# US 8,770,793 B2 · LED bulb > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,793 B2 - Document ID: US8770793B2 - Status: Granted - Kind: B2 - Application number: 13/415,323 - Filed: 2012-03-08 - Published: 2012-09-13 - Granted: 2014-07-08 - Earliest claimed: 2011-03-11 - Assignees: Rohm Co., Ltd. - Applicants: Kohei Mizuta; Saizo Suzuki - Inventors: Kohei Mizuta; Saizo Suzuki - Web page: https://patentgrep.com/patent/US8770793B2 ## CPC - F21V 7/0091: {using total internal reflection} - F21K 9/233: specially adapted for generating a spot light distribution, e.g. for substitution of reflector lamps - F21K 9/61: using light guides - F21Y 2105/10: comprising a two-dimensional [2D] array of point-like light-generating elements - F21Y 2115/10: Light-emitting diodes [LED] - F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR - F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR - F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED ## Abstract The present invention provides an LED bulb, which includes a light source portion including at least one LED chip); a housing including a bottom portion supporting the light source portion and a sidewall portion surrounding the light source portion, and opening at one side of a first direction; a base disposed on the other side of the first direction relative to the housing; and a light guide body disposed in a space surrounded by the sidewall portion, and including an incident surface facing the light source portion, a light-emitting surface for making the light from the incident surface emit toward the one side of the first direction, and a peripheral side surface located between the incident surface and the light-emitting surface, wherein the cross-sectional area of the peripheral side surface becomes increasingly larger from a side of the incident surface toward a side of the light-emitting surface. ## Claims ### Claim 1 An LED bulb, comprising: a light source portion, comprising at least one LED chip; a housing, comprising a bottom portion supporting the light source portion and a sidewall portion surrounding the light source portion, and opening at one side of a first direction; a base, disposed on the other side of the first direction relative to the housing; and a light guide body, disposed in a space surrounded by the sidewall portion, and comprising an incident surface facing the light source portion, a light-emitting surface for making the light from the incident surface emit toward the one side of the first direction, and a peripheral side surface located between the incident surface and the light-emitting surface, wherein a cross-sectional area of the peripheral side surface becomes increasingly larger from a side of the incident surface toward a side of the light-emitting surface. ### Claim 2 (depends on 1) The LED bulb according to claim 1, wherein the light source portion further comprises a light-transmitting resin covering the LED chip and allowing the light from the LED chip to pass through. ### Claim 3 (depends on 2) The LED bulb according to claim 2, wherein the light-transmitting resin contains a fluorescent material, the fluorescent material is excited by the light from the LED chip and emits a light having a wavelength that is different from the light from the LED chip. ### Claim 4 (depends on 2) The LED bulb according to claim 2, wherein the light-transmitting resin is in a shape of dome. ### Claim 5 (depends on 4) The LED bulb according to claim 4, wherein the light source portion further comprises a lead carrying the LED chip and a case covering at least one part of the lead. ### Claim 6 (depends on 4) The LED bulb according to claim 4, wherein the incident surface of the light guide body is a recessed surface that is recessed toward the one side of the first direction, and accommodates the light source portion. ### Claim 7 (depends on 6) The LED bulb according to claim 6, wherein the light-emitting surface of the light guide body comprises a recessed surface overlapping the incident surface as viewed in the first direction and being recessed toward the other side of the first direction. ### Claim 8 (depends on 6) The LED bulb according to claim 6, wherein the light-emitting surface of the light guide body comprises a plurality of lens surfaces, each being in shape of dome. ### Claim 9 (depends on 2) The LED bulb according to claim 2, wherein the light source portion further comprises a LED substrate carrying a plurality of LED chips, and a weir portion formed on the LED substrate to surround the LED chips; and the light-transmitting resin is formed in an area surrounded by the weir portion, and comprises a flat light-emitting surface toward the one side of the first direction. ### Claim 10 (depends on 9) The LED bulb according to claim 9, wherein the light-emitting surface of the light-transmitting resin is located further on the other side of the first direction than the end of weir portion at the one side of the first direction. ### Claim 11 (depends on 10) The LED bulb according to claim 10, wherein the light guide body further comprises a ring groove surrounding the incident surface and engaging the weir portion. ### Claim 12 (depends on 9) The LED bulb according to claim 9, wherein the incident surface of the light guide body is a recessed surface that is recessed toward the one side of the first direction and is spaced apart from the light-emitting surface of the light-transmitting resin. ### Claim 13 (depends on 12) The LED bulb according to claim 12, wherein the incident surface of the light guide body comprises a circular bottom surface and a side surface with a circular cross-section. ### Claim 14 (depends on 12) The LED bulb according to claim 12, wherein the light-emitting surface of the light guide body comprises a recessed surface overlapping the incident surface as viewed in the first direction and being recessed toward the other side of the first direction. ### Claim 15 (depends on 12) The LED bulb according to claim 12, wherein the light-emitting surface of the light guide body comprises a plurality of lens surfaces, each being in shape of dome. ### Claim 16 (depends on 9) The LED bulb according to claim 9, wherein the incident surface of the light guide body is smaller than the light-emitting surface of the light-transmitting resin. ### Claim 17 (depends on 16) The LED bulb according to claim 16, wherein the incident surface of the light guide body and the light-emitting surface of the light-transmitting resin are in contact with each other. ### Claim 18 (depends on 16) The LED bulb according to claim 16, wherein the sidewall portion is bright white. ### Claim 19 (depends on 1) The LED bulb according to claim 1, further comprising a holder having a shape of surrounding a part of the light guide body at the one side of the first direction, and the light guide body being held between the holder and the bottom portion of the housing; wherein the holder is mounted on the housing. ### Claim 20 (depends on 19) The LED bulb according to claim 19, wherein the housing further comprises a female screw formed on the sidewall portion, and the holder comprises a male screw threadably engaged with the female screw of the housing. ### Claim 21 (depends on 1) The LED bulb according to claim 1, wherein the housing further comprises a heat-dissipating element constituting the bottom portion and the sidewall portion and being made of metal. ### Claim 22 (depends on 21) The LED bulb according to claim 21, wherein the heat-dissipating element comprises a plurality of fins. ### Claim 23 (depends on 21) The LED bulb according to claim 21, further comprising a power source providing electric power to the LED chip; and the housing further comprising a power source accommodating portion mounted on the other side of the first direction relative to the heat-dissipating element, wherein the power source accommodating portion accommodates the power source and is made of resin. ### Claim 24 (depends on 1) The LED bulb according to claim 1, wherein the sidewall portion of the housing comprises an inner side surface surrounding the peripheral side surface of the light guide body with a gap therebetween. ### Claim 25 (depends on 24) The LED bulb according to claim 24, wherein the cross-sectional area of the inner side surface becomes increasingly larger toward the one side of the first direction. ### Claim 26 (depends on 24) The LED bulb according to claim 24, wherein the inner side surface is a bright white surface or a metallic luster surface.