JP2007206668A - Image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display furnished with a telecentric optical system in which aberration generated by the difference in optical paths of a plurality of light beams emitted from respective light sources is minimized and light condensing characteristic is improved. <P>SOLUTION: The image display includes the telecentric optical system provided with: a plurality of light sources 2 (2a, 2b, 2c and others); a condensing lens 5 which condenses the light beams emitted from the plurality of light sources 2; and a light receiving plate 6 having a light receiving face which receives light beams condensed with the condensing lens 5, wherein each of the plurality of light sources 2 (2a, 2b, 2c and others) is so arranged that the aberration of the respective light sources 2 is minimized and the distances on the lines vertically drawn from the respective light sources 2 to the plane which passes through the center of the condensing lens 5 and is perpendicular to an optical axis are different from each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device, and more particularly to a two-dimensional scan type display device.

  Conventionally, as an image display device, as disclosed in Patent Document 8, an image display device including a light beam and a scanning optical system has been widely used. As the scanning optical system, a telecentric optical system is well known and disclosed in Patent Document 1, Patent Document 2, and the like. In the telecentric optical system described above, aberrations inevitably occur, so an extremely large number of lenses are combined, many aspheric surfaces are used in the lens, and design elements such as the refractive index of the lens are used to make aberrations. Is corrected. In the invention of Patent Document 3, a special lens such as a cylindrical lens is used, and the aberration is corrected by placing a light receiving plate at a sagittal image plane position with little aberration.

  Further, Patent Literature 4, Patent Literature 5, Patent Literature 6, and the like are disclosed as optical systems that perform aberration correction on the light receiving plate. Patent Document 4 discloses an imaging apparatus that suppresses the occurrence of aberrations by forming a light-receiving plate that is curved along a curved image surface by a spherical lens. Patent Document 5 discloses a CCD detector having a light receiving plate having a curvature radius that matches the curvature radius of the curved surface of the image surface. Furthermore, Patent Document 6 discloses a solid-state imaging camera that freely adjusts the radius of curvature of the light receiving plate of the solid-state imaging chip, corrects the curvature aberration, and increases the resolution.

Further, Patent Document 7 is disclosed as an optical system that corrects aberration by moving a light source.
Japanese Patent Laid-Open No. 2-88620 (published on January 12, 1990) JP 2000-111793 A (published on April 21, 2000) JP 58-93027 A (published June 2, 1983) JP 63-96616 A (published April 27, 1988) Japanese Patent Laid-Open No. 4-150276 (published on May 22, 1992) Japanese Patent Laid-Open No. 10-108078 (published on April 24, 1998) Japanese Patent Laid-Open No. 2-8809 (published on January 12, 1990) US Pat. No. 5,701,132 (published December 23, 1997)

  However, as in the telecentric optical system disclosed in Patent Document 1 and Patent Document 2, aberration correction using only a condensing lens inevitably increases the number of lenses. Therefore, it is disadvantageous for downsizing as an image display device and has a great demerit that it is costly. In addition to the above reasons, since the material of the lens is limited in order to reduce the cost, there is a problem that the lens design becomes difficult and the time required for the design is prolonged.

  In the case of a telecentric optical system having a plurality of light sources, the optical path lengths of the plurality of light sources differ depending on their positions, so that it is difficult to correct aberrations using only lenses.

  Furthermore, the optical system disclosed in Patent Document 3 uses a special lens such as a cylindrical lens, and such a lens has the disadvantages that it is very difficult to manufacture and the cost is high.

  Furthermore, in the optical systems disclosed in Patent Document 4, Patent Document 5, and Patent Document 6, the light receiving surface of the curved light receiving plate is an image sensor such as a CCD, and the light receiving surface of the light receiving plate is an observation device such as a screen. It cannot be applied to an optical system such as a display that a person sees.

  Further, as disclosed in Patent Document 7, the method of correcting aberration by moving the light source in parallel cannot cope with an optical system having a plurality of light sources.

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to minimize the aberration caused by the difference in the optical path lengths of the light emitted from each of the plurality of light sources, and to collect the light. It is an object of the present invention to provide an image display device including a telecentric optical system that can improve the performance.

  In order to solve the above problems, an image display device of the present invention includes a plurality of light sources, a condensing lens that condenses light emitted from the plurality of light sources, and light collected by the condensing lens. A telecentric optical system including a light receiving plate having a light receiving surface, and each light source in the plurality of light sources is perpendicular to the optical axis through the central portion of the condenser lens so that the aberration of each light source is reduced. It is characterized in that the distances perpendicular to the surface from each light source are different from each other.

  According to the invention, each light source of the plurality of light sources is arranged at different distances perpendicular to each light source with respect to a plane that passes through the central portion of the condenser lens and is perpendicular to the optical axis. The difference in the optical path length of the light emitted from each light source can be reduced as compared with the conventional case. Therefore, it is possible to realize a telecentric optical system with good light condensing property by minimizing the aberration caused by the difference in optical path length.

  In order to solve the above problems, the image display device of the present invention is focused by a plurality of light sources, a condensing lens that condenses light emitted from the plurality of light sources, and the condensing lens. A telecentric optical system including a light receiving plate having a light receiving surface for receiving light, wherein the light receiving surface is curved so as to reduce the aberration of each light source.

  According to the above invention, since the light receiving plate having the light receiving surface is curved toward the condenser lens, the aberration caused by the difference in the optical path length of the light emitted from each light source is received. It can be made as small as possible on the light receiving surface of the plate. Therefore, it is possible to realize a telecentric optical system with good light condensing property by minimizing the aberration caused by the difference in optical path length.

  In the image display device of the present invention, it is more preferable that the light receiving surface is curved in a concave shape toward the condenser lens.

  Thereby, the aberration generated by the difference in the optical path length of the light emitted from each light source can be made as small as possible, and a telecentric optical system with better light collection can be realized.

  In the image display device of the present invention, each light source in the plurality of light sources has a light source with respect to a plane perpendicular to the optical axis through the central portion of the condenser lens so that the aberration of each light source is reduced. It is more preferable that the distances perpendicular to each other are different.

  Thereby, the difference of the optical path length of the light radiate | emitted from each light source can be made smaller, and the aberration which generate | occur | produces by the said optical path length difference can be made as small as possible.

  In the image display device of the present invention, it is more preferable that the substrate on which the plurality of light sources are mounted has a stepped portion on the condenser lens side so that the aberration of each light source is reduced.

  As a result, each light source of the plurality of light sources is arranged with different distances perpendicular to each light source with respect to a plane that passes through the central portion of the condenser lens and is perpendicular to the optical axis. High aberration correction can be realized.

  In the image display device of the present invention, it is preferable that the base is further provided with a stepped portion in a concave shape toward the condenser lens.

  Thereby, aberration correction with higher accuracy can be realized.

  In the image display device of the present invention, it is more preferable that the substrate on which the plurality of light sources are mounted is curved so that the aberration of each light source is reduced.

  As a result, each light source of the plurality of light sources is arranged with different distances perpendicular to each light source with respect to a plane that passes through the central portion of the condenser lens and is perpendicular to the optical axis. High aberration correction can be realized. Further, since the base is curved toward the condenser lens, the amount of light incident on the condenser lens is increased, so that a brighter image can be obtained.

  In the image display device of the present invention, it is more preferable that the base is further curved in a concave shape toward the condenser lens.

  Thereby, since the light quantity of the light which injects into a condensing lens increases more, a still brighter image can be obtained.

  In the image display device of the present invention, it is more preferable that the substrate on which the plurality of light sources are mounted further includes an adjusting unit that arbitrarily adjusts the height of the stepped portion.

  Thereby, it becomes possible to adjust the height which mounts each light source more easily.

  In the image display device of the present invention, it is more preferable that each light source of the plurality of light sources is mounted on the base toward the central portion of the condenser lens.

  As a result, since light is collected near the center of the condenser lens, a difference in optical path length between the light sources hardly occurs, and aberrations can be corrected more easily.

  Further, since the amount of light incident on the condenser lens can be increased, a brighter image can be obtained on the light receiving surface of the light receiving plate.

  In addition, since the light is collected near the center of the condenser lens, the lens diameter of the condenser lens can be reduced, and the telecentric optical system can be realized more compactly and at lower cost.

  In the image display device of the present invention, it is more preferable that the plurality of light sources are laser light sources.

  Thereby, since the laser light source has good directivity, the diameter of the light incident on the condenser lens can be further reduced. Therefore, it becomes easy to correct aberrations by designing the condenser lens.

  Further, since the laser light source has a small light spread angle, the lens radius of the condenser lens can be further reduced. Therefore, the telecentric optical system can be realized more compactly and at a lower cost.

  In the image display device of the present invention, it is more preferable that the plurality of light sources are light emitting diodes.

  Thereby, cost reduction can be achieved. Also, the use of the three primary colors of light is possible, and when a full-color display is considered, the ability to use the three primary colors of light is a greater advantage.

  As described above, the image display device of the present invention includes a plurality of light sources, a condensing lens that condenses light emitted from the plurality of light sources, and a light receiving surface that receives the light collected by the condensing lens. Each light source in the plurality of light sources, with respect to a plane perpendicular to the optical axis through the center of the condenser lens so that the aberration of each light source is reduced. Thus, the distance from each light source is vertically different.

  Therefore, the difference in the optical path length of the light emitted from each of the light sources can be reduced, and the aberration caused by the difference in the optical path length can be minimized.

  The image display device of the present invention includes a plurality of light sources, a light collecting lens that collects light emitted from the plurality of light sources, and a light receiving surface that receives light collected by the light collecting lens. A telecentric optical system including a plate, and the light receiving surface is curved toward the condenser lens.

  Therefore, the difference in the optical path length of the light emitted from each of the light sources can be reduced, and the aberration caused by the difference in the optical path length can be reduced as much as possible on the light receiving surface of the light receiving plate.

  In this way, by making the position of the light source or the shape of the light receiving plate having the light receiving surface flexible, the telecentric optical system capable of minimizing the aberration caused by the difference in the optical path length and improving the light condensing performance is provided. There is an effect that an image display device is provided.

[Embodiment 1]
An embodiment of the present invention will be described with reference to FIGS. 1 to 3 as follows.

  FIG. 1A is a plan view schematically showing an optical arrangement according to an embodiment of the present invention. FIG. 1B is a front view showing an outline of the mounting board 1 according to the embodiment of the present invention. FIG. 1C is a front view showing an outline of the two-dimensional scan mirror 4 according to the embodiment of the present invention.

  As shown in FIG. 1A, the image display apparatus according to the present embodiment includes a plurality of light sources 2, a mounting substrate 1 on which a plurality of light sources 2 are mounted, a two-dimensional scan mirror 4, and a condenser lens 5. And the main part is comprised by the light-receiving plate 6 which has a light-receiving surface.

  In the present embodiment, as an example, the plurality of light sources 2 are monochromatic light emitting diodes (hereinafter referred to as LEDs (LEDs)), and are perpendicular to the optical axis 3 of the condenser lens 5. Are arranged at intervals of 2.5 mm. For the sake of explanation, three light sources among the five light sources 2 are referred to as light sources 2a, 2b, and 2c.

  For the sake of explanation, the focal length of the condenser lens 5 is 30 mm and the lens radius is 10 mm. Further, the condensing lens 5 includes a distance between the light source 2c existing on the optical axis of the plurality of light sources 2 and the central portion of the condensing lens 5, and the central portion of the condensing lens 5 and the central portion of the light receiving plate 6. The distance is set to be 60 mm.

  However, each numerical value mentioned above is an example for description, and the present invention is not limited to this.

  Further, the two-dimensional scan mirror 4 can move in a two-dimensional direction as shown in FIGS. 1A and 1B so that the image formed by the condenser lens 5 can be scanned. ing.

  Here, the behavior of light rays in the image display apparatus according to the present embodiment will be described.

  The light emitted from the plurality of light sources 2 is condensed on the light receiving surface of the light receiving plate 6 by the condenser lens 5. Between the condenser lens 5 and the light receiving plate 6, the two-dimensional scan mirror 4 which is an optical scanner device is disposed, and light is scanned two-dimensionally. More specifically, when the image formed from the light emitted from the first light source 2a is scanned by the two-dimensional scan mirror 4, the first image formed from the light emitted from the first light source 2a is scanned. The optical axis 3 of the condenser lens 5 extends from the top (hereinafter, “up” indicates the upward direction in FIG. 1A) to the top of the image formed from the light emitted from the second light source 2b. , While scanning in the vertical direction (hereinafter referred to as the horizontal direction), the scanning is gradually lowered in the direction perpendicular to the horizontal direction (hereinafter referred to as the vertical direction). Similarly, when the image formed from the light emitted from the second light source 2b is scanned by the two-dimensional scan mirror 4, the image formed from the light emitted from the second light source 2b is viewed from the top. Similarly, the two-dimensional scan is performed up to the top of the image formed from the light emitted from the third light source 2c. That is, it is possible to scan so as to complement the gap between the image formed from the light emitted from the first light source 2a and the image formed from the light emitted from the second light source 2b.

  As described above, by using the two-dimensional scanning mirror 4 to scan so as to complement the space between the images formed from the light emitted from the plurality of scattered light sources 2. It is possible to form an image with no omission on the light receiving surface.

  The light receiving plate 6 functions as a screen, and light once condensed on the screen is diffused on the screen. The screen is transparent to transmit the imaged light, and the observer can see the image by looking at the diffused light. If a light diffusing plate is used as the screen, the viewing angle can be widened.

  Here, the result of the ray tracing simulation of the image forming apparatus configured as described above will be described with reference to FIGS. However, the simulation shown in FIG. 2 does not strictly represent the actual state of light rays, but examines the amount of aberration that occurs.

  In FIG. 2, for easy understanding, as an example, three light sources 2a, 2b, and 2c out of the five light sources 2 are extracted and simulated.

  As an example, it is assumed that the three light sources 2a, 2b, and 2c are arranged at intervals of 0 mm, 2.5 mm, and 5 mm in the vertical direction from the optical axis 3, respectively. The light emitted from the three light sources 2a, 2b, and 2c is referred to as light rays 2a ', 2b', and 2c ', respectively. The three light sources 2a, 2b, and 2c are arranged toward the central direction of the condenser lens 5, respectively.

  However, each numerical value mentioned above is an example for description, and the present invention is not limited to this.

  As shown in FIG. 2, the light beams 2a ′, 2b ′, and 2c ′ emitted from the three light sources 2a, 2b, and 2c are bent on the light path by the condensing lens 5 and condensed on the light receiving surface of the light receiving plate 6. You can see how it goes.

  Next, an enlarged view of the vicinity of the light receiving plate 6 in FIG. 2 is shown in FIG.

  As can be seen from FIG. 3, the light beam 2 c ′ is completely condensed on the light receiving surface of the light receiving plate 6.

  However, the light beam 2b ′ emitted from the light source 2b is condensed slightly on the condenser lens 5 side than the light receiving plate 6, and the light beam 2a ′ emitted from the light source 2a is collected by the light beam 2b ′. The light is condensed on the condensing lens 5 side further than the point where the light is reflected.

  This is because the light emitted from the light source 2 arranged at a position away from the optical axis 3 in the vertical direction has a larger difference in optical path length than the light passing through the center of the condensing lens 5, and the condensing position is This is because they are displaced. Therefore, the light whose focal position is shifted in this way is not properly focused on the light receiving surface of the light receiving plate 6 and becomes a blurred image. Thus, the difference between the completely condensed image and the blurred image is the amount of aberration.

  Based on the amount of aberration determined from this simulation, connecting each in-focus location produces a curved surface as shown in FIG. A curved light receiving plate 7 is formed by bending the light receiving plate 6 along the curved surface, and the curved light receiving plate 7 is curved in a concave shape toward the condenser lens. In other words, the radius of curvature of the curved light receiving plate 7 is determined by the amount of aberration of the light collected by the lens.

  When the curved light receiving plate 7 is used in this way, the light beam 2b 'placed at any position can be obtained by reducing the aberration on the light receiving surface of the curved light receiving plate 7 as much as possible and condensing the image in a more complete state. Can be tied.

  Moreover, when the observer looks at the curved light receiving plate 7 as in the present embodiment, the image looks distorted. However, since the light emitted from the light source 2 arranged at any position is condensed on the light receiving surface of the curved light receiving plate 7 in a more nearly complete state, a very high-definition image can be obtained. it can. Further, when the radius of curvature of the curved light receiving plate 7 is large, the distortion of the image due to the curvature is considered to be very small visually. Generally, if the radius of curvature of the light receiving plate is 2.5 m or more, it is considered that distortion of the image due to curvature is allowed.

  Here, since the curved light receiving plate 7 is viewed by an observer, a light diffusing plate or the like is preferable, and if the light diffusing plate is formed of a flexible material such as plastic, the curved light receiving plate is used. 7 is easily formed.

  In addition, what is used as the curved light-receiving plate 7 is not limited to the light diffusing plate, but may be formed of a transparent material so that it can be seen by an observer.

  As described above, by using the curved light receiving plate 7, the aberration is corrected to a certain extent, so that the remaining generated aberration can be corrected with a simpler lens design than in the prior art. Therefore, the lens design time is shortened, and the cost can be reduced.

  Further, when the observer sees the light receiving surface of the curved light receiving plate 7, the light emitted from all the light sources 2 ... is condensed on the light receiving surface of the curved light receiving plate 7 in a state where the aberration is suppressed to be small. The resolution of the image reflected on the light receiving surface of the curved light receiving plate 7 can be improved.

[Embodiment 2]
Further, another embodiment of the present invention will be described with reference to FIGS.

  Configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 are given the same reference numerals, and explanation thereof is omitted.

  In this embodiment, instead of correcting the aberration generated by the optical path difference of the light emitted from the plurality of light sources 2... Using the curved light receiving plate 7, the positions of the plurality of light sources 2. It is corrected.

  FIG. 4 is a side view schematically showing a plurality of light sources 2 mounted on the step-type mounting board 8 in the present embodiment. The step-type mounting base 8 is provided with a step portion on the condensing lens side so that each light source is disposed in a concave shape toward the condensing lens. The height of the stepped portion on which each light source 2 is mounted is determined by the aberration amount of each light ray determined by the above simulation. However, the amount of aberration is not limited to the above-described simulation, but the amount of aberration actually measured in a prototype stage or the like may be used.

  Here, a procedure for correcting the aberration amount using the step-type mounting substrate 8 will be described.

  First, the distance between the light source 2c and the central portion of the condenser lens 5 is determined so as to suppress the aberration of the light beam 2c 'on the light receiving surface of the light receiving plate 6 (hereinafter referred to as distance A).

  Next, similarly, the distance perpendicular to the light source 2b with respect to the surface passing through the central portion of the condenser lens 5 and perpendicular to the optical axis so as to suppress the aberration of the light beam 2b 'on the light receiving surface of the light receiving plate 6 is small. That is, the shortest distance from the light source 2b to the surface passing through the central portion of the condenser lens 5 and perpendicular to the optical axis is determined (hereinafter referred to as distance B).

  Then, the values of the distance A and the distance B are different from each other. This height difference determines the height of the stepped portion of the stepped mounting substrate 8 of the light source 2b.

  In this manner, by mounting the plurality of light sources 2 on the step-type mounting substrate 8, the difference in the optical path length between the light emitted from the light source 2c and the light emitted from the other light sources 2. The light from the light sources 2 can be condensed on the light receiving surface of the light receiving plate 6 more completely.

  Further, as shown in FIG. 5, there are a submount 12 and a stem 10 as the step height adjusting means (adjusting means) for forming the step portion on the step type mounting base 8. The stem 10 can be designed arbitrarily in height. Here, the one higher than the stem 10 is referred to as an extended stem 11.

  Here, the submount 12 is a rectangular parallelepiped member on which an LD (LD: Laser Diode) chip is mounted as shown in FIG. The submount 12 is excellent in heat dissipation and can be used as a heat dissipation member, while also serving as a circuit board.

  Further, as shown in FIG. 7, the stem 10 and the extended stem 11 are directly bonded to the submount 12 on which the LD chip 13 is mounted or the LED chip 14 with a conductive material and can be easily wired to the power source. It has at least two and terminals 17.

  Actually, when the LD chip 13 is mounted on the submount 12, or when the submount 12 having the LD chip 13 mounted on the stem 10 or when the LED chip 14 is mounted directly on the stem 10, The height of the submount 12, the height of the stem 10, and the length of the extended stem 11 are adjusted in accordance with the position of each light source 2 so that the aberration generated on the light receiving surface is corrected.

  Further, as shown in FIG. 7, a spacer 15 having a different height is sandwiched between the stem 10 and the step-type mounting base 8 according to the mounting position of each light source 2, thereby generating on the light receiving surface of the light receiving plate 6. The aberration to be corrected may be corrected.

  That is, an image in which aberration is corrected on the light receiving surface of the light receiving plate 6 by properly using the stem 10, the extended stem 11, the submount 12, and the spacer 15 according to the amount of aberration of the light emitted from each light source 2. Can be formed.

  As described above, when the stem 10, the extended stem 11, and the submount 12 are used, each light source 2 is designed to have various heights so as to correspond to the aberration generated on the light receiving surface of the light receiving plate 6. Aberration can be easily corrected by simply mounting on the extended stem 11, the extended stem 11 or the submount 12.

  Further, when the aberration generated on the light receiving surface of the light receiving plate 6 is corrected using the spacer 15, the spacer 15 may be easily sandwiched or removed between the stem 10 and the step-type mounting substrate 8. It becomes possible. Therefore, the aberration generated on the light receiving surface of the light receiving plate 6 can be corrected more easily. Further, from the trial production stage, using the spacers 15 of various heights, the light receiving plate has a shortest distance perpendicular to each light source 2 with respect to a plane passing through the central portion of the condenser lens 5 and perpendicular to the optical axis. 6 can be easily attempted to correct aberrations occurring on the light receiving surface.

  As described above, the shortest distances perpendicular to each light source 2 are different from each other so as to reduce the aberration of each light source 2 and to a plane that passes through the central portion of the condenser lens 5 and is perpendicular to the optical axis. Since each light source 2 is arranged to correct the aberration to some extent, the remaining generated aberration can be corrected with a simpler lens design than in the prior art. Therefore, the lens design time is shortened, and the cost can be reduced.

[Embodiment 3]
Further, still another embodiment of the present invention will be described with reference to FIGS.

  Configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 are given the same reference numerals, and explanation thereof is omitted.

  In still another embodiment of the present invention, instead of the step-type mounting base 8, a curved type in which a base on which a plurality of light sources 2 are mounted is curved toward the condenser lens 5 as shown in FIG. The mounting base 9 is used. The curved mounting base 9 is curved toward the condenser lens so that each light source is disposed in a concave shape toward the condenser lens.

  FIG. 8 is a diagram in which a plurality of light sources 2 are mounted on the curved mounting base 9.

  The light emitted from the plurality of light sources 2 mounted on the curved mounting base 9 is bent on the optical path by the condensing lens 5 and then converged on the light receiving surface of the light receiving plate 6 as an image side telecentric light beam. To do. At that time, each light source 2 is directed toward the center of the condenser lens 5 and the lens holder frame 16 serves as an entrance pupil.

  Further, the radius of curvature of the curved mounting base 9 is a circle whose center is the center of the condensing lens 5 in order to increase the amount of light entering the condensing lens 5 and whose radius is the distance from the center to the light source 2c. It is preferable to use a curvature radius as a basis (hereinafter referred to as a basic curvature radius) and to correct the curvature radius so that the aberration generated on the light receiving surface of the light receiving plate 6 is corrected.

  As in the present embodiment, when the distance between the light source 2c and the central portion of the condenser lens 5 is 60 mm, the radius of curvature of the curved mounting base 9 is about 60 mm.

  As described above, mounting the light sources 2 on the curved mounting base 9 not only facilitates correction of aberrations generated on the light receiving surface of the light receiving plate 6, but also improves light condensing performance. . That is, as described above, since each light source 2 is arranged in the center direction of the condenser lens 5, the amount of light incident on the condenser lens 5 is increased, and a bright image can be formed.

  In addition, since light is collected near the center of the condenser lens 5, a difference in optical path length between the light sources 2 hardly occurs, and correction of aberration becomes easy. Further, the fact that the light is collected near the center of the condenser lens 5 makes it possible to reduce the lens diameter of the condenser lens 5, thereby realizing a compact and low cost optical system.

  Here, the change in the condensing state on the light receiving surface of the light receiving plate 6 when the height and the radius of curvature of the base on which the light sources 2 are mounted will be described in more detail with reference to FIG. As an example, a description will be given of a change in the condensing state of the light beam 2a ′ on the light receiving surface of the light receiving plate 6 when the light source 2a is mounted on the step-type mounting base 8 or the curved mounting base 9.

  The left side of FIG. 9 shows a condensing state on the light receiving surface of the light receiving plate 6 when the light beam 2a 'is mounted on the flat substrate.

  The right side of FIG. 9 shows a condensing state on the light receiving surface of the light receiving plate 6 when the light source 2 a is moved 1.5 mm in a direction approaching the condensing lens 5. Moreover, the position of the arrow represents the focal position.

  As can be seen from FIG. 9, the focal position of the light beam 2 a ′ can be moved onto the light receiving surface of the light receiving plate 6 by moving the light source 2 a by 1.5 mm in the direction approaching the condenser lens 5.

  That is, when the step-type mounting substrate 8 is used, the step type is used by using the stem 10, the extended stem 11, the submount 12, the spacer 15, etc. so as to move the light source 2 a to the 1.5 mm condenser lens 5 side. A stepped portion having a height of 1.5 mm may be formed on the mounting substrate 8. When the curved mounting base 9 is used, the curvature radius of the curved mounting base 9 may be modified from the basic curvature radius so that the light source 2a is moved to the 1.5 mm condenser lens 5 side.

  As described above, each of the light sources 2 of the plurality of light sources 2... Using the step-type mounting base 8 or the curved mounting base 9 is passed through the central portion of the condenser lens 5 with respect to the plane perpendicular to the optical axis. By arranging them so that the shortest distances perpendicular to each light source 2 are different from each other, the aberration generated on the light receiving surface of the light receiving plate 6 can be corrected better.

[Embodiment 4]
When a laser light source is used as the light source 2..., Correction of aberrations generated on the light receiving surface of the light receiving plate 6 becomes easier. Since the light emitted from the laser light source originally has a small divergence angle and good directivity, the diameter of the light incident on the condenser lens 5 can be reduced even in the object-side telecentric optical arrangement. Therefore, aberration correction by the condenser lens 5 is facilitated.

  Also, as will be described later, since the light spread angle is narrower than when LEDs are used as the light sources 2..., The lens radius of the condenser lens 5 can be made smaller than that of LEDs.

[Embodiment 5]
In addition, when LEDs are used as the light sources 2..., It is more difficult to correct aberrations than when a laser light source is used as the light sources 2. However, the unit price is lower than that of a laser light source, and the three primary colors of light can be used. When a plurality of LEDs of the three primary colors are used as the light source 2..., Each color, for example, red, blue, and green, is arranged in the horizontal direction with the surface including the optical axis 3, and the same color is perpendicular to the surface including the optical axis 3. Arrange LEDs. Thus, when considering a full-color display, the ability to use the three primary colors of light is a great advantage.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention can be applied to an image display device provided with a plurality of light sources. Specifically, it can be used for a display using a laser as a light source, a display using an organic EL light emitting element, an inorganic EL light emitting element, an LED chip, an LD chip, or the like as a light source, or a plasma display. It can also be used for a two-dimensional scan display.

(A) is a top view which shows the outline of the optical arrangement | positioning of one Embodiment of this invention. (B) is a front view which shows the outline of the mounting base | substrate of one Embodiment of this invention. (C) is a front view which shows the outline of the two-dimensional scan mirror of one Embodiment of this invention. It is a figure which shows the outline of the result of the ray tracing simulation of the image forming apparatus in this invention. It is a side view showing the outline of the light condensing state when the light receiving plate of the image forming apparatus in the embodiment of the present invention is curved. It is a side view which shows the outline of the state which mounted the several light source of the image forming apparatus in other embodiment of this invention in the level | step-difference type mounting base. It is a side view which shows the outline of the adjustment means which forms the level | step-difference part of the said level | step-shaped mounting board | substrate. It is a side view which shows the outline of the submount which is an example of the said adjustment means. It is a side view which shows the outline of the spacer which is an example of the said adjustment means. It is a side view which shows the outline of the state which mounted the some light source of the image forming apparatus in further another embodiment of this invention in the curved mounting base. It is a side view which shows the outline of the change of the condensing state in the light-receiving surface of a light-receiving plate when the light source arrange | positioned at the position of 5 mm perpendicularly | vertically from an optical axis is moved to the direction which approaches a 1.5-mm condensing lens. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mounting board | substrate 2 Light source 2a Light source arrange | positioned in the position of 5 mm perpendicularly | vertically from an optical axis 2b Light source arranged in the position of 2.5 mm perpendicularly | vertically from an optical axis 2c It arrange | positions in the position of 0 mm perpendicularly | vertically from an optical axis The light source 2a 'The light beam 2b' emitted from the light source 2a 2b The light beam emitted from the light source 2b 2c 'The light beam emitted from the light source 2c 3 Optical axis 4 Two-dimensional scan mirror 5 Condensing lens 6 Light receiving plate 7 Curved in the aberration correction direction Screen (light receiving plate)
8 Step type mounting base 9 Curved type mounting base 10 Stem 11 Extended stem 12 Submount 13 LD chip 14 LED chip 15 Spacer 16 Lens holder frame 17 Terminal

Claims (12)

Multiple light sources;
A condensing lens for condensing light emitted from the plurality of light sources;
A telecentric optical system including a light receiving plate having a light receiving surface for receiving the light collected by the condenser lens,
Each light source in the plurality of light sources has a smaller distance from each light source perpendicularly to a surface that passes through the central portion of the condenser lens and is perpendicular to the optical axis as the aberration of each light source decreases. An image display device characterized by being arranged. Multiple light sources;
A condensing lens for condensing light emitted from the plurality of light sources;
A telecentric optical system including a light receiving plate having a light receiving surface for receiving the light collected by the condenser lens,
The image display device, wherein the light receiving surface is curved so that the aberration of each light source is reduced.   The image display device according to claim 2, wherein the light receiving surface is curved in a concave shape toward the condenser lens.   Each of the light sources in the plurality of light sources has different distances perpendicular to each light source with respect to a plane that passes through the central portion of the condenser lens and is perpendicular to the optical axis so that the aberration of each light source is reduced. The image display device according to claim 2, wherein the image display device is disposed on the screen.   The image display apparatus according to claim 1, wherein the substrate on which the plurality of light sources are mounted is provided with a step portion on the condenser lens side so that the aberration of each light source is reduced.   The image display device according to claim 5, wherein the base is further provided with a stepped portion concave toward the condenser lens.   5. The image display device according to claim 1, wherein the substrate on which the plurality of light sources are mounted is curved so as to reduce the aberration of each light source.   The image display device according to claim 6, wherein the base is further curved in a concave shape toward the condenser lens.   7. The image display device according to claim 5, wherein the base further includes an adjusting unit capable of arbitrarily adjusting the height of the stepped portion.   9. The image display device according to claim 7, wherein each light source of the plurality of light sources is mounted on the base toward a central portion of the condenser lens.   The image display device according to claim 1, wherein the plurality of light sources are laser light sources.   The image display device according to claim 1, wherein the plurality of light sources are light emitting diodes.

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