light guide plate for instruments shown in FIG. (A) is a top view of the instrument light-guide plate shown in FIG. 2, (b) is a principal part expansion perspective view. It is the principal part enlarged front view which abbreviate | omitted the dial of the vehicle-mounted instrument provided with the light guide plate for instruments shown in FIG. It is a principal part enlarged front view which abbreviate | omitted the dial of the vehicle-mounted instrument provided with the conventional light guide plate for instruments.

Embodiments according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the prism 11 that is a light guide plate for an instrument according to an embodiment of the present invention can be suitably used for a water temperature meter 25 that is attached to a combination meter 13 that is a meter for an automobile. The combination meter 13 is attached to an instrument panel (not shown) of the vehicle, for example. The combination meter 13 includes a speedometer 15 for instructing the vehicle speed, a liquid crystal display device 19 using a liquid crystal plate (LCD) 17, a turn L display unit 21, a turn R display unit 23, and an engine coolant temperature. Water temperature meter 25 to display, fuel meter 27, shift indicator 29, warning lamp 31 such as a seat belt non-wearing warning light, a high beam indicator light, a charging warning light, a half door warning light, a fog lamp indicator light, an engine warning light, and the like , Is provided.

  These speedometer 15, liquid crystal display device 19, turn L display section 21, turn R display section 23, water temperature gauge 25, fuel gauge 27, shift indicator 29, and warning lamp 31 are the main body case 33 of the combination meter 13 (see FIG. 4). ). A facing 35 is attached to the front surface of the main body case 33, and the facing 35 hides the wiring board 37, the meter driving unit, and the like housed in the main body case 33. A front glass is attached to the front side of the main body case 33.

  The prism 11 according to the present embodiment is provided in the water temperature gauge 25. The water temperature gauge 25 has a dial plate 43 (see FIG. 1) in which a through hole of the pointer shaft 39 is formed. The dial plate 43 is made of a transparent or translucent material that transmits visible light, and has a scale 45 or the like as a design portion on the surface. A pointer shaft 39 is inserted into the through-hole 41 (see FIG. 4) of the main body case 33, and the pointer shaft 39 rotated by a driving unit (not shown) rotates a pointer 47 provided at the tip to turn the scale 45. Point to.

The prism 11 is provided in the main body case 33 below the dial plate 43 and is disposed under the design portion formed on the dial plate 43.
As shown in FIG. 2, the prism 11 has a flat surface portion 49 having a shape corresponding to a range where the design portion is formed. The flat portion 49 is formed in a shape that avoids the through hole 41 of the main body case 33. That is, the flat portion 49 is formed in a shape that bypasses the pointer shaft 39 that rotates the pointer 47. Further, the prism 11 is provided with a plurality of positioning portions 51 for the dial plate 43 and a plurality of locking portions 53 for fixing to the main body case 33 (two each in this embodiment).

  As shown in FIGS. 2 and 3A, the prism 11 of the present embodiment is formed with a first daylighting unit 55 and a second daylighting unit 57, which are a plurality of daylighting units. The first daylighting unit 55 and the second daylighting unit 57 have a shape that is bent so that the tips hang from the flat surface part 49. A wiring board 37 fixed to the main body case 33 is disposed below the prism 11. A first light source 59 and a second light source 61 that are a plurality of light sources are mounted on the wiring board 37. In the present embodiment, the first light source 59 and the second light source 61 are LED (Light Emitting Diode) light sources. The first light source 59 is disposed opposite to the first daylighting unit 55, and the second light source 61 is disposed opposite to the second daylighting unit 57. In other words, the first daylighting unit 55 and the second daylighting unit 57, which are a plurality of daylighting units, are arranged such that the optical axes of the light from the first light source 59 and the second light source 61 intersect in the plane portion 49. .

  Here, in the flat portion 49, a portion where incident light from the first daylighting portion 55 and the second daylighting portion 57 intersect and gather is a light concentration portion 63 (see FIG. 4). The light concentration portion 63 is provided with a luminance adjusting hole 65. As shown in FIG. 3B, the brightness adjusting hole 65 of the present embodiment has a plurality of reflecting surfaces 67 that diffusely reflect incident light. In the illustrated example, the luminance adjusting hole 65 is formed in a substantially parallelogram, but the shape of the luminance adjusting hole 65 is not limited to this.

Next, the operation of the prism 11 having the above configuration will be described.
According to the prism 11 according to the present embodiment, when the first light source 59 and the second light source 61 are driven, the light from the first light source 59 and the second light source 61 are respectively provided correspondingly. The light is incident on the plane portion 49 from the daylighting unit 55 and the second daylighting unit 57. The light introduced from the first daylighting unit 55 and the second daylighting unit 57 propagates through the plane part 49. The light propagating through the flat portion 49 is emitted from the light emitting surface when the incident angle is smaller than a predetermined incident angle with respect to the light emitting surface on the upper surface facing the dial plate 43. The light emitted from the light exit surface becomes illumination light and illuminates the dial 43 through transmission.

Here, when a light beam propagating in parallel with the flat surface portion 49 is considered, the optical axes of the light beams from the first and second light collecting portions 55 and 57 intersect in the flat surface portion 49. A luminance adjusting hole 65 is formed in the light concentration portion 63 of the flat surface portion 49 where incident light from the first and second daylighting portions 55 and 57 gathers.
The brightness adjusting hole 65 is formed in the thickness direction of the flat portion 49, thereby forming a boundary surface with the outside (air) in the flat portion 49. The light propagating in the plane portion 49 becomes the reflecting surface 67 at this boundary surface, and part of the light having a small incident angle is refracted and transmitted, and part of the light having the incident angle larger than the total reflection angle is again transmitted. It is reflected back into the plane part 49. That is, since the plurality of incident lights from the first daylighting unit 55 and the second daylighting unit 57 are diffusely reflected by the brightness adjusting hole 65, the light concentration portion in the plane portion 49 where the plurality of incident lights intersect and gather. Luminance unevenness can be reduced by reducing the amount of light 63.

In addition, the size, the angle, the position, and the number of the reflecting surface 67 can be appropriately set by changing the size, shape, and number of the luminance adjustment holes 65 of the present embodiment. As a result, it is easy to reduce luminance unevenness even for LED light sources with particularly high directivity.
Further, according to the prism 11 of the present embodiment, it is not necessary to provide a through hole for inserting the pointer shaft 39 in the flat portion 49. Therefore, a weld line at the time of injection molding hardly occurs, and injection molding of the prism 11 with a synthetic resin material becomes easy.

  In addition, the water thermometer 25 using the prism 11 of the present embodiment includes the prism 11 having a complicated shape in order to avoid the pointer shaft 39. However, as described above, luminance unevenness is reduced and good visibility is achieved. Can be obtained.

Therefore, according to the prism 11 according to the present embodiment, luminance unevenness can be reduced and good illumination can be obtained.
In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

11 ... Prism (light guide plate for instrument)
25 ... Water thermometer (In-vehicle instrument)
39 ... Pointer shaft 43 ... Dial 45 ... Scale (design part)
47 ... pointer 49 ... flat part 55 ... first daylighting part (daylighting part)
57 ... 2nd lighting part (lighting part)
59 ... 1st light source (light source)
61 ... Second light source (light source)
63 ... Light concentration part 65 ... Luminance adjustment hole 67 ... Reflecting surface

Claims (3)

It is a light guide plate for instruments arranged under the design part formed on the dial,
A plane portion having a shape corresponding to a range in which the design portion is formed;
A plurality of daylighting units arranged so that optical axes of light from the light source intersect in the plane part;
A brightness adjusting hole having a reflecting surface that diffuses and reflects the incident light, which is provided in a light concentration portion of the planar portion where incident light from the plurality of daylighting portions intersect and gather;
An instrumental light guide plate characterized by comprising:   The instrument light guide plate according to claim 1, wherein the flat portion is formed in a shape that bypasses a pointer shaft that rotates the pointer.   A vehicle-mounted instrument, wherein the instrument light guide plate according to claim 1 or 2 is used.

Images