JP2005050743A - Backlight device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the whole device thin for a backlight device. <P>SOLUTION: In the backlight device 26, where light from a light source 33 is introduced from one end face 34a of a light guide plate 34 into the inside of the light guide plate 34, this introduced light is guided in the light guide plate 34, and this guided light is emitted from the upper surface of the light guide plate 34 to achieve surface emission; a flat surface 37 lower by one step is formed via an inclined surface 37 on the upper surface of the light guide plate 34 except for one end side of the light guide plate 34 where the light source 33 is located; and this flat surface 37 lower by one step is provided with a sheet member 40 having diffusibility. Thus, even if the sheet member 40 has the same thickness as that of conventional one, the whole device can be made thin, if the light guide plate 34 is made thin, and the device as a whole can be further made thin. In addition, the bottom of the light guide plate 34 is formed to be a flat surface, and is located at such a depth that the height of each upper surface of a film substrate 35 arranged at one end of the light guide plate 34 and the sheet member 40 becomes nearly equal, the flat surface 37 is formed on the upper surface of the light guide plate 34 to be lower by one step, allowing the thickness of the device as a whole to be uniform. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flat light-emitting backlight device and an imaging device using the same.

  Conventionally, a backlight device that is used in an imaging device such as an electronic camera to illuminate the back surface of a liquid crystal display device takes light from a light source into the light guide plate from one end surface of the light guide plate. There is a structure that emits light from one surface of the light guide plate and emits light while guiding the light within the light guide plate.

  In this type of backlight device, one surface of the light guide side of the light guide plate is formed flat, and the entire other surface located on the opposite side of the light guide plate moves from one end side to the other end side of the light source side. It is formed on an inclined surface that is inclined so that the thickness is gradually reduced, and has a structure in which a diffusion sheet is provided on one flat surface on the light emitting side, and a reflective sheet is provided on the other inclined surface.

In such a backlight device, even if the thickness of the light guide plate is reduced as the entire device becomes thinner, one surface of the light output side of the light guide plate is formed on a flat surface. Since the diffusion sheet is provided, the thickness of the diffusion sheet directly affects the thickness of the entire apparatus, and there is a disadvantage that the entire apparatus cannot be made sufficiently thin.
JP-A-9-236800

The first problem to be solved by the present invention is that even if the light guide plate is formed thin, the entire apparatus cannot be made sufficiently thin.
The second problem is that the thickness of the entire apparatus cannot be made substantially uniform.

According to the first aspect of the present invention, light from a light source is taken into the light guide plate from one end face of the light guide plate, and the taken light is emitted from one surface of the light guide plate while being guided in the light guide plate. In the backlight device that emits surface light,
In the light guide plate, except for the one end side where the light source is located, a flat surface that is one step lower is formed on the one surface on the light emitting side of the light guide plate via an inclined surface. A backlight device characterized in that a diffusive sheet member is provided.

  According to a second aspect of the present invention, the other surface of the light guide plate located on the side opposite to the light emitting side is formed in a plane parallel to the one lower flat surface of the light emitting side, and a reflective sheet is formed on the other surface. The backlight device according to claim 1, wherein the backlight device is provided.

  According to a third aspect of the present invention, a film substrate on which the light source is mounted is disposed so as to protrude laterally from the one end portion on the one surface on the light emitting side of the one end portion of the light guide plate, 3. The back according to claim 1, wherein the flat surface that is one step lower is formed so as to have a depth that makes the surfaces of the film substrate and the sheet member have substantially the same height. Light device.

The invention according to claim 4 includes the backlight device according to any one of claims 1 to 3, a display device, a photographing unit, a memory storage unit, and a strobe unit in the same case,
The backlight device and the display device are arranged so as to overlap in the thickness direction of the same case, and the photographing unit, the memory storage unit, and the strobe unit are arranged with respect to the backlight device and the display device. The imaging device is arranged so as not to overlap in the thickness direction of the same case.

  According to the first aspect of the present invention, except for the one end portion side of the light guide plate where the light source is located, a flat surface that is one step lower is formed on one surface of the light output side of the light guide plate via the inclined surface. Since the sheet member having diffusibility is provided on the lower flat surface, even if the thickness of the sheet member having diffusibility is the same as the conventional thickness, the thickness of the entire backlight device is reduced by the lower flat surface of the light guide plate. Therefore, if the thickness of the light guide plate is reduced, the thickness of the entire device can be further reduced, so that the thickness of the entire device can be sufficiently reduced.

  According to the second aspect of the present invention, the other surface located on the side opposite to the light emitting side of the light guide plate is formed in a plane parallel to the one lower flat surface on the light emitting side. Even if it is provided, the thickness of the entire backlight device can be made substantially uniform, and the light loss from the other surface side of the light guide plate can be prevented by the reflection sheet, and light can be efficiently transmitted from one surface of the light output side of the light guide plate. Can be emitted.

  According to the invention described in claim 3, the surface of the film substrate disposed at one end of the light guide plate and the sheet member disposed on the flat surface that is one step lower are guided to a depth such that the surfaces are substantially the same height. Since the flat surface, which is one step lower than the light plate, is formed one step lower, even if the film substrate on which the light source is mounted is disposed at one end of the light guide plate, the thickness of the entire backlight device can be made uniform.

  According to the fourth aspect of the present invention, when the backlight device, the display device, the photographing unit, the memory storage unit, and the strobe unit are assembled in the same case, the backlight device and the display device are installed in the same case. Since it is arranged in the thickness direction and the shooting unit, memory housing and strobe unit are arranged so as not to overlap in the thickness direction of the same case with respect to the backlight device and the display device, the thickness of the same case As a result, it is possible to reduce the thickness of the entire device and to obtain a device with excellent portability.

Hereinafter, an embodiment in which the present invention is applied to an electronic camera will be described with reference to FIGS.
1 is a perspective view of the electronic camera of the present invention as viewed from the front side, FIG. 2 is a perspective view of the electronic camera as viewed from the rear side, and FIG. 3 is an exploded perspective view showing the internal structure of the electronic camera.
As shown in FIGS. 1 and 2, the electronic camera includes a camera body 1 that is a device case. The camera body 1 includes a front case 2 and a rear case 3, and the front case 2 and the rear case 3 are formed of a thin metal plate having high rigidity such as stainless steel.

  In this case, as shown in FIG. 1, an imaging unit 4 is provided at the upper right corner of the front surface of the front case 2, and an optical viewfinder 5 is provided at a position located on the left side, and further on the left side. A strobe light emitting unit 6 is provided at a place where the light is emitted. A shutter button 7 and a first menu button 8 are provided on the left side (right side in FIG. 2) of the front surface of the front case 2 and the rear case 3. Further, as shown in FIG. 2, a display portion 9 is provided at a position on the left side of the rear surface of the rear case 3 (front surface in FIG. 2). An operable cursor key 10 is provided. A second menu button 11 and a power button 12 are respectively provided at positions on the upper and right sides of the cursor key 10, and a position positioned on the upper side of the display unit 9 continues from the front case 2 side. An optical finder 5 is provided.

  On the other hand, in the camera body 1, as shown in FIG. 3, the photographing unit 13, the strobe unit 14, the substrate unit 15 and the display unit 16 are positioned by the first to fourth holder members 17 to 20, respectively. The camera body 1 is incorporated in a plane without overlapping each other in the thickness direction of the camera body 1. In this case, as shown in FIG. 3, the photographing unit 13 has a structure in which the photographing unit 4 and the optical viewfinder 5 including a solid-state imaging device such as a CCD and a photographing lens are attached to the first holder member 17. The strobe unit 14 has a structure in which the strobe light emitting unit 6 and the strobe capacitor unit 21 are attached to the second holder member 18. The board unit 15 is configured to be attached to the third holder member 19 in a state where various electronic components 22 such as LSI and a memory card socket 23 are mounted on the circuit board 24. The display unit 16 has a structure in which the liquid crystal display device 25 and the backlight device 26 corresponding to the display unit 9 are attached to the fourth holder member 20 in a state where the display unit 16 is overlapped in the thick direction of the camera body 1.

  As shown in FIG. 4, the liquid crystal display device 25 of the display unit 16 encloses the liquid crystal 29 between the pair of transparent electrode substrates 27 and 28 in a state surrounded by the sealing material 30, and the upper electrode substrate 27. Polarizing plates 31 and 32 are provided on the upper surface and the lower surface of the lower electrode substrate 28, respectively, and in this state, a predetermined voltage is selectively applied between the pair of transparent electrode substrates 27 and 28, thereby It is configured to display information such as an image electro-optically. The backlight device 26 is for illuminating the back side of the liquid crystal display device 25, and takes light from the light source 33 from one end surface 34a of the light guide plate 34 into the light guide plate 34 as shown in FIG. The light thus picked up is emitted from the upper surface of the light guide plate 34 while being guided in the light guide plate 34 to emit light.

  That is, the light source 33 is formed of an LED (light emitting diode), is provided on the lower surface of the light-shielding film substrate 35, and is disposed corresponding to one end surface 34a of the light guide plate 34. In this state, the transparent sealing material 36 is sealed. In this case, as shown in FIG. 4, one side portion of the film substrate 35 is disposed on the upper surface of one end portion (right end portion in the figure) of the light guide plate 34, and in this state, the other side portion is the light guide plate 34. The light source 33 protrudes from the one end surface 34a to the upper side, and the light source 33 is provided on the lower surface of the protruded portion. Although not shown, the film substrate 35 is electrically connected to the circuit board 24 of the substrate unit 15.

  The light guide plate 34 is made of a transparent or translucent light-transmitting material, is formed in a thin plate shape, and is disposed to face the lower surface of the liquid crystal display device 25 as shown in FIG. On the upper surface of the light guide plate 34, a flat surface 37 that is one step lower is formed via an inclined surface 38 except for one end portion side (the right end portion side in FIG. 4) where the light source 33 is located. A sheet member 40 having diffusibility is provided on the flat surface 37 that is one step lower than the light guide plate 34. In this case, the lower flat surface 37 of the light guide plate 34 is formed to be lower by a depth such that the upper surface of the film substrate 35 and the upper surface of the sheet member 40 are substantially the same height. The inclined surface 38 is provided at a gentle inclination angle so as not to cause a steep step between the one end portion on the light source 33 side and the flat surface 37 that is one step lower, whereby light guided in the light guide plate 34 is inclined. It is comprised so that it may not leak outside from 38.

  The sheet member 40 has a structure in which a first prism sheet 41, a second prism sheet 42, and a diffusion sheet 43 are laminated in order from the bottom. The first and second prism sheets 41 and 42 have a structure in which a large number of line-shaped fine prisms are arranged, with the prism lines of the first prism sheet 41 and the prism lines of the second prism sheet 42 being orthogonal to each other. It is superimposed. The diffusion sheet 41 is configured to diffuse the light transmitted through the first and second prism sheets 41 and 42 and emit the light upward.

  The light guide plate 34 has a lower surface formed on a flat surface parallel to the flat surface 37 that is one step lower than the upper surface. A reflective sheet 44 is provided on the flat lower surface. A fourth holder member 20 is disposed on the lower surface. In this case, the reflection sheet 44 is provided over the entire lower surface of the light guide plate 34, and is provided from the lower side of the light source 33 to the rear surface side (right side surface in FIG. 4) of the light source 33, and the rear surface thereof. Is bent in a semicircular arc shape, thereby preventing light from the light source 33 from leaking from the lower surface and the rear surface side, and reflecting the light from the light source 33 toward the one end surface 34a of the light guide plate 34. It is comprised so that it may also have.

  In the backlight device 26 of such an electronic camera, when the light source 33 emits light, the light enters the light guide plate 34 from the one end surface 34a of the light guide plate 34 through the transparent sealing material 36, and the incident light is While being guided in the light guide plate 34, the light is sequentially emitted upward from the lower flat surface 37 of the light guide plate 34. At this time, light is reflected from the lower surface of the light guide plate 34 so as not to leak downward by the reflection sheet 44 provided on the lower surface of the light guide plate 34, thereby being emitted upward from the flat surface 37 on the upper surface side. The light emitted upward in this way passes through the first and second prism sheets 41 and 42 of the sheet member 40 and is diffused upward from the diffusion sheet 43 and emitted. As a result, the backlight device 26 emits light to illuminate the entire lower surface of the display effective area of the liquid crystal display device 25.

  As described above, according to the backlight device 26, the flat surface 37 that is one step lower is formed on the upper surface of the light guide plate 34 via the inclined surface 38 except for one end of the light guide plate 34 where the light source 33 is located. Since the sheet member 40 having diffusibility is provided on the flat surface 37 that is one step lower, even if the thickness of the sheet member 40 is the same as the conventional thickness, the thickness of the entire backlight device 26 can be reduced. For this reason, if the thickness of the light guide plate 34 is reduced, the overall thickness of the backlight device 26 can be further reduced, so that the overall thickness of the backlight device 26 can be sufficiently reduced. In this case, the lower surface of the light guide plate 34 is formed in a flat surface parallel to the flat surface 37 that is one step lower than the upper surface, and the depth is such that the upper surface of the film substrate 35 and the upper surface of the sheet member 40 are substantially the same height. Since the flat surface 37 on the upper surface of the light guide plate 34 is formed one step lower, even if the reflective sheet 44 is provided on the lower surface of the light guide plate 34, the film substrate 35 on which the light source 33 is mounted is connected to the light source 33 side of the light guide plate 34. Even if it arrange | positions on the one end part, the thickness of the backlight apparatus 26 whole can be made uniform.

  Incidentally, in the backlight device 26, the thickness t1 of one end portion of the light guide plate 34 on the light source 33 side is about 0.7 mm, the thickness t2 of the sheet member 40 is about 0.188 mm, and the thickness t3 of the film substrate 35 is about At 0.14 mm, the thickness t4 between the reflection sheet 44 and the holder member 19 is about 0.165 mm, and the thickest part (t1 + t3 + t4) of the backlight device 26 is about 1.005 mm. Therefore, the thickness is as thin as about 1 mm. The backlight device 26 can be obtained. Further, since the entire thickness of the portion corresponding to the lower flat surface 37 of the upper surface of the light guide plate 34 is thinner than the thickness of the one end portion on the light source 33 side, the sheet member Even if the thickness t2 (about 0.188 mm) of 40 is larger than the thickness t4 (about 0.14 mm) of the film substrate 35, the entire thickness of the backlight device 26 can be made uniform.

  Further, in this backlight device 26, the reflection sheet 44 is provided on the lower surface of the light guide plate 34, so that light emitted downward from the lower surface of the light guide plate 34 is reflected by the reflection sheet 44 toward the inside of the light guide plate 34. In this way, loss of light from the lower surface of the light guide plate 34 can be prevented, and in particular, the reflection sheet 44 is provided from the lower side of the light source 33 to the rear side of the light source 33 (right side in FIG. 4). In addition, since the rear surface is curved in a semicircular arc shape, the light from the light source 33 can be prevented from leaking from the lower surface and the rear surface side, and the light source is curved in the semicircular arc shape on the rear surface. The light from the light source 33 can be reflected toward the one end surface 34 a of the light guide plate 34, whereby the light from the light source 33 can be efficiently taken into the light guide plate 34 and taken in by the light guide plate 34. Light effect It can be emitted from step lower flat surface 37 of the upper surface of the well light guide plate 34.

  As described above, according to the electronic camera using the backlight device 26, the backlight device 26, the liquid crystal display device 25, the imaging unit 13, and the memory card are provided in the camera body 1 including the front case 2 and the rear case 3. When the socket 23 and the strobe unit 14 are assembled, the backlight device 26 and the liquid crystal display device 25 are arranged so as to overlap in the thickness direction of the camera body 1, and the imaging unit 13, the memory card socket 23, and the strobe unit 14 are arranged. Since the backlight device 26 and the liquid crystal display device 25 are arranged so as not to overlap in the thickness direction of the camera body 1, the camera body 1 can be thinned, thereby reducing the thickness of the entire device. In addition to being able to achieve this, a product with excellent portability can be obtained.

  In the above embodiment, the case where the backlight device 26 of the liquid crystal display device 25 is applied to an electronic camera has been described. However, the present invention is not limited to this. For example, a mobile phone, electronic notebook, electronic dictionary, PDA (personal digital It can be widely applied to electronic devices such as assistants.

It is the perspective view which looked at the electronic camera which applied the backlight apparatus of this invention from the front side. It is the perspective view which looked at the electronic camera of FIG. 1 from the rear surface side. It is the disassembled perspective view which showed the internal structure of the electronic camera of FIG. FIG. 4 is an enlarged cross-sectional view illustrating a main part of the backlight device of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 2 Front case 3 Rear case 13 Shooting unit 14 Strobe unit 23 Memory card socket 25 Liquid crystal display device 26 Backlight device 33 Light source 34 Light guide plate 34a One end surface of the light guide plate 35 Film substrate 36 Transparent sealing material 37 Flat surface 38 Inclined surface 40 Sheet member 41, 42 First and second prism sheet 43 Diffusion sheet 44 Reflection sheet

Claims (4)

In the backlight device that takes light from the light source into the light guide plate from one end face of the light guide plate, emits the light taken in from the one surface of the light guide plate while guiding the taken light in the light guide plate,
In the light guide plate, except for the one end side where the light source is located, a flat surface that is one step lower is formed on the light emitting side of the light guide plate via an inclined surface. A backlight device comprising a diffusive sheet member.   The other surface located on the opposite side to the light emitting side of the light guide plate is formed in a plane parallel to the lower flat surface on the light emitting side, and a reflective sheet is provided on the other surface. Item 2. The backlight device according to Item 1.   A film substrate on which the light source is mounted protrudes laterally from the one end portion on the one surface of the one end portion of the light guide plate on the light emitting side, and the flat surface that is one step lower of the light guide plate is the film. 3. The backlight device according to claim 1, wherein each of the surfaces of the substrate and the sheet member is formed at a depth that is substantially the same height, and is lower by one step. In the same case, comprising the backlight device according to any one of claims 1 to 3, a display device, a photographing unit, a memory storage unit, and a strobe unit.
The backlight device and the display device are arranged so as to overlap in the thickness direction of the same case, and the photographing unit, the memory storage unit, and the strobe unit are arranged with respect to the backlight device and the display device. The imaging device is arranged so as not to overlap in the thickness direction of the same case.

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