JP4504915B2 - Backlighting unit and vehicle display device - Google Patents

Description

  The present invention relates to a backlight unit that illuminates an object to be illuminated such as an LCD or a dial from the back using a plurality of LEDs, and a vehicle display device having the backlight unit.

  In recent years, an instrument equipped with an LCD (liquid crystal display) such as an odometer has become widespread in a vehicle meter, and this LCD is so-called a back surface by a plurality of light source elements such as LEDs (Light Emitting Diodes) from the back surface. The lights are illuminated. However, there is a tendency for the LEDs and the LCD to be close to each other due to demands for thinning, and in this case, illumination unevenness that is visually recognized as if the installation locations of the scattered LEDs are clearly raised tends to occur. In order to reduce this illumination unevenness, the number of LEDs should be increased and the arrangement thereof should be made dense. However, it was difficult to increase the number unnecessarily due to cost and space constraints.

Therefore, the present applicant has proposed an illumination structure shown in Patent Document 1 that provides a uniform illumination effect without unevenness without increasing the number of LEDs more than necessary. The illumination structure is configured such that the light directly irradiated on the back surface of the LCD is formed by thickening the portion directly above each of the plurality of light source elements irradiated with the strongest light by the diffusion uneven portion (diffusion plate) to greatly attenuate the light. Has been trying to equalize.
JP 2003-241191 A

  However, when the LCD is illuminated with a plurality of light source elements as described above, the number of light source elements has to be increased as the size of the LCD increases, resulting in an increase in cost. Therefore, an optical member (optical film) that disperses the light from the light source is disposed between the light source and the diffusion plate, and the back surface of the LCD is illuminated by diffusing the light dispersed into a plurality of light by the optical member with the diffusion plate. However, there is a problem that uneven illumination occurs depending on the shape and thickness of the diffusion plate.

  Therefore, in view of the above-described problems, the present invention provides a backlight unit and a vehicle display device that provide uniform illumination without unevenness even when an optical member is disposed between a light source and a diffusion plate. It is said.

In order to solve the above-mentioned problems, a back lighting unit according to claim 1 made according to the present invention includes a plurality of light sources provided at a predetermined interval on a back side of an illumination object, and between the illumination object and the light source. An optical member that splits light from the light source into a plurality of virtual image lights and emits the light from a plurality of emission positions that are offset from the light source, and the illumination object and the optical member A diffuser plate that diffuses the virtual image light dispersed by the optical member and illuminates the illumination target object from the back side, wherein the diffuser plate corresponds to the emission position of the virtual image light by the optical member There have a convex portion formed in a convex shape toward the object to be illuminated, the cross-section of the diffuser, characterized in that is formed such that the wavy line continuous in a predetermined cycle.

  According to the backlight unit of the present invention described in claim 1, the diffusing plate in which the convex portion is formed in a shape corresponding to the emission position of the virtual image light of the optical member has the convex portion corresponding to the emission position. Since each virtual image light emitted from the emission position of the optical member is similarly diffused by the convex portion of the diffusion plate, the back surface of the illumination object is illuminated. Light can be equalized.

  Invention of Claim 2 made | formed in order to solve the said subject WHEREIN: While the said diffusing plate has the recessed part formed in the concave shape between the said convex parts in the back lighting unit of Claim 1, The convex part and the concave part are formed so as to have a curved cross section.

  According to the backlight unit of the present invention described in claim 2, the cross section of the convex portion and the concave portion of the diffuser plate is formed to be a concave and convex curve so as to correspond to the convex portion and the concave portion. Each virtual image light emitted from the emission position of the optical member can be accurately and evenly diffused by the convex portion of the diffusion plate.

  The vehicle display device according to claim 3, which is made according to the present invention to solve the above-described problem, is a display unit that displays predetermined information, and the backlight according to claim 1 or 2 provided on a back side of the display unit. A display unit for a vehicle having a unit, wherein the display unit is an illumination object of the backlight unit.

  According to the vehicle display device of the present invention described in claim 3, since the back lighting unit is provided on the back side of the display unit that is the display target, the light is emitted from the emission position of the optical member of the back lighting unit. Each virtual image light is similarly diffused by the convex part of the diffusion plate, and the light illuminated on the back surface of the illumination object can be equalized.

  As described above, according to the backlight unit of the present invention described in claim 1, each virtual image light emitted from the emission position of the optical member is evenly diffused by the convex portion of the diffusion plate, and the back surface of the illumination object is thus obtained. Therefore, even if an optical member is disposed between the light source and the diffusion plate, uneven illumination can be prevented and uniform illumination can be performed. Moreover, even if a light source with high directivity is used, the unevenness of illumination can be reliably prevented because it can be evenly diffused by the convex portions of the diffusion plate. Furthermore, since the number of light sources can be small, it is possible to easily cope with an increase in the size of an illumination object.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the cross section of the convex portion and the concave portion of the diffusion plate is an uneven curve so as to correspond to the concave portion extending over the convex portion. Since each virtual image light emitted from the emission position of the optical member can be accurately and similarly diffused by the convex portion of the diffusing plate, it is possible to prevent uneven illumination and perform more uniform illumination. be able to.

  As described above, according to the vehicle display device of the present invention described in claim 3, since the backlight unit is provided on the back side of the display unit that is the display object, emission of the optical member of the backlight unit is provided. Each virtual image light emitted from the position is evenly diffused by the convex portion of the diffusion plate, and the light illuminating the back of the object to be illuminated can be equalized, so the optical member is interposed between the light source and the diffusion plate. Even if it arrange | positions, generation | occurrence | production of illumination unevenness can be prevented and uniform illumination can be performed. Moreover, even if a light source with high directivity is used, the unevenness of illumination can be reliably prevented since it can be evenly diffused by the convex portions of the diffusion plate. Furthermore, since the number of light sources can be small, it is possible to easily cope with an increase in the size of an illumination object.

  Hereinafter, an embodiment of a vehicle combination of a backlight unit and a vehicle display device according to the present invention will be described with reference to the drawings of FIGS.

  1 to 4, the vehicle display device 1 to which the backlight unit of the present invention is applied is a combination meter in which a speedometer, a fuel meter, a water temperature meter, a tachometer, an odometer, and the like are integrated.

  The vehicular display device 1 includes a turn 2, a dial 3, a pointer 4, an LCD 5 as a display unit (illumination object), a front cover 7, a back cover (not shown) integrated with the front cover 7, The smoked glass is provided in front of the dial 3 and the backlight unit 10 of the present invention. In addition, a movement, an electronic board, a diffusion plate, and the like (not shown) are mounted on this type of meter.

  The turn-back 2 is formed of, for example, black synthetic resin and has a plurality of display windows corresponding to each display design such as a speedometer, a fuel meter, a water temperature meter, a tachometer, and an odometer.

  The dial plate 3 is made of, for example, a synthetic resin such as polycarbonate, and has a horizontally long shape corresponding to each meter. On the dial 3, display designs 31a and 31b corresponding to a speedometer, a fuel meter and the like, a direction design 31c, various kinds of warning designs 31d, a change lever position design 31e, and the like are formed. In addition, a pointer 4 is attached which indicates a predetermined display design on the dial 3 by being rotated by a predetermined angle based on each measurement value by a movement corresponding to each meter.

  The LCD 5 is an instruction device for an odometer that displays the cumulative travel distance and the like as digital values. The LCD 5 is provided below the LCD window 32c, that is, on the back side of the dial plate 3 so that a predetermined display such as accumulated travel distance information can be displayed outside via the LCD window 32c. The LCD 5 includes a substrate 51, a display unit 52 mounted on the substrate 51, and a plurality of terminals 53.

  Each of the terminals 53 is formed in a substantially L shape, and is erected on the back side of the LCD 5 so that one end side is connected to the substrate 51 and the other side faces the control substrate 9. Each terminal 53 penetrates the terminal hole of the control board 9 and is soldered or press-fitted, so that each wiring pattern between the control board 9 and the board 51 is electrically connected.

  The LCD 5 is formed in a rectangular shape and is a known one. In the display unit 52 on the surface, trip / odd identification information, trip mode identification information, and accumulated travel distance information are displayed on the display element. The display unit 52 of the LCD 5 is illuminated from the back surface by an LED 11 described later at night or the like. The LCD 5 is installed so as to be sandwiched between the back surface of the LCD window 32c of the dial plate 3 and a diffusion plate 13 described later.

  The front cover 7 is formed of a synthetic resin such as plastic, for example, and has a horizontally long dish shape corresponding to the shape of the dial 3. The front cover 7 is integrated with the back cover, and accommodates the movement and an electronic substrate on which various electronic components are mounted so as to be sandwiched from both sides. The front cover 7 has a case 8 that accommodates the LCD 5 and a back lighting unit 10 to be described later. The case 8 is formed integrally with the front cover 7.

  The case 8 has a storage portion 81 standing on the back side from the front cover 7, a stepped contact portion 82 provided continuously with the storage portion, and an inclined portion 83 provided continuously with the contact portion 82. ing. The accommodating part 81 has a rectangular cross section corresponding to the substantially same outer shape as the LCD 5, the optical member 12 and the diffusing plate 13 described later, and the abutting part 82 is formed smaller than the accommodating part 81. Thus, the housing 81 can accommodate these members.

  The backlight unit 10 includes a plurality (three in FIG. 3) of LEDs 11, an optical member 12, and a diffusion plate 13. The backlight unit 10 functions as a backlight for the LCD 5. In addition, although this embodiment demonstrates the case where the back surface of LCD5 of the back surface illumination unit 10 is illuminated, the back surface side of the dial plates 3, such as a speedometer, a fuel meter, a water temperature meter, a tachometer, an odometer, can also be illuminated. .

  The LED 11 is a well-known LED, and is mounted on the surface of the control board 9 by soldering so as to be on the back side of the LCD 5. Each LED 11 is controlled to be turned on and off by a control unit (not shown) mounted on the control board 9. The plurality of LEDs 11 are linearly provided at predetermined intervals in the width direction of the LCD 5. The arrangement of the LEDs 11 can be arbitrarily set based on the shape and size of the LCD 5, the luminance of the LEDs 11, and the like.

  The optical member 12 is interposed between the LCD 5 and the LED 11. As the optical member 12, a well-known optical film (BEF: Brightness Enhane Film) is used, which exhibits a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light. Specifically, when light enters from the LED 11, the optical member 12 reflects linearly polarized light having a predetermined polarization axis or far polarized light in a predetermined direction, and transmits other light. That is, the optical member 12 splits the light incident from the LED 11 and emits the light toward the diffusion plate 13.

  In the present embodiment, as shown in FIG. 3C, the case where the optical member 12 splits the light from the LED 11 into two virtual image lights L will be described, but various forms such as splitting into three or more are used. be able to.

  In the optical member 12, the position where the virtual image light L is emitted is an emission position 12a. That is, in the present embodiment, since the emitted light from the three LEDs 11 is split into two virtual image lights L by the optical member 12, six emitting positions 12a are formed on the optical member 12, and each emitting position is 12a is a position shifted from directly above the LED 11. Thus, the optical member 12 splits the light from the LED 11 into a plurality of virtual image lights L.

  The diffusion plate 13 is for effectively illuminating the LCD 5 from the back side, and is interposed between the LCD 5 and the optical member 12. The diffusion plate 13 is formed in a rectangular shape with a light guide synthetic resin. The diffuser plate 13 includes a plurality of convex portions 13a in which portions corresponding to the emission position 12a of the virtual image light L by the optical member 12 are convex toward the LCD 5, and concave portions formed between the convex portions 13a. 13b.

  The diffusion plate 13 is formed so that the cross section of the convex portion 13a and the concave portion 13b is a continuous curve. In the present embodiment, the case where the cross section of the diffusion plate 13 is formed so as to be a continuous wavy line having a predetermined period will be described. However, various forms such as forming a plane between the convex portions 13a can be used. .

  As described above, the diffusing plate 13 is formed such that the convex portion 13a corresponding to the position immediately above each emission position 12a of the optical member 12 is thicker than other portions. The diffusion plate 13 is formed in a mountain shape so that the brightness of the LCD 5 is uniform. The recess 13b is formed in a valley shape.

  Next, an example of assembling the back lighting unit 10 to the case 8 will be described with reference to the drawings of FIGS.

  When the control board 9 on which the LED 11 is mounted is assembled to the case 8, the optical member 12 is attached to the case 8 at a predetermined interval by bringing the edge of the optical member 12 into contact with the contact portion 82 of the case 8. It is attached. Then, the backlight unit 10 is assembled by stacking the diffusion plate 13 from above the optical member 12. Thus, by laminating | stacking the diffusion plate 13 on the optical member 12, it has the structure where the output position 12a of the optical member 12 and the convex part 13a of the diffusion plate 13 respond | correspond. Then, the LCD 5 is assembled on the diffusion plate 13 to illuminate the LCD 5 from the back. The back surface of the LCD 5 is in contact with the tops of the respective convex portions 13 a of the diffusion plate 13, and the LCD 5 and the backlight unit 10 are integrally assembled by a lock mechanism (not shown) of the case 8.

  Next, an example of the operation (action) at the time of illumination on the LCD 5 of the backlight unit 10 of the present invention will be described.

  The light emitted from each LED 11 in response to a predetermined switch operation is split into two virtual image lights L by the optical member 12 and emitted toward the diffusion plate 13 from each emission position 12a. The virtual image light L spreads in the diffusion plate 13 toward the convex portion 13a, and is diffused from the convex portion 13a with a uniform amount of light as shown in FIG. Thus, the back side of the LCD 5 is uniformly illuminated by the light emitted from the plurality of convex portions 13a.

  As described above, according to the backlight unit 10 of the present invention, each virtual image light L emitted from the emission position 12a of the optical member 12 is uniformly diffused by the convex portion 13a of the diffusion plate 13, and is reflected on the back surface of the LCD 5. Since the light to be illuminated can be equalized, even if the optical member 12 is disposed between the LED 11 and the diffuser plate 13, the occurrence of uneven illumination can be prevented and uniform illumination can be performed. Moreover, even if it uses LED11 with high directivity, since it can diffuse by the convex part 13a of the diffusion plate 13, generation | occurrence | production of illumination nonuniformity can be prevented reliably. Furthermore, since the number of LEDs 11 can be small, it is possible to easily cope with an increase in the size of the LCD 5.

  Further, by forming the cross section of the convex portion 13a and the concave portion 13b of the diffusing plate 13 so as to correspond to a concave and convex continuous curve so as to correspond to the concave portion 13b extending from the convex portion 13a, from the emission position 12a of the optical member 12 Since each emitted virtual image light L can be accurately and evenly diffused by the convex portion 13a of the diffusing plate 13, uneven illumination can be prevented and further uniform illumination can be performed.

  Furthermore, according to the vehicle display device 1 of the present invention, since the backlight unit 10 is provided on the back side of the display unit 52 of the LCD 5, each virtual image emitted from the emission position 12 a of the optical member 12 of the backlight unit 10. Since the light L is similarly diffused by the convex portion 13a of the diffusion plate 13 and the light illuminating the back surface of the LCD 5 can be equalized, the optical member 12 is disposed between the LED 5 and the diffusion plate 13. However, it is possible to prevent illumination unevenness from occurring and perform uniform illumination. In addition, since the number of LEDs 11 is small, it is possible to easily cope with an increase in the size of the LCD 5.

  In the above-described embodiment, the case where the backlight unit 10 is applied to the vehicle display device 1 has been described. However, the present invention is not limited to this, and other than the vehicle display device 1, an LCD or the like can be used. Any lighting object can be used.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a front view which shows an example of the meter for vehicles to which this invention is applied. It is a disassembled perspective view which shows the mounting structure of the backlight unit based on this invention. It is a schematic diagram for demonstrating the relationship of the apparatus structure of the backlight unit of FIG. 3, (a) is sectional drawing which shows the relationship between a light source and an optical member, (b) is a top view of the optical member, (c) ) Is a cross-sectional view of the diffusion plate, and (d) is a top view of the LCD. It is sectional drawing which shows an example of the cross section of the backlight unit based on this invention.

Explanation of symbols

1 Display device for vehicle 5 LCD (display unit, illumination object)
10 Back lighting unit 11 LED (light source)
12 optical member 12a emission position 13 diffuser plate 13a convex portion 13b concave portion L virtual image light

Claims (3)

A plurality of light sources provided at a predetermined interval on the back side of the illumination object, and the light from the light source is split into a plurality of virtual image lights by being interposed between the illumination object and the light source. An optical member that emits light from a plurality of shifted emission positions, and a virtual image light dispersed by the optical member interposed between the illumination object and the optical member to diffuse the illumination object from the back side. A backlight unit having a diffusion plate,
Wavy lines the diffusion plate, the portion corresponding to the exit position of the virtual image light by the optical member have a convex portion formed in a convex shape toward the object to be illuminated, the cross-section of the diffusion plate is contiguous with a predetermined cycle backlighting unit, characterized in that it is formed such that.   2. The back surface according to claim 1, wherein the diffusion plate has a concave portion formed in a concave shape between the convex portions, and the cross section of the convex portion and the concave portion is curved. Lighting unit. In a vehicle display device comprising: a display unit that displays predetermined information; and the backlight unit according to claim 1 or 2 provided on a back side of the display unit.
The display device for vehicles, wherein the display unit is an illumination object of the backlight unit.

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