JP2008027688A5 - - Google Patents

Claims (16)

A plurality of light emitting elements that are not electrically connected to each other in series,
At least a part of a region where each of the light emitting elements emits light overlaps with a region where the other light emitting elements emit light,
further,
A surface light source device including a plurality of drive circuits provided corresponding to the light emitting elements and driving the corresponding light emitting elements. A plurality of sets of the plurality of light emitting elements,
The region where the light emitting element emits light is different for each group,
Each set of light emitting elements is electrically connected in series with the other set of light emitting elements,
The surface light source device is
The surface light source device according to claim 1, further comprising a plurality of drive circuits provided corresponding to the sets of light emitting elements connected in series and driving the corresponding sets of light emitting elements. A first light emitting element to a fourth light emitting element;
The first light emitting element and the second light emitting element are electrically connected in series;
The third light emitting element and the fourth light emitting element are electrically connected in series;
The first light emitting element and the third light emitting element irradiate light in substantially the same region,
The second light emitting element and the fourth light emitting element irradiate light in substantially the same region,
The region where the first light-emitting element and the third light-emitting element irradiate light and the region where the second light-emitting element and the fourth light-emitting element irradiate light all or partly match. Without
further,
A first drive circuit for driving the first light emitting element and the second light emitting element;
The surface light source device of Claim 2 provided with the 2nd drive circuit which drives the said 3rd light emitting element and the said 4th light emitting element. The surface light source device according to claim 3 , wherein the light emitting elements that irradiate light to the substantially same region are collectively arranged. The surface light source device according to claim 3 , wherein each light emitting element that irradiates light to the substantially same region is sealed in the same package. The surface light source device further includes:
The light emitted from the first light emitting element to the fourth light emitting element is controlled to irradiate light from the first light emitting element and the third light emitting element to substantially the same region, and A region in which light from two light emitting elements and the fourth light emitting element are irradiated in substantially the same region, and a region in which the first light emitting element and the third light emitting element emit light, and the second light emitting element 4. The surface light source device according to claim 3, further comprising a light distribution unit that does not match all or part of a region where the fourth light emitting element emits light. The surface light source device further includes:
When the light emitting element breaks down, the drive control circuit controls the drive circuit to increase the luminance of the light emitting element that irradiates light in a region substantially the same as the region where the broken light emitting element radiated light. A surface light source device according to claim 1, 2 or 3 . The surface light source device further includes:
When the light emitting element is in an abnormal lighting state, the driving circuit is controlled to stop driving the light emitting element connected in series with the light emitting element in the abnormal lighting normal state, and the abnormal lighting is performed. 4. The surface light source device according to claim 2, further comprising a drive control circuit that increases the luminance of the light emitting elements that are not connected in series with the light emitting elements that have become normal. The surface light source device according to claim 7 , wherein the drive circuit includes a failure detection unit that detects a conduction failure of the light emitting element. The failure detection unit includes a conversion element that converts a current output from the light emitting element to the drive circuit into a voltage, compares the converted voltage with a predetermined voltage, and the converted voltage is higher The surface light source device according to claim 9, wherein the surface light source device is determined to be a conduction failure. Wherein the drive circuit, a surface light source device according to claim 7 or 8, wherein comprising a failure detection unit for detecting a disconnection failure of the light emitting element. The failure detection unit includes a conversion element that converts a current output from the light emitting element to the drive circuit into a voltage, compares the converted voltage with a predetermined voltage, and the converted voltage is lower The surface light source device according to claim 11, wherein the surface light source device is determined to be a disconnection failure. The surface light source device according to claim 1, wherein the light emitting element is a light emitting diode. An illumination device comprising the surface light source device according to claim 1. The backlight apparatus provided with the surface light source device in any one of Claims 1-13. A display device comprising the backlight device according to claim 15.