JP2010232100A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make light volume unevenness hard to occur even if light source parts 14 are displaced from a light guide plate 12 in its thickness direction. <P>SOLUTION: The light source parts 14 adjacent to each other in a width direction X among a plurality of them are shifted in a thickness direction Y of the light guide plate 12. With this, a light volume distribution is scattered in the thickness direction Y of the light guide plate 12 to have a light volume peak reduced. Therefore, a light volume unevenness is hard to occur, even if the light source parts 14 are displaced from the light guide plate 12 in its thickness direction Y. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light source device that emits light.

  As the light source device, the surface illumination body disclosed in Patent Document 1 is known. In the configuration of Patent Document 1, the light source of the backlight 13 is configured by a diode circuit 41 in which a plurality of LEDs 12 are connected in series, and the LEDs 12 that are in a predetermined luminous intensity region and chromaticity coordinate region are selected and used.

  According to this configuration, since a plurality of light emitting diodes are selected and used from at least a predetermined light intensity region and a chromaticity coordinate region, a difference in optical characteristics of each LED is reduced. This makes it possible to improve brightness unevenness and color unevenness.

JP 2007-128822 A (FIG. 4)

  In the above-mentioned Patent Document 1, although unevenness in the amount of light based on the optical characteristics of the individual LEDs can be suppressed, the LEDs serving as the light source units are arranged in a line, so that the LEDs are in the thickness direction of the light guide plate with respect to the light guide plate. If the position is shifted, unevenness in the amount of light occurs on the light exit surface of the light guide plate.

  In view of the above facts, an object of the present invention is to provide a light source device in which unevenness in the amount of light is less likely to occur even when the light source unit is displaced in the thickness direction of the light guide plate with respect to the light guide plate.

  A light source device according to claim 1 of the present invention has an incident end face into which light is incident inside, and an exit surface from which light is emitted to the outside in a direction intersecting the incident direction to the incident end face. A light guide plate that reflects light incident from the incident end face and emits the light from the exit surface, and a plurality of light guides arranged along the width direction orthogonal to the thickness direction of the light guide plate, and another light source for one light source unit And a light source part that is arranged so as to be shifted in the thickness direction and that allows light to enter the incident end face of the light guide plate.

  According to this configuration, the light from the light source unit enters the incident end face of the light guide plate. The light incident on the incident end face of the light guide plate is reflected inside the light guide plate and is emitted from the exit surface of the light guide plate.

  Here, in the configuration of claim 1, the plurality of light source units arranged along the width direction of the light guide plate are arranged so that the other light source units are shifted in the thickness direction with respect to one light source unit. Compared with the configuration in which the light source portions are arranged in a line along the width direction, the light amount distribution is dispersed in the thickness direction of the light guide plate, and the peak of the light amount is reduced. For this reason, even when the light source unit is displaced in the thickness direction of the light guide plate with respect to the light guide plate, the light amount unevenness is less likely to occur.

The light source device according to a second aspect of the present invention is the configuration of the first aspect, wherein the same number of the light source units are arranged per unit length in the width direction.
According to this configuration, since the plurality of light source units arranged along the width direction of the light guide plate are arranged in the same number per unit length in the width direction, the light amount distribution is made uniform in the width direction of the light guide plate, Uneven light intensity is suppressed.

  The light source device according to a third aspect of the present invention is the light source device according to the first or second aspect, wherein the light source portions adjacent to each other in the width direction are shifted in the thickness direction of the light guide plate.

  According to this configuration, since the light source units adjacent to each other in the width direction of the plurality of light source units are displaced in the thickness direction of the light guide plate, the light amount distribution is dispersed in the thickness direction of the light guide plate, and the light amount peak is reduced. For this reason, even when the light source unit is displaced in the thickness direction of the light guide plate with respect to the light guide plate, the light amount unevenness is less likely to occur.

  A light source device according to a fourth aspect of the present invention is the light source device according to any one of the first to third aspects, wherein the plurality of light source sections are arranged at the same pitch in the width direction.

  According to this configuration, since the plurality of light source units are arranged at the same pitch in the width direction, the light amount distribution is made uniform in the width direction of the light guide plate, and light amount unevenness is suppressed.

  The light source device according to a fifth aspect of the present invention is the light source device according to the first or second aspect, wherein the plurality of light source sections include a plurality of rows in which a plurality of light source sections are arranged along a straight line extending in the width direction. Each of the rows is shifted in the thickness direction.

  According to this configuration, there are a plurality of rows in which a plurality of light source portions are arranged along a straight line extending in the width direction, and each row is shifted in the thickness direction, so that the light source portions are randomly arranged without regularity. Compared with the configuration, the light quantity distribution can be made uniform.

  The light source device according to a sixth aspect of the present invention is the light source device according to the fifth aspect, wherein the light source portions in each row are arranged at the same pitch in the width direction, and the pitch for each row is the same.

  According to this configuration, the light source units in each column are arranged at the same pitch in the width direction, and the pitch for each column is the same, so the light source units in each column are arranged at different pitches in the width direction. In comparison, the light quantity distribution can be made uniform.

  The light source device according to a seventh aspect of the present invention is the light source device according to the fifth aspect, wherein the light source portions of each row are arranged at the same pitch in the width direction, and the pitch for each row is different.

  According to this configuration, the light source units in each row are arranged at the same pitch in the width direction, and the pitch for each row is different, so that the light source units in each row are arranged at different pitches in the width direction. , The light intensity distribution can be made uniform.

  Since the present invention has the above-described configuration, even when the light source unit is displaced in the thickness direction of the light guide plate with respect to the light guide plate, the light amount unevenness hardly occurs.

FIG. 1 is a schematic side view showing the configuration of the light source device according to the present embodiment. FIG. 2 is a schematic plan view showing the configuration of the light source device according to this embodiment. FIG. 3 is a schematic view showing a configuration in which the light source unit according to the present embodiment is brought into contact with the anisotropic diffusion plate. FIG. 4A is a schematic plan view of the light source device schematically showing the arrangement of the light source units according to the present embodiment. FIG. 4B schematically shows the arrangement of the light source units, and is a schematic view of the substrate viewed from the emission side. FIG. 5 is a schematic view schematically showing a light amount distribution when the light source unit according to the present embodiment is arranged in the thickness direction of the light guide plate. FIG. 6 is a schematic view schematically showing a light amount distribution when the light source unit according to the present embodiment is arranged in the width direction of the light guide plate. FIG. 7 is a schematic diagram schematically showing a modified example in which the arrangement of the light source units according to the present embodiment is modified.

Below, an example of an embodiment concerning the present invention is described based on a drawing.
(Configuration of light source device according to this embodiment)
First, the configuration of the light source device according to the present embodiment will be described. FIG. 1 is a schematic side view showing the configuration of the light source device according to the present embodiment. FIG. 2 is a schematic plan view showing the configuration of the light source device according to this embodiment. FIG. 2 schematically shows the light source device viewed from above, and the number of the light source units 14 in the drawing is different from the actual one.

  The light source device 10 according to the present embodiment includes a light guide plate 12 that internally reflects light incident from the incident end surface 12A and emits the light from the output surface 12B, and a light source unit 14 that causes light to enter the incident end surface 12A of the light guide plate 12. It is equipped with.

The light guide plate 12 is formed in a plate shape, and is made of, for example, an acrylic plate.
The light guide plate 12 is formed of a hexahedron having a front surface, a back surface facing the front surface, and four end surfaces connecting the front surface and the back surface.

  Of the four end faces of the light guide plate 12, the two opposite end faces serve as an incident end face 12A through which light enters the light guide plate 12, and the remaining two end faces receive light incident from the incident end face 12A. A reflection surface 12 </ b> C is reflected inside the light guide plate 12. The light source unit 14 is disposed on each of the two incident end faces 12A (see FIG. 4).

  Of the four end surfaces of the light guide plate 12, one end surface is an incident end surface 12A where light enters the light guide plate 12, and the remaining three end surfaces receive light incident from the incident end surface 12A. The configuration may be a reflecting surface 12 </ b> C that reflects inside the light guide plate 12.

  Further, the surface of the light guide plate 12 has an emission surface 12B from which light is emitted to the outside in an emission direction B (arrow B direction in FIG. 1) intersecting the incident direction A (arrow A direction in FIG. 1) of the incident end surface 12A. The back surface of the light guide plate 12 is a reflection surface 12D that reflects the light incident from the incident end surface 12A to the inside of the light guide plate 12.

  On the incident end surface 12A of the light guide plate 12, the light from the light source unit 14 is transmitted in the thickness direction Y (the arrow Y direction in FIG. 1) and the width direction X (the arrow X direction in FIG. 2) perpendicular to the thickness direction Y. An anisotropic diffusion plate 16 that diffuses into the surface is in close contact. Specifically, the width direction X is the longitudinal direction of the incident end face 12A.

  The close contact between the light guide plate 12 and the anisotropic diffusion plate 16 here means an optical contact. The optical contact means that no air layer is interposed between the light guide plate 12 and the anisotropic diffusion plate 16, that is, an adhesive or liquid having a refractive index close to that of the light guide plate 12 and the anisotropic diffusion plate 16 is interposed. It means that As described above, when the light guide plate 12 and the anisotropic diffusion plate 16 are in close contact with each other, it is possible to suppress a reduction in incident efficiency due to light incident on the light guide plate 12 being reflected by the incident end face 12A.

  The light guide plate 12 and the anisotropic diffusion plate 16 may not be in close contact with each other, and an air layer may be interposed therebetween.

  In the present embodiment, the anisotropic diffusion plate 16 has a diffusion angle θ2 in the width direction X larger than a diffusion angle θ1 in the thickness direction Y.

  Specifically, for example, when the diffusion angle θ0 of the LED 14X is 20 °, θ1 is 30 ° and θ2 is 80 °.

  Note that the diffusion angle is based on the diffusion angle when parallel light is incident on the anisotropic diffusion plate 16, and the position at which the center luminance of the diffused light becomes half value when the parallel light is incident is expressed in full angles. Say things.

  As the anisotropic diffusion plate 16, for example, a lens diffusion plate (model number: LSD 60 × 10PC (elliptical diffusion 60 ° × 10 °)) manufactured by Luminit can be used.

  In this lens diffusion plate, light is diffused by a refraction action like a microlens by a surface relief hologram pattern formed on the surface thereof. Due to the shape of the surface relief hologram pattern, elliptical diffusion is possible in which the diffusion angle θ2 in the width direction X is larger than the diffusion angle θ1 in the thickness direction Y.

  In the present embodiment, the reflecting surface 12D, the emitting surface 12B, and the reflecting surface 12C are in contact with a layer (for example, an air layer) having a refractive index lower than that of the light guide plate 12. As a result, the light that has entered the light guide plate 12 from the incident end face 12A undergoes total reflection when the incident angles with respect to the reflecting surface 12D, the emitting surface 12B, and the reflecting surface 12C are equal to or greater than a predetermined critical angle, and the light guide plate 12 is confined inside.

  On the surface of the reflecting surface 12D of the light guide plate 12, a dot pattern 22 of diffusing ink that diffuses the light incident from the incident end surface 12A to the output surface 12B is formed. Thereby, the light incident from the incident end surface 12A is diffused by the reflection surface 12D of the light guide plate 12, and a part of the light whose incident angle with respect to the emission surface 12B is less than the critical angle is extracted from the emission surface 12B.

  On the reflective surface 12D side opposite to the exit surface 12B of the light guide plate 12, as an example of a reflector that reflects the light leaked from the reflective surface 12D of the light incident from the incident end surface 12A toward the exit surface 12B. A reflection sheet 20 is provided. The reflection sheet 20 extends from the light guide plate 12 to the light source unit 14 and can be used for positioning the anisotropic diffusion plate 16 and the light source unit 14.

  In addition, a diffusion plate 24 that diffuses light emitted from the emission surface 12B to the outside is provided on the emission surface 12B of the light guide plate 12.

  On the other hand, the light source unit 14 includes an LED 14X as an example of a light source that emits light, and a condensing lens 14Y as an example of an optical member that condenses the light from the LED 14X in the plane of the anisotropic diffusion plate 16. I have. In addition, as the light source part 14, what is called a bullet-type LED with which LED and the optical member were united is used preferably.

  In addition, as a light source, it is not restricted to LED, For example, other point light sources, such as a light bulb, may be sufficient. The condensing optical member is not limited to a lens such as the condensing lens 14Y, and may be formed of a reflecting plate such as a mirror, for example.

  A plurality of LEDs 14X are attached to the substrate 15 along the incident surface of the anisotropic diffusion plate 16, and a condensing lens 14Y is disposed for each LED 14X.

  The substrate 15 is disposed on the surface of the reflection sheet 20, and the position of the LED 14 </ b> X disposed on the substrate 15 can be adjusted with reference to the reflection sheet 20.

  The condenser lens 14 </ b> Y is separated from the anisotropic diffusion plate 16, and a space is formed between the condenser lens 14 </ b> Y and the anisotropic diffusion plate 16.

  The light source unit 14 may be configured to contact the anisotropic diffusion plate 16 as shown in FIG. In the configuration shown in FIG. 3, the substrate 15 is provided with a pressing spring 18 as an example of a biasing member that biases the light source unit 14 toward the anisotropic diffusion plate 16. The pressing spring 18 is disposed on the back surface of the substrate 15 on the side opposite to the surface of the substrate 15 on which the LEDs 14X are disposed. By pressing the substrate 15, the condensing lens 14Y is attached to the anisotropic diffusion plate 16. In contact.

  The contact between the condenser lens 14Y and the anisotropic diffusion plate 16 here does not mean an optical contact. Therefore, an air layer is interposed between the condenser lens 14Y and the anisotropic diffusion plate 16. The condensing lens 14Y and the anisotropic diffusion plate 16 may be in close contact (may be an optical contact).

  Further, in the configuration shown in FIG. 3, the substrate 15 may be deformable so that the LED 14 </ b> X moves toward the anisotropic diffusion plate 16. Thereby, even when the distance between the condenser lens 14Y and the anisotropic diffusion plate 16 differs for each LED 14X due to variations in the mounting position of the LED 14X and the condenser lens 14Y, the condenser lens 14Y is satisfactorily anisotropic. The diffusing plate 16 is brought into contact.

  Note that the urging member is not limited to the push spring 18, and other spring members such as a leaf spring and a tension spring, and an elastic body such as rubber may be used.

Here, the arrangement of the light source unit 14 will be described.
FIG. 4A is a schematic plan view of the light source device 10 schematically showing the arrangement of the light source unit 14. FIG. 4B schematically shows the arrangement of the light source unit 14 and is a schematic view when the substrate 15 is viewed from the emission side.
In the present embodiment, the plurality of light source units 14 are arranged along the width direction X orthogonal to the thickness direction Y of the light guide plate 12 as shown in FIG. Further, as shown in FIG. 4B, the plurality of light source units 14 are arranged at the same pitch in the width direction X, and the same number is arranged per unit length in the width direction X.
The unit length in the width direction X here is the length of one delimiter when the width direction X is continuously delimited by an arbitrary length. Further, the same number here may be plural or singular.
Further, as long as the same number of light source units 14 are arranged per unit length in the width direction X, the pitch of the light source units 14 in the width direction X may be different. Further, a different number of light source units 14 may be arranged per unit length in the width direction X.

Further, the other light source unit 14 is arranged so as to be shifted in the thickness direction Y with respect to the one light source unit 14. Specifically, the light source portions 14 adjacent in the width direction X are shifted in the thickness direction Y of the light guide plate 12. In this configuration, the amount of deviation of the light source unit 14 in the thickness direction Y has no regularity and is irregularly shifted.
Note that, among the plurality of light source units 14, at least one light source unit 14 may be disposed so as to be shifted in the thickness direction Y with respect to one light source unit 14, and adjacent light source units 14 in the width direction X are guided. There is no need to shift in the thickness direction Y of the optical plate 12.

  By the way, the light source device 10 which concerns on this embodiment can be used for a radiation detector. The radiation detector is used in an X-ray imaging apparatus or the like, and includes an electrostatic recording unit including a photoconductive layer that exhibits conductivity when irradiated with radiation, and the radiation detector carries image information. The image information is recorded upon irradiation, and an image signal representing the recorded image information is output.

  For example, as disclosed in JP-A-9-9153 (corresponding US Pat. No. 5,563,421), a configuration in which the light source device 10 is used for a radiation detector is a light-emitting device in which a residual charge is generated in a photoconductive layer. A configuration in which residual charges are excited and removed by irradiating light from the outside of the conductive layer with the light source device 10 is conceivable.

  Further, as disclosed in Japanese Patent Application Laid-Open No. 2004-146769 (corresponding US Pat. Nos. 6,995,375 and 7034312), the electric field generated in the radiation detector provided with the divided electrodes by light irradiation from the light source device 10 is stabilized. By doing so, a configuration that eliminates sensitivity fluctuations can be considered.

(Operation of this embodiment)
Next, the operation of the above embodiment will be described.
The light from the light source unit 14 is diffused by the anisotropic diffusion plate 16 in the width direction X along the emission surface 12B of the light guide plate 12 and in the thickness direction Y orthogonal to the width direction X, and incident on the light guide plate 12. Incident on the end face 12A.

  The light incident on the incident end surface 12A of the light guide plate 12 is reflected inside the light guide plate 12 by the reflecting surface 12C and the reflecting surface 12D of the light guide plate 12, and exits from the exit surface 12B of the light guide plate 12 in the incident direction A. The light is emitted in the direction B.

  Here, in this embodiment, the plurality of light source units 14 arranged along the width direction X of the light guide plate 12 are arranged at the same pitch in the width direction X, and the same number per unit length in the width direction X. Since they are arranged, the light amount distribution is made uniform in the width direction X of the light guide plate 12, and unevenness in the light amount is suppressed.

  Furthermore, since the light source part 14 adjacent to the width direction X has shifted | deviated to the thickness direction Y of the light-guide plate 12, when the some light source part 14 is seen from the one end side of the width direction X, as shown in FIG. The light quantity distribution is dispersed in the thickness direction Y of the light guide plate 12, and the peak of the light quantity is reduced. For this reason, even when the light source unit 14 is displaced with respect to the light guide plate 12 in the thickness direction Y of the light guide plate 12, unevenness in the amount of light hardly occurs.

  On the other hand, in the configuration in which the plurality of light source units 14 are arranged in a line along the width direction X, the light amount is concentrated on a part of the light guide plate 12 in the thickness direction Y when viewed from one end side in the width direction X. , The peak of the light intensity increases. For this reason, when the light source unit 14 is displaced in the thickness direction Y of the light guide plate 12 with respect to the light guide plate 12, light amount unevenness is likely to occur.

FIG. 5 shows a configuration in which the light source units 14 </ b> A and the light source units 14 </ b> B as the plurality of light source units 14 are shifted in the thickness direction Y of the light guide plate 12. In FIG. 5, the light amount distribution of the light source unit 14A is indicated by A, the light amount distribution of the light source unit 14B is indicated by B, and a combination of the light amount distributions A and B is indicated by the light amount distribution AB.
Further, the light source unit 14A, the light source unit 14B, and the combined light amount distribution AB when the light source unit 14A and the light source unit 14B are displaced in the thickness direction Y of the light guide plate 12 are indicated by a two-dot chain line. Further, the amount of light that deviates from the region that should originally be irradiated when the light source unit 14A and the light source unit 14B are displaced in the thickness direction Y of the light guide plate 12 is indicated by a hatched portion ab.

  FIG. 6 shows a configuration in which a light source unit 14 </ b> C and a light source unit 14 </ b> D as a plurality of light source units 14 are arranged along the width direction X of the light guide plate 12. In FIG. 6, the light amount distribution of the light source unit 14 </ b> C is indicated by C, the light amount distribution of the light source unit 14 </ b> D is indicated by D, and a combination of the light amount distributions C and D is indicated by the light amount distribution CD.

In addition, the light source unit 14C, the light source unit 14D, and the combined light amount distribution CD when the light source unit 14C and the light source unit 14D are displaced in the thickness direction Y of the light guide plate 12 are indicated by a two-dot chain line. Further, the amount of light that deviates from the region that should originally be irradiated when the light source unit 14C and the light source unit 14D are displaced in the thickness direction Y of the light guide plate 12 is indicated by a hatched portion cd.
The hatched portion cd in FIG. 6 is larger than the hatched portion ab in FIG. 5, and it can be seen that the configuration shown in FIG. 6 has a greater influence of light amount fluctuation when the light source unit 14 is displaced.

The arrangement of the light source unit 14 is not limited to the one shown above, and may be arranged as shown in FIGS. 7 (A) and 7 (B).
In the example illustrated in FIG. 7A, the plurality of light source units 14 includes a plurality of rows 26 in which a plurality of light source units 14 are arranged along a straight line extending in the width direction X. In this configuration, the column 26A and the column 26B are composed of two columns. The row 26B is shifted in the thickness direction Y with respect to the row 26A.

In addition, the light source sections 14 in the rows 26A and 26B are arranged at the same pitch in the width direction X, respectively. Further, the pitch of the light source sections 14 in the row 26A and the row 26B is the same.
Further, the column 26B is shifted by 1/2 pitch in the width direction X with respect to the column 26A, and the plurality of light source units 14 including the column 26A and the column 26B have the light source units 14 adjacent to each other in the width direction X. They are arranged at the same pitch in the width direction X.

By arranging in this way, the light amount distribution can be made uniform as compared with the configuration in which the light source units 14 are randomly arranged without regularity. Thereby, even when the light source unit 14 is displaced with respect to the light guide plate 12, unevenness in the amount of light hardly occurs.
Note that the number of columns in which a plurality of light source units 14 are arranged may be three or more. In this case, when the number of columns is N, it is desirable that the columns are arranged with a shift of 1 / N pitch in the width direction X.

In the example shown in FIG. 7B, the plurality of light source units 14 includes a plurality of rows 27 in which a plurality of light source units 14 are arranged along a straight line extending in the width direction X. In this configuration, there are two columns, a column 27A and a column 27B. The row 27B is shifted in the thickness direction Y with respect to the row 27A.
In addition, the light source units 14 in the rows 27A and 27B are arranged at the same pitch in the width direction X, respectively. Further, the pitches of the light source sections 14 in the row 27A and the row 27B are different.

By arranging in this way, the light amount distribution can be made uniform as compared with the configuration in which the light source units 14 are randomly arranged without regularity. Thereby, even when the light source unit 14 is displaced with respect to the light guide plate 12, unevenness in the amount of light hardly occurs.
The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

DESCRIPTION OF SYMBOLS 10 Light source device 12 Light guide plate 14 Light source part

Claims (7)

An incident end surface where light is incident on the inside and an exit surface from which light is emitted to the outside in a direction crossing the incident direction on the incident end surface, and the light incident from the incident end surface is reflected internally A light guide plate to be emitted from the emission surface;
A plurality of light sources are arranged along a width direction orthogonal to the thickness direction of the light guide plate, and other light source units are arranged to be shifted in the thickness direction with respect to one light source unit, and light is incident on an incident end surface of the light guide plate. A light source unit;
A light source device comprising:   The light source device according to claim 1, wherein the same number of light source units are arranged per unit length in the width direction.   The light source device according to claim 1, wherein the light source units adjacent to each other in the width direction are displaced in a thickness direction of the light guide plate.   The light source device according to claim 1, wherein the plurality of light source units are arranged at the same pitch in the width direction.   3. The light source device according to claim 1, wherein the plurality of light source units includes a plurality of columns in which a plurality of light source units are arranged along a straight line extending in the width direction, and each column is shifted in a thickness direction. . The light source sections in each row are arranged at the same pitch in the width direction,
The light source device according to claim 5, wherein the pitch for each row is the same. The light source sections in each row are arranged at the same pitch in the width direction,
The light source device according to claim 5, wherein the pitch for each row is different.

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