# US 9,436,073 B2 · Illumination optical system and image projection apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,436,073 B2 - Document ID: US9436073B2 - Status: Granted - Kind: B2 - Application number: 14/178,857 - Filed: 2014-02-12 - Published: 2014-08-14 - Granted: 2016-09-06 - Earliest claimed: 2013-02-13 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Takehito Kawasumi - Web page: https://patentgrep.com/patent/US9436073B2 ## CPC - G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)} - G02B 27/0961: {Lens arrays (lens arrays per se G02B3/0006)} - G03B 21/208: {Homogenising, shaping of the illumination light} - H04N 9/3152: {for shaping the light beam (beam shaping per se G02B27/09)} - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An illumination optical system is capable of changing a light beam diameter in one of first and second cross sections orthogonal to each other that include an optical axis, and includes a light source, a condenser lens that concentrates light from the light source, a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident, a second fly-eye lens including a second lens cell, a polarization conversion element that performs polarization conversion on light from the second fly-eye lens, and an image display element that displays an image based on light from the polarization conversion element, and widths of the image display element and a light emitting surface of the light source, widths of the first and second fly-eye lens, and change rates α and β of the light beam diameters are set within appropriate ranges. ## Claims ### Claim 1 An illumination optical system capable of changing a light beam diameter in at least one of a first cross section and a second cross section orthogonal to each other, the first and second cross sections including an optical axis, the illumination optical system comprising: a light source; a condenser lens configured to concentrate light from the light source; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; a polarization conversion element configured to perform polarization conversion on light from the second fly-eye lens; and an image display element configured to display an image based on light from the polarization conversion element, wherein the following relations are satisfied: (αX/2)/(βY)<0.9 or 1.1<(αX/2)/(βY), and 0.78<(αX/2)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in the first and second cross sections respectively, x and y are widths of a light emitting surface of the light source in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of the light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y. ### Claim 2 (depends on 1) The illumination optical system according to claim 1, wherein the following relation is satisfied: (αX/2)/(βY)×(y/x)=1. ### Claim 3 (depends on 1) The illumination optical system according to claim 1, wherein a shape of the light emitting surface of the light source is a rectangle. ### Claim 4 (depends on 1) The illumination optical system according to claim 1, wherein a shape of the light emitting surface of the light source is an ellipse. ### Claim 5 (depends on 1) The illumination optical system according to claim 1, wherein the light emitting surface of the light source is formed by arraying unit light emitting surfaces. ### Claim 6 (depends on 1) The illumination optical system according to claim 1, wherein the light source is a surface-emitting light source. ### Claim 7 (depends on 1) The illumination optical system according to claim 1, wherein the light source is a light emitting diode. ### Claim 8 (depends on 1) The illumination optical system according to claim 1, wherein the light source is a laser light source. ### Claim 9 (depends on 1) The illumination optical system according to claim 1, wherein the light source is an organic electro-luminescence device. ### Claim 10 An illumination optical system capable of changing a light beam diameter in at least one of a first cross section and a second cross section orthogonal to each other, the first and second cross sections including an optical axis, the illumination optical system comprising: a light source; a condenser lens configured to concentrate light from the light source; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; and an image display element configured to display an image based on light from the second fly-eye lens, wherein the following relations are satisfied: (αX)/(βY)<0.9 or 1.1<(αX)/(βY), and 0.78<(αX)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in the first and second cross sections respectively, x and y are widths of a light emitting surface of the light source in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of the light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y. ### Claim 11 (depends on 10) The illumination optical system according to claim 10, wherein the following relation is satisfied: (αX)/(βY)×(y/x)=1. ### Claim 12 An illumination optical system capable of changing a light beam diameter in at least one of a first cross section and a second cross section orthogonal to each other, the first and second cross sections including an optical axis, the illumination optical system comprising: a light source; a condenser lens configured to concentrate light from the light source; a rod integrator on which light concentrated by the condenser lens is incident; and an image display element configured to display an image based on light from the rod integrator, wherein the following relations are satisfied: (αX)/(βY)<0.9 or 1.1<(αX)/(βY), and 0.78<(αX)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in the first and second cross sections respectively, x and y are widths of a light emitting surface of the light source in the first and second cross sections respectively, D3x and D3y are widths of an exit surface of the rod integrator in the first and second cross sections respectively, D4x and D4y are widths of an entrance surface of the rod integrator in the first and second cross sections respectively, and change rates α and β of the light beam diameters in the first and second cross sections respectively are defined as α=D4x/D3x and β=D4y/D3y. ### Claim 13 (depends on 12) The illumination optical system according to claim 12, wherein the following relation is satisfied: (αX)/(βY)×(y/x)=1. ### Claim 14 An image projection apparatus capable of changing a light beam diameter in at least one of a first cross section and a second cross section orthogonal to each other, the first and second cross sections including an optical axis, the image projection apparatus comprising: a light source; a condenser lens configured to concentrate light from the light source; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; a polarization conversion element configured to perform polarization conversion on light from the second fly-eye lens; and an image display element configured to display an image based on light from the polarization conversion element, wherein the following relations are satisfied: (αX/2)/(βY)<0.9 or 1.1<(αX/2)/(βY), and 0.78<(αX/2)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in the first and second cross sections respectively, x and y are widths of a light emitting surface of the light source in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of the light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y. ### Claim 15 An illumination optical system comprising: a light emitting surface; a condenser lens configured to concentrate light from the light emitting surface; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; a polarization conversion element configured to perform polarization conversion on light from the second fly-eye lens; and an image display element configured to display an image based on light from the polarization conversion element, wherein the following relations are satisfied: (αX/2)/(βY)<0.9 or 1.1<(αX/2)/(βY), and 0.78<(αX/2)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in a first cross section and a second cross section respectively, the first and second cross sections are orthogonal to each other and include an optical axis of the illumination system, x and y are widths of the light emitting surface in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of a light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y. ### Claim 16 An illumination optical system comprising: a light emitting surface; a condenser lens configured to concentrate light from the light emitting surface; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; and an image display element configured to display an image based on light from the second fly-eye lens, wherein the following relations are satisfied: (αX)/(βY)<0.9 or 1.1<(αX)/(βY), and 0.78<(αX)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in a first cross section and a second cross section respectively, the first and second cross sections are orthogonal to each other and include an optical axis of the illumination system, x and y are widths of the light emitting surface in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of a light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y. ### Claim 17 An illumination optical system comprising: a light emitting surface; a condenser lens configured to concentrate light from the light emitting surface; a rod integrator on which light concentrated by the condenser lens is incident; and an image display element configured to display an image based on light from the rod integrator, wherein the following relations are satisfied: (αX)/(βY)<0.9 or 1.1<(αX)/(βY), and 0.78<(αX)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in a first cross section and a second cross section respectively, the first and second cross sections are orthogonal to each other and include an optical axis of the illumination system, x and y are widths of the light emitting surface in the first and second cross sections respectively, D3x and D3y are widths of an exit surface of the rod integrator in the first and second cross sections respectively, D4x and D4y are widths of an entrance surface of the rod integrator in the first and second cross sections respectively, and change rates α and β of a light beam diameters in the first and second cross sections respectively are defined as α=D4x/D3x and β=D4y/D3y. ### Claim 18 An image projection apparatus comprising: a light emitting surface; a condenser lens configured to concentrate light from the light emitting surface; a first fly-eye lens including a first lens cell on which light concentrated by the condenser lens is incident; a second fly-eye lens including a second lens cell corresponding to the first lens cell; a polarization conversion element configured to perform polarization conversion on light from the second fly-eye lens; and an image display element configured to display an image based on light from the polarization conversion element, wherein the following relations are satisfied: (αX/2)/(βY)<0.9 or 1.1<(αX/2)/(βY), and 0.78<(αX/2)/(βY)×(y/x)<1.28, where X and Y are widths of the image display element in a first cross section and a second cross section respectively, the first and second cross sections are orthogonal to each other and include an optical axis of the illumination system, x and y are widths of the light emitting surface in the first and second cross sections respectively, D1x and D1y are widths of the first fly-eye lens in the first and second cross sections respectively, D2x and D2y are widths of the second fly-eye lens in the first and second cross sections respectively, and change rates α and β of a light beam diameters in the first and second cross sections respectively are defined as α=D2x/D1x and β=D2y/D1y.