JP4716437B2 - 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 in these devices, for example, there is a method using a dichroic prism for a color projector or a projection type color television (see, for example, Patent Document 1). In addition, since this dichroic prism is an expensive member, the price as a device is increased, and this method has a drawback that inherently causes a large amount of light loss. A light source device that uses a sheet to make a plurality of light beams into a single light beam has been proposed. (For example, see Patent Document 2.)

  Hereinafter, the structure of the light source device in the prior art will be described based on the drawings. 15 and 16 show the configuration of the color projector shown in Patent Document 2, FIG. 15 is a configuration diagram of the color projector, and FIG. 16 is a partial sectional view of the linear prism plate shown in FIG. In FIG. 16, reference numeral 50 denotes a linear prism plate. The upper surface constitutes an exit surface having a large number of prism rows, and the lower surface constitutes 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.

  That is, 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 can be respectively transmitted to the prism. The light is refracted at the two emission surfaces 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. 15 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. 55 is a projection lens, 56 is a projection screen, 57 is an R light source, 58 is a G light source, 59 is a B light source, 61, 62, and 63 are relay lenses for the R light source 57, the G light source 58, and the B light source 59, respectively. It is.

  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 is incident on 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 °. Become.

  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.

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

  However, the light source device in the prior art has the following problems. The light source device using the dichroic prism in Patent Document 1 is an expensive member having a structure in which the dichroic prism is bonded to four glass members provided with a dichroic mirror. There is a problem that it involves a substantial loss of light.

  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, B, and three color LEDs, an arrangement interval having a predetermined angle is provided in the two linear prisms. Since the arrangement space for the linear prism is widened, the shape of the light source device as a whole becomes large, which makes it 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, resulting in a further different aspect ratio.

(Object of invention)
The present invention has been made in view of the above problems, and is made thin by using a single prism sheet in which a plurality of fine prism rows are formed on two opposing surfaces and the prism rows cross at a predetermined angle. 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, and has excellent photosynthesis performance by devising the incident direction of the light source and allowing the prism sheet to perform the synthesis function.

  A plurality of light sources and a plurality of fine prism rows are formed on two opposing surfaces, and the prism rows cross each other at a predetermined angle. The plurality of light sources are arranged on the lower surface side of the prism sheet. Is inclined at a predetermined angle, and the incident light from the plurality of light sources incident at a predetermined angle from the lower surface side of the prism sheet is output as output light synthesized from the upper surface side of the prism sheet. Features.

  According to the above configuration, incident light from a plurality of light sources can be synthesized by a single prism sheet, so that the arrangement space between the sheets necessary for the synthesis by two linear prisms is not required, and a thin configuration In addition, it is possible to provide a light source device in which photosynthesis is realized with a single sheet member without using an expensive member, the member cost is low, the shape is small and thin, and the price is low.

  The light sources of the plurality of light sources are distributed and arranged in four zones that are divided by the intersection of the prism rows formed on two opposing surfaces of the prism sheet.

  Incident light of each light source of the plurality of light sources is incident along the vicinity of the center line of the intersection angle of each prism row formed on two opposing surfaces of the prism sheet.

  Incident light of each light source of the plurality of light sources is incident toward a predetermined condensing point on the prism sheet.

  Each light source of the plurality of light sources is arranged point-symmetrically with respect to a predetermined condensing point on the prism sheet.

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

  As in the above configuration, a plurality of light sources are distributed and arranged in four zones divided by the intersection of each prism row formed on two opposing surfaces of the prism sheet, and the incident light of each light source The incident light is incident along the vicinity of the center line of the crossing angle of the prism row, and further, all incident light of each light source is incident toward a predetermined condensing point on the prism sheet. The light combining function can be performed by one prism sheet.

  The prisms formed on two opposing surfaces of the prism sheet have the same apex 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. In addition, it is difficult to discriminate the prism apex angle of the fine prism row by visual appearance, and it becomes possible to use either the front or back side by setting the apex angle of each prism row formed on the two opposing surfaces to the same angle. Handling becomes easy.

  Each of the plurality of light sources includes a condensing lens in front of the light emitting surface.

  The lens 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. Therefore, it is possible to provide a light source device having optically excellent photosynthesis performance.

  A plurality of light sources having different emission colors and a plurality of fine prism rows are formed on two opposing surfaces, and the prism rows are formed by one prism sheet intersecting at a predetermined angle, on the lower surface side of the prism sheet, By arranging the plurality of light sources to be inclined at a predetermined angle, incident light from the plurality of light sources incident at a predetermined angle from the lower surface side of the prism sheet is output as emitted light obtained by mixing colors from the upper surface side of the prism sheet. It is characterized by doing.

  According to the above configuration, since incident light from a plurality of light sources having different emission colors can be mixed by one prism sheet, the arrangement space between the sheets required for color mixing by two linear prisms is increased. An optical system with a thin configuration is possible because it is unnecessary, and color mixing is realized with a single sheet member without using an expensive member, so that the material cost is low, the shape is small and thin, and the price is low. be able to.

The light sources of the plurality of light sources are distributed and arranged in four zones that are divided by the intersection of the prism rows formed on two opposing surfaces of the prism sheet.

  Incident light of each light source of the plurality of light sources is incident along the vicinity of the center line of the crossing angle of each prism row formed on two opposing surfaces of the prism sheet.

  Incident light of each light source of the plurality of light sources is incident toward a predetermined condensing point on the prism sheet.

  Each light source of the plurality of light sources is arranged point-symmetrically with respect to a predetermined condensing point on the prism sheet.

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

  As in the above configuration, a plurality of light sources having different emission colors are distributed and arranged in four zones divided by the intersection of each prism row formed on two opposing surfaces of the prism sheet, and the incident light of each light source is Incident of multiple light sources peculiar to the present application in which light is incident along the vicinity of the center line of the crossing angle of each prism row in the prism sheet, and all incident light of each light source is incident toward a predetermined condensing point in the prism sheet. Depending on the method, a color mixing function can be performed by a single prism sheet.

  The prisms formed on two opposing surfaces of the prism sheet have the same apex angle.

  Each of the plurality of light sources includes a condensing lens in front of the light emitting surface.

  The lens 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. Therefore, it is possible to provide a light source device having excellent optical color mixing performance.

  The plurality of light sources include red, green, and blue LED light sources.

  The red, green, and blue LED light sources are disposed at three locations in the four zones of the prism sheet, and the green LED light sources are disposed at the remaining one location.

  The prism sheet is characterized in that red, green, and blue LED light sources are disposed at three locations in four zones, and a white LED light source is disposed at the remaining one location.

  According to the above configuration, in the emission of white light by mixing the red, green, and blue LED light sources, the number of green LED light sources that emit less light than the red and blue LED light sources is increased, thereby efficiently performing color. A well-balanced white light can be emitted. Moreover, a bright light source device with good color rendering can be realized by adding a white LED light source different from the emission spectrum included in the red, green, and blue LED light sources.

  As described above, in the light source device of the present invention, incident light from a plurality of light sources can be synthesized and mixed by a single prism sheet, so that an optical system with a thin configuration is possible, and the price is small and thin. It is possible to provide a light source device that is optically excellent in photosynthesis and color mixing performance.

  The light source device of the present embodiment includes a plurality of light sources and a prism sheet that has a plurality of fine prism rows formed on two opposing surfaces and intersects at a predetermined angle. The plurality of light sources are arranged at a predetermined angle on the incident surface side of the prism sheet.

  The arrangement inclined at a predetermined angle is to output incident light from a plurality of light sources incident at a predetermined angle from the incident surface side of the prism sheet as output light synthesized from the output surface side of the prism sheet. The arrangement is such that the emitted light is emitted in the same direction, for example, directly above, and the light emitted from the light source is emitted toward a predetermined condensing point on the prism sheet. Similarly, the prism rows crossed at a predetermined angle are also in a state in which the light emitted from the plurality of light sources is combined by the prism sheet so as to be emitted in the same direction. It is determined by the refractive index of the sheet, the prism shape, the prism apex angle, and the like.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 7 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, FIG. 2 is a top view and a side view showing a configuration of a prism sheet, and FIG. It is a top view which shows the relationship between a prism sheet and several light sources. In FIG. 1, reference numeral 10 denotes a light source device, which is composed of a prism sheet PS and four light sources K1, K2, K3, and K4 arranged at a predetermined angle on the lower surface side of the prism sheet PS. 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 PS, and are mixed in the prism sheet PS to be emitted in the vertical direction from the emission surface of the prism sheet PS as a single white light Pw obtained by combining the R light, the G light, and the B light. Let

  Next, the positional relationship between the prism sheet PS 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 prism sheet PS, showing a top view of the prism sheet PS in the center, a side view seen from the X-axis direction on the left side, and a side view seen from the Y-axis direction on the lower side. The figure is shown. FIG. 3 shows an arrangement relationship of the four light sources K1, K2, K3, and K4 with respect to the top view of the prism sheet PS shown in FIG.

  As shown in FIG. 2, the prism sheet PS is formed with fine prism rows that are crossed at a predetermined angle on the upper and lower surfaces, and the lower prism row is PS1 and the upper prism row is PS2. In the present embodiment, the prism rows PS1 and PS2 are arranged so that each apex angle is 60 ° and each prism row crosses at an orthogonal angle. Accordingly, the solid line parallel to the Y axis in the top view of the prism sheet PS indicates the top and valley lines in the prism row of the upper prism row PS2, and the dotted line parallel to the X axis indicates the prism of the lower prism row PS1. The top and trough lines in the row are shown, and the solid line and the dotted line constitute an orthogonal grid. The pitch of each prism row is a fine pitch of 1 μm to 100 μm.

  Next, the positional relationship between the prism sheet PS and the four light sources K1, K2, K3, K4 is four zones divided by the intersection of the prism rows formed on the upper and lower surfaces of the prism sheet PS, as shown in FIG. Four light sources K1, K2, K3, and K4 are distributed and arranged in four zones S1, S2, S3, and S4 obtained by dividing the plane of the prism sheet PS by the X axis and the Y axis. Therefore, the incident light P1 radiated from the light source K1, the incident light P2 radiated from the light source K2, the incident light P3 radiated from the light source K3, and the incident light P4 radiated from the light source K4 are crossed by the prism rows in the prism sheet PS. It enters along the vicinity of the corner center lines N and M, and enters in a concentrated manner toward a predetermined condensing point Po of the prism sheet PS. In the present embodiment, the predetermined condensing point Po of the prism sheet PS is set as the upper center point of the upper prism row PS2.

  As a result, as shown in FIG. 3, the light source K1, the light source K4, the light source K2, and the light source K3 are arranged at point-symmetrical positions with respect to the condensing point Po, and the light source K1 and the light source K3. In addition, 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 material of the prism sheet PS. In the present embodiment, acrylic (PMMA) having a refractive index n of 1.49 is used as the material of the prism sheet PS, and the prism apex angle is set to 60 ° in both the prism rows PS1 and PS2. Therefore, all the light sources K1, K2, K3, and K4 are disposed at the same angle of 47.8 ° 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, the angles are the same even if the directions of the light beams are different. In order to emit the emitted light in the directly upward direction with the refractive index n of the prism sheet PS being 1.49 and the prism apex angle being 60 ° both vertically, Are incident at the same angle of ± 47.8 ° with respect to the X axis.

  The incident conditions from each light source on the prism sheet PS in the present invention will be described in detail later, but a basic light synthesis (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 prism sheet PS, that is, the direction perpendicular to the X-axis / Y-axis plane is the Z-axis, and one prism slope constituting the prism surface of the prism row PS1 is L1. When the slope is L2, one prism slope constituting the prism surface of the prism row PS2 is U1, and the other prism slope is U2, each light source K1, K2, K3, K4 is placed on the lower surface side of the prism row PS1 on the Z axis. As described above, it is disposed at a predetermined angle from the X axis and at a position 47.8 ° 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 radiated from the light source K1 enters from the prism slope L2 of the prism row PS1, passes through the prism slope U2 of the prism row PS2, and becomes output light. Incident light P2 radiated from K2 enters from the prism slope L2 of the prism row PS1, passes through the prism slope U1 of the prism row PS2, and incident light P3 radiated from the light source K3 enters from the prism slope L1 of the prism row PS1. Incident light P4 that has passed through the prism slope U2 of the prism row PS2 and radiated from the light source K4 enters from the prism slope L1 of the prism row PS1, passes through the prism slope U1 of the prism row PS2, and becomes emitted light.

  In addition, incident light having a wide area emitted from each light source is incident on each inclined surface of a large number of prism rows provided on the prism sheet PS and refracts radiation. As described above, the pitch of each prism row is Since it has a fine pitch of 1 μm to 100 μm, it is not visually recognized as separate emitted light but is recognized as a single synthesized emitted 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 prism sheet PS will be described. FIG. 4 is a partially enlarged view of the prism row PS2 in the prism sheet PS shown in FIG. 2, and shows the optical path of each incident light passing through the prism row PS2 while being refracted. FIG. 5 is a partially enlarged view of the prism row PS1 in the prism sheet PS shown in FIG. 2, and shows the optical path of each incident light that passes through the prism row PS1 while being reflected and refracted. In the present embodiment, acrylic having a refractive index of 1.49 is used as the material of the prism sheet PS, and the prism apex angle is 60 ° both in the vertical direction.

  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 an outgoing 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 upper prism row PS2 of the prism sheet PS in 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 prism row PS1 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 PS 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 prism row PS1 into the air based on the above result, the inside of the prism sheet is the same. It is possible to obtain outgoing light in a direction immediately above the prism row PS2.

  Next, the actual optical path of incident light from each light source for the two prism rows PS1 and PS2 will be described with reference to FIGS. In the case of the upper prism row PS2 shown in FIG. 4, the X-axis / Z-axis plane is shown, and the incident light P1 from the light source K1 and the incident light P3 from the light source K3 shown in FIG. The incident light P2 from the light source K2 and the incident light P4 from the light source K4 pass through the prism inclined surface U2 and are emitted in the upward direction through the prism inclined surface U1 on the left side of the prism row PS2. Accordingly, the incident light from the lower side of the prism row PS2 is incident light P1, P3 is inclined right, and the incident light P2, P4 is inclined left and the incident direction is reversed, but the incident light travels at all angles. The same angle.

  That is, the angles β2 and α2 with respect to the boundary normal line (shown by dotted lines) of the prism slope of the prism row PS2 in each incident light are all the same. These angles use acrylic having a refractive index of 1.49, and in the prism row PS2 having a prism apex angle of 60 °, β2 = 35.5 ° and α2 = 60.0 °.

  Next, in the case of the lower prism row PS1 shown in FIG. 5, the Y-axis-Z-axis plane is shown, and each incident light is refracted and incident on the prism row PS1, and the incident prism surface has a reverse inclination. The light is totally reflected on the prism surface and advances through the prism sheet. The angles α1, β1, and γ with the boundary surface normal (shown by dotted lines) of the prism row PS1 in each incident light are all the same. These angles use acrylic with a refractive index of 1.49, and α1 = 38.1 °, β1 = 24.5 °, and γ = 62.9 ° in the prism array PS1 having a prism apex angle of 60 °. . In addition, although each output light P1-P4 from prism row | line | column 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 Y-axis-Z-axis plane of FIG. However, actually, the emitted lights P1 and P3 have an inclination angle toward the back of the paper surface, and the emitted lights P2 and P4 have an inclination angle toward the near side of the paper surface. Similarly, α1 and β1 in FIG. 5 are illustrated at a minute angle, but actually have an inclination angle in a direction perpendicular to the paper surface.

  6A and 6B are a top view and a side view showing a passing optical path of incident light, showing a top view of the prism sheet PS in the center, a side view seen from the X-axis direction shown in FIG. 5 on the left side, and FIG. The side view seen from the Y-axis direction shown in FIG. The solid line and the dotted line in the top view of the prism sheet PS indicate the top and trough lines in the prism row as in FIG. In FIG. 6, the light beam directed directly upward is only the light emitted from the prism row PS2, and in FIG. 5, the light beam that has an inclination angle in the direction perpendicular to the paper surface and cannot be illustrated is also a top view and a side view in a different direction. From the above, the inclination and traveling direction of the light beam can be understood. The inclination directions of the incident lights P1 to P4 are different from each other, but the inclination angles are all the same, 66.8 ° with respect to the Z axis, and 47 with respect to the X axis in the X axis-Y axis plane. It has the same angle of inclination of 8 °. If this is based on the normal to the boundary surface of the prism slope in the prism row PS1, the inclination becomes 38.1 ° and oblique light is incident. The angle of each incident light with respect to each prism boundary surface normal is as described above, and is transmitted through the prism row PS2 and emitted in a direction directly above the upper surface. In FIGS. 4 to 6, the incident lights P <b> 1 to P <b> 4 are shown in a state in which they pass through different prism slopes and are emitted directly upward for easy understanding. It also passes through the prism slope at the same time and is synthesized.

  FIG. 7 schematically shows a traveling state of an optical path through which incident light continuously passes through the two prism rows PS1 and PS2, and only the incident light P1 is representatively shown. That is, the incident light P1 traveling from the lower side of the two prism rows to the prism row PS1 at an angle of 66.8 ° with respect to the Z axis and 47.8 ° with respect to the X axis in the X axis-Y axis plane is Then, the light beam enters the prism slope L2 of the prism row PS1 with an inclination of 38.1 ° from the boundary surface normal (f1). The light beam is refracted and travels through the prism sheet with an inclination of 24.5 ° from the boundary surface normal and travels toward the prism slope L1. The light beam reaching the prism slope L1 is at an angle of 62.9 ° from the boundary normal to the prism slope L1, and is totally reflected because it reaches the boundary surface at an angle larger than the critical angle (f2). The totally reflected light beam travels in the prism sheet at an angle of 62.9 ° from the boundary normal similar to that at the time of arrival, travels toward the prism row PS2, and 35.5 ° from the boundary normal to the prism slope U2 of the prism row PS2. (F3). The light beam is refracted and emitted into the air in the direction of 60.0 ° from the boundary surface normal, that is, directly above the Z axis. Although illustration is omitted, incident light P2, P3, and P4 are also emitted in the same manner according to the optical paths shown in FIGS.

  As described above, in the present embodiment, the incident light is inclined with respect to the prism sheet having the prism rows formed by intersecting the two opposing surfaces, and the angle between the X axis-Y axis plane direction and the Z axis direction. The prism slope is used diagonally. As a result, under the same optical conditions, incident light from four directions can be simultaneously incident and synthesized.

  Next, the spread of light rays in the light source device of this embodiment will be described. FIG. 8 is a side view showing the spread of light when incident light P1 and P4 are incident on the lower surface of the prism sheet PS. 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 (66.8 °) from the Z axis is the incident optical axis from the light sources K1 and K4. The horizontal axis is an axis rotated 47.8 ° from the X axis of the prism sheet PS. Considering the case where incident light P1 having a light flux width H from the light source K1 is incident on the lower surface of the prism sheet PS, a light beam having a width is incident from an oblique direction toward the horizontal plane. Spreads and is emitted as a light beam having a width of 2.5H. 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. 9 is a plan view showing the spread of light rays when incident light is incident on the prism sheet PS from four directions by the four light sources K1 to K4 in the light source device shown in FIG. In FIG. 9, the dotted line is an axis rotated 47.8 ° 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 having a short axis having a width H of incident light and a long axis having a width H of outgoing light of 2.5H. 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. 10 is a side view showing the spread of light when incident light P1 and P4 are incident on the lower surface of the prism sheet PS from the light sources K1 and K4, and corresponds to FIG. 8 in the light source device of the first embodiment. . Therefore, the same elements as those of the light source device of FIG. The light source device of FIG. 10 is different from the light source device of FIG. 8 in that lenses having different radii of curvature in the vertical and horizontal directions are provided in the optical path between the light source K1 and the light source K4 and the lower surface of the prism sheet PS1. In the present embodiment, an anamorphic lens 12 is provided.

  Next, the spreading state of light rays 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. 11A 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. 12 is a plan view showing the spread of light rays when incident light is incident on the prism sheet PS from four directions by four light sources K1 to K4 in the light source device having the anamorphic lens 12 shown in FIG. This corresponds to FIG. 9 in the light source device of the first embodiment. 12 differs from FIG. 9 in that 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 both have a circular shape with a diameter of 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. In the light source device of FIG. 10, 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. 8 is not limited to this, and is provided in each light source K. An anamorphic lens 12 may be provided instead of the condensing lens 2.

  The amount of light spread in the light source device can be adjusted by the refractive index and prism apex angle of the prism sheet PS used in the light source device. The prism sheet PS of the present embodiment uses a prism array having a refractive index of 1.49 and a prism apex angle of 60 ° both in the vertical direction, and the light beam width is 2.5 times larger. For example, when only the apex angle of the lower prism row PS1 is changed to 50 ° from this prism sheet, the direction inclined by 52.0 ° from the Z-axis is the incident optical axis from the light source, and the amount of light spread is 1. As a result, the load of adjusting the aspect ratio by the anamorphic lens 12 can be reduced. However, the prism row of the prism sheet PS is fine, and it is difficult to distinguish the prism apex angle from the visual appearance. It is more preferable that the prism apex angle is adjusted at the same angle on both sides so that the prism sheet PS can be used on either the front or back side and is easy to handle.

  Next, a light source device according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a perspective view of the light source device according to the third embodiment. The basic configuration is the same as that of the light source device according to the first embodiment shown in FIG. Omitted. In FIG. 13, reference numeral 20 denotes a light source device, which is different from the light source device 10 of FIG. 1 in that a white LED 1w is disposed instead of G · LED as a light emitting means of the light source K3.

  Next, the configuration of the white LED 1w will be described. FIG. 14 is a cross-sectional view of a phosphor mixed color white LED. In the white LED 1w, 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 in which YAG-based fluorescent particles 35 are mixed.

  In the operation of the white LED 1w, when a drive voltage is applied to the electrodes 31, 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 light Pb emitted from the B LED 1b and output without colliding with the fluorescent particles 35 and the yellow light Pe having collided with the fluorescent particles 35 and wavelength-converted are mixed from the white LED 1w. Light is emitted as fluorescent white light Pwy.

  As shown in FIG. 13, the light source device 20 performs color mixing by arranging the R · LED 1r for the light source K1, the G · LED 1g for the light source K2, the white LED 1w for the light source K3, and the B · LED 1b for the light source K4. Therefore, in addition to the color mixture by the R, G, and B LEDs, the bright white light Pwy by the white LED 1w 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 and mixed by a thin optical system using a single prism sheet. A light source device having excellent photosynthetic performance can be provided.

  The light source device of the present invention can realize a condensing light source device that synthesizes light sources of the same wavelength and a mixed color 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 upper side figure and side view which show the structure of the prism sheet shown in FIG. FIG. 3 is a plan view showing the relationship between the prism sheet shown in FIG. 2 and a plurality of light sources. It is the elements on larger scale of the prism sheet shown in FIG. It is the elements on larger scale of the prism sheet shown in FIG. It is the top view and side view which show the passage optical path of the incident light in the prism sheet shown in FIG. FIG. 3 is a perspective view schematically showing a passing optical path of incident light in the prism sheet shown 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. 8 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. It is a top view of the light ray which injected into the prism sheet shown in FIG. 10 from 4 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 white LED shown in FIG. It is a block diagram of the conventional color projector. FIG. 16 is a partial cross-sectional view of the linear prism plate shown in FIG. 15.

Explanation of symbols

1 LED
1r red LED
1b Blue LED
1g green LED
1w white LED
2 Condensing lens 3 Case 10, 20 Light source device 12 Anamorphic lens PS Prism sheet PS1, PS2 Prism rows K1, K2, K3, K4 Light sources P1, P2, P3, P4 Incident light L1, L2, U1, U2 Prism slope Po Collection Light spot 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 are formed on two opposing surfaces, and the prism rows cross each other at a predetermined angle. The plurality of light sources are arranged on the lower surface side of the prism sheet. Is inclined at a predetermined angle, and the incident light from the plurality of light sources incident at a predetermined angle from the lower surface side of the prism sheet is output as output light synthesized from the upper surface side of the prism sheet. A light source device.   2. The light sources of the plurality of light sources are distributed and arranged in four zones divided by intersections of prism rows formed on two opposing surfaces of the prism sheet. Light source device.   The incident light of each light source of the plurality of light sources is incident along the vicinity of the center line of the crossing angle of each prism row formed on two opposing surfaces of the prism sheet. Light source device.   4. The light source device according to claim 1, wherein incident light of each light source of the plurality of light sources is incident toward a predetermined condensing point on the prism sheet. 5.   5. The light source device according to claim 4, wherein the light sources of the plurality of light sources are arranged point-symmetrically with respect to a predetermined condensing point on the prism sheet.   5. The light source device according to claim 4, wherein each light source of the plurality of light sources is arranged symmetrically with respect to an axis passing through a predetermined condensing point in the prism sheet.   7. The light source device according to claim 1, wherein apex angles of the prism rows formed on two opposing surfaces of the prism sheet are the same.   8. 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, wherein a condensing lens is provided in front of a light emitting surface of each of the plurality of light sources.   The light source device according to claim 9, wherein the lens is a lens having different radii of curvature in the vertical and horizontal directions.   A plurality of light sources having different emission colors and a plurality of fine prism rows are formed on two opposing surfaces, and the prism rows are formed by one prism sheet intersecting at a predetermined angle. By arranging the plurality of light sources to be inclined at a predetermined angle, incident light from the plurality of light sources incident at a predetermined angle from the lower surface side of the prism sheet is output as emitted light obtained by mixing colors from the upper surface side of the prism sheet. And a light source device.   12. The light sources of the plurality of light sources are distributed and arranged in four zones divided by intersections of prism rows formed on two opposing surfaces of a prism sheet. Light source device.   The incident light of each light source of the plurality of light sources is incident along the vicinity of the center line of the crossing angle of each prism row formed on two opposing surfaces of the prism sheet. Light source device.   14. The light source device according to claim 11, wherein incident light of each light source of the plurality of light sources is incident toward a predetermined condensing point on the prism sheet.   The light source device according to claim 14, wherein the light sources of the plurality of light sources are arranged point-symmetrically with respect to a predetermined condensing point on the prism sheet.   The light source device according to claim 14, wherein the light sources of the plurality of light sources are arranged in line symmetry with respect to an axis passing through a predetermined condensing point in the prism sheet.   The light source device according to any one of claims 11 to 16, wherein apex angles of the respective prism rows formed on two opposing surfaces of the prism sheet are the same.   18. The light source device according to claim 11, wherein a condensing lens is provided in front of a light emitting surface of each of the plurality of light sources.   19. The light source device according to claim 18, wherein the lens is a lens having different radii of curvature in the vertical and horizontal directions.   The light source device according to any one of claims 11 to 19, wherein the plurality of light sources include red, green, and blue LED light sources.   21. The light source device according to claim 20, wherein red, green, and blue LED light sources are disposed at three locations in the four zones of the prism sheet, and a green LED light source is disposed at the remaining one location.   21. The light source device according to claim 20, wherein red, green, and blue LED light sources are disposed at three locations in the four zones of the prism sheet, and a white LED light source is disposed at the remaining one location.

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