# US 10,310,365 B2 · Illumination unit and display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,310,365 B2 - Document ID: US10310365B2 - Status: Granted - Kind: B2 - Application number: 15/856,897 - Filed: 2017-12-28 - Published: 2018-05-03 - Granted: 2019-06-04 - Earliest claimed: 2011-07-12 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: Kazumasa Kaneda - Web page: https://patentgrep.com/patent/US10310365B2 ## CPC - G03B 21/006: {using LCD's} - G03B 21/2053: {Intensity control of illuminating light (controlled by video signal processing H04N5/74 or H04N9/31)} - G02B 27/10: Beam splitting or combining systems (polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; {beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905}) - G03B 21/2033: {LED or laser light sources} - G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)} - G03B 33/12: using beam-splitting or beam-combining systems, e.g. dichroic mirrors - H04N 9/3161: {using laser light sources (using laser beams scanning the display screen H04N9/3129)} - H04N 9/3164: {using multiple light sources} - H04N 9/3167: {for polarizing the light beam (polarizing optical systems per se G02B27/28)} - H04N 9/3194: {including sensor feedback} - G02F 1/13355: {Polarising beam splitters [PBS]} - G02F 1/135: Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied {(G02F1/133348 takes precedence)} - 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 - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract An illumination unit includes: a light source section including a laser light source; an optical-path branching device outputting light incident from the light source section, by branching the light into an outgoing optical path of illumination light and other optical path; a photodetector receiving a light flux that travels on the other optical path; a control section controlling an emitted light quantity in the laser light source, based on a quantity of the light flux received by the photodetector; and a light-quantity-distribution control device disposed between the optical-path branching device and the photodetector on the other optical path, the light-quantity-distribution control device controlling a light quantity distribution in the light flux to be incident upon the photodetector. ## Claims ### Claim 1 An illumination unit, comprising: a plurality of laser light sources; a dichroic prism configured to output light incident from the plurality of laser light sources, wherein the output light comprises a first optical path and a second optical path; a photodetector configured to receive a light flux that travels on the second optical path; an automatic power controller configured to control a quantity of the light emitted from the plurality of laser light sources based on a quantity of the light flux received by the photodetector; and a coupling lens configured to control a distribution of the quantity of the light flux received by the photodetector. ### Claim 2 (depends on 1) The illumination unit according to claim 1, further comprising: a reflection transmission film configured to control polarized components to increase polarization of a first polarized component in the light flux which travels on the second optical path, wherein the first polarized component in the light flux is same as a main polarized component in the emitted light. ### Claim 3 (depends on 2) The illumination unit according to claim 2, wherein: the reflection transmission film is disposed between the dichroic prism and the photodetector on the second optical path, and the reflection transmission film selectively allows the first polarized component in the light flux to pass therethrough. ### Claim 4 (depends on 2) The illumination unit according to claim 2, wherein optical characteristics of the dichroic prism are set to allow each of an optical reflectance and an optical transmittance in the dichroic prism to be constant without dependence on the polarized components. ### Claim 5 (depends on 4) The illumination unit according to claim 4, wherein: the dichroic prism includes the reflection transmission film which defines each of the optical reflectance and the optical transmittance, and the optical characteristics are set by the reflection transmission film. ### Claim 6 (depends on 2) The illumination unit according to claim 2, wherein an optical reflectance and an optical transmittance for each of the polarized components are set to allow a temperature change rate of a reflected light quantity from the reflection transmission film to be equal to a temperature change rate of a transmitted light quantity from the reflection transmission film. ### Claim 7 (depends on 6) The illumination unit according to claim 6, wherein the optical reflectance and the optical transmittance for each of the polarized components are set to allow an amount of difference between the temperature change rate of the reflected light quantity and the temperature change rate of the transmitted light quantity to be at most 10%. ### Claim 8 (depends on 6) The illumination unit according to claim 6, wherein: the dichroic prism includes the reflection transmission film which defines each of the optical reflectance and the optical transmittance, and a ratio between the temperature change rate of the reflected light quantity and the temperature change rate of the transmitted light quantity is set by the reflection transmission film. ### Claim 9 (depends on 1) The illumination unit according to claim 1, wherein the coupling lens is a refractive lens with positive power. ### Claim 10 (depends on 1) The illumination unit according to claim 1, wherein the coupling lens is further configured to: diffuse the light flux traveling on the second optical path; and output the diffused light flux. ### Claim 11 (depends on 1) The illumination unit according to claim 1, wherein the automatic power controller is further configured to control the emitted light quantity from the plurality of laser light sources to allow the emitted light quantity to be constant without dependence on a temperature change. ### Claim 12 (depends on 1) The illumination unit according to claim 1, wherein the plurality of laser light sources include three kinds of laser light sources which emit red light, green light, and blue light. ### Claim 13 (depends on 12) The illumination unit according to claim 12, wherein the plurality of laser light sources are semiconductor lasers. ### Claim 14 (depends on 1) The illumination unit according to claim 1, wherein the coupling lens is disposed between the dichroic prism and the photodetector on the second optical path. ### Claim 15 (depends on 1) The illumination unit according to claim 1, wherein the plurality of laser light sources include LED source. ### Claim 16 A display, comprising: an illumination unit that is configured to emit illumination light; and a light modulation unit that is configured to modulate the illumination light based on an image signal, wherein: the illumination unit includes: a plurality of laser light sources, a dichroic prism configured to output light incident from the plurality of laser light sources, wherein the output light comprises a first optical path and a second optical path, a photodetector configured to receive a light flux traveling on the second optical path, an automatic power controller configured to control a quantity of the light emitted from the plurality of laser light sources, based on a quantity of the light flux received by the photodetector, and a coupling lens configured to control a distribution of the quantity of the light flux received by the photodetector. ### Claim 17 (depends on 16) The display according to claim 16, further comprising: a projection optical unit that is configured to project the illumination light, modulated by the light modulation unit, onto a projection surface. ### Claim 18 (depends on 16) The display according to claim 16, wherein the light modulation unit is a liquid crystal device.