JP4693180B2 - Light source device - Google Patents

Description

  The present invention relates to a light source device that synthesizes or mixes and emits incident light from a plurality of light sources, and more particularly to a light source device that can be reduced in size and thickness.

  Conventional display devices using a color light source include a color projector, a projection-type color television, and a liquid crystal display device using a backlight. As a light source device used for these devices, for example, there is a method using a dichroic prism for a color projector or a projection type color television. (For example, refer to Patent Document 1.) Further, since this dichroic prism is an expensive member, the price of the apparatus is increased, and this method has a disadvantage that inherently causes a large light loss. As a method for solving the drawbacks, a light source device has been proposed in which a plurality of light beams are converted into a single light beam using a linear prism. (For example, refer to Patent Document 2.) Further, as a backlight of a liquid crystal display device or the like, a light source device has been proposed in which the light emitted from the LED light source is improved in luminance uniformity by using two prism sheets. (For example, refer to Patent Document 3.)

  Hereinafter, the configuration of the light source device in the prior art will be described with reference to the drawings. 14 and 15 show the configuration of the color projector shown in Patent Document 2, FIG. 14 is a configuration diagram of the color projector, and FIG. 15 is a partial sectional view of the linear prism plate shown in FIG. In FIG. 15, reference numeral 50 denotes a linear prism plate. The upper surface forms an exit surface having a large number of prism rows, and the lower surface forms a flat entrance surface. Incident light P51a and P51b incident on the incident surface 51 on the lower surface side of the linear prism plate 50 from two different oblique directions are refracted by the incident surface 51 and then refracted by the two exit surfaces 52 and 53 of the prism to be the same. Direction light P52 and P53.

  In other words, by appropriately designing the refractive index determined by the material of the linear prism plate 50 and the apex angle (tip angle) of the prism, two types of incident light incident from two directions orthogonal to the prism row are each 2 of the prism. The light is refracted at one emission surface and emitted in the same direction. Based on this principle, it is possible to emit as a single light obtained by combining incident light from two types of light sources. When the two types of light sources are different color lights, two colors can be emitted as mixed color light. Further, when it is desired to combine three or more types of light sources, it can be executed by repeating the combination using a plurality of linear prism plates 50.

  FIG. 14 shows a color projector having a light source device for combining three color lights of red (hereinafter R), green (hereinafter G) and blue (hereinafter B) using two linear prism plates 50 shown in FIG. Reference numerals 50a and 50b denote linear prism plates having the same configuration as the linear prism plate 50. Reference numeral 55 denotes a projection lens, 56 denotes a projection screen, 57 denotes an R light source, 58 denotes a G light source, 59 denotes a B light source, and 61, 62, and 63 denote relay lenses for the R light source 57, the G light source 58, and the B light source 59, respectively. is there.

  In the above-described configuration, the R light and the G light emitted from the R light source 57 and the G light source 58 arranged at different angles of 45 ° with respect to the incident surface of the linear prism plate 50a are respectively connected to the relay lens 61. , 62 to be collimated and then incident on the incident surface of the linear prism plate 50a from different oblique directions of 45 °. The two incident lights of R light and G light are emitted in the vertical direction from the emission surface of the linear prism plate 50a as a single light synthesized by the linear prism plate 50a. The combined outgoing light from the linear prism plate 50a enters the incident surface of the linear prism plate 50b disposed at an angular position of 45 ° with respect to the linear prism plate 50a from an oblique direction of 45 °. .

  Further, after the B light emitted from the B light source 59 is converted into parallel rays through the relay lens 63, the linear prism is viewed from an oblique direction of 45 ° different from the single light synthesized from the R light and the G light. The light enters the incident surface of the plate 50b. As a result, the combined single light of the R light and the G light and the B light are combined by the linear prism plate 50b, and emitted from the linear prism plate 50b as a single light that combines the R light, the G light, and the B light. The light is emitted vertically from the surface.

  Next, the configuration of the surface light emitting device shown in the cited document 3 will be described with reference to FIGS. 16 is an exploded perspective view of the surface light emitting device, and FIG. 17 is a partially enlarged side view showing a light emitting state of the light emitting substrate shown in FIG. In FIG. 16, reference numeral 70 denotes a surface light emitting device, which includes a plurality of LEDs 72 and a plurality of reflectors 73 on a lower side of two prism sheets 70 a and 70 b that are arranged so that each prism row is orthogonally crossed. A configured light emitting substrate 75 is disposed. The liquid crystal unit 80 is arranged on the upper surface side of the surface light emitting device 70 to constitute a liquid crystal display device using the surface light emitting device 70 as a backlight.

  A plurality of LEDs 72 are arranged in a matrix, for example, on the light emitting substrate 75, and each reflector 73 is provided so as to collectively cover the LEDs 72 arranged in one row. As shown in the partial enlarged side view of the light emitting substrate 75 in FIG. 17, each of the reflectors 73 has a first surface 73 a that faces the light emitting surface of the LED 72 and a second surface 73 b that covers the upper surface. The radiated light emitted from the LED 72 is reflected laterally by the first surface 73a of the reflector 73 and is incident on the adjacent reflector 73, and is reflected upward by the second surface 73b of the adjacent reflector 73 to be laminated. The light enters the arranged prism sheets 70a and 70b. The stacked prism sheets 70a and 70b arrange the optical path of the reflected light incident from the second surfaces 73b of the plurality of reflectors 73 provided on the light emitting substrate 75 and emit the light upward (in the direction of the liquid crystal unit 80). Have a role to let you.

  The surface light emitting device 70 having the above-described configuration emits white light as a backlight. Accordingly, white light is emitted from the light emitting substrate 75. White LEDs can be broadly divided into a type in which an LED having a specific emission wavelength and a phosphor are combined, and R, G, B in one package. There are three types of LEDs, and any type can be used. The plurality of LEDs 72 arranged on the light emitting substrate 75 are three kinds of LEDs of R, G, and B, and reflected so that these three colors of light are mixed by the first surface 73a and the second surface 73b of the reflector 73. By emitting the light, it is possible to realize a white light surface emitting device.

Japanese Patent Application Laid-Open No. 2002-244211 JP-A-63-132215 JP 2006-228710 A

  However, the light source device in the prior art has the following problems. In the light source device using the dichroic prism in Patent Document 1, since the dichroic prism is an expensive member, there is a problem that the price of the device is high and that this method has a substantial loss of light amount.

  Further, in the light source device using a plurality of linear prisms in Patent Document 2, for example, when combining light sources of R, G, and three color LEDs, it is necessary to provide an arrangement interval having a predetermined angle between the two linear prisms. As a result, the arrangement space for the linear prism is widened, so that the shape of the light source device as a whole becomes large, and it is difficult to reduce the thickness of the device. In addition, since the light beam incident on the linear prism is incident from an oblique direction, the light beam width when exiting from the linear prism is extended, resulting in a difference in the light beam width between the incident light and the light output and a change in the aspect ratio of the light beam. This amount of change increases with the number of oblique light incidences of the linear prism. That is, in the case of the light source device shown in FIG. 14, R light and G light are obliquely incident on the linear prism plate 50a and combined, and then the combined single light is obliquely incident on the linear prism plate 50b and B light. Therefore, with respect to the R light and the G light, the oblique light incidence of the linear prism is performed twice, and the aspect ratio is twice different.

  Furthermore, in the light source device using the light emitting substrate with the reflector and the two prism sheets in Patent Document 3, the prism rows of the two prism sheets are stacked so as to be orthogonal to each other. The two prism sheets arranged in a stacked manner with the prism rows being orthogonal to each other are used only for the purpose of changing the optical path of the synthesized light.

(Object of invention)
The present invention has been made in view of the above problems, and the two prism sheets are thinned by stacking the prism rows so that the prism rows are orthogonal to each other, and the incident directions of a plurality of light sources are devised and stacked. It is an object of the present invention to provide a light source device that is inexpensive and can be reduced in size and thickness by providing a prism sheet with a combining function, and that has excellent light combining performance.

  A plurality of light sources and a plurality of fine prism rows on one surface and two prism sheets on the other surface are flat, and the two prism sheets cross each other at a predetermined angle. By stacking and arranging the plurality of light sources at a predetermined angle on the lower surface side of the two stacked prism sheets, a predetermined angle is obtained from the lower surface side of the two stacked prism sheets. Incident light from a plurality of light sources incident at an angle is output as outgoing light obtained by combining the upper surfaces of two prism sheets.

  According to the above configuration, incident light from a plurality of light sources can be synthesized by an optical system having a thin configuration in which two prism sheets are laminated. Therefore, the shape is small and thin, and the optical synthesis performance is excellent. A light source device can be provided.

  Each of the light sources is distributed and arranged in four zones formed by the intersection of the prism rows in the two stacked prism sheets.

  Incident light of each light source is incident along the vicinity of the center line of the crossing angle of each prism row in the two stacked prism sheets.

  Incident light from each of the light sources is incident toward a predetermined condensing point in the two stacked prism sheets.

  Each of the light sources is arranged symmetrically with respect to a predetermined condensing point in the two prism sheets.

  Each of the light sources is arranged symmetrically with respect to an axis passing through a predetermined condensing point in the two prism sheets.

  As described above, a plurality of light sources are arranged dispersed in four zones formed by the intersection of the prism rows in the two prism sheets stacked, and the incident light of each light source is In this application, the light is incident along the center line of the prism sheet in the vicinity of the crossing angle of the prism rows, and all incident light of each light source is incident on a predetermined condensing point in the two stacked prism sheets. The light combining function can be performed on the two prism sheets arranged in a stacked manner by a peculiar incidence method of a plurality of light sources.

  The vertical angle of the fine prism row is substantially a right angle.

  The pitch of the plurality of fine prism rows is 1 μm to 100 μm.

  As described above, by making the pitch of the prism row as fine as 1 μm to 100 μm, it is possible to visually recognize a plurality of light beams emitted from the fine prism surfaces as synthesized outgoing light.

  Each of the plurality of light sources includes a condensing optical device (lens) in front of the light emitting surface.

  The optical device may be a lens having different radii of curvature in the vertical and horizontal directions.

  According to the above configuration, incident light can be converted into parallel rays, and by using lenses having different radii of curvature in the vertical and horizontal directions, the spread of the light beam width of the outgoing light due to the incident light entering obliquely is suppressed. be able to.

  A plurality of light sources having different emission colors and a plurality of fine prism rows on one surface and two prism sheets having a flat surface on the other surface, each prism row being a predetermined prism row Laminate and arrange so as to cross at an angle, and arrange the plurality of light sources at a predetermined angle on the lower surface side of the two stacked prism sheets, thereby lower surface side of the two stacked prism sheets Incident light from a plurality of light sources incident at a predetermined angle is output as emitted light obtained by mixing colors from the upper surface side of two prism sheets.

  According to the above configuration, incident light from a plurality of light sources having different emission colors can be mixed by a thin optical system in which two prism sheets are laminated. A light source device with excellent performance can be provided.

  Each of the light sources is distributed and arranged in four zones formed by the intersection of the prism rows in the two stacked prism sheets.

  Incident light of each light source is incident along the vicinity of the center line of the crossing angle of each prism row in the two stacked prism sheets.

  Incident light from each of the light sources is incident toward a predetermined condensing point in the two stacked prism sheets.

  Each of the light sources is arranged symmetrically with respect to a predetermined condensing point in the two prism sheets.

  Each of the light sources is arranged symmetrically with respect to an axis passing through a predetermined condensing point in the two prism sheets.

  As in the above configuration, a plurality of light sources having different emission colors are arranged dispersed in four zones formed by the intersection of each prism row in two stacked prism sheets, and the incident light of each light source is stacked. The incident light is incident along the vicinity of the center line of the crossing angle of each prism row in the two prism sheets, and all incident light of each light source is directed toward a predetermined condensing point in the two stacked prism sheets. By using an incident method of a plurality of light sources unique to the present application, the two prism sheets arranged in a stacked manner can be made to perform a color mixing function.

  The vertical angle of the fine prism row is substantially a right angle.

  Each of the plurality of light sources includes a condensing optical device (lens) in front of the light emitting surface.

  The optical device may be a lens having different radii of curvature in the vertical and horizontal directions.

  According to the above configuration, incident light can be converted into parallel rays, and by using lenses having different radii of curvature in the vertical and horizontal directions, the spread of the light beam width of the outgoing light due to the incident light entering obliquely is suppressed. be able to.

  The plurality of light sources include R, G, and B LED light sources.

  R, G, and B LED light sources are disposed at three positions in the two prism sheets stacked, and a G / LED light source is disposed at the remaining one position.

  R, G, and B LED light sources are disposed at three locations in the two prism sheets stacked, and a BlueYAG / LED light source is disposed at the remaining one location.

  According to the above configuration, in the emission of white light by the color mixture of the R, G, and B LED light sources, the number of G / LED light sources that emit less light than the R and B LED light sources is increased. Good white light can be emitted.

  As described above, in the light source device of the present invention, incident light from a plurality of light sources can be synthesized by an optical system having a thin structure in which two prism sheets are laminated. In addition, a light source device having excellent photosynthetic performance can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 8 show a light source device according to a first embodiment of the present invention. FIG. 1 is an external perspective view of the light source device, and FIG. 2 is a top view and a side view showing the configuration of two prism sheets. FIG. 3 is a plan view showing the relationship between two prism sheets and a plurality of light sources. In FIG. 1, reference numeral 10 denotes a light source device, and two prism sheets PS1 and PS2 arranged in a stacked manner and four light sources arranged at a predetermined angle on the lower surface side of the two prism sheets PS1 and PS2. It is comprised by K1, K2, K3, K4. Each light source K includes an LED 1, a condenser lens 2, and a case 3 that accommodates the LED 1 and the condenser lens 2. In the first embodiment, the LED of the light source K 1 is a red LED 1 r (hereinafter referred to as R • LED). ), A blue LED 1b (hereinafter B.LED) is used as the LED of the light source K4, and a green LED 1g (hereinafter G.LED) is used as the LEDs of the light source K2 and the light source K3.

  The light source device 10 includes red light (hereinafter R light) emitted from the light source K1, blue light (hereinafter B light) emitted from the light source K4, and two green lights (hereinafter G light) emitted from the light sources K2 and K3. Are input from the lower surface side of the prism sheet PS1 and mixed by the two prism sheets PS1 and PS2, thereby emitting light from the prism sheet PS2 as a single white light Pw obtained by combining the R light, the G light, and the B light. The light is emitted in a more vertical direction.

  Next, the arrangement relationship between the two prism sheets PS1 and PS2 and the four light sources K1, K2, K3, and K4 will be described with reference to FIGS. FIG. 2 is a top view and a side view showing the configuration of the two prism sheets PS1 and PS2, showing a top view of the prism sheets PS1 and PS2 stacked in the center, and a side view as seen from the X-axis direction on the left side. The side view seen from the Y-axis direction is shown on the side. FIG. 3 shows the positional relationship of the four light sources K1, K2, K3, and K4 with respect to the top view of the stacked prism sheets PS1 and PS2 shown in FIG.

  As shown in FIG. 2, the prism sheets PS1 and PS2 are arranged in a stacked manner with the prism sheet PS1 on the lower side and the prism sheet PS2 on the upper side, with the prism rows crossed at a predetermined angle. The prism sheets PS1 and PS2 in the present embodiment have a top surface as a prism surface and a bottom surface as a plane, and are arranged so that each apex angle is substantially a right angle and each prism row intersects at an orthogonal angle. . Accordingly, the solid line parallel to the X axis in the top view of the prism sheets PS1 and PS2 indicates the top and valley lines in the prism row of the upper prism sheet PS2, and the dotted line parallel to the Y axis indicates the lower prism sheet PS1. The top and trough lines in the prism row are shown, and the solid line and the dotted line constitute an orthogonal mesh. The pitch of each prism row is a fine pitch of 1 μm to 100 μm.

  Next, the arrangement relationship between the two prism sheets PS1, PS2 and the four light sources K1, K2, K3, K4 is formed by crossing the prism rows of the two stacked prism sheets PS1, PS2, as shown in FIG. Four light sources K1, K2, K3, and K4 are dispersed in four zones S1, S2, S3, and S4 obtained by dividing the planes of the prism sheets PS1 and PS2 by the X axis and the Y axis. Has been placed. Accordingly, the incident light P1 emitted from the light source K1, the incident light P2 emitted from the light source K2, the incident light P3 emitted from the light source K3, and the incident light P4 emitted from the light source K4 are laminated two prism sheets PS1. , PS2 is incident along the vicinity of the center line N, M of the crossing angle of each prism row, and is intensively incident toward a predetermined condensing point Po of the two prism sheets PS1, PS2. ing. In the present embodiment, the predetermined condensing point Po of the two prism sheets PS1 and PS2 is the upper center point of the upper prism sheet PS2.

  As a result, as shown in FIG. 3, the light source K1 and the light source K4, and the light source K2 and the light source K3 are arranged at positions symmetrical with respect to the condensing point Po, and the light source K1 and the light source K3 The light source K2 and the light source K4 are arranged at positions symmetrical with respect to the X axis passing through the condensing point Po. The angles from the X axis of each light source are all the same, and this angle is determined by the refractive index and prism apex angle depending on the materials of the two prism sheets PS1 and PS2. In the present embodiment, acrylic (PMMA) having a refractive index n of 1.49 is used as the material of the two prism sheets PS1 and PS2, and the prism apex angle is 90 °. Therefore, all the light sources K1, K2, and K3 are used. , K4 are arranged at the same angle of 43.5 ° from the X axis. This is because the prism angle has +-, and therefore, the direction of the light beam differs in four directions depending on the contact surface, but the four directions are the same when viewed from the angle with the normal of the surface. That is, even if the directions of the light beams are different, the angles are the same. In order to emit the emitted light directly upward with the refractive index n of the prism sheets PS1 and PS2 being 1.49 and the prism apex angle being 90 °, the incident light Are incident at the same angle of ± 43.5 ° with respect to the X axis.

  The incident conditions from each light source on the two prism sheets PS1 and PS2 stacked in the present invention will be described in detail later, but a basic photosynthesis (color mixing) operation will be described with reference to FIG. The direction of the emitted light with respect to the X-axis / Y-axis plane of the two prism sheets PS1 and PS2, that is, one prism inclined surface constituting the prism surface of the prism sheet PS1 with the direction perpendicular to the X-axis / Y-axis plane as the Z-axis When L1, the other prism inclined surface is L2, one prism inclined surface constituting the prism surface of the prism sheet PS2 is U1, and the other prism inclined surface is U2, each light source K1, K2, K3, K4 is the prism sheet PS1. As described above, it is arranged at a predetermined angle on the lower surface side, and is arranged at a position of 43.5 ° from the X axis.

  Incident light from each light source arranged at the above position is incident obliquely on the X-axis / Y-axis plane with respect to the prism surface and also incident obliquely on the Z-axis. That is, the light source device 10 according to the present invention allows incident light from each light source to be incident obliquely on the prism surface and obliquely use the prism surface so that incident light from four directions can be refracted and emitted under the same conditions. I have to. For each incident light, as shown in FIG. 2, the incident light P1 emitted from the light source K1 passes through the prism inclined surface L1 of the prism sheet PS1 and the prism inclined surface U2 of the prism sheet PS2 to become emitted light, and similarly from the light source K2. The emitted incident light P2 passes through the prism slope L2 of the prism sheet PS1 and the prism slope U2 of the prism sheet PS2, and the incident light P3 emitted from the light source K3 is the prism slope L1 of the prism sheet PS1 and the prism slope of the prism sheet PS2. Incident light P4 that has passed through U1 and emitted from the light source K4 passes through the prism slope L2 of the prism sheet PS1 and the prism slope U1 of the prism sheet PS2, and becomes emitted light.

  In addition, incident light having a large area emitted from each light source is incident on each inclined surface of a large number of prism rows provided on the two prism sheets PS1 and PS2 and refracts radiation. Since the pitch of the prism row is a fine pitch of 1 μm to 100 μm, it is not visually recognized as separate outgoing light but is recognized as a single synthesized outgoing light. Accordingly, when the light source K1 is R light, the light source K4 is B light, and the light sources K2 and K3 are G light as the conditions of each light source, the emitted light is mixed with R light, B light, and G light to produce white light. Pw is emitted.

  Next, an optical path of incident light from each light source with respect to the two prism sheets PS1 and PS2 will be described. FIG. 4 is a partially enlarged view of the prism sheet PS2 shown in FIG. 2, and shows optical paths of incident lights that pass through the prism sheet PS2 while being refracted. FIG. 5 is a partially enlarged view of the prism sheet PS1 shown in FIG. 2, and shows the optical path of each incident light passing through the prism sheet PS1 while being refracted. In the present embodiment, the two prism sheets PS1 and PS2 are made of acrylic having a refractive index of 1.49 as a material, and the prism apex angle is 90 °.

  In general, the method for obtaining the optical path of the prism is as follows. That is, when incident light is input from the lower surface side of one prism sheet and the emitted light is obtained directly above the prism sheet, a method of tracing in the opposite direction is performed as a method of obtaining the optical path. For example, in the case of the prism sheet PS2 which is the upper prism sheet of FIG. 4, it is necessary to first emit the white light Pw mixed as the emitted light in the upward direction, so that the emitted light from each light source is reversed, The light is incident on the prism sheet made of acrylic from right above the prism sheet. At this time, the Snell's law is applied to the incident light by the difference in refractive index between air and acrylic, and a predetermined refraction angle is given at the boundary surface and proceeds in the prism sheet. Further, when the light is emitted from the lower surface of the prism sheet PS2 into the air, a predetermined refraction angle according to Snell's law is given to the boundary surface, and the light is emitted into the air.

  When the prism sheet PS2 is used as an actual light source device, if the incident light from each light source is incident at the angle of the emitted light emitted from the lower surface of the prism sheet PS2 into the air based on the above results, Can proceed at the same predetermined refraction angle, and output light can be obtained in the direction directly above the upper surface of the prism sheet PS2.

  Next, the optical path of the incident light from each light source with respect to the two prism sheets PS1 and PS2 will be described with reference to FIGS. In the case of the upper prism sheet PS2 shown in FIG. 4, the Y-axis / Z-axis plane is shown, and the incident light P1 from the light source K1 and the incident light P2 from the light source K2 shown in FIG. The light passes through the prism slope U2, and the incident light P3 from the light source K3 and the incident light P4 from the light source K4 pass through the prism slope U1 on the right side of the prism sheet PS2 and are emitted directly upward. Accordingly, the incident light P1 and P2 are inclined to the left and the incident lights P3 and P4 are inclined right and the incident direction is reversed, but the incident light travels at the same angle. It becomes.

  That is, the angles θ2 and γ2 with the boundary surface normal (indicated by the dotted line) of the lower surface of the prism sheet PS2 in each incident light, and the boundary surface normal (indicated by the dotted line) of the prism slope of the prism sheet PS2 in each outgoing light The angles β2 and α2 are all the same. These angles use acrylic having a refractive index of 1.49, and in the prism sheet PS2 having a prism apex angle of 90 °, α2 = 45.0 °, β2 = 28.3 °, γ2 = 16.7 °, θ2 = 25.3 °.

  Next, in the case of the lower prism sheet PS1 shown in FIG. 5, the X-axis / Z-axis plane is shown, and the angle θ1 with the boundary normal line (shown by the dotted line) of the lower surface of the prism sheet PS1 in each incident light, and The angles β1 and α1 between γ1 and the boundary normal to the prism slope of the prism sheet PS1 in each outgoing light (shown by dotted lines) are all the same. These angles use acrylic having a refractive index of 1.49, and in the prism sheet PS1 having a prism apex angle of 90 °, α1 = 50.3 °, β1 = 31.1 °, γ1 = 24.6 °, θ1 = 38.4 °. In addition, although each output light P1-P4 from prism sheet PS1 in FIG. 5 is shown in figure so that it may radiate | emit in the directly upward direction on drawing, these output light has an inclination angle in the orthogonal | vertical direction with respect to a paper surface. This is because the inclination is not visible on the X-axis-Z-axis plane of FIG. However, actually, the outgoing lights P1 and P2 have an inclination angle toward the back of the paper, and the outgoing lights P3 and P4 have an inclination angle toward the front of the paper.

  That is, the inclination directions of the outgoing lights P1 to P4 are opposite, but the inclination angles are all the same and have an inclination of 25.3 ° with respect to the Z axis, which is the prism in the prism sheet PS1. The slope is 50.3 ° with reference to the boundary normal of the slope. Accordingly, each of the outgoing lights P1 to P4 of the lower prism sheet PS1 having an inclination of 25.3 ° with respect to the Z axis is 25.3 ° with respect to the boundary normal to the lower surface of the upper prism sheet PS2. Incident light having an incident angle, that is, an incident angle of θ2, is refracted inside the prism sheet PS2 and is emitted in a direction directly above the upper surface. 4 and 5 show a state in which the incident light P1 and the incident light P2 and the incident light P3 and the incident light P4 are incident on different prism inclined surfaces for easy understanding. Are simultaneously incident on the same prism slope and synthesized.

  FIG. 6 schematically shows the traveling state of an optical path through which incident light continuously passes through two prism sheets PS1 and PS2, and only incident light P1 is representatively shown. That is, the incident light P1 from the lower surface of the lower prism sheet PS1 is 43.5 ° from the X axis to the prism row at an angle of 43.5 ° in the X-axis to Y-axis plane direction, and 38.4 ° from the lower surface boundary normal. When incident at an angle (θ1) in the Z-axis direction, the light is refracted in the prism sheet PS1 and then emitted into the air from the prism slope L1. The emitted incident light P1 is incident from the lower surface of the upper prism sheet PS2 at an angle (θ2) in the Z-axis direction of 25.3 ° from the boundary surface normal, and is refracted in the prism sheet PS2. The light is emitted into the air directly above the prism slope U2. Although not shown, incident light P2, P3, and P4 are also emitted in the same manner according to the optical paths shown in FIGS. In order to make the drawing of FIG. 6 easier to understand, the two prism sheets PS1 and PS2 are shown slightly apart from the actual one, and the X-axis is used as a virtual axis to make the arrangement position of the prism sheet PS2 easier to understand. The X ′ axis corresponding to is provided.

  As described above, according to the present invention, the incident light is obliquely incident on the prism rows in the two prism sheets arranged in a stacked manner by intersecting the prism rows and having an angle in the X axis-Y axis plane direction and an angle in the Z axis direction. By making it enter from the direction, the prism slope is used diagonally. As a result, it is possible to simultaneously combine incident light from four directions under the same optical conditions.

  Next, the spread of light rays in the light source device of the present invention will be described. FIG. 7 is a side view showing the spread of rays when incident light P1 and P4 are incident on the lower surface of the lower prism sheet PS1. When this light source device is an illuminating device, the direction parallel to the Z axis is the outgoing optical axis of the illuminating device, and the direction inclined by θ1 (38.4 °) from the Z axis is the incident optical axis from the light sources K1 and K4. The horizontal axis is an axis rotated 43.5 ° from the X axis of the prism sheet PS1. Considering the case where the incident light P1 having a light flux width H from the light source K1 is incident on the lower surface of the prism sheet PS1, since a light beam having a width is incident from an oblique direction toward the horizontal plane, the width of the light beam on the incident surface. Spreads and is emitted as a light beam having a width of 1.28H. Further, the incident light P4 from the light source K4 is also incident from a symmetrical position under the same conditions as the incident light P1 of the light source K1, and has the same spread.

  FIG. 8 is a plan view showing the spread of light rays when incident light is incident from four directions by the four light sources K1 to K4 on the two prism sheets PS1 and PS2 stacked in the light source device shown in FIG. It is. In FIG. 8, the dotted line is an axis rotated by 43.5 ° from the X axis. S14 is illumination light composed of the light sources K1 and K4, and S23 is illumination light composed of the light sources K2 and K3. Each of the short axes has a width H of incident light and the long axis has a width of 1.28H of outgoing light. It is oval. The two elliptical illumination lights S14 and S23 are overlapped with a common center point. As a result, the two elliptical overlapping portions indicated by diagonal lines are the combined illumination light S of the four light sources K1 to K4. Available as That is, when the four light sources K1 to K4 are R light, B light, G light, and G light, they can be used as white light Pw in which the illumination light S is mixed.

  Next, a light source device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a side view showing the spread of light rays when the incident lights P1 and P4 are incident on the lower surface of the lower prism sheet PS1 from the light sources K1 and K4, and corresponds to FIG. 7 in the light source device of the first embodiment. Is. Therefore, the same elements as those of the light source device of FIG. The light source device of FIG. 9 differs from the light source device of FIG. 7 in that a lens having a different radius of curvature is provided as an optical device in the optical path between the light source K1 and the light source K4 and the lower surface of the prism sheet PS1. In this embodiment, the anamorphic lens 12 is provided.

  Next, the spreading state of the light beam will be described with reference to FIGS. Considering the case where incident light P1 having a circular shape with a diameter H as shown in FIG. 10A is emitted from the light source K1, the incident light P1 passes through the anamorphic lens 12 to be vertically and horizontally. By receiving different optical changes, the incident light P1 has an elliptical light beam shape in which the major axis in the horizontal direction is H and the minor axis in the vertical direction is Hs as shown in FIG. Incident on the lower surface of the sheet PS1. As a result, the incident light P1 incident from the oblique direction toward the horizontal plane has a light beam width Hs widened to H by the increase in the vertical width of the light beam on the incident surface, and the diameter shown in FIG. The light beam having a circular shape is restored and emitted. That is, by using the anamorphic lens 12 to reduce the incident light P1 in advance by an amount corresponding to the incident oblique light, outgoing light having the same shape as the incident light is obtained.

  FIG. 11 shows a light source device having the anamorphic lens 12 shown in FIG. 9, in which incident light is incident on four stacked prism sheets PS1 and PS2 from four directions by four light sources K1 to K4. It is a top view which shows a breadth, and respond | corresponds to FIG. 8 in the light source device of 1st Embodiment. 11 differs from FIG. 8 in that both the illumination light S14 composed of the light sources K1 and K4 and the illumination light S23 composed of the light sources K2 and K3 have a circular shape with a diameter H. It becomes a circle with a diameter of H. Accordingly, the illumination lights S14, S23, and S are all in one circle indicated by diagonal lines. That is, since the light source device in the second embodiment can use all incident light as illumination light, it becomes an efficient illumination device. 9 shows the configuration in which the anamorphic lens 12 is provided in the optical path of the light source device of the first embodiment shown in FIG. 7, but the configuration is not limited to this, and the light source device is provided in each light source K. An anamorphic lens 12 may be provided instead of the condensing lens 2.

  Next, a light source device according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a perspective view of the light source device according to the third embodiment, and the basic configuration is the same as that of the light source device according to the first embodiment shown in FIG. Omitted. In FIG. 12, reference numeral 20 denotes a light source device, which is different from the light source device 10 of FIG. 1 in that a BlueYAG • LED 1by is disposed instead of G • LED as the light emitting means of the light source K3.

  Next, the configuration of the BlueYAG • LED1by will be described. FIG. 13 is a cross-sectional view of a BlueYAG LED, which is a phosphor mixed color white light emitting device. Reference numeral 1by denotes a BlueYAG • LED, and a B • LED 1b is connected to a substrate 33 having electrodes 31 and 32, and the B • LED 1b is molded with a transparent resin 36 mixed with YAG-based fluorescent particles 35.

  In the operation of the BlueYAG • LED 1by, when a drive voltage is applied to the electrodes 31 and 32, the B • LED 1b emits blue light Pb. When this blue light Pb collides with the fluorescent particles 35 mixed in the transparent resin 36, the fluorescent particles 35 are excited and wavelength conversion is performed, and yellow light Pe is emitted from the fluorescent particles 35 as shown in the figure. As a result, the blue YAG • LED 1by mixes the blue light Pb emitted from the B • LED 1b and output without colliding with the fluorescent particles 35, and the yellow light Pe that has collided with the fluorescent particles 35 and is wavelength-converted. The fluorescent white light Pwy is emitted.

  As shown in FIG. 12, in the light source device 20, the R / LED 1r is disposed as the light source K1, the G / LED 1g as the light source K2, the BlueYAG / LED 1by as the light source K3, and the B / LED 1b as the light source K4. Therefore, in addition to the color mixture by the R, G, B LEDs, the bright white light Pwy by the BlueYAG • LED 1by is mixed, thereby realizing a bright illumination device with good color rendering.

  In the first to third embodiments described above, the embodiment in which the light from the four light sources is combined has been described. However, the number of light sources is not particularly limited. The present invention can also be applied to a collective light source device that combines light sources having the same wavelength.

  According to the embodiment described above, incident light from a plurality of light sources can be synthesized by an optical system having a thin configuration in which two prism sheets are laminated. A light source device with excellent performance can be provided.

  The light source device of the present invention can realize a condensing type light source device that synthesizes light sources of the same wavelength and a mixed color type light source device that synthesizes light sources of different wavelengths. In addition, it can be used for a light source for a projector, a backlight for a liquid crystal display device, and the like.

It is an external appearance perspective view of the light source device in 1st Embodiment of this invention. It is the top view and side view which show the structure of the two prism sheets shown in FIG. FIG. 3 is a plan view showing a relationship between two prism sheets shown in FIG. 2 and a plurality of light sources. It is the elements on larger scale of prism sheet PS2 shown in FIG. It is the elements on larger scale of prism sheet PS1 shown in FIG. FIG. 3 is a perspective view schematically illustrating a passing optical path of incident light in two prism sheets illustrated in FIG. 2. It is a side view which shows the breadth of a light ray when incident light inclines into the prism sheet of this invention. It is a top view of the light ray which injected into the prism sheet shown in FIG. 7 from 4 light sources. It is a side view which shows the breadth of a light ray when incident light inclines into the prism sheet of the light source device in 2nd Embodiment of this invention. It is a top view of the incident light to the prism sheet shown in FIG. FIG. 10 is a plan view of light rays incident on the prism sheet shown in FIG. 9 from four light sources. It is an external appearance perspective view of the light source device in 3rd Embodiment of this invention. It is sectional drawing of BlueYAG * LED shown in FIG. It is a block diagram of the conventional color projector. It is a fragmentary sectional view of the linear prism board shown in FIG. It is a disassembled perspective view of the conventional surface emitting device. FIG. 17 is a partially enlarged side view of the light emitting substrate shown in FIG. 16.

Explanation of symbols

1 LED
1r red LED
1b Blue LED
1g green LED
1by BlueYAG ・ LED
2 Condensing lens 3 Case 10, 20 Light source device 12 Anamorphic lens PS1, PS2 Prism sheet K1, K2, K3, K4 Light source P1, P2, P3, P4 Incident light L1, L2, U1, U2 Prism slope Po Condensing point S , S14, S23 Illumination light 31, 32 Electrode 33 Substrate 35 Fluorescent particle 36 Transparent resin Pb Blue light Pe Yellow light Pwy, Pw White light

Claims (22)

  A plurality of light sources and a plurality of fine prism rows on one surface and two prism sheets on the other surface are flat, and the two prism sheets cross each other at a predetermined angle. By stacking and arranging the plurality of light sources at a predetermined angle on the lower surface side of the two stacked prism sheets, a predetermined angle is obtained from the lower surface side of the two stacked prism sheets. A light source device characterized in that incident light from a plurality of light sources incident at an angle is output as emitted light obtained by combining the upper surfaces of two prism sheets.   2. The light source device according to claim 1, wherein each of the light sources is distributed and arranged in four zones formed by crossing of the respective prism rows in the two stacked prism sheets.   3. The light source device according to claim 1, wherein the incident light of each light source is incident along the vicinity of the center line of the crossing angle of each prism row in the two stacked prism sheets.   4. The light source device according to claim 1, wherein incident light from each of the light sources is incident toward a predetermined condensing point in the two prism sheets stacked. 5.   5. The light source device according to claim 4, wherein each of the light sources is arranged point-symmetrically with respect to a predetermined condensing point in the two prism sheets.   5. The light source device according to claim 4, wherein each of the light sources is arranged symmetrically with respect to an axis passing through a predetermined condensing point in the two prism sheets.   The light source device according to claim 1, wherein an apex angle of the fine prism row is substantially a right angle.   The light source device according to claim 1, wherein a pitch of the plurality of fine prism rows is 1 μm to 100 μm.   9. The light source device according to claim 1, further comprising a condensing optical device (lens) in front of a light emitting surface of the plurality of light sources. 10.   The light source device according to claim 9, wherein the optical device is a lens having different radii of curvature in the vertical and horizontal directions.   A plurality of light sources having different emission colors, a plurality of fine prism rows on one surface, and two prism sheets having a flat surface on the other surface, each prism row being a predetermined one. The lower surfaces of the two prism sheets stacked by arranging the plurality of light sources at a predetermined angle on the lower surface side of the two stacked prism sheets. A light source device that outputs incident light from a plurality of light sources incident at a predetermined angle from the side as emitted light obtained by mixing colors from the upper surface side of two prism sheets.   The light source device according to claim 11, wherein the light sources are distributed and arranged in four zones formed by intersections of the prism rows in the two stacked prism sheets.   13. The light source device according to claim 11 or 12, wherein the incident light of each light source is incident along the vicinity of the center line of the intersection angle of each prism row in the two stacked prism sheets.   14. The light source device according to claim 11, wherein incident light of each light source is incident toward a predetermined condensing point in the two stacked prism sheets.   The light source device according to claim 14, wherein each of the light sources is arranged point-symmetrically with respect to a predetermined condensing point in the two prism sheets.   The light source device according to claim 14, wherein each of the light sources is arranged symmetrically with respect to an axis passing through a predetermined condensing point in the two prism sheets.   The light source device according to claim 11, wherein an apex angle of the fine prism row is substantially a right angle.   18. The light source device according to claim 11, further comprising a condensing optical device (lens) in front of the light emitting surfaces of the plurality of light sources.   The light source device according to claim 18, wherein the optical device is a lens having different radii of curvature in the vertical and horizontal directions.   The light source device according to claim 11, wherein the plurality of light sources include R, G, and B LED light sources.   21. The light source device according to claim 20, wherein R, G, and B LED light sources are disposed at three positions in the two prism sheets stacked, and a G / LED light source is disposed at the remaining one position.   21. The light source device according to claim 20, wherein R, G, and B LED light sources are disposed at three locations in the two prism sheets stacked, and a BlueYAG / LED light source is disposed at the remaining one location.

Images